mm: compaction: prevent kswapd compacting memory to reduce CPU usage

[linux/fpc-iii.git] / fs / xfs / xfs_inode_item.c

/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program 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.
 *
 * This program is distributed in the hope that it would 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; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_trans_priv.h"
#include "xfs_bmap_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_error.h"
#include "xfs_trace.h"


kmem_zone_t     *xfs_ili_zone;          /* inode log item zone */

static inline struct xfs_inode_log_item *INODE_ITEM(struct xfs_log_item *lip)
{
        return container_of(lip, struct xfs_inode_log_item, ili_item);
}


/*
 * This returns the number of iovecs needed to log the given inode item.
 *
 * We need one iovec for the inode log format structure, one for the
 * inode core, and possibly one for the inode data/extents/b-tree root
 * and one for the inode attribute data/extents/b-tree root.
 */
STATIC uint
xfs_inode_item_size(
        struct xfs_log_item     *lip)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;
        uint                    nvecs = 2;

        /*
         * Only log the data/extents/b-tree root if there is something
         * left to log.
         */
        iip->ili_format.ilf_fields |= XFS_ILOG_CORE;

        switch (ip->i_d.di_format) {
        case XFS_DINODE_FMT_EXTENTS:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
                          XFS_ILOG_DEV | XFS_ILOG_UUID);
                if ((iip->ili_format.ilf_fields & XFS_ILOG_DEXT) &&
                    (ip->i_d.di_nextents > 0) &&
                    (ip->i_df.if_bytes > 0)) {
                        ASSERT(ip->i_df.if_u1.if_extents != NULL);
                        nvecs++;
                } else {
                        iip->ili_format.ilf_fields &= ~XFS_ILOG_DEXT;
                }
                break;

        case XFS_DINODE_FMT_BTREE:
                ASSERT(ip->i_df.if_ext_max ==
                       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_DDATA | XFS_ILOG_DEXT |
                          XFS_ILOG_DEV | XFS_ILOG_UUID);
                if ((iip->ili_format.ilf_fields & XFS_ILOG_DBROOT) &&
                    (ip->i_df.if_broot_bytes > 0)) {
                        ASSERT(ip->i_df.if_broot != NULL);
                        nvecs++;
                } else {
                        ASSERT(!(iip->ili_format.ilf_fields &
                                 XFS_ILOG_DBROOT));
#ifdef XFS_TRANS_DEBUG
                        if (iip->ili_root_size > 0) {
                                ASSERT(iip->ili_root_size ==
                                       ip->i_df.if_broot_bytes);
                                ASSERT(memcmp(iip->ili_orig_root,
                                            ip->i_df.if_broot,
                                            iip->ili_root_size) == 0);
                        } else {
                                ASSERT(ip->i_df.if_broot_bytes == 0);
                        }
#endif
                        iip->ili_format.ilf_fields &= ~XFS_ILOG_DBROOT;
                }
                break;

        case XFS_DINODE_FMT_LOCAL:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_DEXT | XFS_ILOG_DBROOT |
                          XFS_ILOG_DEV | XFS_ILOG_UUID);
                if ((iip->ili_format.ilf_fields & XFS_ILOG_DDATA) &&
                    (ip->i_df.if_bytes > 0)) {
                        ASSERT(ip->i_df.if_u1.if_data != NULL);
                        ASSERT(ip->i_d.di_size > 0);
                        nvecs++;
                } else {
                        iip->ili_format.ilf_fields &= ~XFS_ILOG_DDATA;
                }
                break;

        case XFS_DINODE_FMT_DEV:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
                          XFS_ILOG_DEXT | XFS_ILOG_UUID);
                break;

        case XFS_DINODE_FMT_UUID:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
                          XFS_ILOG_DEXT | XFS_ILOG_DEV);
                break;

        default:
                ASSERT(0);
                break;
        }

        /*
         * If there are no attributes associated with this file,
         * then there cannot be anything more to log.
         * Clear all attribute-related log flags.
         */
        if (!XFS_IFORK_Q(ip)) {
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_ADATA | XFS_ILOG_ABROOT | XFS_ILOG_AEXT);
                return nvecs;
        }

        /*
         * Log any necessary attribute data.
         */
        switch (ip->i_d.di_aformat) {
        case XFS_DINODE_FMT_EXTENTS:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_ADATA | XFS_ILOG_ABROOT);
                if ((iip->ili_format.ilf_fields & XFS_ILOG_AEXT) &&
                    (ip->i_d.di_anextents > 0) &&
                    (ip->i_afp->if_bytes > 0)) {
                        ASSERT(ip->i_afp->if_u1.if_extents != NULL);
                        nvecs++;
                } else {
                        iip->ili_format.ilf_fields &= ~XFS_ILOG_AEXT;
                }
                break;

        case XFS_DINODE_FMT_BTREE:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_ADATA | XFS_ILOG_AEXT);
                if ((iip->ili_format.ilf_fields & XFS_ILOG_ABROOT) &&
                    (ip->i_afp->if_broot_bytes > 0)) {
                        ASSERT(ip->i_afp->if_broot != NULL);
                        nvecs++;
                } else {
                        iip->ili_format.ilf_fields &= ~XFS_ILOG_ABROOT;
                }
                break;

        case XFS_DINODE_FMT_LOCAL:
                iip->ili_format.ilf_fields &=
                        ~(XFS_ILOG_AEXT | XFS_ILOG_ABROOT);
                if ((iip->ili_format.ilf_fields & XFS_ILOG_ADATA) &&
                    (ip->i_afp->if_bytes > 0)) {
                        ASSERT(ip->i_afp->if_u1.if_data != NULL);
                        nvecs++;
                } else {
                        iip->ili_format.ilf_fields &= ~XFS_ILOG_ADATA;
                }
                break;

        default:
                ASSERT(0);
                break;
        }

        return nvecs;
}

/*
 * This is called to fill in the vector of log iovecs for the
 * given inode log item.  It fills the first item with an inode
 * log format structure, the second with the on-disk inode structure,
 * and a possible third and/or fourth with the inode data/extents/b-tree
 * root and inode attributes data/extents/b-tree root.
 */
STATIC void
xfs_inode_item_format(
        struct xfs_log_item     *lip,
        struct xfs_log_iovec    *vecp)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;
        uint                    nvecs;
        size_t                  data_bytes;
        xfs_bmbt_rec_t          *ext_buffer;
        xfs_mount_t             *mp;

        vecp->i_addr = &iip->ili_format;
        vecp->i_len  = sizeof(xfs_inode_log_format_t);
        vecp->i_type = XLOG_REG_TYPE_IFORMAT;
        vecp++;
        nvecs        = 1;

        /*
         * Clear i_update_core if the timestamps (or any other
         * non-transactional modification) need flushing/logging
         * and we're about to log them with the rest of the core.
         *
         * This is the same logic as xfs_iflush() but this code can't
         * run at the same time as xfs_iflush because we're in commit
         * processing here and so we have the inode lock held in
         * exclusive mode.  Although it doesn't really matter
         * for the timestamps if both routines were to grab the
         * timestamps or not.  That would be ok.
         *
         * We clear i_update_core before copying out the data.
         * This is for coordination with our timestamp updates
         * that don't hold the inode lock. They will always
         * update the timestamps BEFORE setting i_update_core,
         * so if we clear i_update_core after they set it we
         * are guaranteed to see their updates to the timestamps
         * either here.  Likewise, if they set it after we clear it
         * here, we'll see it either on the next commit of this
         * inode or the next time the inode gets flushed via
         * xfs_iflush().  This depends on strongly ordered memory
         * semantics, but we have that.  We use the SYNCHRONIZE
         * macro to make sure that the compiler does not reorder
         * the i_update_core access below the data copy below.
         */
        if (ip->i_update_core)  {
                ip->i_update_core = 0;
                SYNCHRONIZE();
        }

        /*
         * Make sure to get the latest timestamps from the Linux inode.
         */
        xfs_synchronize_times(ip);

        vecp->i_addr = &ip->i_d;
        vecp->i_len  = sizeof(struct xfs_icdinode);
        vecp->i_type = XLOG_REG_TYPE_ICORE;
        vecp++;
        nvecs++;
        iip->ili_format.ilf_fields |= XFS_ILOG_CORE;

        /*
         * If this is really an old format inode, then we need to
         * log it as such.  This means that we have to copy the link
         * count from the new field to the old.  We don't have to worry
         * about the new fields, because nothing trusts them as long as
         * the old inode version number is there.  If the superblock already
         * has a new version number, then we don't bother converting back.
         */
        mp = ip->i_mount;
        ASSERT(ip->i_d.di_version == 1 || xfs_sb_version_hasnlink(&mp->m_sb));
        if (ip->i_d.di_version == 1) {
                if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
                        /*
                         * Convert it back.
                         */
                        ASSERT(ip->i_d.di_nlink <= XFS_MAXLINK_1);
                        ip->i_d.di_onlink = ip->i_d.di_nlink;
                } else {
                        /*
                         * The superblock version has already been bumped,
                         * so just make the conversion to the new inode
                         * format permanent.
                         */
                        ip->i_d.di_version = 2;
                        ip->i_d.di_onlink = 0;
                        memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
                }
        }

        switch (ip->i_d.di_format) {
        case XFS_DINODE_FMT_EXTENTS:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
                          XFS_ILOG_DEV | XFS_ILOG_UUID)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_DEXT) {
                        ASSERT(ip->i_df.if_bytes > 0);
                        ASSERT(ip->i_df.if_u1.if_extents != NULL);
                        ASSERT(ip->i_d.di_nextents > 0);
                        ASSERT(iip->ili_extents_buf == NULL);
                        ASSERT((ip->i_df.if_bytes /
                                (uint)sizeof(xfs_bmbt_rec_t)) > 0);
#ifdef XFS_NATIVE_HOST
                       if (ip->i_d.di_nextents == ip->i_df.if_bytes /
                                               (uint)sizeof(xfs_bmbt_rec_t)) {
                                /*
                                 * There are no delayed allocation
                                 * extents, so just point to the
                                 * real extents array.
                                 */
                                vecp->i_addr = ip->i_df.if_u1.if_extents;
                                vecp->i_len = ip->i_df.if_bytes;
                                vecp->i_type = XLOG_REG_TYPE_IEXT;
                        } else
#endif
                        {
                                /*
                                 * There are delayed allocation extents
                                 * in the inode, or we need to convert
                                 * the extents to on disk format.
                                 * Use xfs_iextents_copy()
                                 * to copy only the real extents into
                                 * a separate buffer.  We'll free the
                                 * buffer in the unlock routine.
                                 */
                                ext_buffer = kmem_alloc(ip->i_df.if_bytes,
                                        KM_SLEEP);
                                iip->ili_extents_buf = ext_buffer;
                                vecp->i_addr = ext_buffer;
                                vecp->i_len = xfs_iextents_copy(ip, ext_buffer,
                                                XFS_DATA_FORK);
                                vecp->i_type = XLOG_REG_TYPE_IEXT;
                        }
                        ASSERT(vecp->i_len <= ip->i_df.if_bytes);
                        iip->ili_format.ilf_dsize = vecp->i_len;
                        vecp++;
                        nvecs++;
                }
                break;

        case XFS_DINODE_FMT_BTREE:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_DDATA | XFS_ILOG_DEXT |
                          XFS_ILOG_DEV | XFS_ILOG_UUID)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_DBROOT) {
                        ASSERT(ip->i_df.if_broot_bytes > 0);
                        ASSERT(ip->i_df.if_broot != NULL);
                        vecp->i_addr = ip->i_df.if_broot;
                        vecp->i_len = ip->i_df.if_broot_bytes;
                        vecp->i_type = XLOG_REG_TYPE_IBROOT;
                        vecp++;
                        nvecs++;
                        iip->ili_format.ilf_dsize = ip->i_df.if_broot_bytes;
                }
                break;

        case XFS_DINODE_FMT_LOCAL:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
                          XFS_ILOG_DEV | XFS_ILOG_UUID)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_DDATA) {
                        ASSERT(ip->i_df.if_bytes > 0);
                        ASSERT(ip->i_df.if_u1.if_data != NULL);
                        ASSERT(ip->i_d.di_size > 0);

                        vecp->i_addr = ip->i_df.if_u1.if_data;
                        /*
                         * Round i_bytes up to a word boundary.
                         * The underlying memory is guaranteed to
                         * to be there by xfs_idata_realloc().
                         */
                        data_bytes = roundup(ip->i_df.if_bytes, 4);
                        ASSERT((ip->i_df.if_real_bytes == 0) ||
                               (ip->i_df.if_real_bytes == data_bytes));
                        vecp->i_len = (int)data_bytes;
                        vecp->i_type = XLOG_REG_TYPE_ILOCAL;
                        vecp++;
                        nvecs++;
                        iip->ili_format.ilf_dsize = (unsigned)data_bytes;
                }
                break;

        case XFS_DINODE_FMT_DEV:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
                          XFS_ILOG_DDATA | XFS_ILOG_UUID)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_DEV) {
                        iip->ili_format.ilf_u.ilfu_rdev =
                                ip->i_df.if_u2.if_rdev;
                }
                break;

        case XFS_DINODE_FMT_UUID:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
                          XFS_ILOG_DDATA | XFS_ILOG_DEV)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_UUID) {
                        iip->ili_format.ilf_u.ilfu_uuid =
                                ip->i_df.if_u2.if_uuid;
                }
                break;

        default:
                ASSERT(0);
                break;
        }

        /*
         * If there are no attributes associated with the file,
         * then we're done.
         * Assert that no attribute-related log flags are set.
         */
        if (!XFS_IFORK_Q(ip)) {
                ASSERT(nvecs == lip->li_desc->lid_size);
                iip->ili_format.ilf_size = nvecs;
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_ADATA | XFS_ILOG_ABROOT | XFS_ILOG_AEXT)));
                return;
        }

        switch (ip->i_d.di_aformat) {
        case XFS_DINODE_FMT_EXTENTS:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_ADATA | XFS_ILOG_ABROOT)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_AEXT) {
#ifdef DEBUG
                        int nrecs = ip->i_afp->if_bytes /
                                (uint)sizeof(xfs_bmbt_rec_t);
                        ASSERT(nrecs > 0);
                        ASSERT(nrecs == ip->i_d.di_anextents);
                        ASSERT(ip->i_afp->if_bytes > 0);
                        ASSERT(ip->i_afp->if_u1.if_extents != NULL);
                        ASSERT(ip->i_d.di_anextents > 0);
#endif
#ifdef XFS_NATIVE_HOST
                        /*
                         * There are not delayed allocation extents
                         * for attributes, so just point at the array.
                         */
                        vecp->i_addr = ip->i_afp->if_u1.if_extents;
                        vecp->i_len = ip->i_afp->if_bytes;
#else
                        ASSERT(iip->ili_aextents_buf == NULL);
                        /*
                         * Need to endian flip before logging
                         */
                        ext_buffer = kmem_alloc(ip->i_afp->if_bytes,
                                KM_SLEEP);
                        iip->ili_aextents_buf = ext_buffer;
                        vecp->i_addr = ext_buffer;
                        vecp->i_len = xfs_iextents_copy(ip, ext_buffer,
                                        XFS_ATTR_FORK);
#endif
                        vecp->i_type = XLOG_REG_TYPE_IATTR_EXT;
                        iip->ili_format.ilf_asize = vecp->i_len;
                        vecp++;
                        nvecs++;
                }
                break;

        case XFS_DINODE_FMT_BTREE:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_ADATA | XFS_ILOG_AEXT)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_ABROOT) {
                        ASSERT(ip->i_afp->if_broot_bytes > 0);
                        ASSERT(ip->i_afp->if_broot != NULL);
                        vecp->i_addr = ip->i_afp->if_broot;
                        vecp->i_len = ip->i_afp->if_broot_bytes;
                        vecp->i_type = XLOG_REG_TYPE_IATTR_BROOT;
                        vecp++;
                        nvecs++;
                        iip->ili_format.ilf_asize = ip->i_afp->if_broot_bytes;
                }
                break;

        case XFS_DINODE_FMT_LOCAL:
                ASSERT(!(iip->ili_format.ilf_fields &
                         (XFS_ILOG_ABROOT | XFS_ILOG_AEXT)));
                if (iip->ili_format.ilf_fields & XFS_ILOG_ADATA) {
                        ASSERT(ip->i_afp->if_bytes > 0);
                        ASSERT(ip->i_afp->if_u1.if_data != NULL);

                        vecp->i_addr = ip->i_afp->if_u1.if_data;
                        /*
                         * Round i_bytes up to a word boundary.
                         * The underlying memory is guaranteed to
                         * to be there by xfs_idata_realloc().
                         */
                        data_bytes = roundup(ip->i_afp->if_bytes, 4);
                        ASSERT((ip->i_afp->if_real_bytes == 0) ||
                               (ip->i_afp->if_real_bytes == data_bytes));
                        vecp->i_len = (int)data_bytes;
                        vecp->i_type = XLOG_REG_TYPE_IATTR_LOCAL;
                        vecp++;
                        nvecs++;
                        iip->ili_format.ilf_asize = (unsigned)data_bytes;
                }
                break;

        default:
                ASSERT(0);
                break;
        }

        ASSERT(nvecs == lip->li_desc->lid_size);
        iip->ili_format.ilf_size = nvecs;
}


/*
 * This is called to pin the inode associated with the inode log
 * item in memory so it cannot be written out.
 */
STATIC void
xfs_inode_item_pin(
        struct xfs_log_item     *lip)
{
        struct xfs_inode        *ip = INODE_ITEM(lip)->ili_inode;

        ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));

        trace_xfs_inode_pin(ip, _RET_IP_);
        atomic_inc(&ip->i_pincount);
}


/*
 * This is called to unpin the inode associated with the inode log
 * item which was previously pinned with a call to xfs_inode_item_pin().
 *
 * Also wake up anyone in xfs_iunpin_wait() if the count goes to 0.
 */
STATIC void
xfs_inode_item_unpin(
        struct xfs_log_item     *lip,
        int                     remove)
{
        struct xfs_inode        *ip = INODE_ITEM(lip)->ili_inode;

        trace_xfs_inode_unpin(ip, _RET_IP_);
        ASSERT(atomic_read(&ip->i_pincount) > 0);
        if (atomic_dec_and_test(&ip->i_pincount))
                wake_up(&ip->i_ipin_wait);
}

/*
 * This is called to attempt to lock the inode associated with this
 * inode log item, in preparation for the push routine which does the actual
 * iflush.  Don't sleep on the inode lock or the flush lock.
 *
 * If the flush lock is already held, indicating that the inode has
 * been or is in the process of being flushed, then (ideally) we'd like to
 * see if the inode's buffer is still incore, and if so give it a nudge.
 * We delay doing so until the pushbuf routine, though, to avoid holding
 * the AIL lock across a call to the blackhole which is the buffer cache.
 * Also we don't want to sleep in any device strategy routines, which can happen
 * if we do the subsequent bawrite in here.
 */
STATIC uint
xfs_inode_item_trylock(
        struct xfs_log_item     *lip)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;

        if (xfs_ipincount(ip) > 0)
                return XFS_ITEM_PINNED;

        if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED))
                return XFS_ITEM_LOCKED;

        if (!xfs_iflock_nowait(ip)) {
                /*
                 * inode has already been flushed to the backing buffer,
                 * leave it locked in shared mode, pushbuf routine will
                 * unlock it.
                 */
                return XFS_ITEM_PUSHBUF;
        }

        /* Stale items should force out the iclog */
        if (ip->i_flags & XFS_ISTALE) {
                xfs_ifunlock(ip);
                /*
                 * we hold the AIL lock - notify the unlock routine of this
                 * so it doesn't try to get the lock again.
                 */
                xfs_iunlock(ip, XFS_ILOCK_SHARED|XFS_IUNLOCK_NONOTIFY);
                return XFS_ITEM_PINNED;
        }

#ifdef DEBUG
        if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
                ASSERT(iip->ili_format.ilf_fields != 0);
                ASSERT(iip->ili_logged == 0);
                ASSERT(lip->li_flags & XFS_LI_IN_AIL);
        }
#endif
        return XFS_ITEM_SUCCESS;
}

/*
 * Unlock the inode associated with the inode log item.
 * Clear the fields of the inode and inode log item that
 * are specific to the current transaction.  If the
 * hold flags is set, do not unlock the inode.
 */
STATIC void
xfs_inode_item_unlock(
        struct xfs_log_item     *lip)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;
        unsigned short          lock_flags;

        ASSERT(iip->ili_inode->i_itemp != NULL);
        ASSERT(xfs_isilocked(iip->ili_inode, XFS_ILOCK_EXCL));

        /*
         * Clear the transaction pointer in the inode.
         */
        ip->i_transp = NULL;

        /*
         * If the inode needed a separate buffer with which to log
         * its extents, then free it now.
         */
        if (iip->ili_extents_buf != NULL) {
                ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS);
                ASSERT(ip->i_d.di_nextents > 0);
                ASSERT(iip->ili_format.ilf_fields & XFS_ILOG_DEXT);
                ASSERT(ip->i_df.if_bytes > 0);
                kmem_free(iip->ili_extents_buf);
                iip->ili_extents_buf = NULL;
        }
        if (iip->ili_aextents_buf != NULL) {
                ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS);
                ASSERT(ip->i_d.di_anextents > 0);
                ASSERT(iip->ili_format.ilf_fields & XFS_ILOG_AEXT);
                ASSERT(ip->i_afp->if_bytes > 0);
                kmem_free(iip->ili_aextents_buf);
                iip->ili_aextents_buf = NULL;
        }

        lock_flags = iip->ili_lock_flags;
        iip->ili_lock_flags = 0;
        if (lock_flags) {
                xfs_iunlock(iip->ili_inode, lock_flags);
                IRELE(iip->ili_inode);
        }
}

/*
 * This is called to find out where the oldest active copy of the inode log
 * item in the on disk log resides now that the last log write of it completed
 * at the given lsn.  Since we always re-log all dirty data in an inode, the
 * latest copy in the on disk log is the only one that matters.  Therefore,
 * simply return the given lsn.
 *
 * If the inode has been marked stale because the cluster is being freed, we
 * don't want to (re-)insert this inode into the AIL. There is a race condition
 * where the cluster buffer may be unpinned before the inode is inserted into
 * the AIL during transaction committed processing. If the buffer is unpinned
 * before the inode item has been committed and inserted, then it is possible
 * for the buffer to be written and IO completions before the inode is inserted
 * into the AIL. In that case, we'd be inserting a clean, stale inode into the
 * AIL which will never get removed. It will, however, get reclaimed which
 * triggers an assert in xfs_inode_free() complaining about freein an inode
 * still in the AIL.
 *
 * To avoid this, return a lower LSN than the one passed in so that the
 * transaction committed code will not move the inode forward in the AIL but
 * will still unpin it properly.
 */
STATIC xfs_lsn_t
xfs_inode_item_committed(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;

        if (xfs_iflags_test(ip, XFS_ISTALE))
                return lsn - 1;
        return lsn;
}

/*
 * This gets called by xfs_trans_push_ail(), when IOP_TRYLOCK
 * failed to get the inode flush lock but did get the inode locked SHARED.
 * Here we're trying to see if the inode buffer is incore, and if so whether it's
 * marked delayed write. If that's the case, we'll promote it and that will
 * allow the caller to write the buffer by triggering the xfsbufd to run.
 */
STATIC void
xfs_inode_item_pushbuf(
        struct xfs_log_item     *lip)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;
        struct xfs_buf          *bp;

        ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));

        /*
         * If a flush is not in progress anymore, chances are that the
         * inode was taken off the AIL. So, just get out.
         */
        if (completion_done(&ip->i_flush) ||
            !(lip->li_flags & XFS_LI_IN_AIL)) {
                xfs_iunlock(ip, XFS_ILOCK_SHARED);
                return;
        }

        bp = xfs_incore(ip->i_mount->m_ddev_targp, iip->ili_format.ilf_blkno,
                        iip->ili_format.ilf_len, XBF_TRYLOCK);

        xfs_iunlock(ip, XFS_ILOCK_SHARED);
        if (!bp)
                return;
        if (XFS_BUF_ISDELAYWRITE(bp))
                xfs_buf_delwri_promote(bp);
        xfs_buf_relse(bp);
}

/*
 * This is called to asynchronously write the inode associated with this
 * inode log item out to disk. The inode will already have been locked by
 * a successful call to xfs_inode_item_trylock().
 */
STATIC void
xfs_inode_item_push(
        struct xfs_log_item     *lip)
{
        struct xfs_inode_log_item *iip = INODE_ITEM(lip);
        struct xfs_inode        *ip = iip->ili_inode;

        ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));
        ASSERT(!completion_done(&ip->i_flush));

        /*
         * Since we were able to lock the inode's flush lock and
         * we found it on the AIL, the inode must be dirty.  This
         * is because the inode is removed from the AIL while still
         * holding the flush lock in xfs_iflush_done().  Thus, if
         * we found it in the AIL and were able to obtain the flush
         * lock without sleeping, then there must not have been
         * anyone in the process of flushing the inode.
         */
        ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) ||
               iip->ili_format.ilf_fields != 0);

        /*
         * Push the inode to it's backing buffer. This will not remove the
         * inode from the AIL - a further push will be required to trigger a
         * buffer push. However, this allows all the dirty inodes to be pushed
         * to the buffer before it is pushed to disk. THe buffer IO completion
         * will pull th einode from the AIL, mark it clean and unlock the flush
         * lock.
         */
        (void) xfs_iflush(ip, 0);
        xfs_iunlock(ip, XFS_ILOCK_SHARED);
}

/*
 * XXX rcc - this one really has to do something.  Probably needs
 * to stamp in a new field in the incore inode.
 */
STATIC void
xfs_inode_item_committing(
        struct xfs_log_item     *lip,
        xfs_lsn_t               lsn)
{
        INODE_ITEM(lip)->ili_last_lsn = lsn;
}

/*
 * This is the ops vector shared by all buf log items.
 */
static struct xfs_item_ops xfs_inode_item_ops = {
        .iop_size       = xfs_inode_item_size,
        .iop_format     = xfs_inode_item_format,
        .iop_pin        = xfs_inode_item_pin,
        .iop_unpin      = xfs_inode_item_unpin,
        .iop_trylock    = xfs_inode_item_trylock,
        .iop_unlock     = xfs_inode_item_unlock,
        .iop_committed  = xfs_inode_item_committed,
        .iop_push       = xfs_inode_item_push,
        .iop_pushbuf    = xfs_inode_item_pushbuf,
        .iop_committing = xfs_inode_item_committing
};


/*
 * Initialize the inode log item for a newly allocated (in-core) inode.
 */
void
xfs_inode_item_init(
        struct xfs_inode        *ip,
        struct xfs_mount        *mp)
{
        struct xfs_inode_log_item *iip;

        ASSERT(ip->i_itemp == NULL);
        iip = ip->i_itemp = kmem_zone_zalloc(xfs_ili_zone, KM_SLEEP);

        iip->ili_inode = ip;
        xfs_log_item_init(mp, &iip->ili_item, XFS_LI_INODE,
                                                &xfs_inode_item_ops);
        iip->ili_format.ilf_type = XFS_LI_INODE;
        iip->ili_format.ilf_ino = ip->i_ino;
        iip->ili_format.ilf_blkno = ip->i_imap.im_blkno;
        iip->ili_format.ilf_len = ip->i_imap.im_len;
        iip->ili_format.ilf_boffset = ip->i_imap.im_boffset;
}

/*
 * Free the inode log item and any memory hanging off of it.
 */
void
xfs_inode_item_destroy(
        xfs_inode_t     *ip)
{
#ifdef XFS_TRANS_DEBUG
        if (ip->i_itemp->ili_root_size != 0) {
                kmem_free(ip->i_itemp->ili_orig_root);
        }
#endif
        kmem_zone_free(xfs_ili_zone, ip->i_itemp);
}


/*
 * This is the inode flushing I/O completion routine.  It is called
 * from interrupt level when the buffer containing the inode is
 * flushed to disk.  It is responsible for removing the inode item
 * from the AIL if it has not been re-logged, and unlocking the inode's
 * flush lock.
 *
 * To reduce AIL lock traffic as much as possible, we scan the buffer log item
 * list for other inodes that will run this function. We remove them from the
 * buffer list so we can process all the inode IO completions in one AIL lock
 * traversal.
 */
void
xfs_iflush_done(
        struct xfs_buf          *bp,
        struct xfs_log_item     *lip)
{
        struct xfs_inode_log_item *iip;
        struct xfs_log_item     *blip;
        struct xfs_log_item     *next;
        struct xfs_log_item     *prev;
        struct xfs_ail          *ailp = lip->li_ailp;
        int                     need_ail = 0;

        /*
         * Scan the buffer IO completions for other inodes being completed and
         * attach them to the current inode log item.
         */
        blip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
        prev = NULL;
        while (blip != NULL) {
                if (lip->li_cb != xfs_iflush_done) {
                        prev = blip;
                        blip = blip->li_bio_list;
                        continue;
                }

                /* remove from list */
                next = blip->li_bio_list;
                if (!prev) {
                        XFS_BUF_SET_FSPRIVATE(bp, next);
                } else {
                        prev->li_bio_list = next;
                }

                /* add to current list */
                blip->li_bio_list = lip->li_bio_list;
                lip->li_bio_list = blip;

                /*
                 * while we have the item, do the unlocked check for needing
                 * the AIL lock.
                 */
                iip = INODE_ITEM(blip);
                if (iip->ili_logged && blip->li_lsn == iip->ili_flush_lsn)
                        need_ail++;

                blip = next;
        }

        /* make sure we capture the state of the initial inode. */
        iip = INODE_ITEM(lip);
        if (iip->ili_logged && lip->li_lsn == iip->ili_flush_lsn)
                need_ail++;

        /*
         * We only want to pull the item from the AIL if it is
         * actually there and its location in the log has not
         * changed since we started the flush.  Thus, we only bother
         * if the ili_logged flag is set and the inode's lsn has not
         * changed.  First we check the lsn outside
         * the lock since it's cheaper, and then we recheck while
         * holding the lock before removing the inode from the AIL.
         */
        if (need_ail) {
                struct xfs_log_item *log_items[need_ail];
                int i = 0;
                spin_lock(&ailp->xa_lock);
                for (blip = lip; blip; blip = blip->li_bio_list) {
                        iip = INODE_ITEM(blip);
                        if (iip->ili_logged &&
                            blip->li_lsn == iip->ili_flush_lsn) {
                                log_items[i++] = blip;
                        }
                        ASSERT(i <= need_ail);
                }
                /* xfs_trans_ail_delete_bulk() drops the AIL lock. */
                xfs_trans_ail_delete_bulk(ailp, log_items, i);
        }


        /*
         * clean up and unlock the flush lock now we are done. We can clear the
         * ili_last_fields bits now that we know that the data corresponding to
         * them is safely on disk.
         */
        for (blip = lip; blip; blip = next) {
                next = blip->li_bio_list;
                blip->li_bio_list = NULL;

                iip = INODE_ITEM(blip);
                iip->ili_logged = 0;
                iip->ili_last_fields = 0;
                xfs_ifunlock(iip->ili_inode);
        }
}

/*
 * This is the inode flushing abort routine.  It is called
 * from xfs_iflush when the filesystem is shutting down to clean
 * up the inode state.
 * It is responsible for removing the inode item
 * from the AIL if it has not been re-logged, and unlocking the inode's
 * flush lock.
 */
void
xfs_iflush_abort(
        xfs_inode_t             *ip)
{
        xfs_inode_log_item_t    *iip = ip->i_itemp;

        iip = ip->i_itemp;
        if (iip) {
                struct xfs_ail  *ailp = iip->ili_item.li_ailp;
                if (iip->ili_item.li_flags & XFS_LI_IN_AIL) {
                        spin_lock(&ailp->xa_lock);
                        if (iip->ili_item.li_flags & XFS_LI_IN_AIL) {
                                /* xfs_trans_ail_delete() drops the AIL lock. */
                                xfs_trans_ail_delete(ailp, (xfs_log_item_t *)iip);
                        } else
                                spin_unlock(&ailp->xa_lock);
                }
                iip->ili_logged = 0;
                /*
                 * Clear the ili_last_fields bits now that we know that the
                 * data corresponding to them is safely on disk.
                 */
                iip->ili_last_fields = 0;
                /*
                 * Clear the inode logging fields so no more flushes are
                 * attempted.
                 */
                iip->ili_format.ilf_fields = 0;
        }
        /*
         * Release the inode's flush lock since we're done with it.
         */
        xfs_ifunlock(ip);
}

void
xfs_istale_done(
        struct xfs_buf          *bp,
        struct xfs_log_item     *lip)
{
        xfs_iflush_abort(INODE_ITEM(lip)->ili_inode);
}

/*
 * convert an xfs_inode_log_format struct from either 32 or 64 bit versions
 * (which can have different field alignments) to the native version
 */
int
xfs_inode_item_format_convert(
        xfs_log_iovec_t         *buf,
        xfs_inode_log_format_t  *in_f)
{
        if (buf->i_len == sizeof(xfs_inode_log_format_32_t)) {
                xfs_inode_log_format_32_t *in_f32 = buf->i_addr;

                in_f->ilf_type = in_f32->ilf_type;
                in_f->ilf_size = in_f32->ilf_size;
                in_f->ilf_fields = in_f32->ilf_fields;
                in_f->ilf_asize = in_f32->ilf_asize;
                in_f->ilf_dsize = in_f32->ilf_dsize;
                in_f->ilf_ino = in_f32->ilf_ino;
                /* copy biggest field of ilf_u */
                memcpy(in_f->ilf_u.ilfu_uuid.__u_bits,
                       in_f32->ilf_u.ilfu_uuid.__u_bits,
                       sizeof(uuid_t));
                in_f->ilf_blkno = in_f32->ilf_blkno;
                in_f->ilf_len = in_f32->ilf_len;
                in_f->ilf_boffset = in_f32->ilf_boffset;
                return 0;
        } else if (buf->i_len == sizeof(xfs_inode_log_format_64_t)){
                xfs_inode_log_format_64_t *in_f64 = buf->i_addr;

                in_f->ilf_type = in_f64->ilf_type;
                in_f->ilf_size = in_f64->ilf_size;
                in_f->ilf_fields = in_f64->ilf_fields;
                in_f->ilf_asize = in_f64->ilf_asize;
                in_f->ilf_dsize = in_f64->ilf_dsize;
                in_f->ilf_ino = in_f64->ilf_ino;
                /* copy biggest field of ilf_u */
                memcpy(in_f->ilf_u.ilfu_uuid.__u_bits,
                       in_f64->ilf_u.ilfu_uuid.__u_bits,
                       sizeof(uuid_t));
                in_f->ilf_blkno = in_f64->ilf_blkno;
                in_f->ilf_len = in_f64->ilf_len;
                in_f->ilf_boffset = in_f64->ilf_boffset;
                return 0;
        }
        return EFSCORRUPTED;
}