exportfs: remove old methods

[wrt350n-kernel.git] / fs / nfs / file.c

/*
 *  linux/fs/nfs/file.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  Changes Copyright (C) 1994 by Florian La Roche
 *   - Do not copy data too often around in the kernel.
 *   - In nfs_file_read the return value of kmalloc wasn't checked.
 *   - Put in a better version of read look-ahead buffering. Original idea
 *     and implementation by Wai S Kok elekokws@ee.nus.sg.
 *
 *  Expire cache on write to a file by Wai S Kok (Oct 1994).
 *
 *  Total rewrite of read side for new NFS buffer cache.. Linus.
 *
 *  nfs regular file handling functions
 */

#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>
#include <linux/aio.h>

#include <asm/uaccess.h>
#include <asm/system.h>

#include "delegation.h"
#include "internal.h"
#include "iostat.h"

#define NFSDBG_FACILITY         NFSDBG_FILE

static int nfs_file_open(struct inode *, struct file *);
static int nfs_file_release(struct inode *, struct file *);
static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
                                        struct pipe_inode_info *pipe,
                                        size_t count, unsigned int flags);
static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
                                unsigned long nr_segs, loff_t pos);
static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
                                unsigned long nr_segs, loff_t pos);
static int  nfs_file_flush(struct file *, fl_owner_t id);
static int  nfs_fsync(struct file *, struct dentry *dentry, int datasync);
static int nfs_check_flags(int flags);
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);

static struct vm_operations_struct nfs_file_vm_ops;

const struct file_operations nfs_file_operations = {
        .llseek         = nfs_file_llseek,
        .read           = do_sync_read,
        .write          = do_sync_write,
        .aio_read       = nfs_file_read,
        .aio_write      = nfs_file_write,
        .mmap           = nfs_file_mmap,
        .open           = nfs_file_open,
        .flush          = nfs_file_flush,
        .release        = nfs_file_release,
        .fsync          = nfs_fsync,
        .lock           = nfs_lock,
        .flock          = nfs_flock,
        .splice_read    = nfs_file_splice_read,
        .check_flags    = nfs_check_flags,
        .setlease       = nfs_setlease,
};

const struct inode_operations nfs_file_inode_operations = {
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
};

#ifdef CONFIG_NFS_V3
const struct inode_operations nfs3_file_inode_operations = {
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
        .listxattr      = nfs3_listxattr,
        .getxattr       = nfs3_getxattr,
        .setxattr       = nfs3_setxattr,
        .removexattr    = nfs3_removexattr,
};
#endif  /* CONFIG_NFS_v3 */

/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode)     (0)
#endif

static int nfs_check_flags(int flags)
{
        if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
                return -EINVAL;

        return 0;
}

/*
 * Open file
 */
static int
nfs_file_open(struct inode *inode, struct file *filp)
{
        int res;

        res = nfs_check_flags(filp->f_flags);
        if (res)
                return res;

        nfs_inc_stats(inode, NFSIOS_VFSOPEN);
        lock_kernel();
        res = NFS_PROTO(inode)->file_open(inode, filp);
        unlock_kernel();
        return res;
}

static int
nfs_file_release(struct inode *inode, struct file *filp)
{
        /* Ensure that dirty pages are flushed out with the right creds */
        if (filp->f_mode & FMODE_WRITE)
                nfs_wb_all(filp->f_path.dentry->d_inode);
        nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
        return NFS_PROTO(inode)->file_release(inode, filp);
}

/**
 * nfs_revalidate_size - Revalidate the file size
 * @inode - pointer to inode struct
 * @file - pointer to struct file
 *
 * Revalidates the file length. This is basically a wrapper around
 * nfs_revalidate_inode() that takes into account the fact that we may
 * have cached writes (in which case we don't care about the server's
 * idea of what the file length is), or O_DIRECT (in which case we
 * shouldn't trust the cache).
 */
static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_inode *nfsi = NFS_I(inode);

        if (server->flags & NFS_MOUNT_NOAC)
                goto force_reval;
        if (filp->f_flags & O_DIRECT)
                goto force_reval;
        if (nfsi->npages != 0)
                return 0;
        if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
                return 0;
force_reval:
        return __nfs_revalidate_inode(server, inode);
}

static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
{
        /* origin == SEEK_END => we must revalidate the cached file length */
        if (origin == SEEK_END) {
                struct inode *inode = filp->f_mapping->host;
                int retval = nfs_revalidate_file_size(inode, filp);
                if (retval < 0)
                        return (loff_t)retval;
        }
        return remote_llseek(filp, offset, origin);
}

/*
 * Helper for nfs_file_flush() and nfs_fsync()
 *
 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
 * disk, but it retrieves and clears ctx->error after synching, despite
 * the two being set at the same time in nfs_context_set_write_error().
 * This is because the former is used to notify the _next_ call to
 * nfs_file_write() that a write error occured, and hence cause it to
 * fall back to doing a synchronous write.
 */
static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
{
        int have_error, status;
        int ret = 0;

        have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
        status = nfs_wb_all(inode);
        have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
        if (have_error)
                ret = xchg(&ctx->error, 0);
        if (!ret)
                ret = status;
        return ret;
}

/*
 * Flush all dirty pages, and check for write errors.
 *
 */
static int
nfs_file_flush(struct file *file, fl_owner_t id)
{
        struct nfs_open_context *ctx = nfs_file_open_context(file);
        struct inode    *inode = file->f_path.dentry->d_inode;
        int             status;

        dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);

        if ((file->f_mode & FMODE_WRITE) == 0)
                return 0;
        nfs_inc_stats(inode, NFSIOS_VFSFLUSH);

        /* Ensure that data+attribute caches are up to date after close() */
        status = nfs_do_fsync(ctx, inode);
        if (!status)
                nfs_revalidate_inode(NFS_SERVER(inode), inode);
        return status;
}

static ssize_t
nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
                unsigned long nr_segs, loff_t pos)
{
        struct dentry * dentry = iocb->ki_filp->f_path.dentry;
        struct inode * inode = dentry->d_inode;
        ssize_t result;
        size_t count = iov_length(iov, nr_segs);

#ifdef CONFIG_NFS_DIRECTIO
        if (iocb->ki_filp->f_flags & O_DIRECT)
                return nfs_file_direct_read(iocb, iov, nr_segs, pos);
#endif

        dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
                dentry->d_parent->d_name.name, dentry->d_name.name,
                (unsigned long) count, (unsigned long) pos);

        result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
        nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
        if (!result)
                result = generic_file_aio_read(iocb, iov, nr_segs, pos);
        return result;
}

static ssize_t
nfs_file_splice_read(struct file *filp, loff_t *ppos,
                     struct pipe_inode_info *pipe, size_t count,
                     unsigned int flags)
{
        struct dentry *dentry = filp->f_path.dentry;
        struct inode *inode = dentry->d_inode;
        ssize_t res;

        dfprintk(VFS, "nfs: splice_read(%s/%s, %lu@%Lu)\n",
                dentry->d_parent->d_name.name, dentry->d_name.name,
                (unsigned long) count, (unsigned long long) *ppos);

        res = nfs_revalidate_mapping(inode, filp->f_mapping);
        if (!res)
                res = generic_file_splice_read(filp, ppos, pipe, count, flags);
        return res;
}

static int
nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
{
        struct dentry *dentry = file->f_path.dentry;
        struct inode *inode = dentry->d_inode;
        int     status;

        dfprintk(VFS, "nfs: mmap(%s/%s)\n",
                dentry->d_parent->d_name.name, dentry->d_name.name);

        status = nfs_revalidate_mapping(inode, file->f_mapping);
        if (!status) {
                vma->vm_ops = &nfs_file_vm_ops;
                vma->vm_flags |= VM_CAN_NONLINEAR;
                file_accessed(file);
        }
        return status;
}

/*
 * Flush any dirty pages for this process, and check for write errors.
 * The return status from this call provides a reliable indication of
 * whether any write errors occurred for this process.
 */
static int
nfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
        struct nfs_open_context *ctx = nfs_file_open_context(file);
        struct inode *inode = dentry->d_inode;

        dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);

        nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
        return nfs_do_fsync(ctx, inode);
}

/*
 * This does the "real" work of the write. We must allocate and lock the
 * page to be sent back to the generic routine, which then copies the
 * data from user space.
 *
 * If the writer ends up delaying the write, the writer needs to
 * increment the page use counts until he is done with the page.
 */
static int nfs_write_begin(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned flags,
                        struct page **pagep, void **fsdata)
{
        int ret;
        pgoff_t index;
        struct page *page;
        index = pos >> PAGE_CACHE_SHIFT;

        page = __grab_cache_page(mapping, index);
        if (!page)
                return -ENOMEM;
        *pagep = page;

        ret = nfs_flush_incompatible(file, page);
        if (ret) {
                unlock_page(page);
                page_cache_release(page);
        }
        return ret;
}

static int nfs_write_end(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned copied,
                        struct page *page, void *fsdata)
{
        unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
        int status;

        lock_kernel();
        status = nfs_updatepage(file, page, offset, copied);
        unlock_kernel();

        unlock_page(page);
        page_cache_release(page);

        return status < 0 ? status : copied;
}

static void nfs_invalidate_page(struct page *page, unsigned long offset)
{
        if (offset != 0)
                return;
        /* Cancel any unstarted writes on this page */
        nfs_wb_page_cancel(page->mapping->host, page);
}

static int nfs_release_page(struct page *page, gfp_t gfp)
{
        /* If PagePrivate() is set, then the page is not freeable */
        return 0;
}

static int nfs_launder_page(struct page *page)
{
        return nfs_wb_page(page->mapping->host, page);
}

const struct address_space_operations nfs_file_aops = {
        .readpage = nfs_readpage,
        .readpages = nfs_readpages,
        .set_page_dirty = __set_page_dirty_nobuffers,
        .writepage = nfs_writepage,
        .writepages = nfs_writepages,
        .write_begin = nfs_write_begin,
        .write_end = nfs_write_end,
        .invalidatepage = nfs_invalidate_page,
        .releasepage = nfs_release_page,
#ifdef CONFIG_NFS_DIRECTIO
        .direct_IO = nfs_direct_IO,
#endif
        .launder_page = nfs_launder_page,
};

static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
{
        struct file *filp = vma->vm_file;
        unsigned pagelen;
        int ret = -EINVAL;
        void *fsdata;
        struct address_space *mapping;
        loff_t offset;

        lock_page(page);
        mapping = page->mapping;
        if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping) {
                unlock_page(page);
                return -EINVAL;
        }
        pagelen = nfs_page_length(page);
        offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
        unlock_page(page);

        /*
         * we can use mapping after releasing the page lock, because:
         * we hold mmap_sem on the fault path, which should pin the vma
         * which should pin the file, which pins the dentry which should
         * hold a reference on inode.
         */

        if (pagelen) {
                struct page *page2 = NULL;
                ret = nfs_write_begin(filp, mapping, offset, pagelen,
                                0, &page2, &fsdata);
                if (!ret)
                        ret = nfs_write_end(filp, mapping, offset, pagelen,
                                        pagelen, page2, fsdata);
        }
        return ret;
}

static struct vm_operations_struct nfs_file_vm_ops = {
        .fault = filemap_fault,
        .page_mkwrite = nfs_vm_page_mkwrite,
};

static int nfs_need_sync_write(struct file *filp, struct inode *inode)
{
        struct nfs_open_context *ctx;

        if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
                return 1;
        ctx = nfs_file_open_context(filp);
        if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
                return 1;
        return 0;
}

static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
                                unsigned long nr_segs, loff_t pos)
{
        struct dentry * dentry = iocb->ki_filp->f_path.dentry;
        struct inode * inode = dentry->d_inode;
        ssize_t result;
        size_t count = iov_length(iov, nr_segs);

#ifdef CONFIG_NFS_DIRECTIO
        if (iocb->ki_filp->f_flags & O_DIRECT)
                return nfs_file_direct_write(iocb, iov, nr_segs, pos);
#endif

        dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%Ld)\n",
                dentry->d_parent->d_name.name, dentry->d_name.name,
                inode->i_ino, (unsigned long) count, (long long) pos);

        result = -EBUSY;
        if (IS_SWAPFILE(inode))
                goto out_swapfile;
        /*
         * O_APPEND implies that we must revalidate the file length.
         */
        if (iocb->ki_filp->f_flags & O_APPEND) {
                result = nfs_revalidate_file_size(inode, iocb->ki_filp);
                if (result)
                        goto out;
        }

        result = count;
        if (!count)
                goto out;

        nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
        result = generic_file_aio_write(iocb, iov, nr_segs, pos);
        /* Return error values for O_SYNC and IS_SYNC() */
        if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
                int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
                if (err < 0)
                        result = err;
        }
out:
        return result;

out_swapfile:
        printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
        goto out;
}

static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
{
        struct inode *inode = filp->f_mapping->host;
        int status = 0;

        lock_kernel();
        /* Try local locking first */
        posix_test_lock(filp, fl);
        if (fl->fl_type != F_UNLCK) {
                /* found a conflict */
                goto out;
        }

        if (nfs_have_delegation(inode, FMODE_READ))
                goto out_noconflict;

        if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
                goto out_noconflict;

        status = NFS_PROTO(inode)->lock(filp, cmd, fl);
out:
        unlock_kernel();
        return status;
out_noconflict:
        fl->fl_type = F_UNLCK;
        goto out;
}

static int do_vfs_lock(struct file *file, struct file_lock *fl)
{
        int res = 0;
        switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
                case FL_POSIX:
                        res = posix_lock_file_wait(file, fl);
                        break;
                case FL_FLOCK:
                        res = flock_lock_file_wait(file, fl);
                        break;
                default:
                        BUG();
        }
        if (res < 0)
                dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
                        " - error %d!\n",
                                __FUNCTION__, res);
        return res;
}

static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
{
        struct inode *inode = filp->f_mapping->host;
        int status;

        /*
         * Flush all pending writes before doing anything
         * with locks..
         */
        nfs_sync_mapping(filp->f_mapping);

        /* NOTE: special case
         *      If we're signalled while cleaning up locks on process exit, we
         *      still need to complete the unlock.
         */
        lock_kernel();
        /* Use local locking if mounted with "-onolock" */
        if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
                status = NFS_PROTO(inode)->lock(filp, cmd, fl);
        else
                status = do_vfs_lock(filp, fl);
        unlock_kernel();
        return status;
}

static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
{
        struct inode *inode = filp->f_mapping->host;
        int status;

        /*
         * Flush all pending writes before doing anything
         * with locks..
         */
        status = nfs_sync_mapping(filp->f_mapping);
        if (status != 0)
                goto out;

        lock_kernel();
        /* Use local locking if mounted with "-onolock" */
        if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) {
                status = NFS_PROTO(inode)->lock(filp, cmd, fl);
                /* If we were signalled we still need to ensure that
                 * we clean up any state on the server. We therefore
                 * record the lock call as having succeeded in order to
                 * ensure that locks_remove_posix() cleans it out when
                 * the process exits.
                 */
                if (status == -EINTR || status == -ERESTARTSYS)
                        do_vfs_lock(filp, fl);
        } else
                status = do_vfs_lock(filp, fl);
        unlock_kernel();
        if (status < 0)
                goto out;
        /*
         * Make sure we clear the cache whenever we try to get the lock.
         * This makes locking act as a cache coherency point.
         */
        nfs_sync_mapping(filp->f_mapping);
        nfs_zap_caches(inode);
out:
        return status;
}

/*
 * Lock a (portion of) a file
 */
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
{
        struct inode * inode = filp->f_mapping->host;

        dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
                        inode->i_sb->s_id, inode->i_ino,
                        fl->fl_type, fl->fl_flags,
                        (long long)fl->fl_start, (long long)fl->fl_end);
        nfs_inc_stats(inode, NFSIOS_VFSLOCK);

        /* No mandatory locks over NFS */
        if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
                return -ENOLCK;

        if (IS_GETLK(cmd))
                return do_getlk(filp, cmd, fl);
        if (fl->fl_type == F_UNLCK)
                return do_unlk(filp, cmd, fl);
        return do_setlk(filp, cmd, fl);
}

/*
 * Lock a (portion of) a file
 */
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
{
        dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
                        filp->f_path.dentry->d_inode->i_sb->s_id,
                        filp->f_path.dentry->d_inode->i_ino,
                        fl->fl_type, fl->fl_flags);

        /*
         * No BSD flocks over NFS allowed.
         * Note: we could try to fake a POSIX lock request here by
         * using ((u32) filp | 0x80000000) or some such as the pid.
         * Not sure whether that would be unique, though, or whether
         * that would break in other places.
         */
        if (!(fl->fl_flags & FL_FLOCK))
                return -ENOLCK;

        /* We're simulating flock() locks using posix locks on the server */
        fl->fl_owner = (fl_owner_t)filp;
        fl->fl_start = 0;
        fl->fl_end = OFFSET_MAX;

        if (fl->fl_type == F_UNLCK)
                return do_unlk(filp, cmd, fl);
        return do_setlk(filp, cmd, fl);
}

static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
{
        /*
         * There is no protocol support for leases, so we have no way
         * to implement them correctly in the face of opens by other
         * clients.
         */
        return -EINVAL;
}