ip6_tunnel: better validate user provided tunnel names

[linux/fpc-iii.git] / fs / ntfs / inode.c

/**
 * inode.c - NTFS kernel inode handling.
 *
 * Copyright (c) 2001-2014 Anton Altaparmakov and Tuxera Inc.
 *
 * This program/include file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/mutex.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/slab.h>
#include <linux/log2.h>

#include "aops.h"
#include "attrib.h"
#include "bitmap.h"
#include "dir.h"
#include "debug.h"
#include "inode.h"
#include "lcnalloc.h"
#include "malloc.h"
#include "mft.h"
#include "time.h"
#include "ntfs.h"

/**
 * ntfs_test_inode - compare two (possibly fake) inodes for equality
 * @vi:         vfs inode which to test
 * @na:         ntfs attribute which is being tested with
 *
 * Compare the ntfs attribute embedded in the ntfs specific part of the vfs
 * inode @vi for equality with the ntfs attribute @na.
 *
 * If searching for the normal file/directory inode, set @na->type to AT_UNUSED.
 * @na->name and @na->name_len are then ignored.
 *
 * Return 1 if the attributes match and 0 if not.
 *
 * NOTE: This function runs with the inode_hash_lock spin lock held so it is not
 * allowed to sleep.
 */
int ntfs_test_inode(struct inode *vi, ntfs_attr *na)
{
        ntfs_inode *ni;

        if (vi->i_ino != na->mft_no)
                return 0;
        ni = NTFS_I(vi);
        /* If !NInoAttr(ni), @vi is a normal file or directory inode. */
        if (likely(!NInoAttr(ni))) {
                /* If not looking for a normal inode this is a mismatch. */
                if (unlikely(na->type != AT_UNUSED))
                        return 0;
        } else {
                /* A fake inode describing an attribute. */
                if (ni->type != na->type)
                        return 0;
                if (ni->name_len != na->name_len)
                        return 0;
                if (na->name_len && memcmp(ni->name, na->name,
                                na->name_len * sizeof(ntfschar)))
                        return 0;
        }
        /* Match! */
        return 1;
}

/**
 * ntfs_init_locked_inode - initialize an inode
 * @vi:         vfs inode to initialize
 * @na:         ntfs attribute which to initialize @vi to
 *
 * Initialize the vfs inode @vi with the values from the ntfs attribute @na in
 * order to enable ntfs_test_inode() to do its work.
 *
 * If initializing the normal file/directory inode, set @na->type to AT_UNUSED.
 * In that case, @na->name and @na->name_len should be set to NULL and 0,
 * respectively. Although that is not strictly necessary as
 * ntfs_read_locked_inode() will fill them in later.
 *
 * Return 0 on success and -errno on error.
 *
 * NOTE: This function runs with the inode->i_lock spin lock held so it is not
 * allowed to sleep. (Hence the GFP_ATOMIC allocation.)
 */
static int ntfs_init_locked_inode(struct inode *vi, ntfs_attr *na)
{
        ntfs_inode *ni = NTFS_I(vi);

        vi->i_ino = na->mft_no;

        ni->type = na->type;
        if (na->type == AT_INDEX_ALLOCATION)
                NInoSetMstProtected(ni);

        ni->name = na->name;
        ni->name_len = na->name_len;

        /* If initializing a normal inode, we are done. */
        if (likely(na->type == AT_UNUSED)) {
                BUG_ON(na->name);
                BUG_ON(na->name_len);
                return 0;
        }

        /* It is a fake inode. */
        NInoSetAttr(ni);

        /*
         * We have I30 global constant as an optimization as it is the name
         * in >99.9% of named attributes! The other <0.1% incur a GFP_ATOMIC
         * allocation but that is ok. And most attributes are unnamed anyway,
         * thus the fraction of named attributes with name != I30 is actually
         * absolutely tiny.
         */
        if (na->name_len && na->name != I30) {
                unsigned int i;

                BUG_ON(!na->name);
                i = na->name_len * sizeof(ntfschar);
                ni->name = kmalloc(i + sizeof(ntfschar), GFP_ATOMIC);
                if (!ni->name)
                        return -ENOMEM;
                memcpy(ni->name, na->name, i);
                ni->name[na->name_len] = 0;
        }
        return 0;
}

typedef int (*set_t)(struct inode *, void *);
static int ntfs_read_locked_inode(struct inode *vi);
static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi);
static int ntfs_read_locked_index_inode(struct inode *base_vi,
                struct inode *vi);

/**
 * ntfs_iget - obtain a struct inode corresponding to a specific normal inode
 * @sb:         super block of mounted volume
 * @mft_no:     mft record number / inode number to obtain
 *
 * Obtain the struct inode corresponding to a specific normal inode (i.e. a
 * file or directory).
 *
 * If the inode is in the cache, it is just returned with an increased
 * reference count. Otherwise, a new struct inode is allocated and initialized,
 * and finally ntfs_read_locked_inode() is called to read in the inode and
 * fill in the remainder of the inode structure.
 *
 * Return the struct inode on success. Check the return value with IS_ERR() and
 * if true, the function failed and the error code is obtained from PTR_ERR().
 */
struct inode *ntfs_iget(struct super_block *sb, unsigned long mft_no)
{
        struct inode *vi;
        int err;
        ntfs_attr na;

        na.mft_no = mft_no;
        na.type = AT_UNUSED;
        na.name = NULL;
        na.name_len = 0;

        vi = iget5_locked(sb, mft_no, (test_t)ntfs_test_inode,
                        (set_t)ntfs_init_locked_inode, &na);
        if (unlikely(!vi))
                return ERR_PTR(-ENOMEM);

        err = 0;

        /* If this is a freshly allocated inode, need to read it now. */
        if (vi->i_state & I_NEW) {
                err = ntfs_read_locked_inode(vi);
                unlock_new_inode(vi);
        }
        /*
         * There is no point in keeping bad inodes around if the failure was
         * due to ENOMEM. We want to be able to retry again later.
         */
        if (unlikely(err == -ENOMEM)) {
                iput(vi);
                vi = ERR_PTR(err);
        }
        return vi;
}

/**
 * ntfs_attr_iget - obtain a struct inode corresponding to an attribute
 * @base_vi:    vfs base inode containing the attribute
 * @type:       attribute type
 * @name:       Unicode name of the attribute (NULL if unnamed)
 * @name_len:   length of @name in Unicode characters (0 if unnamed)
 *
 * Obtain the (fake) struct inode corresponding to the attribute specified by
 * @type, @name, and @name_len, which is present in the base mft record
 * specified by the vfs inode @base_vi.
 *
 * If the attribute inode is in the cache, it is just returned with an
 * increased reference count. Otherwise, a new struct inode is allocated and
 * initialized, and finally ntfs_read_locked_attr_inode() is called to read the
 * attribute and fill in the inode structure.
 *
 * Note, for index allocation attributes, you need to use ntfs_index_iget()
 * instead of ntfs_attr_iget() as working with indices is a lot more complex.
 *
 * Return the struct inode of the attribute inode on success. Check the return
 * value with IS_ERR() and if true, the function failed and the error code is
 * obtained from PTR_ERR().
 */
struct inode *ntfs_attr_iget(struct inode *base_vi, ATTR_TYPE type,
                ntfschar *name, u32 name_len)
{
        struct inode *vi;
        int err;
        ntfs_attr na;

        /* Make sure no one calls ntfs_attr_iget() for indices. */
        BUG_ON(type == AT_INDEX_ALLOCATION);

        na.mft_no = base_vi->i_ino;
        na.type = type;
        na.name = name;
        na.name_len = name_len;

        vi = iget5_locked(base_vi->i_sb, na.mft_no, (test_t)ntfs_test_inode,
                        (set_t)ntfs_init_locked_inode, &na);
        if (unlikely(!vi))
                return ERR_PTR(-ENOMEM);

        err = 0;

        /* If this is a freshly allocated inode, need to read it now. */
        if (vi->i_state & I_NEW) {
                err = ntfs_read_locked_attr_inode(base_vi, vi);
                unlock_new_inode(vi);
        }
        /*
         * There is no point in keeping bad attribute inodes around. This also
         * simplifies things in that we never need to check for bad attribute
         * inodes elsewhere.
         */
        if (unlikely(err)) {
                iput(vi);
                vi = ERR_PTR(err);
        }
        return vi;
}

/**
 * ntfs_index_iget - obtain a struct inode corresponding to an index
 * @base_vi:    vfs base inode containing the index related attributes
 * @name:       Unicode name of the index
 * @name_len:   length of @name in Unicode characters
 *
 * Obtain the (fake) struct inode corresponding to the index specified by @name
 * and @name_len, which is present in the base mft record specified by the vfs
 * inode @base_vi.
 *
 * If the index inode is in the cache, it is just returned with an increased
 * reference count.  Otherwise, a new struct inode is allocated and
 * initialized, and finally ntfs_read_locked_index_inode() is called to read
 * the index related attributes and fill in the inode structure.
 *
 * Return the struct inode of the index inode on success. Check the return
 * value with IS_ERR() and if true, the function failed and the error code is
 * obtained from PTR_ERR().
 */
struct inode *ntfs_index_iget(struct inode *base_vi, ntfschar *name,
                u32 name_len)
{
        struct inode *vi;
        int err;
        ntfs_attr na;

        na.mft_no = base_vi->i_ino;
        na.type = AT_INDEX_ALLOCATION;
        na.name = name;
        na.name_len = name_len;

        vi = iget5_locked(base_vi->i_sb, na.mft_no, (test_t)ntfs_test_inode,
                        (set_t)ntfs_init_locked_inode, &na);
        if (unlikely(!vi))
                return ERR_PTR(-ENOMEM);

        err = 0;

        /* If this is a freshly allocated inode, need to read it now. */
        if (vi->i_state & I_NEW) {
                err = ntfs_read_locked_index_inode(base_vi, vi);
                unlock_new_inode(vi);
        }
        /*
         * There is no point in keeping bad index inodes around.  This also
         * simplifies things in that we never need to check for bad index
         * inodes elsewhere.
         */
        if (unlikely(err)) {
                iput(vi);
                vi = ERR_PTR(err);
        }
        return vi;
}

struct inode *ntfs_alloc_big_inode(struct super_block *sb)
{
        ntfs_inode *ni;

        ntfs_debug("Entering.");
        ni = kmem_cache_alloc(ntfs_big_inode_cache, GFP_NOFS);
        if (likely(ni != NULL)) {
                ni->state = 0;
                return VFS_I(ni);
        }
        ntfs_error(sb, "Allocation of NTFS big inode structure failed.");
        return NULL;
}

static void ntfs_i_callback(struct rcu_head *head)
{
        struct inode *inode = container_of(head, struct inode, i_rcu);
        kmem_cache_free(ntfs_big_inode_cache, NTFS_I(inode));
}

void ntfs_destroy_big_inode(struct inode *inode)
{
        ntfs_inode *ni = NTFS_I(inode);

        ntfs_debug("Entering.");
        BUG_ON(ni->page);
        if (!atomic_dec_and_test(&ni->count))
                BUG();
        call_rcu(&inode->i_rcu, ntfs_i_callback);
}

static inline ntfs_inode *ntfs_alloc_extent_inode(void)
{
        ntfs_inode *ni;

        ntfs_debug("Entering.");
        ni = kmem_cache_alloc(ntfs_inode_cache, GFP_NOFS);
        if (likely(ni != NULL)) {
                ni->state = 0;
                return ni;
        }
        ntfs_error(NULL, "Allocation of NTFS inode structure failed.");
        return NULL;
}

static void ntfs_destroy_extent_inode(ntfs_inode *ni)
{
        ntfs_debug("Entering.");
        BUG_ON(ni->page);
        if (!atomic_dec_and_test(&ni->count))
                BUG();
        kmem_cache_free(ntfs_inode_cache, ni);
}

/*
 * The attribute runlist lock has separate locking rules from the
 * normal runlist lock, so split the two lock-classes:
 */
static struct lock_class_key attr_list_rl_lock_class;

/**
 * __ntfs_init_inode - initialize ntfs specific part of an inode
 * @sb:         super block of mounted volume
 * @ni:         freshly allocated ntfs inode which to initialize
 *
 * Initialize an ntfs inode to defaults.
 *
 * NOTE: ni->mft_no, ni->state, ni->type, ni->name, and ni->name_len are left
 * untouched. Make sure to initialize them elsewhere.
 *
 * Return zero on success and -ENOMEM on error.
 */
void __ntfs_init_inode(struct super_block *sb, ntfs_inode *ni)
{
        ntfs_debug("Entering.");
        rwlock_init(&ni->size_lock);
        ni->initialized_size = ni->allocated_size = 0;
        ni->seq_no = 0;
        atomic_set(&ni->count, 1);
        ni->vol = NTFS_SB(sb);
        ntfs_init_runlist(&ni->runlist);
        mutex_init(&ni->mrec_lock);
        ni->page = NULL;
        ni->page_ofs = 0;
        ni->attr_list_size = 0;
        ni->attr_list = NULL;
        ntfs_init_runlist(&ni->attr_list_rl);
        lockdep_set_class(&ni->attr_list_rl.lock,
                                &attr_list_rl_lock_class);
        ni->itype.index.block_size = 0;
        ni->itype.index.vcn_size = 0;
        ni->itype.index.collation_rule = 0;
        ni->itype.index.block_size_bits = 0;
        ni->itype.index.vcn_size_bits = 0;
        mutex_init(&ni->extent_lock);
        ni->nr_extents = 0;
        ni->ext.base_ntfs_ino = NULL;
}

/*
 * Extent inodes get MFT-mapped in a nested way, while the base inode
 * is still mapped. Teach this nesting to the lock validator by creating
 * a separate class for nested inode's mrec_lock's:
 */
static struct lock_class_key extent_inode_mrec_lock_key;

inline ntfs_inode *ntfs_new_extent_inode(struct super_block *sb,
                unsigned long mft_no)
{
        ntfs_inode *ni = ntfs_alloc_extent_inode();

        ntfs_debug("Entering.");
        if (likely(ni != NULL)) {
                __ntfs_init_inode(sb, ni);
                lockdep_set_class(&ni->mrec_lock, &extent_inode_mrec_lock_key);
                ni->mft_no = mft_no;
                ni->type = AT_UNUSED;
                ni->name = NULL;
                ni->name_len = 0;
        }
        return ni;
}

/**
 * ntfs_is_extended_system_file - check if a file is in the $Extend directory
 * @ctx:        initialized attribute search context
 *
 * Search all file name attributes in the inode described by the attribute
 * search context @ctx and check if any of the names are in the $Extend system
 * directory.
 *
 * Return values:
 *         1: file is in $Extend directory
 *         0: file is not in $Extend directory
 *    -errno: failed to determine if the file is in the $Extend directory
 */
static int ntfs_is_extended_system_file(ntfs_attr_search_ctx *ctx)
{
        int nr_links, err;

        /* Restart search. */
        ntfs_attr_reinit_search_ctx(ctx);

        /* Get number of hard links. */
        nr_links = le16_to_cpu(ctx->mrec->link_count);

        /* Loop through all hard links. */
        while (!(err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, 0, 0, NULL, 0,
                        ctx))) {
                FILE_NAME_ATTR *file_name_attr;
                ATTR_RECORD *attr = ctx->attr;
                u8 *p, *p2;

                nr_links--;
                /*
                 * Maximum sanity checking as we are called on an inode that
                 * we suspect might be corrupt.
                 */
                p = (u8*)attr + le32_to_cpu(attr->length);
                if (p < (u8*)ctx->mrec || (u8*)p > (u8*)ctx->mrec +
                                le32_to_cpu(ctx->mrec->bytes_in_use)) {
err_corrupt_attr:
                        ntfs_error(ctx->ntfs_ino->vol->sb, "Corrupt file name "
                                        "attribute. You should run chkdsk.");
                        return -EIO;
                }
                if (attr->non_resident) {
                        ntfs_error(ctx->ntfs_ino->vol->sb, "Non-resident file "
                                        "name. You should run chkdsk.");
                        return -EIO;
                }
                if (attr->flags) {
                        ntfs_error(ctx->ntfs_ino->vol->sb, "File name with "
                                        "invalid flags. You should run "
                                        "chkdsk.");
                        return -EIO;
                }
                if (!(attr->data.resident.flags & RESIDENT_ATTR_IS_INDEXED)) {
                        ntfs_error(ctx->ntfs_ino->vol->sb, "Unindexed file "
                                        "name. You should run chkdsk.");
                        return -EIO;
                }
                file_name_attr = (FILE_NAME_ATTR*)((u8*)attr +
                                le16_to_cpu(attr->data.resident.value_offset));
                p2 = (u8*)attr + le32_to_cpu(attr->data.resident.value_length);
                if (p2 < (u8*)attr || p2 > p)
                        goto err_corrupt_attr;
                /* This attribute is ok, but is it in the $Extend directory? */
                if (MREF_LE(file_name_attr->parent_directory) == FILE_Extend)
                        return 1;       /* YES, it's an extended system file. */
        }
        if (unlikely(err != -ENOENT))
                return err;
        if (unlikely(nr_links)) {
                ntfs_error(ctx->ntfs_ino->vol->sb, "Inode hard link count "
                                "doesn't match number of name attributes. You "
                                "should run chkdsk.");
                return -EIO;
        }
        return 0;       /* NO, it is not an extended system file. */
}

/**
 * ntfs_read_locked_inode - read an inode from its device
 * @vi:         inode to read
 *
 * ntfs_read_locked_inode() is called from ntfs_iget() to read the inode
 * described by @vi into memory from the device.
 *
 * The only fields in @vi that we need to/can look at when the function is
 * called are i_sb, pointing to the mounted device's super block, and i_ino,
 * the number of the inode to load.
 *
 * ntfs_read_locked_inode() maps, pins and locks the mft record number i_ino
 * for reading and sets up the necessary @vi fields as well as initializing
 * the ntfs inode.
 *
 * Q: What locks are held when the function is called?
 * A: i_state has I_NEW set, hence the inode is locked, also
 *    i_count is set to 1, so it is not going to go away
 *    i_flags is set to 0 and we have no business touching it.  Only an ioctl()
 *    is allowed to write to them. We should of course be honouring them but
 *    we need to do that using the IS_* macros defined in include/linux/fs.h.
 *    In any case ntfs_read_locked_inode() has nothing to do with i_flags.
 *
 * Return 0 on success and -errno on error.  In the error case, the inode will
 * have had make_bad_inode() executed on it.
 */
static int ntfs_read_locked_inode(struct inode *vi)
{
        ntfs_volume *vol = NTFS_SB(vi->i_sb);
        ntfs_inode *ni;
        struct inode *bvi;
        MFT_RECORD *m;
        ATTR_RECORD *a;
        STANDARD_INFORMATION *si;
        ntfs_attr_search_ctx *ctx;
        int err = 0;

        ntfs_debug("Entering for i_ino 0x%lx.", vi->i_ino);

        /* Setup the generic vfs inode parts now. */

        /*
         * This is for checking whether an inode has changed w.r.t. a file so
         * that the file can be updated if necessary (compare with f_version).
         */
        vi->i_version = 1;

        vi->i_uid = vol->uid;
        vi->i_gid = vol->gid;
        vi->i_mode = 0;

        /*
         * Initialize the ntfs specific part of @vi special casing
         * FILE_MFT which we need to do at mount time.
         */
        if (vi->i_ino != FILE_MFT)
                ntfs_init_big_inode(vi);
        ni = NTFS_I(vi);

        m = map_mft_record(ni);
        if (IS_ERR(m)) {
                err = PTR_ERR(m);
                goto err_out;
        }
        ctx = ntfs_attr_get_search_ctx(ni, m);
        if (!ctx) {
                err = -ENOMEM;
                goto unm_err_out;
        }

        if (!(m->flags & MFT_RECORD_IN_USE)) {
                ntfs_error(vi->i_sb, "Inode is not in use!");
                goto unm_err_out;
        }
        if (m->base_mft_record) {
                ntfs_error(vi->i_sb, "Inode is an extent inode!");
                goto unm_err_out;
        }

        /* Transfer information from mft record into vfs and ntfs inodes. */
        vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);

        /*
         * FIXME: Keep in mind that link_count is two for files which have both
         * a long file name and a short file name as separate entries, so if
         * we are hiding short file names this will be too high. Either we need
         * to account for the short file names by subtracting them or we need
         * to make sure we delete files even though i_nlink is not zero which
         * might be tricky due to vfs interactions. Need to think about this
         * some more when implementing the unlink command.
         */
        set_nlink(vi, le16_to_cpu(m->link_count));
        /*
         * FIXME: Reparse points can have the directory bit set even though
         * they would be S_IFLNK. Need to deal with this further below when we
         * implement reparse points / symbolic links but it will do for now.
         * Also if not a directory, it could be something else, rather than
         * a regular file. But again, will do for now.
         */
        /* Everyone gets all permissions. */
        vi->i_mode |= S_IRWXUGO;
        /* If read-only, no one gets write permissions. */
        if (IS_RDONLY(vi))
                vi->i_mode &= ~S_IWUGO;
        if (m->flags & MFT_RECORD_IS_DIRECTORY) {
                vi->i_mode |= S_IFDIR;
                /*
                 * Apply the directory permissions mask set in the mount
                 * options.
                 */
                vi->i_mode &= ~vol->dmask;
                /* Things break without this kludge! */
                if (vi->i_nlink > 1)
                        set_nlink(vi, 1);
        } else {
                vi->i_mode |= S_IFREG;
                /* Apply the file permissions mask set in the mount options. */
                vi->i_mode &= ~vol->fmask;
        }
        /*
         * Find the standard information attribute in the mft record. At this
         * stage we haven't setup the attribute list stuff yet, so this could
         * in fact fail if the standard information is in an extent record, but
         * I don't think this actually ever happens.
         */
        err = ntfs_attr_lookup(AT_STANDARD_INFORMATION, NULL, 0, 0, 0, NULL, 0,
                        ctx);
        if (unlikely(err)) {
                if (err == -ENOENT) {
                        /*
                         * TODO: We should be performing a hot fix here (if the
                         * recover mount option is set) by creating a new
                         * attribute.
                         */
                        ntfs_error(vi->i_sb, "$STANDARD_INFORMATION attribute "
                                        "is missing.");
                }
                goto unm_err_out;
        }
        a = ctx->attr;
        /* Get the standard information attribute value. */
        si = (STANDARD_INFORMATION*)((u8*)a +
                        le16_to_cpu(a->data.resident.value_offset));

        /* Transfer information from the standard information into vi. */
        /*
         * Note: The i_?times do not quite map perfectly onto the NTFS times,
         * but they are close enough, and in the end it doesn't really matter
         * that much...
         */
        /*
         * mtime is the last change of the data within the file. Not changed
         * when only metadata is changed, e.g. a rename doesn't affect mtime.
         */
        vi->i_mtime = ntfs2utc(si->last_data_change_time);
        /*
         * ctime is the last change of the metadata of the file. This obviously
         * always changes, when mtime is changed. ctime can be changed on its
         * own, mtime is then not changed, e.g. when a file is renamed.
         */
        vi->i_ctime = ntfs2utc(si->last_mft_change_time);
        /*
         * Last access to the data within the file. Not changed during a rename
         * for example but changed whenever the file is written to.
         */
        vi->i_atime = ntfs2utc(si->last_access_time);

        /* Find the attribute list attribute if present. */
        ntfs_attr_reinit_search_ctx(ctx);
        err = ntfs_attr_lookup(AT_ATTRIBUTE_LIST, NULL, 0, 0, 0, NULL, 0, ctx);
        if (err) {
                if (unlikely(err != -ENOENT)) {
                        ntfs_error(vi->i_sb, "Failed to lookup attribute list "
                                        "attribute.");
                        goto unm_err_out;
                }
        } else /* if (!err) */ {
                if (vi->i_ino == FILE_MFT)
                        goto skip_attr_list_load;
                ntfs_debug("Attribute list found in inode 0x%lx.", vi->i_ino);
                NInoSetAttrList(ni);
                a = ctx->attr;
                if (a->flags & ATTR_COMPRESSION_MASK) {
                        ntfs_error(vi->i_sb, "Attribute list attribute is "
                                        "compressed.");
                        goto unm_err_out;
                }
                if (a->flags & ATTR_IS_ENCRYPTED ||
                                a->flags & ATTR_IS_SPARSE) {
                        if (a->non_resident) {
                                ntfs_error(vi->i_sb, "Non-resident attribute "
                                                "list attribute is encrypted/"
                                                "sparse.");
                                goto unm_err_out;
                        }
                        ntfs_warning(vi->i_sb, "Resident attribute list "
                                        "attribute in inode 0x%lx is marked "
                                        "encrypted/sparse which is not true.  "
                                        "However, Windows allows this and "
                                        "chkdsk does not detect or correct it "
                                        "so we will just ignore the invalid "
                                        "flags and pretend they are not set.",
                                        vi->i_ino);
                }
                /* Now allocate memory for the attribute list. */
                ni->attr_list_size = (u32)ntfs_attr_size(a);
                ni->attr_list = ntfs_malloc_nofs(ni->attr_list_size);
                if (!ni->attr_list) {
                        ntfs_error(vi->i_sb, "Not enough memory to allocate "
                                        "buffer for attribute list.");
                        err = -ENOMEM;
                        goto unm_err_out;
                }
                if (a->non_resident) {
                        NInoSetAttrListNonResident(ni);
                        if (a->data.non_resident.lowest_vcn) {
                                ntfs_error(vi->i_sb, "Attribute list has non "
                                                "zero lowest_vcn.");
                                goto unm_err_out;
                        }
                        /*
                         * Setup the runlist. No need for locking as we have
                         * exclusive access to the inode at this time.
                         */
                        ni->attr_list_rl.rl = ntfs_mapping_pairs_decompress(vol,
                                        a, NULL);
                        if (IS_ERR(ni->attr_list_rl.rl)) {
                                err = PTR_ERR(ni->attr_list_rl.rl);
                                ni->attr_list_rl.rl = NULL;
                                ntfs_error(vi->i_sb, "Mapping pairs "
                                                "decompression failed.");
                                goto unm_err_out;
                        }
                        /* Now load the attribute list. */
                        if ((err = load_attribute_list(vol, &ni->attr_list_rl,
                                        ni->attr_list, ni->attr_list_size,
                                        sle64_to_cpu(a->data.non_resident.
                                        initialized_size)))) {
                                ntfs_error(vi->i_sb, "Failed to load "
                                                "attribute list attribute.");
                                goto unm_err_out;
                        }
                } else /* if (!a->non_resident) */ {
                        if ((u8*)a + le16_to_cpu(a->data.resident.value_offset)
                                        + le32_to_cpu(
                                        a->data.resident.value_length) >
                                        (u8*)ctx->mrec + vol->mft_record_size) {
                                ntfs_error(vi->i_sb, "Corrupt attribute list "
                                                "in inode.");
                                goto unm_err_out;
                        }
                        /* Now copy the attribute list. */
                        memcpy(ni->attr_list, (u8*)a + le16_to_cpu(
                                        a->data.resident.value_offset),
                                        le32_to_cpu(
                                        a->data.resident.value_length));
                }
        }
skip_attr_list_load:
        /*
         * If an attribute list is present we now have the attribute list value
         * in ntfs_ino->attr_list and it is ntfs_ino->attr_list_size bytes.
         */
        if (S_ISDIR(vi->i_mode)) {
                loff_t bvi_size;
                ntfs_inode *bni;
                INDEX_ROOT *ir;
                u8 *ir_end, *index_end;

                /* It is a directory, find index root attribute. */
                ntfs_attr_reinit_search_ctx(ctx);
                err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE,
                                0, NULL, 0, ctx);
                if (unlikely(err)) {
                        if (err == -ENOENT) {
                                // FIXME: File is corrupt! Hot-fix with empty
                                // index root attribute if recovery option is
                                // set.
                                ntfs_error(vi->i_sb, "$INDEX_ROOT attribute "
                                                "is missing.");
                        }
                        goto unm_err_out;
                }
                a = ctx->attr;
                /* Set up the state. */
                if (unlikely(a->non_resident)) {
                        ntfs_error(vol->sb, "$INDEX_ROOT attribute is not "
                                        "resident.");
                        goto unm_err_out;
                }
                /* Ensure the attribute name is placed before the value. */
                if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
                                le16_to_cpu(a->data.resident.value_offset)))) {
                        ntfs_error(vol->sb, "$INDEX_ROOT attribute name is "
                                        "placed after the attribute value.");
                        goto unm_err_out;
                }
                /*
                 * Compressed/encrypted index root just means that the newly
                 * created files in that directory should be created compressed/
                 * encrypted. However index root cannot be both compressed and
                 * encrypted.
                 */
                if (a->flags & ATTR_COMPRESSION_MASK)
                        NInoSetCompressed(ni);
                if (a->flags & ATTR_IS_ENCRYPTED) {
                        if (a->flags & ATTR_COMPRESSION_MASK) {
                                ntfs_error(vi->i_sb, "Found encrypted and "
                                                "compressed attribute.");
                                goto unm_err_out;
                        }
                        NInoSetEncrypted(ni);
                }
                if (a->flags & ATTR_IS_SPARSE)
                        NInoSetSparse(ni);
                ir = (INDEX_ROOT*)((u8*)a +
                                le16_to_cpu(a->data.resident.value_offset));
                ir_end = (u8*)ir + le32_to_cpu(a->data.resident.value_length);
                if (ir_end > (u8*)ctx->mrec + vol->mft_record_size) {
                        ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is "
                                        "corrupt.");
                        goto unm_err_out;
                }
                index_end = (u8*)&ir->index +
                                le32_to_cpu(ir->index.index_length);
                if (index_end > ir_end) {
                        ntfs_error(vi->i_sb, "Directory index is corrupt.");
                        goto unm_err_out;
                }
                if (ir->type != AT_FILE_NAME) {
                        ntfs_error(vi->i_sb, "Indexed attribute is not "
                                        "$FILE_NAME.");
                        goto unm_err_out;
                }
                if (ir->collation_rule != COLLATION_FILE_NAME) {
                        ntfs_error(vi->i_sb, "Index collation rule is not "
                                        "COLLATION_FILE_NAME.");
                        goto unm_err_out;
                }
                ni->itype.index.collation_rule = ir->collation_rule;
                ni->itype.index.block_size = le32_to_cpu(ir->index_block_size);
                if (ni->itype.index.block_size &
                                (ni->itype.index.block_size - 1)) {
                        ntfs_error(vi->i_sb, "Index block size (%u) is not a "
                                        "power of two.",
                                        ni->itype.index.block_size);
                        goto unm_err_out;
                }
                if (ni->itype.index.block_size > PAGE_SIZE) {
                        ntfs_error(vi->i_sb, "Index block size (%u) > "
                                        "PAGE_SIZE (%ld) is not "
                                        "supported.  Sorry.",
                                        ni->itype.index.block_size,
                                        PAGE_SIZE);
                        err = -EOPNOTSUPP;
                        goto unm_err_out;
                }
                if (ni->itype.index.block_size < NTFS_BLOCK_SIZE) {
                        ntfs_error(vi->i_sb, "Index block size (%u) < "
                                        "NTFS_BLOCK_SIZE (%i) is not "
                                        "supported.  Sorry.",
                                        ni->itype.index.block_size,
                                        NTFS_BLOCK_SIZE);
                        err = -EOPNOTSUPP;
                        goto unm_err_out;
                }
                ni->itype.index.block_size_bits =
                                ffs(ni->itype.index.block_size) - 1;
                /* Determine the size of a vcn in the directory index. */
                if (vol->cluster_size <= ni->itype.index.block_size) {
                        ni->itype.index.vcn_size = vol->cluster_size;
                        ni->itype.index.vcn_size_bits = vol->cluster_size_bits;
                } else {
                        ni->itype.index.vcn_size = vol->sector_size;
                        ni->itype.index.vcn_size_bits = vol->sector_size_bits;
                }

                /* Setup the index allocation attribute, even if not present. */
                NInoSetMstProtected(ni);
                ni->type = AT_INDEX_ALLOCATION;
                ni->name = I30;
                ni->name_len = 4;

                if (!(ir->index.flags & LARGE_INDEX)) {
                        /* No index allocation. */
                        vi->i_size = ni->initialized_size =
                                        ni->allocated_size = 0;
                        /* We are done with the mft record, so we release it. */
                        ntfs_attr_put_search_ctx(ctx);
                        unmap_mft_record(ni);
                        m = NULL;
                        ctx = NULL;
                        goto skip_large_dir_stuff;
                } /* LARGE_INDEX: Index allocation present. Setup state. */
                NInoSetIndexAllocPresent(ni);
                /* Find index allocation attribute. */
                ntfs_attr_reinit_search_ctx(ctx);
                err = ntfs_attr_lookup(AT_INDEX_ALLOCATION, I30, 4,
                                CASE_SENSITIVE, 0, NULL, 0, ctx);
                if (unlikely(err)) {
                        if (err == -ENOENT)
                                ntfs_error(vi->i_sb, "$INDEX_ALLOCATION "
                                                "attribute is not present but "
                                                "$INDEX_ROOT indicated it is.");
                        else
                                ntfs_error(vi->i_sb, "Failed to lookup "
                                                "$INDEX_ALLOCATION "
                                                "attribute.");
                        goto unm_err_out;
                }
                a = ctx->attr;
                if (!a->non_resident) {
                        ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
                                        "is resident.");
                        goto unm_err_out;
                }
                /*
                 * Ensure the attribute name is placed before the mapping pairs
                 * array.
                 */
                if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
                                le16_to_cpu(
                                a->data.non_resident.mapping_pairs_offset)))) {
                        ntfs_error(vol->sb, "$INDEX_ALLOCATION attribute name "
                                        "is placed after the mapping pairs "
                                        "array.");
                        goto unm_err_out;
                }
                if (a->flags & ATTR_IS_ENCRYPTED) {
                        ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
                                        "is encrypted.");
                        goto unm_err_out;
                }
                if (a->flags & ATTR_IS_SPARSE) {
                        ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
                                        "is sparse.");
                        goto unm_err_out;
                }
                if (a->flags & ATTR_COMPRESSION_MASK) {
                        ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
                                        "is compressed.");
                        goto unm_err_out;
                }
                if (a->data.non_resident.lowest_vcn) {
                        ntfs_error(vi->i_sb, "First extent of "
                                        "$INDEX_ALLOCATION attribute has non "
                                        "zero lowest_vcn.");
                        goto unm_err_out;
                }
                vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
                ni->initialized_size = sle64_to_cpu(
                                a->data.non_resident.initialized_size);
                ni->allocated_size = sle64_to_cpu(
                                a->data.non_resident.allocated_size);
                /*
                 * We are done with the mft record, so we release it. Otherwise
                 * we would deadlock in ntfs_attr_iget().
                 */
                ntfs_attr_put_search_ctx(ctx);
                unmap_mft_record(ni);
                m = NULL;
                ctx = NULL;
                /* Get the index bitmap attribute inode. */
                bvi = ntfs_attr_iget(vi, AT_BITMAP, I30, 4);
                if (IS_ERR(bvi)) {
                        ntfs_error(vi->i_sb, "Failed to get bitmap attribute.");
                        err = PTR_ERR(bvi);
                        goto unm_err_out;
                }
                bni = NTFS_I(bvi);
                if (NInoCompressed(bni) || NInoEncrypted(bni) ||
                                NInoSparse(bni)) {
                        ntfs_error(vi->i_sb, "$BITMAP attribute is compressed "
                                        "and/or encrypted and/or sparse.");
                        goto iput_unm_err_out;
                }
                /* Consistency check bitmap size vs. index allocation size. */
                bvi_size = i_size_read(bvi);
                if ((bvi_size << 3) < (vi->i_size >>
                                ni->itype.index.block_size_bits)) {
                        ntfs_error(vi->i_sb, "Index bitmap too small (0x%llx) "
                                        "for index allocation (0x%llx).",
                                        bvi_size << 3, vi->i_size);
                        goto iput_unm_err_out;
                }
                /* No longer need the bitmap attribute inode. */
                iput(bvi);
skip_large_dir_stuff:
                /* Setup the operations for this inode. */
                vi->i_op = &ntfs_dir_inode_ops;
                vi->i_fop = &ntfs_dir_ops;
                vi->i_mapping->a_ops = &ntfs_mst_aops;
        } else {
                /* It is a file. */
                ntfs_attr_reinit_search_ctx(ctx);

                /* Setup the data attribute, even if not present. */
                ni->type = AT_DATA;
                ni->name = NULL;
                ni->name_len = 0;

                /* Find first extent of the unnamed data attribute. */
                err = ntfs_attr_lookup(AT_DATA, NULL, 0, 0, 0, NULL, 0, ctx);
                if (unlikely(err)) {
                        vi->i_size = ni->initialized_size =
                                        ni->allocated_size = 0;
                        if (err != -ENOENT) {
                                ntfs_error(vi->i_sb, "Failed to lookup $DATA "
                                                "attribute.");
                                goto unm_err_out;
                        }
                        /*
                         * FILE_Secure does not have an unnamed $DATA
                         * attribute, so we special case it here.
                         */
                        if (vi->i_ino == FILE_Secure)
                                goto no_data_attr_special_case;
                        /*
                         * Most if not all the system files in the $Extend
                         * system directory do not have unnamed data
                         * attributes so we need to check if the parent
                         * directory of the file is FILE_Extend and if it is
                         * ignore this error. To do this we need to get the
                         * name of this inode from the mft record as the name
                         * contains the back reference to the parent directory.
                         */
                        if (ntfs_is_extended_system_file(ctx) > 0)
                                goto no_data_attr_special_case;
                        // FIXME: File is corrupt! Hot-fix with empty data
                        // attribute if recovery option is set.
                        ntfs_error(vi->i_sb, "$DATA attribute is missing.");
                        goto unm_err_out;
                }
                a = ctx->attr;
                /* Setup the state. */
                if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_SPARSE)) {
                        if (a->flags & ATTR_COMPRESSION_MASK) {
                                NInoSetCompressed(ni);
                                if (vol->cluster_size > 4096) {
                                        ntfs_error(vi->i_sb, "Found "
                                                        "compressed data but "
                                                        "compression is "
                                                        "disabled due to "
                                                        "cluster size (%i) > "
                                                        "4kiB.",
                                                        vol->cluster_size);
                                        goto unm_err_out;
                                }
                                if ((a->flags & ATTR_COMPRESSION_MASK)
                                                != ATTR_IS_COMPRESSED) {
                                        ntfs_error(vi->i_sb, "Found unknown "
                                                        "compression method "
                                                        "or corrupt file.");
                                        goto unm_err_out;
                                }
                        }
                        if (a->flags & ATTR_IS_SPARSE)
                                NInoSetSparse(ni);
                }
                if (a->flags & ATTR_IS_ENCRYPTED) {
                        if (NInoCompressed(ni)) {
                                ntfs_error(vi->i_sb, "Found encrypted and "
                                                "compressed data.");
                                goto unm_err_out;
                        }
                        NInoSetEncrypted(ni);
                }
                if (a->non_resident) {
                        NInoSetNonResident(ni);
                        if (NInoCompressed(ni) || NInoSparse(ni)) {
                                if (NInoCompressed(ni) && a->data.non_resident.
                                                compression_unit != 4) {
                                        ntfs_error(vi->i_sb, "Found "
                                                        "non-standard "
                                                        "compression unit (%u "
                                                        "instead of 4).  "
                                                        "Cannot handle this.",
                                                        a->data.non_resident.
                                                        compression_unit);
                                        err = -EOPNOTSUPP;
                                        goto unm_err_out;
                                }
                                if (a->data.non_resident.compression_unit) {
                                        ni->itype.compressed.block_size = 1U <<
                                                        (a->data.non_resident.
                                                        compression_unit +
                                                        vol->cluster_size_bits);
                                        ni->itype.compressed.block_size_bits =
                                                        ffs(ni->itype.
                                                        compressed.
                                                        block_size) - 1;
                                        ni->itype.compressed.block_clusters =
                                                        1U << a->data.
                                                        non_resident.
                                                        compression_unit;
                                } else {
                                        ni->itype.compressed.block_size = 0;
                                        ni->itype.compressed.block_size_bits =
                                                        0;
                                        ni->itype.compressed.block_clusters =
                                                        0;
                                }
                                ni->itype.compressed.size = sle64_to_cpu(
                                                a->data.non_resident.
                                                compressed_size);
                        }
                        if (a->data.non_resident.lowest_vcn) {
                                ntfs_error(vi->i_sb, "First extent of $DATA "
                                                "attribute has non zero "
                                                "lowest_vcn.");
                                goto unm_err_out;
                        }
                        vi->i_size = sle64_to_cpu(
                                        a->data.non_resident.data_size);
                        ni->initialized_size = sle64_to_cpu(
                                        a->data.non_resident.initialized_size);
                        ni->allocated_size = sle64_to_cpu(
                                        a->data.non_resident.allocated_size);
                } else { /* Resident attribute. */
                        vi->i_size = ni->initialized_size = le32_to_cpu(
                                        a->data.resident.value_length);
                        ni->allocated_size = le32_to_cpu(a->length) -
                                        le16_to_cpu(
                                        a->data.resident.value_offset);
                        if (vi->i_size > ni->allocated_size) {
                                ntfs_error(vi->i_sb, "Resident data attribute "
                                                "is corrupt (size exceeds "
                                                "allocation).");
                                goto unm_err_out;
                        }
                }
no_data_attr_special_case:
                /* We are done with the mft record, so we release it. */
                ntfs_attr_put_search_ctx(ctx);
                unmap_mft_record(ni);
                m = NULL;
                ctx = NULL;
                /* Setup the operations for this inode. */
                vi->i_op = &ntfs_file_inode_ops;
                vi->i_fop = &ntfs_file_ops;
                vi->i_mapping->a_ops = &ntfs_normal_aops;
                if (NInoMstProtected(ni))
                        vi->i_mapping->a_ops = &ntfs_mst_aops;
                else if (NInoCompressed(ni))
                        vi->i_mapping->a_ops = &ntfs_compressed_aops;
        }
        /*
         * The number of 512-byte blocks used on disk (for stat). This is in so
         * far inaccurate as it doesn't account for any named streams or other
         * special non-resident attributes, but that is how Windows works, too,
         * so we are at least consistent with Windows, if not entirely
         * consistent with the Linux Way. Doing it the Linux Way would cause a
         * significant slowdown as it would involve iterating over all
         * attributes in the mft record and adding the allocated/compressed
         * sizes of all non-resident attributes present to give us the Linux
         * correct size that should go into i_blocks (after division by 512).
         */
        if (S_ISREG(vi->i_mode) && (NInoCompressed(ni) || NInoSparse(ni)))
                vi->i_blocks = ni->itype.compressed.size >> 9;
        else
                vi->i_blocks = ni->allocated_size >> 9;
        ntfs_debug("Done.");
        return 0;
iput_unm_err_out:
        iput(bvi);
unm_err_out:
        if (!err)
                err = -EIO;
        if (ctx)
                ntfs_attr_put_search_ctx(ctx);
        if (m)
                unmap_mft_record(ni);
err_out:
        ntfs_error(vol->sb, "Failed with error code %i.  Marking corrupt "
                        "inode 0x%lx as bad.  Run chkdsk.", err, vi->i_ino);
        make_bad_inode(vi);
        if (err != -EOPNOTSUPP && err != -ENOMEM)
                NVolSetErrors(vol);
        return err;
}

/**
 * ntfs_read_locked_attr_inode - read an attribute inode from its base inode
 * @base_vi:    base inode
 * @vi:         attribute inode to read
 *
 * ntfs_read_locked_attr_inode() is called from ntfs_attr_iget() to read the
 * attribute inode described by @vi into memory from the base mft record
 * described by @base_ni.
 *
 * ntfs_read_locked_attr_inode() maps, pins and locks the base inode for
 * reading and looks up the attribute described by @vi before setting up the
 * necessary fields in @vi as well as initializing the ntfs inode.
 *
 * Q: What locks are held when the function is called?
 * A: i_state has I_NEW set, hence the inode is locked, also
 *    i_count is set to 1, so it is not going to go away
 *
 * Return 0 on success and -errno on error.  In the error case, the inode will
 * have had make_bad_inode() executed on it.
 *
 * Note this cannot be called for AT_INDEX_ALLOCATION.
 */
static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
{
        ntfs_volume *vol = NTFS_SB(vi->i_sb);
        ntfs_inode *ni, *base_ni;
        MFT_RECORD *m;
        ATTR_RECORD *a;
        ntfs_attr_search_ctx *ctx;
        int err = 0;

        ntfs_debug("Entering for i_ino 0x%lx.", vi->i_ino);

        ntfs_init_big_inode(vi);

        ni      = NTFS_I(vi);
        base_ni = NTFS_I(base_vi);

        /* Just mirror the values from the base inode. */
        vi->i_version   = base_vi->i_version;
        vi->i_uid       = base_vi->i_uid;
        vi->i_gid       = base_vi->i_gid;
        set_nlink(vi, base_vi->i_nlink);
        vi->i_mtime     = base_vi->i_mtime;
        vi->i_ctime     = base_vi->i_ctime;
        vi->i_atime     = base_vi->i_atime;
        vi->i_generation = ni->seq_no = base_ni->seq_no;

        /* Set inode type to zero but preserve permissions. */
        vi->i_mode      = base_vi->i_mode & ~S_IFMT;

        m = map_mft_record(base_ni);
        if (IS_ERR(m)) {
                err = PTR_ERR(m);
                goto err_out;
        }
        ctx = ntfs_attr_get_search_ctx(base_ni, m);
        if (!ctx) {
                err = -ENOMEM;
                goto unm_err_out;
        }
        /* Find the attribute. */
        err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
                        CASE_SENSITIVE, 0, NULL, 0, ctx);
        if (unlikely(err))
                goto unm_err_out;
        a = ctx->attr;
        if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_SPARSE)) {
                if (a->flags & ATTR_COMPRESSION_MASK) {
                        NInoSetCompressed(ni);
                        if ((ni->type != AT_DATA) || (ni->type == AT_DATA &&
                                        ni->name_len)) {
                                ntfs_error(vi->i_sb, "Found compressed "
                                                "non-data or named data "
                                                "attribute.  Please report "
                                                "you saw this message to "
                                                "linux-ntfs-dev@lists."
                                                "sourceforge.net");
                                goto unm_err_out;
                        }
                        if (vol->cluster_size > 4096) {
                                ntfs_error(vi->i_sb, "Found compressed "
                                                "attribute but compression is "
                                                "disabled due to cluster size "
                                                "(%i) > 4kiB.",
                                                vol->cluster_size);
                                goto unm_err_out;
                        }
                        if ((a->flags & ATTR_COMPRESSION_MASK) !=
                                        ATTR_IS_COMPRESSED) {
                                ntfs_error(vi->i_sb, "Found unknown "
                                                "compression method.");
                                goto unm_err_out;
                        }
                }
                /*
                 * The compressed/sparse flag set in an index root just means
                 * to compress all files.
                 */
                if (NInoMstProtected(ni) && ni->type != AT_INDEX_ROOT) {
                        ntfs_error(vi->i_sb, "Found mst protected attribute "
                                        "but the attribute is %s.  Please "
                                        "report you saw this message to "
                                        "linux-ntfs-dev@lists.sourceforge.net",
                                        NInoCompressed(ni) ? "compressed" :
                                        "sparse");
                        goto unm_err_out;
                }
                if (a->flags & ATTR_IS_SPARSE)
                        NInoSetSparse(ni);
        }
        if (a->flags & ATTR_IS_ENCRYPTED) {
                if (NInoCompressed(ni)) {
                        ntfs_error(vi->i_sb, "Found encrypted and compressed "
                                        "data.");
                        goto unm_err_out;
                }
                /*
                 * The encryption flag set in an index root just means to
                 * encrypt all files.
                 */
                if (NInoMstProtected(ni) && ni->type != AT_INDEX_ROOT) {
                        ntfs_error(vi->i_sb, "Found mst protected attribute "
                                        "but the attribute is encrypted.  "
                                        "Please report you saw this message "
                                        "to linux-ntfs-dev@lists.sourceforge."
                                        "net");
                        goto unm_err_out;
                }
                if (ni->type != AT_DATA) {
                        ntfs_error(vi->i_sb, "Found encrypted non-data "
                                        "attribute.");
                        goto unm_err_out;
                }
                NInoSetEncrypted(ni);
        }
        if (!a->non_resident) {
                /* Ensure the attribute name is placed before the value. */
                if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
                                le16_to_cpu(a->data.resident.value_offset)))) {
                        ntfs_error(vol->sb, "Attribute name is placed after "
                                        "the attribute value.");
                        goto unm_err_out;
                }
                if (NInoMstProtected(ni)) {
                        ntfs_error(vi->i_sb, "Found mst protected attribute "
                                        "but the attribute is resident.  "
                                        "Please report you saw this message to "
                                        "linux-ntfs-dev@lists.sourceforge.net");
                        goto unm_err_out;
                }
                vi->i_size = ni->initialized_size = le32_to_cpu(
                                a->data.resident.value_length);
                ni->allocated_size = le32_to_cpu(a->length) -
                                le16_to_cpu(a->data.resident.value_offset);
                if (vi->i_size > ni->allocated_size) {
                        ntfs_error(vi->i_sb, "Resident attribute is corrupt "
                                        "(size exceeds allocation).");
                        goto unm_err_out;
                }
        } else {
                NInoSetNonResident(ni);
                /*
                 * Ensure the attribute name is placed before the mapping pairs
                 * array.
                 */
                if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
                                le16_to_cpu(
                                a->data.non_resident.mapping_pairs_offset)))) {
                        ntfs_error(vol->sb, "Attribute name is placed after "
                                        "the mapping pairs array.");
                        goto unm_err_out;
                }
                if (NInoCompressed(ni) || NInoSparse(ni)) {
                        if (NInoCompressed(ni) && a->data.non_resident.
                                        compression_unit != 4) {
                                ntfs_error(vi->i_sb, "Found non-standard "
                                                "compression unit (%u instead "
                                                "of 4).  Cannot handle this.",
                                                a->data.non_resident.
                                                compression_unit);
                                err = -EOPNOTSUPP;
                                goto unm_err_out;
                        }
                        if (a->data.non_resident.compression_unit) {
                                ni->itype.compressed.block_size = 1U <<
                                                (a->data.non_resident.
                                                compression_unit +
                                                vol->cluster_size_bits);
                                ni->itype.compressed.block_size_bits =
                                                ffs(ni->itype.compressed.
                                                block_size) - 1;
                                ni->itype.compressed.block_clusters = 1U <<
                                                a->data.non_resident.
                                                compression_unit;
                        } else {
                                ni->itype.compressed.block_size = 0;
                                ni->itype.compressed.block_size_bits = 0;
                                ni->itype.compressed.block_clusters = 0;
                        }
                        ni->itype.compressed.size = sle64_to_cpu(
                                        a->data.non_resident.compressed_size);
                }
                if (a->data.non_resident.lowest_vcn) {
                        ntfs_error(vi->i_sb, "First extent of attribute has "
                                        "non-zero lowest_vcn.");
                        goto unm_err_out;
                }
                vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
                ni->initialized_size = sle64_to_cpu(
                                a->data.non_resident.initialized_size);
                ni->allocated_size = sle64_to_cpu(
                                a->data.non_resident.allocated_size);
        }
        vi->i_mapping->a_ops = &ntfs_normal_aops;
        if (NInoMstProtected(ni))
                vi->i_mapping->a_ops = &ntfs_mst_aops;
        else if (NInoCompressed(ni))
                vi->i_mapping->a_ops = &ntfs_compressed_aops;
        if ((NInoCompressed(ni) || NInoSparse(ni)) && ni->type != AT_INDEX_ROOT)
                vi->i_blocks = ni->itype.compressed.size >> 9;
        else
                vi->i_blocks = ni->allocated_size >> 9;
        /*
         * Make sure the base inode does not go away and attach it to the
         * attribute inode.
         */
        igrab(base_vi);
        ni->ext.base_ntfs_ino = base_ni;
        ni->nr_extents = -1;

        ntfs_attr_put_search_ctx(ctx);
        unmap_mft_record(base_ni);

        ntfs_debug("Done.");
        return 0;

unm_err_out:
        if (!err)
                err = -EIO;
        if (ctx)
                ntfs_attr_put_search_ctx(ctx);
        unmap_mft_record(base_ni);
err_out:
        ntfs_error(vol->sb, "Failed with error code %i while reading attribute "
                        "inode (mft_no 0x%lx, type 0x%x, name_len %i).  "
                        "Marking corrupt inode and base inode 0x%lx as bad.  "
                        "Run chkdsk.", err, vi->i_ino, ni->type, ni->name_len,
                        base_vi->i_ino);
        make_bad_inode(vi);
        if (err != -ENOMEM)
                NVolSetErrors(vol);
        return err;
}

/**
 * ntfs_read_locked_index_inode - read an index inode from its base inode
 * @base_vi:    base inode
 * @vi:         index inode to read
 *
 * ntfs_read_locked_index_inode() is called from ntfs_index_iget() to read the
 * index inode described by @vi into memory from the base mft record described
 * by @base_ni.
 *
 * ntfs_read_locked_index_inode() maps, pins and locks the base inode for
 * reading and looks up the attributes relating to the index described by @vi
 * before setting up the necessary fields in @vi as well as initializing the
 * ntfs inode.
 *
 * Note, index inodes are essentially attribute inodes (NInoAttr() is true)
 * with the attribute type set to AT_INDEX_ALLOCATION.  Apart from that, they
 * are setup like directory inodes since directories are a special case of
 * indices ao they need to be treated in much the same way.  Most importantly,
 * for small indices the index allocation attribute might not actually exist.
 * However, the index root attribute always exists but this does not need to
 * have an inode associated with it and this is why we define a new inode type
 * index.  Also, like for directories, we need to have an attribute inode for
 * the bitmap attribute corresponding to the index allocation attribute and we
 * can store this in the appropriate field of the inode, just like we do for
 * normal directory inodes.
 *
 * Q: What locks are held when the function is called?
 * A: i_state has I_NEW set, hence the inode is locked, also
 *    i_count is set to 1, so it is not going to go away
 *
 * Return 0 on success and -errno on error.  In the error case, the inode will
 * have had make_bad_inode() executed on it.
 */
static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
{
        loff_t bvi_size;
        ntfs_volume *vol = NTFS_SB(vi->i_sb);
        ntfs_inode *ni, *base_ni, *bni;
        struct inode *bvi;
        MFT_RECORD *m;
        ATTR_RECORD *a;
        ntfs_attr_search_ctx *ctx;
        INDEX_ROOT *ir;
        u8 *ir_end, *index_end;
        int err = 0;

        ntfs_debug("Entering for i_ino 0x%lx.", vi->i_ino);
        ntfs_init_big_inode(vi);
        ni      = NTFS_I(vi);
        base_ni = NTFS_I(base_vi);
        /* Just mirror the values from the base inode. */
        vi->i_version   = base_vi->i_version;
        vi->i_uid       = base_vi->i_uid;
        vi->i_gid       = base_vi->i_gid;
        set_nlink(vi, base_vi->i_nlink);
        vi->i_mtime     = base_vi->i_mtime;
        vi->i_ctime     = base_vi->i_ctime;
        vi->i_atime     = base_vi->i_atime;
        vi->i_generation = ni->seq_no = base_ni->seq_no;
        /* Set inode type to zero but preserve permissions. */
        vi->i_mode      = base_vi->i_mode & ~S_IFMT;
        /* Map the mft record for the base inode. */
        m = map_mft_record(base_ni);
        if (IS_ERR(m)) {
                err = PTR_ERR(m);
                goto err_out;
        }
        ctx = ntfs_attr_get_search_ctx(base_ni, m);
        if (!ctx) {
                err = -ENOMEM;
                goto unm_err_out;
        }
        /* Find the index root attribute. */
        err = ntfs_attr_lookup(AT_INDEX_ROOT, ni->name, ni->name_len,
                        CASE_SENSITIVE, 0, NULL, 0, ctx);
        if (unlikely(err)) {
                if (err == -ENOENT)
                        ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is "
                                        "missing.");
                goto unm_err_out;
        }
        a = ctx->attr;
        /* Set up the state. */
        if (unlikely(a->non_resident)) {
                ntfs_error(vol->sb, "$INDEX_ROOT attribute is not resident.");
                goto unm_err_out;
        }
        /* Ensure the attribute name is placed before the value. */
        if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
                        le16_to_cpu(a->data.resident.value_offset)))) {
                ntfs_error(vol->sb, "$INDEX_ROOT attribute name is placed "
                                "after the attribute value.");
                goto unm_err_out;
        }
        /*
         * Compressed/encrypted/sparse index root is not allowed, except for
         * directories of course but those are not dealt with here.
         */
        if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_ENCRYPTED |
                        ATTR_IS_SPARSE)) {
                ntfs_error(vi->i_sb, "Found compressed/encrypted/sparse index "
                                "root attribute.");
                goto unm_err_out;
        }
        ir = (INDEX_ROOT*)((u8*)a + le16_to_cpu(a->data.resident.value_offset));
        ir_end = (u8*)ir + le32_to_cpu(a->data.resident.value_length);
        if (ir_end > (u8*)ctx->mrec + vol->mft_record_size) {
                ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is corrupt.");
                goto unm_err_out;
        }
        index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
        if (index_end > ir_end) {
                ntfs_error(vi->i_sb, "Index is corrupt.");
                goto unm_err_out;
        }
        if (ir->type) {
                ntfs_error(vi->i_sb, "Index type is not 0 (type is 0x%x).",
                                le32_to_cpu(ir->type));
                goto unm_err_out;
        }
        ni->itype.index.collation_rule = ir->collation_rule;
        ntfs_debug("Index collation rule is 0x%x.",
                        le32_to_cpu(ir->collation_rule));
        ni->itype.index.block_size = le32_to_cpu(ir->index_block_size);
        if (!is_power_of_2(ni->itype.index.block_size)) {
                ntfs_error(vi->i_sb, "Index block size (%u) is not a power of "
                                "two.", ni->itype.index.block_size);
                goto unm_err_out;
        }
        if (ni->itype.index.block_size > PAGE_SIZE) {
                ntfs_error(vi->i_sb, "Index block size (%u) > PAGE_SIZE "
                                "(%ld) is not supported.  Sorry.",
                                ni->itype.index.block_size, PAGE_SIZE);
                err = -EOPNOTSUPP;
                goto unm_err_out;
        }
        if (ni->itype.index.block_size < NTFS_BLOCK_SIZE) {
                ntfs_error(vi->i_sb, "Index block size (%u) < NTFS_BLOCK_SIZE "
                                "(%i) is not supported.  Sorry.",
                                ni->itype.index.block_size, NTFS_BLOCK_SIZE);
                err = -EOPNOTSUPP;
                goto unm_err_out;
        }
        ni->itype.index.block_size_bits = ffs(ni->itype.index.block_size) - 1;
        /* Determine the size of a vcn in the index. */
        if (vol->cluster_size <= ni->itype.index.block_size) {
                ni->itype.index.vcn_size = vol->cluster_size;
                ni->itype.index.vcn_size_bits = vol->cluster_size_bits;
        } else {
                ni->itype.index.vcn_size = vol->sector_size;
                ni->itype.index.vcn_size_bits = vol->sector_size_bits;
        }
        /* Check for presence of index allocation attribute. */
        if (!(ir->index.flags & LARGE_INDEX)) {
                /* No index allocation. */
                vi->i_size = ni->initialized_size = ni->allocated_size = 0;
                /* We are done with the mft record, so we release it. */
                ntfs_attr_put_search_ctx(ctx);
                unmap_mft_record(base_ni);
                m = NULL;
                ctx = NULL;
                goto skip_large_index_stuff;
        } /* LARGE_INDEX:  Index allocation present.  Setup state. */
        NInoSetIndexAllocPresent(ni);
        /* Find index allocation attribute. */
        ntfs_attr_reinit_search_ctx(ctx);
        err = ntfs_attr_lookup(AT_INDEX_ALLOCATION, ni->name, ni->name_len,
                        CASE_SENSITIVE, 0, NULL, 0, ctx);
        if (unlikely(err)) {
                if (err == -ENOENT)
                        ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
                                        "not present but $INDEX_ROOT "
                                        "indicated it is.");
                else
                        ntfs_error(vi->i_sb, "Failed to lookup "
                                        "$INDEX_ALLOCATION attribute.");
                goto unm_err_out;
        }
        a = ctx->attr;
        if (!a->non_resident) {
                ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
                                "resident.");
                goto unm_err_out;
        }
        /*
         * Ensure the attribute name is placed before the mapping pairs array.
         */
        if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
                        le16_to_cpu(
                        a->data.non_resident.mapping_pairs_offset)))) {
                ntfs_error(vol->sb, "$INDEX_ALLOCATION attribute name is "
                                "placed after the mapping pairs array.");
                goto unm_err_out;
        }
        if (a->flags & ATTR_IS_ENCRYPTED) {
                ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
                                "encrypted.");
                goto unm_err_out;
        }
        if (a->flags & ATTR_IS_SPARSE) {
                ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is sparse.");
                goto unm_err_out;
        }
        if (a->flags & ATTR_COMPRESSION_MASK) {
                ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
                                "compressed.");
                goto unm_err_out;
        }
        if (a->data.non_resident.lowest_vcn) {
                ntfs_error(vi->i_sb, "First extent of $INDEX_ALLOCATION "
                                "attribute has non zero lowest_vcn.");
                goto unm_err_out;
        }
        vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
        ni->initialized_size = sle64_to_cpu(
                        a->data.non_resident.initialized_size);
        ni->allocated_size = sle64_to_cpu(a->data.non_resident.allocated_size);
        /*
         * We are done with the mft record, so we release it.  Otherwise
         * we would deadlock in ntfs_attr_iget().
         */
        ntfs_attr_put_search_ctx(ctx);
        unmap_mft_record(base_ni);
        m = NULL;
        ctx = NULL;
        /* Get the index bitmap attribute inode. */
        bvi = ntfs_attr_iget(base_vi, AT_BITMAP, ni->name, ni->name_len);
        if (IS_ERR(bvi)) {
                ntfs_error(vi->i_sb, "Failed to get bitmap attribute.");
                err = PTR_ERR(bvi);
                goto unm_err_out;
        }
        bni = NTFS_I(bvi);
        if (NInoCompressed(bni) || NInoEncrypted(bni) ||
                        NInoSparse(bni)) {
                ntfs_error(vi->i_sb, "$BITMAP attribute is compressed and/or "
                                "encrypted and/or sparse.");
                goto iput_unm_err_out;
        }
        /* Consistency check bitmap size vs. index allocation size. */
        bvi_size = i_size_read(bvi);
        if ((bvi_size << 3) < (vi->i_size >> ni->itype.index.block_size_bits)) {
                ntfs_error(vi->i_sb, "Index bitmap too small (0x%llx) for "
                                "index allocation (0x%llx).", bvi_size << 3,
                                vi->i_size);
                goto iput_unm_err_out;
        }
        iput(bvi);
skip_large_index_stuff:
        /* Setup the operations for this index inode. */
        vi->i_mapping->a_ops = &ntfs_mst_aops;
        vi->i_blocks = ni->allocated_size >> 9;
        /*
         * Make sure the base inode doesn't go away and attach it to the
         * index inode.
         */
        igrab(base_vi);
        ni->ext.base_ntfs_ino = base_ni;
        ni->nr_extents = -1;

        ntfs_debug("Done.");
        return 0;
iput_unm_err_out:
        iput(bvi);
unm_err_out:
        if (!err)
                err = -EIO;
        if (ctx)
                ntfs_attr_put_search_ctx(ctx);
        if (m)
                unmap_mft_record(base_ni);
err_out:
        ntfs_error(vi->i_sb, "Failed with error code %i while reading index "
                        "inode (mft_no 0x%lx, name_len %i.", err, vi->i_ino,
                        ni->name_len);
        make_bad_inode(vi);
        if (err != -EOPNOTSUPP && err != -ENOMEM)
                NVolSetErrors(vol);
        return err;
}

/*
 * The MFT inode has special locking, so teach the lock validator
 * about this by splitting off the locking rules of the MFT from
 * the locking rules of other inodes. The MFT inode can never be
 * accessed from the VFS side (or even internally), only by the
 * map_mft functions.
 */
static struct lock_class_key mft_ni_runlist_lock_key, mft_ni_mrec_lock_key;

/**
 * ntfs_read_inode_mount - special read_inode for mount time use only
 * @vi:         inode to read
 *
 * Read inode FILE_MFT at mount time, only called with super_block lock
 * held from within the read_super() code path.
 *
 * This function exists because when it is called the page cache for $MFT/$DATA
 * is not initialized and hence we cannot get at the contents of mft records
 * by calling map_mft_record*().
 *
 * Further it needs to cope with the circular references problem, i.e. cannot
 * load any attributes other than $ATTRIBUTE_LIST until $DATA is loaded, because
 * we do not know where the other extent mft records are yet and again, because
 * we cannot call map_mft_record*() yet.  Obviously this applies only when an
 * attribute list is actually present in $MFT inode.
 *
 * We solve these problems by starting with the $DATA attribute before anything
 * else and iterating using ntfs_attr_lookup($DATA) over all extents.  As each
 * extent is found, we ntfs_mapping_pairs_decompress() including the implied
 * ntfs_runlists_merge().  Each step of the iteration necessarily provides
 * sufficient information for the next step to complete.
 *
 * This should work but there are two possible pit falls (see inline comments
 * below), but only time will tell if they are real pits or just smoke...
 */
int ntfs_read_inode_mount(struct inode *vi)
{
        VCN next_vcn, last_vcn, highest_vcn;
        s64 block;
        struct super_block *sb = vi->i_sb;
        ntfs_volume *vol = NTFS_SB(sb);
        struct buffer_head *bh;
        ntfs_inode *ni;
        MFT_RECORD *m = NULL;
        ATTR_RECORD *a;
        ntfs_attr_search_ctx *ctx;
        unsigned int i, nr_blocks;
        int err;

        ntfs_debug("Entering.");

        /* Initialize the ntfs specific part of @vi. */
        ntfs_init_big_inode(vi);

        ni = NTFS_I(vi);

        /* Setup the data attribute. It is special as it is mst protected. */
        NInoSetNonResident(ni);
        NInoSetMstProtected(ni);
        NInoSetSparseDisabled(ni);
        ni->type = AT_DATA;
        ni->name = NULL;
        ni->name_len = 0;
        /*
         * This sets up our little cheat allowing us to reuse the async read io
         * completion handler for directories.
         */
        ni->itype.index.block_size = vol->mft_record_size;
        ni->itype.index.block_size_bits = vol->mft_record_size_bits;

        /* Very important! Needed to be able to call map_mft_record*(). */
        vol->mft_ino = vi;

        /* Allocate enough memory to read the first mft record. */
        if (vol->mft_record_size > 64 * 1024) {
                ntfs_error(sb, "Unsupported mft record size %i (max 64kiB).",
                                vol->mft_record_size);
                goto err_out;
        }
        i = vol->mft_record_size;
        if (i < sb->s_blocksize)
                i = sb->s_blocksize;
        m = (MFT_RECORD*)ntfs_malloc_nofs(i);
        if (!m) {
                ntfs_error(sb, "Failed to allocate buffer for $MFT record 0.");
                goto err_out;
        }

        /* Determine the first block of the $MFT/$DATA attribute. */
        block = vol->mft_lcn << vol->cluster_size_bits >>
                        sb->s_blocksize_bits;
        nr_blocks = vol->mft_record_size >> sb->s_blocksize_bits;
        if (!nr_blocks)
                nr_blocks = 1;

        /* Load $MFT/$DATA's first mft record. */
        for (i = 0; i < nr_blocks; i++) {
                bh = sb_bread(sb, block++);
                if (!bh) {
                        ntfs_error(sb, "Device read failed.");
                        goto err_out;
                }
                memcpy((char*)m + (i << sb->s_blocksize_bits), bh->b_data,
                                sb->s_blocksize);
                brelse(bh);
        }

        /* Apply the mst fixups. */
        if (post_read_mst_fixup((NTFS_RECORD*)m, vol->mft_record_size)) {
                /* FIXME: Try to use the $MFTMirr now. */
                ntfs_error(sb, "MST fixup failed. $MFT is corrupt.");
                goto err_out;
        }

        /* Need this to sanity check attribute list references to $MFT. */
        vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);

        /* Provides readpage() for map_mft_record(). */
        vi->i_mapping->a_ops = &ntfs_mst_aops;

        ctx = ntfs_attr_get_search_ctx(ni, m);
        if (!ctx) {
                err = -ENOMEM;
                goto err_out;
        }

        /* Find the attribute list attribute if present. */
        err = ntfs_attr_lookup(AT_ATTRIBUTE_LIST, NULL, 0, 0, 0, NULL, 0, ctx);
        if (err) {
                if (unlikely(err != -ENOENT)) {
                        ntfs_error(sb, "Failed to lookup attribute list "
                                        "attribute. You should run chkdsk.");
                        goto put_err_out;
                }
        } else /* if (!err) */ {
                ATTR_LIST_ENTRY *al_entry, *next_al_entry;
                u8 *al_end;
                static const char *es = "  Not allowed.  $MFT is corrupt.  "
                                "You should run chkdsk.";

                ntfs_debug("Attribute list attribute found in $MFT.");
                NInoSetAttrList(ni);
                a = ctx->attr;
                if (a->flags & ATTR_COMPRESSION_MASK) {
                        ntfs_error(sb, "Attribute list attribute is "
                                        "compressed.%s", es);
                        goto put_err_out;
                }
                if (a->flags & ATTR_IS_ENCRYPTED ||
                                a->flags & ATTR_IS_SPARSE) {
                        if (a->non_resident) {
                                ntfs_error(sb, "Non-resident attribute list "
                                                "attribute is encrypted/"
                                                "sparse.%s", es);
                                goto put_err_out;
                        }
                        ntfs_warning(sb, "Resident attribute list attribute "
                                        "in $MFT system file is marked "
                                        "encrypted/sparse which is not true.  "
                                        "However, Windows allows this and "
                                        "chkdsk does not detect or correct it "
                                        "so we will just ignore the invalid "
                                        "flags and pretend they are not set.");
                }
                /* Now allocate memory for the attribute list. */
                ni->attr_list_size = (u32)ntfs_attr_size(a);
                ni->attr_list = ntfs_malloc_nofs(ni->attr_list_size);
                if (!ni->attr_list) {
                        ntfs_error(sb, "Not enough memory to allocate buffer "
                                        "for attribute list.");
                        goto put_err_out;
                }
                if (a->non_resident) {
                        NInoSetAttrListNonResident(ni);
                        if (a->data.non_resident.lowest_vcn) {
                                ntfs_error(sb, "Attribute list has non zero "
                                                "lowest_vcn. $MFT is corrupt. "
                                                "You should run chkdsk.");
                                goto put_err_out;
                        }
                        /* Setup the runlist. */
                        ni->attr_list_rl.rl = ntfs_mapping_pairs_decompress(vol,
                                        a, NULL);
                        if (IS_ERR(ni->attr_list_rl.rl)) {
                                err = PTR_ERR(ni->attr_list_rl.rl);
                                ni->attr_list_rl.rl = NULL;
                                ntfs_error(sb, "Mapping pairs decompression "
                                                "failed with error code %i.",
                                                -err);
                                goto put_err_out;
                        }
                        /* Now load the attribute list. */
                        if ((err = load_attribute_list(vol, &ni->attr_list_rl,
                                        ni->attr_list, ni->attr_list_size,
                                        sle64_to_cpu(a->data.
                                        non_resident.initialized_size)))) {
                                ntfs_error(sb, "Failed to load attribute list "
                                                "attribute with error code %i.",
                                                -err);
                                goto put_err_out;
                        }
                } else /* if (!ctx.attr->non_resident) */ {
                        if ((u8*)a + le16_to_cpu(
                                        a->data.resident.value_offset) +
                                        le32_to_cpu(
                                        a->data.resident.value_length) >
                                        (u8*)ctx->mrec + vol->mft_record_size) {
                                ntfs_error(sb, "Corrupt attribute list "
                                                "attribute.");
                                goto put_err_out;
                        }
                        /* Now copy the attribute list. */
                        memcpy(ni->attr_list, (u8*)a + le16_to_cpu(
                                        a->data.resident.value_offset),
                                        le32_to_cpu(
                                        a->data.resident.value_length));
                }
                /* The attribute list is now setup in memory. */
                /*
                 * FIXME: I don't know if this case is actually possible.
                 * According to logic it is not possible but I have seen too
                 * many weird things in MS software to rely on logic... Thus we
                 * perform a manual search and make sure the first $MFT/$DATA
                 * extent is in the base inode. If it is not we abort with an
                 * error and if we ever see a report of this error we will need
                 * to do some magic in order to have the necessary mft record
                 * loaded and in the right place in the page cache. But
                 * hopefully logic will prevail and this never happens...
                 */
                al_entry = (ATTR_LIST_ENTRY*)ni->attr_list;
                al_end = (u8*)al_entry + ni->attr_list_size;
                for (;; al_entry = next_al_entry) {
                        /* Out of bounds check. */
                        if ((u8*)al_entry < ni->attr_list ||
                                        (u8*)al_entry > al_end)
                                goto em_put_err_out;
                        /* Catch the end of the attribute list. */
                        if ((u8*)al_entry == al_end)
                                goto em_put_err_out;
                        if (!al_entry->length)
                                goto em_put_err_out;
                        if ((u8*)al_entry + 6 > al_end || (u8*)al_entry +
                                        le16_to_cpu(al_entry->length) > al_end)
                                goto em_put_err_out;
                        next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry +
                                        le16_to_cpu(al_entry->length));
                        if (le32_to_cpu(al_entry->type) > le32_to_cpu(AT_DATA))
                                goto em_put_err_out;
                        if (AT_DATA != al_entry->type)
                                continue;
                        /* We want an unnamed attribute. */
                        if (al_entry->name_length)
                                goto em_put_err_out;
                        /* Want the first entry, i.e. lowest_vcn == 0. */
                        if (al_entry->lowest_vcn)
                                goto em_put_err_out;
                        /* First entry has to be in the base mft record. */
                        if (MREF_LE(al_entry->mft_reference) != vi->i_ino) {
                                /* MFT references do not match, logic fails. */
                                ntfs_error(sb, "BUG: The first $DATA extent "
                                                "of $MFT is not in the base "
                                                "mft record. Please report "
                                                "you saw this message to "
                                                "linux-ntfs-dev@lists."
                                                "sourceforge.net");
                                goto put_err_out;
                        } else {
                                /* Sequence numbers must match. */
                                if (MSEQNO_LE(al_entry->mft_reference) !=
                                                ni->seq_no)
                                        goto em_put_err_out;
                                /* Got it. All is ok. We can stop now. */
                                break;
                        }
                }
        }

        ntfs_attr_reinit_search_ctx(ctx);

        /* Now load all attribute extents. */
        a = NULL;
        next_vcn = last_vcn = highest_vcn = 0;
        while (!(err = ntfs_attr_lookup(AT_DATA, NULL, 0, 0, next_vcn, NULL, 0,
                        ctx))) {
                runlist_element *nrl;

                /* Cache the current attribute. */
                a = ctx->attr;
                /* $MFT must be non-resident. */
                if (!a->non_resident) {
                        ntfs_error(sb, "$MFT must be non-resident but a "
                                        "resident extent was found. $MFT is "
                                        "corrupt. Run chkdsk.");
                        goto put_err_out;
                }
                /* $MFT must be uncompressed and unencrypted. */
                if (a->flags & ATTR_COMPRESSION_MASK ||
                                a->flags & ATTR_IS_ENCRYPTED ||
                                a->flags & ATTR_IS_SPARSE) {
                        ntfs_error(sb, "$MFT must be uncompressed, "
                                        "non-sparse, and unencrypted but a "
                                        "compressed/sparse/encrypted extent "
                                        "was found. $MFT is corrupt. Run "
                                        "chkdsk.");
                        goto put_err_out;
                }
                /*
                 * Decompress the mapping pairs array of this extent and merge
                 * the result into the existing runlist. No need for locking
                 * as we have exclusive access to the inode at this time and we
                 * are a mount in progress task, too.
                 */
                nrl = ntfs_mapping_pairs_decompress(vol, a, ni->runlist.rl);
                if (IS_ERR(nrl)) {
                        ntfs_error(sb, "ntfs_mapping_pairs_decompress() "
                                        "failed with error code %ld.  $MFT is "
                                        "corrupt.", PTR_ERR(nrl));
                        goto put_err_out;
                }
                ni->runlist.rl = nrl;

                /* Are we in the first extent? */
                if (!next_vcn) {
                        if (a->data.non_resident.lowest_vcn) {
                                ntfs_error(sb, "First extent of $DATA "
                                                "attribute has non zero "
                                                "lowest_vcn. $MFT is corrupt. "
                                                "You should run chkdsk.");
                                goto put_err_out;
                        }
                        /* Get the last vcn in the $DATA attribute. */
                        last_vcn = sle64_to_cpu(
                                        a->data.non_resident.allocated_size)
                                        >> vol->cluster_size_bits;
                        /* Fill in the inode size. */
                        vi->i_size = sle64_to_cpu(
                                        a->data.non_resident.data_size);
                        ni->initialized_size = sle64_to_cpu(
                                        a->data.non_resident.initialized_size);
                        ni->allocated_size = sle64_to_cpu(
                                        a->data.non_resident.allocated_size);
                        /*
                         * Verify the number of mft records does not exceed
                         * 2^32 - 1.
                         */
                        if ((vi->i_size >> vol->mft_record_size_bits) >=
                                        (1ULL << 32)) {
                                ntfs_error(sb, "$MFT is too big! Aborting.");
                                goto put_err_out;
                        }
                        /*
                         * We have got the first extent of the runlist for
                         * $MFT which means it is now relatively safe to call
                         * the normal ntfs_read_inode() function.
                         * Complete reading the inode, this will actually
                         * re-read the mft record for $MFT, this time entering
                         * it into the page cache with which we complete the
                         * kick start of the volume. It should be safe to do
                         * this now as the first extent of $MFT/$DATA is
                         * already known and we would hope that we don't need
                         * further extents in order to find the other
                         * attributes belonging to $MFT. Only time will tell if
                         * this is really the case. If not we will have to play
                         * magic at this point, possibly duplicating a lot of
                         * ntfs_read_inode() at this point. We will need to
                         * ensure we do enough of its work to be able to call
                         * ntfs_read_inode() on extents of $MFT/$DATA. But lets
                         * hope this never happens...
                         */
                        ntfs_read_locked_inode(vi);
                        if (is_bad_inode(vi)) {
                                ntfs_error(sb, "ntfs_read_inode() of $MFT "
                                                "failed. BUG or corrupt $MFT. "
                                                "Run chkdsk and if no errors "
                                                "are found, please report you "
                                                "saw this message to "
                                                "linux-ntfs-dev@lists."
                                                "sourceforge.net");
                                ntfs_attr_put_search_ctx(ctx);
                                /* Revert to the safe super operations. */
                                ntfs_free(m);
                                return -1;
                        }
                        /*
                         * Re-initialize some specifics about $MFT's inode as
                         * ntfs_read_inode() will have set up the default ones.
                         */
                        /* Set uid and gid to root. */
                        vi->i_uid = GLOBAL_ROOT_UID;
                        vi->i_gid = GLOBAL_ROOT_GID;
                        /* Regular file. No access for anyone. */
                        vi->i_mode = S_IFREG;
                        /* No VFS initiated operations allowed for $MFT. */
                        vi->i_op = &ntfs_empty_inode_ops;
                        vi->i_fop = &ntfs_empty_file_ops;
                }

                /* Get the lowest vcn for the next extent. */
                highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
                next_vcn = highest_vcn + 1;

                /* Only one extent or error, which we catch below. */
                if (next_vcn <= 0)
                        break;

                /* Avoid endless loops due to corruption. */
                if (next_vcn < sle64_to_cpu(
                                a->data.non_resident.lowest_vcn)) {
                        ntfs_error(sb, "$MFT has corrupt attribute list "
                                        "attribute. Run chkdsk.");
                        goto put_err_out;
                }
        }
        if (err != -ENOENT) {
                ntfs_error(sb, "Failed to lookup $MFT/$DATA attribute extent. "
                                "$MFT is corrupt. Run chkdsk.");
                goto put_err_out;
        }
        if (!a) {
                ntfs_error(sb, "$MFT/$DATA attribute not found. $MFT is "
                                "corrupt. Run chkdsk.");
                goto put_err_out;
        }
        if (highest_vcn && highest_vcn != last_vcn - 1) {
                ntfs_error(sb, "Failed to load the complete runlist for "
                                "$MFT/$DATA. Driver bug or corrupt $MFT. "
                                "Run chkdsk.");
                ntfs_debug("highest_vcn = 0x%llx, last_vcn - 1 = 0x%llx",
                                (unsigned long long)highest_vcn,
                                (unsigned long long)last_vcn - 1);
                goto put_err_out;
        }
        ntfs_attr_put_search_ctx(ctx);
        ntfs_debug("Done.");
        ntfs_free(m);

        /*
         * Split the locking rules of the MFT inode from the
         * locking rules of other inodes:
         */
        lockdep_set_class(&ni->runlist.lock, &mft_ni_runlist_lock_key);
        lockdep_set_class(&ni->mrec_lock, &mft_ni_mrec_lock_key);

        return 0;

em_put_err_out:
        ntfs_error(sb, "Couldn't find first extent of $DATA attribute in "
                        "attribute list. $MFT is corrupt. Run chkdsk.");
put_err_out:
        ntfs_attr_put_search_ctx(ctx);
err_out:
        ntfs_error(sb, "Failed. Marking inode as bad.");
        make_bad_inode(vi);
        ntfs_free(m);
        return -1;
}

static void __ntfs_clear_inode(ntfs_inode *ni)
{
        /* Free all alocated memory. */
        down_write(&ni->runlist.lock);
        if (ni->runlist.rl) {
                ntfs_free(ni->runlist.rl);
                ni->runlist.rl = NULL;
        }
        up_write(&ni->runlist.lock);

        if (ni->attr_list) {
                ntfs_free(ni->attr_list);
                ni->attr_list = NULL;
        }

        down_write(&ni->attr_list_rl.lock);
        if (ni->attr_list_rl.rl) {
                ntfs_free(ni->attr_list_rl.rl);
                ni->attr_list_rl.rl = NULL;
        }
        up_write(&ni->attr_list_rl.lock);

        if (ni->name_len && ni->name != I30) {
                /* Catch bugs... */
                BUG_ON(!ni->name);
                kfree(ni->name);
        }
}

void ntfs_clear_extent_inode(ntfs_inode *ni)
{
        ntfs_debug("Entering for inode 0x%lx.", ni->mft_no);

        BUG_ON(NInoAttr(ni));
        BUG_ON(ni->nr_extents != -1);

#ifdef NTFS_RW
        if (NInoDirty(ni)) {
                if (!is_bad_inode(VFS_I(ni->ext.base_ntfs_ino)))
                        ntfs_error(ni->vol->sb, "Clearing dirty extent inode!  "
                                        "Losing data!  This is a BUG!!!");
                // FIXME:  Do something!!!
        }
#endif /* NTFS_RW */

        __ntfs_clear_inode(ni);

        /* Bye, bye... */
        ntfs_destroy_extent_inode(ni);
}

/**
 * ntfs_evict_big_inode - clean up the ntfs specific part of an inode
 * @vi:         vfs inode pending annihilation
 *
 * When the VFS is going to remove an inode from memory, ntfs_clear_big_inode()
 * is called, which deallocates all memory belonging to the NTFS specific part
 * of the inode and returns.
 *
 * If the MFT record is dirty, we commit it before doing anything else.
 */
void ntfs_evict_big_inode(struct inode *vi)
{
        ntfs_inode *ni = NTFS_I(vi);

        truncate_inode_pages_final(&vi->i_data);
        clear_inode(vi);

#ifdef NTFS_RW
        if (NInoDirty(ni)) {
                bool was_bad = (is_bad_inode(vi));

                /* Committing the inode also commits all extent inodes. */
                ntfs_commit_inode(vi);

                if (!was_bad && (is_bad_inode(vi) || NInoDirty(ni))) {
                        ntfs_error(vi->i_sb, "Failed to commit dirty inode "
                                        "0x%lx.  Losing data!", vi->i_ino);
                        // FIXME:  Do something!!!
                }
        }
#endif /* NTFS_RW */

        /* No need to lock at this stage as no one else has a reference. */
        if (ni->nr_extents > 0) {
                int i;

                for (i = 0; i < ni->nr_extents; i++)
                        ntfs_clear_extent_inode(ni->ext.extent_ntfs_inos[i]);
                kfree(ni->ext.extent_ntfs_inos);
        }

        __ntfs_clear_inode(ni);

        if (NInoAttr(ni)) {
                /* Release the base inode if we are holding it. */
                if (ni->nr_extents == -1) {
                        iput(VFS_I(ni->ext.base_ntfs_ino));
                        ni->nr_extents = 0;
                        ni->ext.base_ntfs_ino = NULL;
                }
        }
        return;
}

/**
 * ntfs_show_options - show mount options in /proc/mounts
 * @sf:         seq_file in which to write our mount options
 * @root:       root of the mounted tree whose mount options to display
 *
 * Called by the VFS once for each mounted ntfs volume when someone reads
 * /proc/mounts in order to display the NTFS specific mount options of each
 * mount. The mount options of fs specified by @root are written to the seq file
 * @sf and success is returned.
 */
int ntfs_show_options(struct seq_file *sf, struct dentry *root)
{
        ntfs_volume *vol = NTFS_SB(root->d_sb);
        int i;

        seq_printf(sf, ",uid=%i", from_kuid_munged(&init_user_ns, vol->uid));
        seq_printf(sf, ",gid=%i", from_kgid_munged(&init_user_ns, vol->gid));
        if (vol->fmask == vol->dmask)
                seq_printf(sf, ",umask=0%o", vol->fmask);
        else {
                seq_printf(sf, ",fmask=0%o", vol->fmask);
                seq_printf(sf, ",dmask=0%o", vol->dmask);
        }
        seq_printf(sf, ",nls=%s", vol->nls_map->charset);
        if (NVolCaseSensitive(vol))
                seq_printf(sf, ",case_sensitive");
        if (NVolShowSystemFiles(vol))
                seq_printf(sf, ",show_sys_files");
        if (!NVolSparseEnabled(vol))
                seq_printf(sf, ",disable_sparse");
        for (i = 0; on_errors_arr[i].val; i++) {
                if (on_errors_arr[i].val & vol->on_errors)
                        seq_printf(sf, ",errors=%s", on_errors_arr[i].str);
        }
        seq_printf(sf, ",mft_zone_multiplier=%i", vol->mft_zone_multiplier);
        return 0;
}

#ifdef NTFS_RW

static const char *es = "  Leaving inconsistent metadata.  Unmount and run "
                "chkdsk.";

/**
 * ntfs_truncate - called when the i_size of an ntfs inode is changed
 * @vi:         inode for which the i_size was changed
 *
 * We only support i_size changes for normal files at present, i.e. not
 * compressed and not encrypted.  This is enforced in ntfs_setattr(), see
 * below.
 *
 * The kernel guarantees that @vi is a regular file (S_ISREG() is true) and
 * that the change is allowed.
 *
 * This implies for us that @vi is a file inode rather than a directory, index,
 * or attribute inode as well as that @vi is a base inode.
 *
 * Returns 0 on success or -errno on error.
 *
 * Called with ->i_mutex held.
 */
int ntfs_truncate(struct inode *vi)
{
        s64 new_size, old_size, nr_freed, new_alloc_size, old_alloc_size;
        VCN highest_vcn;
        unsigned long flags;
        ntfs_inode *base_ni, *ni = NTFS_I(vi);
        ntfs_volume *vol = ni->vol;
        ntfs_attr_search_ctx *ctx;
        MFT_RECORD *m;
        ATTR_RECORD *a;
        const char *te = "  Leaving file length out of sync with i_size.";
        int err, mp_size, size_change, alloc_change;
        u32 attr_len;

        ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
        BUG_ON(NInoAttr(ni));
        BUG_ON(S_ISDIR(vi->i_mode));
        BUG_ON(NInoMstProtected(ni));
        BUG_ON(ni->nr_extents < 0);
retry_truncate:
        /*
         * Lock the runlist for writing and map the mft record to ensure it is
         * safe to mess with the attribute runlist and sizes.
         */
        down_write(&ni->runlist.lock);
        if (!NInoAttr(ni))
                base_ni = ni;
        else
                base_ni = ni->ext.base_ntfs_ino;
        m = map_mft_record(base_ni);
        if (IS_ERR(m)) {
                err = PTR_ERR(m);
                ntfs_error(vi->i_sb, "Failed to map mft record for inode 0x%lx "
                                "(error code %d).%s", vi->i_ino, err, te);
                ctx = NULL;
                m = NULL;
                goto old_bad_out;
        }
        ctx = ntfs_attr_get_search_ctx(base_ni, m);
        if (unlikely(!ctx)) {
                ntfs_error(vi->i_sb, "Failed to allocate a search context for "
                                "inode 0x%lx (not enough memory).%s",
                                vi->i_ino, te);
                err = -ENOMEM;
                goto old_bad_out;
        }
        err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
                        CASE_SENSITIVE, 0, NULL, 0, ctx);
        if (unlikely(err)) {
                if (err == -ENOENT) {
                        ntfs_error(vi->i_sb, "Open attribute is missing from "
                                        "mft record.  Inode 0x%lx is corrupt.  "
                                        "Run chkdsk.%s", vi->i_ino, te);
                        err = -EIO;
                } else
                        ntfs_error(vi->i_sb, "Failed to lookup attribute in "
                                        "inode 0x%lx (error code %d).%s",
                                        vi->i_ino, err, te);
                goto old_bad_out;
        }
        m = ctx->mrec;
        a = ctx->attr;
        /*
         * The i_size of the vfs inode is the new size for the attribute value.
         */
        new_size = i_size_read(vi);
        /* The current size of the attribute value is the old size. */
        old_size = ntfs_attr_size(a);
        /* Calculate the new allocated size. */
        if (NInoNonResident(ni))
                new_alloc_size = (new_size + vol->cluster_size - 1) &
                                ~(s64)vol->cluster_size_mask;
        else
                new_alloc_size = (new_size + 7) & ~7;
        /* The current allocated size is the old allocated size. */
        read_lock_irqsave(&ni->size_lock, flags);
        old_alloc_size = ni->allocated_size;
        read_unlock_irqrestore(&ni->size_lock, flags);
        /*
         * The change in the file size.  This will be 0 if no change, >0 if the
         * size is growing, and <0 if the size is shrinking.
         */
        size_change = -1;
        if (new_size - old_size >= 0) {
                size_change = 1;
                if (new_size == old_size)
                        size_change = 0;
        }
        /* As above for the allocated size. */
        alloc_change = -1;
        if (new_alloc_size - old_alloc_size >= 0) {
                alloc_change = 1;
                if (new_alloc_size == old_alloc_size)
                        alloc_change = 0;
        }
        /*
         * If neither the size nor the allocation are being changed there is
         * nothing to do.
         */
        if (!size_change && !alloc_change)
                goto unm_done;
        /* If the size is changing, check if new size is allowed in $AttrDef. */
        if (size_change) {
                err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
                if (unlikely(err)) {
                        if (err == -ERANGE) {
                                ntfs_error(vol->sb, "Truncate would cause the "
                                                "inode 0x%lx to %simum size "
                                                "for its attribute type "
                                                "(0x%x).  Aborting truncate.",
                                                vi->i_ino,
                                                new_size > old_size ? "exceed "
                                                "the max" : "go under the min",
                                                le32_to_cpu(ni->type));
                                err = -EFBIG;
                        } else {
                                ntfs_error(vol->sb, "Inode 0x%lx has unknown "
                                                "attribute type 0x%x.  "
                                                "Aborting truncate.",
                                                vi->i_ino,
                                                le32_to_cpu(ni->type));
                                err = -EIO;
                        }
                        /* Reset the vfs inode size to the old size. */
                        i_size_write(vi, old_size);
                        goto err_out;
                }
        }
        if (NInoCompressed(ni) || NInoEncrypted(ni)) {
                ntfs_warning(vi->i_sb, "Changes in inode size are not "
                                "supported yet for %s files, ignoring.",
                                NInoCompressed(ni) ? "compressed" :
                                "encrypted");
                err = -EOPNOTSUPP;
                goto bad_out;
        }
        if (a->non_resident)
                goto do_non_resident_truncate;
        BUG_ON(NInoNonResident(ni));
        /* Resize the attribute record to best fit the new attribute size. */
        if (new_size < vol->mft_record_size &&
                        !ntfs_resident_attr_value_resize(m, a, new_size)) {
                /* The resize succeeded! */
                flush_dcache_mft_record_page(ctx->ntfs_ino);
                mark_mft_record_dirty(ctx->ntfs_ino);
                write_lock_irqsave(&ni->size_lock, flags);
                /* Update the sizes in the ntfs inode and all is done. */
                ni->allocated_size = le32_to_cpu(a->length) -
                                le16_to_cpu(a->data.resident.value_offset);
                /*
                 * Note ntfs_resident_attr_value_resize() has already done any
                 * necessary data clearing in the attribute record.  When the
                 * file is being shrunk vmtruncate() will already have cleared
                 * the top part of the last partial page, i.e. since this is
                 * the resident case this is the page with index 0.  However,
                 * when the file is being expanded, the page cache page data
                 * between the old data_size, i.e. old_size, and the new_size
                 * has not been zeroed.  Fortunately, we do not need to zero it
                 * either since on one hand it will either already be zero due
                 * to both readpage and writepage clearing partial page data
                 * beyond i_size in which case there is nothing to do or in the
                 * case of the file being mmap()ped at the same time, POSIX
                 * specifies that the behaviour is unspecified thus we do not
                 * have to do anything.  This means that in our implementation
                 * in the rare case that the file is mmap()ped and a write
                 * occurred into the mmap()ped region just beyond the file size
                 * and writepage has not yet been called to write out the page
                 * (which would clear the area beyond the file size) and we now
                 * extend the file size to incorporate this dirty region
                 * outside the file size, a write of the page would result in
                 * this data being written to disk instead of being cleared.
                 * Given both POSIX and the Linux mmap(2) man page specify that
                 * this corner case is undefined, we choose to leave it like
                 * that as this is much simpler for us as we cannot lock the
                 * relevant page now since we are holding too many ntfs locks
                 * which would result in a lock reversal deadlock.
                 */
                ni->initialized_size = new_size;
                write_unlock_irqrestore(&ni->size_lock, flags);
                goto unm_done;
        }
        /* If the above resize failed, this must be an attribute extension. */
        BUG_ON(size_change < 0);
        /*
         * We have to drop all the locks so we can call
         * ntfs_attr_make_non_resident().  This could be optimised by try-
         * locking the first page cache page and only if that fails dropping
         * the locks, locking the page, and redoing all the locking and
         * lookups.  While this would be a huge optimisation, it is not worth
         * it as this is definitely a slow code path as it only ever can happen
         * once for any given file.
         */
        ntfs_attr_put_search_ctx(ctx);
        unmap_mft_record(base_ni);
        up_write(&ni->runlist.lock);
        /*
         * Not enough space in the mft record, try to make the attribute
         * non-resident and if successful restart the truncation process.
         */
        err = ntfs_attr_make_non_resident(ni, old_size);
        if (likely(!err))
                goto retry_truncate;
        /*
         * Could not make non-resident.  If this is due to this not being
         * permitted for this attribute type or there not being enough space,
         * try to make other attributes non-resident.  Otherwise fail.
         */
        if (unlikely(err != -EPERM && err != -ENOSPC)) {
                ntfs_error(vol->sb, "Cannot truncate inode 0x%lx, attribute "
                                "type 0x%x, because the conversion from "
                                "resident to non-resident attribute failed "
                                "with error code %i.", vi->i_ino,
                                (unsigned)le32_to_cpu(ni->type), err);
                if (err != -ENOMEM)
                        err = -EIO;
                goto conv_err_out;
        }
        /* TODO: Not implemented from here, abort. */
        if (err == -ENOSPC)
                ntfs_error(vol->sb, "Not enough space in the mft record/on "
                                "disk for the non-resident attribute value.  "
                                "This case is not implemented yet.");
        else /* if (err == -EPERM) */
                ntfs_error(vol->sb, "This attribute type may not be "
                                "non-resident.  This case is not implemented "
                                "yet.");
        err = -EOPNOTSUPP;
        goto conv_err_out;
#if 0
        // TODO: Attempt to make other attributes non-resident.
        if (!err)
                goto do_resident_extend;
        /*
         * Both the attribute list attribute and the standard information
         * attribute must remain in the base inode.  Thus, if this is one of
         * these attributes, we have to try to move other attributes out into
         * extent mft records instead.
         */
        if (ni->type == AT_ATTRIBUTE_LIST ||
                        ni->type == AT_STANDARD_INFORMATION) {
                // TODO: Attempt to move other attributes into extent mft
                // records.
                err = -EOPNOTSUPP;
                if (!err)
                        goto do_resident_extend;
                goto err_out;
        }
        // TODO: Attempt to move this attribute to an extent mft record, but
        // only if it is not already the only attribute in an mft record in
        // which case there would be nothing to gain.
        err = -EOPNOTSUPP;
        if (!err)
                goto do_resident_extend;
        /* There is nothing we can do to make enough space. )-: */
        goto err_out;
#endif
do_non_resident_truncate:
        BUG_ON(!NInoNonResident(ni));
        if (alloc_change < 0) {
                highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
                if (highest_vcn > 0 &&
                                old_alloc_size >> vol->cluster_size_bits >
                                highest_vcn + 1) {
                        /*
                         * This attribute has multiple extents.  Not yet
                         * supported.
                         */
                        ntfs_error(vol->sb, "Cannot truncate inode 0x%lx, "
                                        "attribute type 0x%x, because the "
                                        "attribute is highly fragmented (it "
                                        "consists of multiple extents) and "
                                        "this case is not implemented yet.",
                                        vi->i_ino,
                                        (unsigned)le32_to_cpu(ni->type));
                        err = -EOPNOTSUPP;
                        goto bad_out;
                }
        }
        /*
         * If the size is shrinking, need to reduce the initialized_size and
         * the data_size before reducing the allocation.
         */
        if (size_change < 0) {
                /*
                 * Make the valid size smaller (i_size is already up-to-date).
                 */
                write_lock_irqsave(&ni->size_lock, flags);
                if (new_size < ni->initialized_size) {
                        ni->initialized_size = new_size;
                        a->data.non_resident.initialized_size =
                                        cpu_to_sle64(new_size);
                }
                a->data.non_resident.data_size = cpu_to_sle64(new_size);
                write_unlock_irqrestore(&ni->size_lock, flags);
                flush_dcache_mft_record_page(ctx->ntfs_ino);
                mark_mft_record_dirty(ctx->ntfs_ino);
                /* If the allocated size is not changing, we are done. */
                if (!alloc_change)
                        goto unm_done;
                /*
                 * If the size is shrinking it makes no sense for the
                 * allocation to be growing.
                 */
                BUG_ON(alloc_change > 0);
        } else /* if (size_change >= 0) */ {
                /*
                 * The file size is growing or staying the same but the
                 * allocation can be shrinking, growing or staying the same.
                 */
                if (alloc_change > 0) {
                        /*
                         * We need to extend the allocation and possibly update
                         * the data size.  If we are updating the data size,
                         * since we are not touching the initialized_size we do
                         * not need to worry about the actual data on disk.
                         * And as far as the page cache is concerned, there
                         * will be no pages beyond the old data size and any
                         * partial region in the last page between the old and
                         * new data size (or the end of the page if the new
                         * data size is outside the page) does not need to be
                         * modified as explained above for the resident
                         * attribute truncate case.  To do this, we simply drop
                         * the locks we hold and leave all the work to our
                         * friendly helper ntfs_attr_extend_allocation().
                         */
                        ntfs_attr_put_search_ctx(ctx);
                        unmap_mft_record(base_ni);
                        up_write(&ni->runlist.lock);
                        err = ntfs_attr_extend_allocation(ni, new_size,
                                        size_change > 0 ? new_size : -1, -1);
                        /*
                         * ntfs_attr_extend_allocation() will have done error
                         * output already.
                         */
                        goto done;
                }
                if (!alloc_change)
                        goto alloc_done;
        }
        /* alloc_change < 0 */
        /* Free the clusters. */
        nr_freed = ntfs_cluster_free(ni, new_alloc_size >>
                        vol->cluster_size_bits, -1, ctx);
        m = ctx->mrec;
        a = ctx->attr;
        if (unlikely(nr_freed < 0)) {
                ntfs_error(vol->sb, "Failed to release cluster(s) (error code "
                                "%lli).  Unmount and run chkdsk to recover "
                                "the lost cluster(s).", (long long)nr_freed);
                NVolSetErrors(vol);
                nr_freed = 0;
        }
        /* Truncate the runlist. */
        err = ntfs_rl_truncate_nolock(vol, &ni->runlist,
                        new_alloc_size >> vol->cluster_size_bits);
        /*
         * If the runlist truncation failed and/or the search context is no
         * longer valid, we cannot resize the attribute record or build the
         * mapping pairs array thus we mark the inode bad so that no access to
         * the freed clusters can happen.
         */
        if (unlikely(err || IS_ERR(m))) {
                ntfs_error(vol->sb, "Failed to %s (error code %li).%s",
                                IS_ERR(m) ?
                                "restore attribute search context" :
                                "truncate attribute runlist",
                                IS_ERR(m) ? PTR_ERR(m) : err, es);
                err = -EIO;
                goto bad_out;
        }
        /* Get the size for the shrunk mapping pairs array for the runlist. */
        mp_size = ntfs_get_size_for_mapping_pairs(vol, ni->runlist.rl, 0, -1);
        if (unlikely(mp_size <= 0)) {
                ntfs_error(vol->sb, "Cannot shrink allocation of inode 0x%lx, "
                                "attribute type 0x%x, because determining the "
                                "size for the mapping pairs failed with error "
                                "code %i.%s", vi->i_ino,
                                (unsigned)le32_to_cpu(ni->type), mp_size, es);
                err = -EIO;
                goto bad_out;
        }
        /*
         * Shrink the attribute record for the new mapping pairs array.  Note,
         * this cannot fail since we are making the attribute smaller thus by
         * definition there is enough space to do so.
         */
        attr_len = le32_to_cpu(a->length);
        err = ntfs_attr_record_resize(m, a, mp_size +
                        le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
        BUG_ON(err);
        /*
         * Generate the mapping pairs array directly into the attribute record.
         */
        err = ntfs_mapping_pairs_build(vol, (u8*)a +
                        le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
                        mp_size, ni->runlist.rl, 0, -1, NULL);
        if (unlikely(err)) {
                ntfs_error(vol->sb, "Cannot shrink allocation of inode 0x%lx, "
                                "attribute type 0x%x, because building the "
                                "mapping pairs failed with error code %i.%s",
                                vi->i_ino, (unsigned)le32_to_cpu(ni->type),
                                err, es);
                err = -EIO;
                goto bad_out;
        }
        /* Update the allocated/compressed size as well as the highest vcn. */
        a->data.non_resident.highest_vcn = cpu_to_sle64((new_alloc_size >>
                        vol->cluster_size_bits) - 1);
        write_lock_irqsave(&ni->size_lock, flags);
        ni->allocated_size = new_alloc_size;
        a->data.non_resident.allocated_size = cpu_to_sle64(new_alloc_size);
        if (NInoSparse(ni) || NInoCompressed(ni)) {
                if (nr_freed) {
                        ni->itype.compressed.size -= nr_freed <<
                                        vol->cluster_size_bits;
                        BUG_ON(ni->itype.compressed.size < 0);
                        a->data.non_resident.compressed_size = cpu_to_sle64(
                                        ni->itype.compressed.size);
                        vi->i_blocks = ni->itype.compressed.size >> 9;
                }
        } else
                vi->i_blocks = new_alloc_size >> 9;
        write_unlock_irqrestore(&ni->size_lock, flags);
        /*
         * We have shrunk the allocation.  If this is a shrinking truncate we
         * have already dealt with the initialized_size and the data_size above
         * and we are done.  If the truncate is only changing the allocation
         * and not the data_size, we are also done.  If this is an extending
         * truncate, need to extend the data_size now which is ensured by the
         * fact that @size_change is positive.
         */
alloc_done:
        /*
         * If the size is growing, need to update it now.  If it is shrinking,
         * we have already updated it above (before the allocation change).
         */
        if (size_change > 0)
                a->data.non_resident.data_size = cpu_to_sle64(new_size);
        /* Ensure the modified mft record is written out. */
        flush_dcache_mft_record_page(ctx->ntfs_ino);
        mark_mft_record_dirty(ctx->ntfs_ino);
unm_done:
        ntfs_attr_put_search_ctx(ctx);
        unmap_mft_record(base_ni);
        up_write(&ni->runlist.lock);
done:
        /* Update the mtime and ctime on the base inode. */
        /* normally ->truncate shouldn't update ctime or mtime,
         * but ntfs did before so it got a copy & paste version
         * of file_update_time.  one day someone should fix this
         * for real.
         */
        if (!IS_NOCMTIME(VFS_I(base_ni)) && !IS_RDONLY(VFS_I(base_ni))) {
                struct timespec now = current_time(VFS_I(base_ni));
                int sync_it = 0;

                if (!timespec_equal(&VFS_I(base_ni)->i_mtime, &now) ||
                    !timespec_equal(&VFS_I(base_ni)->i_ctime, &now))
                        sync_it = 1;
                VFS_I(base_ni)->i_mtime = now;
                VFS_I(base_ni)->i_ctime = now;

                if (sync_it)
                        mark_inode_dirty_sync(VFS_I(base_ni));
        }

        if (likely(!err)) {
                NInoClearTruncateFailed(ni);
                ntfs_debug("Done.");
        }
        return err;
old_bad_out:
        old_size = -1;
bad_out:
        if (err != -ENOMEM && err != -EOPNOTSUPP)
                NVolSetErrors(vol);
        if (err != -EOPNOTSUPP)
                NInoSetTruncateFailed(ni);
        else if (old_size >= 0)
                i_size_write(vi, old_size);
err_out:
        if (ctx)
                ntfs_attr_put_search_ctx(ctx);
        if (m)
                unmap_mft_record(base_ni);
        up_write(&ni->runlist.lock);
out:
        ntfs_debug("Failed.  Returning error code %i.", err);
        return err;
conv_err_out:
        if (err != -ENOMEM && err != -EOPNOTSUPP)
                NVolSetErrors(vol);
        if (err != -EOPNOTSUPP)
                NInoSetTruncateFailed(ni);
        else
                i_size_write(vi, old_size);
        goto out;
}

/**
 * ntfs_truncate_vfs - wrapper for ntfs_truncate() that has no return value
 * @vi:         inode for which the i_size was changed
 *
 * Wrapper for ntfs_truncate() that has no return value.
 *
 * See ntfs_truncate() description above for details.
 */
#ifdef NTFS_RW
void ntfs_truncate_vfs(struct inode *vi) {
        ntfs_truncate(vi);
}
#endif

/**
 * ntfs_setattr - called from notify_change() when an attribute is being changed
 * @dentry:     dentry whose attributes to change
 * @attr:       structure describing the attributes and the changes
 *
 * We have to trap VFS attempts to truncate the file described by @dentry as
 * soon as possible, because we do not implement changes in i_size yet.  So we
 * abort all i_size changes here.
 *
 * We also abort all changes of user, group, and mode as we do not implement
 * the NTFS ACLs yet.
 *
 * Called with ->i_mutex held.
 */
int ntfs_setattr(struct dentry *dentry, struct iattr *attr)
{
        struct inode *vi = d_inode(dentry);
        int err;
        unsigned int ia_valid = attr->ia_valid;

        err = setattr_prepare(dentry, attr);
        if (err)
                goto out;
        /* We do not support NTFS ACLs yet. */
        if (ia_valid & (ATTR_UID | ATTR_GID | ATTR_MODE)) {
                ntfs_warning(vi->i_sb, "Changes in user/group/mode are not "
                                "supported yet, ignoring.");
                err = -EOPNOTSUPP;
                goto out;
        }
        if (ia_valid & ATTR_SIZE) {
                if (attr->ia_size != i_size_read(vi)) {
                        ntfs_inode *ni = NTFS_I(vi);
                        /*
                         * FIXME: For now we do not support resizing of
                         * compressed or encrypted files yet.
                         */
                        if (NInoCompressed(ni) || NInoEncrypted(ni)) {
                                ntfs_warning(vi->i_sb, "Changes in inode size "
                                                "are not supported yet for "
                                                "%s files, ignoring.",
                                                NInoCompressed(ni) ?
                                                "compressed" : "encrypted");
                                err = -EOPNOTSUPP;
                        } else {
                                truncate_setsize(vi, attr->ia_size);
                                ntfs_truncate_vfs(vi);
                        }
                        if (err || ia_valid == ATTR_SIZE)
                                goto out;
                } else {
                        /*
                         * We skipped the truncate but must still update
                         * timestamps.
                         */
                        ia_valid |= ATTR_MTIME | ATTR_CTIME;
                }
        }
        if (ia_valid & ATTR_ATIME)
                vi->i_atime = timespec_trunc(attr->ia_atime,
                                vi->i_sb->s_time_gran);
        if (ia_valid & ATTR_MTIME)
                vi->i_mtime = timespec_trunc(attr->ia_mtime,
                                vi->i_sb->s_time_gran);
        if (ia_valid & ATTR_CTIME)
                vi->i_ctime = timespec_trunc(attr->ia_ctime,
                                vi->i_sb->s_time_gran);
        mark_inode_dirty(vi);
out:
        return err;
}

/**
 * ntfs_write_inode - write out a dirty inode
 * @vi:         inode to write out
 * @sync:       if true, write out synchronously
 *
 * Write out a dirty inode to disk including any extent inodes if present.
 *
 * If @sync is true, commit the inode to disk and wait for io completion.  This
 * is done using write_mft_record().
 *
 * If @sync is false, just schedule the write to happen but do not wait for i/o
 * completion.  In 2.6 kernels, scheduling usually happens just by virtue of
 * marking the page (and in this case mft record) dirty but we do not implement
 * this yet as write_mft_record() largely ignores the @sync parameter and
 * always performs synchronous writes.
 *
 * Return 0 on success and -errno on error.
 */
int __ntfs_write_inode(struct inode *vi, int sync)
{
        sle64 nt;
        ntfs_inode *ni = NTFS_I(vi);
        ntfs_attr_search_ctx *ctx;
        MFT_RECORD *m;
        STANDARD_INFORMATION *si;
        int err = 0;
        bool modified = false;

        ntfs_debug("Entering for %sinode 0x%lx.", NInoAttr(ni) ? "attr " : "",
                        vi->i_ino);
        /*
         * Dirty attribute inodes are written via their real inodes so just
         * clean them here.  Access time updates are taken care off when the
         * real inode is written.
         */
        if (NInoAttr(ni)) {
                NInoClearDirty(ni);
                ntfs_debug("Done.");
                return 0;
        }
        /* Map, pin, and lock the mft record belonging to the inode. */
        m = map_mft_record(ni);
        if (IS_ERR(m)) {
                err = PTR_ERR(m);
                goto err_out;
        }
        /* Update the access times in the standard information attribute. */
        ctx = ntfs_attr_get_search_ctx(ni, m);
        if (unlikely(!ctx)) {
                err = -ENOMEM;
                goto unm_err_out;
        }
        err = ntfs_attr_lookup(AT_STANDARD_INFORMATION, NULL, 0,
                        CASE_SENSITIVE, 0, NULL, 0, ctx);
        if (unlikely(err)) {
                ntfs_attr_put_search_ctx(ctx);
                goto unm_err_out;
        }
        si = (STANDARD_INFORMATION*)((u8*)ctx->attr +
                        le16_to_cpu(ctx->attr->data.resident.value_offset));
        /* Update the access times if they have changed. */
        nt = utc2ntfs(vi->i_mtime);
        if (si->last_data_change_time != nt) {
                ntfs_debug("Updating mtime for inode 0x%lx: old = 0x%llx, "
                                "new = 0x%llx", vi->i_ino, (long long)
                                sle64_to_cpu(si->last_data_change_time),
                                (long long)sle64_to_cpu(nt));
                si->last_data_change_time = nt;
                modified = true;
        }
        nt = utc2ntfs(vi->i_ctime);
        if (si->last_mft_change_time != nt) {
                ntfs_debug("Updating ctime for inode 0x%lx: old = 0x%llx, "
                                "new = 0x%llx", vi->i_ino, (long long)
                                sle64_to_cpu(si->last_mft_change_time),
                                (long long)sle64_to_cpu(nt));
                si->last_mft_change_time = nt;
                modified = true;
        }
        nt = utc2ntfs(vi->i_atime);
        if (si->last_access_time != nt) {
                ntfs_debug("Updating atime for inode 0x%lx: old = 0x%llx, "
                                "new = 0x%llx", vi->i_ino,
                                (long long)sle64_to_cpu(si->last_access_time),
                                (long long)sle64_to_cpu(nt));
                si->last_access_time = nt;
                modified = true;
        }
        /*
         * If we just modified the standard information attribute we need to
         * mark the mft record it is in dirty.  We do this manually so that
         * mark_inode_dirty() is not called which would redirty the inode and
         * hence result in an infinite loop of trying to write the inode.
         * There is no need to mark the base inode nor the base mft record
         * dirty, since we are going to write this mft record below in any case
         * and the base mft record may actually not have been modified so it
         * might not need to be written out.
         * NOTE: It is not a problem when the inode for $MFT itself is being
         * written out as mark_ntfs_record_dirty() will only set I_DIRTY_PAGES
         * on the $MFT inode and hence ntfs_write_inode() will not be
         * re-invoked because of it which in turn is ok since the dirtied mft
         * record will be cleaned and written out to disk below, i.e. before
         * this function returns.
         */
        if (modified) {
                flush_dcache_mft_record_page(ctx->ntfs_ino);
                if (!NInoTestSetDirty(ctx->ntfs_ino))
                        mark_ntfs_record_dirty(ctx->ntfs_ino->page,
                                        ctx->ntfs_ino->page_ofs);
        }
        ntfs_attr_put_search_ctx(ctx);
        /* Now the access times are updated, write the base mft record. */
        if (NInoDirty(ni))
                err = write_mft_record(ni, m, sync);
        /* Write all attached extent mft records. */
        mutex_lock(&ni->extent_lock);
        if (ni->nr_extents > 0) {
                ntfs_inode **extent_nis = ni->ext.extent_ntfs_inos;
                int i;

                ntfs_debug("Writing %i extent inodes.", ni->nr_extents);
                for (i = 0; i < ni->nr_extents; i++) {
                        ntfs_inode *tni = extent_nis[i];

                        if (NInoDirty(tni)) {
                                MFT_RECORD *tm = map_mft_record(tni);
                                int ret;

                                if (IS_ERR(tm)) {
                                        if (!err || err == -ENOMEM)
                                                err = PTR_ERR(tm);
                                        continue;
                                }
                                ret = write_mft_record(tni, tm, sync);
                                unmap_mft_record(tni);
                                if (unlikely(ret)) {
                                        if (!err || err == -ENOMEM)
                                                err = ret;
                                }
                        }
                }
        }
        mutex_unlock(&ni->extent_lock);
        unmap_mft_record(ni);
        if (unlikely(err))
                goto err_out;
        ntfs_debug("Done.");
        return 0;
unm_err_out:
        unmap_mft_record(ni);
err_out:
        if (err == -ENOMEM) {
                ntfs_warning(vi->i_sb, "Not enough memory to write inode.  "
                                "Marking the inode dirty again, so the VFS "
                                "retries later.");
                mark_inode_dirty(vi);
        } else {
                ntfs_error(vi->i_sb, "Failed (error %i):  Run chkdsk.", -err);
                NVolSetErrors(ni->vol);
        }
        return err;
}

#endif /* NTFS_RW */