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Commit 980802e3 authored by Trond Myklebust's avatar Trond Myklebust Committed by Linus Torvalds
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[PATCH] NFS: Ensure that we revalidate the cached file length for llseek(SEEK_END) 



This fixes a data corruption error for mail delivery applications that
expect to be able to do posix locking and then append writes on NFS.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c22fa3ac

fs/nfs/file.c

+41 −1
Original line number Original line Diff line number Diff line
@@ -37,6 +37,7 @@ 




static int nfs_file_open(struct inode *, struct file *);

static int nfs_file_open(struct inode *, struct file *);

static int nfs_file_release(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 int  nfs_file_mmap(struct file *, struct vm_area_struct *);

static ssize_t nfs_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);

static ssize_t nfs_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);

static ssize_t nfs_file_read(struct kiocb *, char __user *, size_t, loff_t);

static ssize_t nfs_file_read(struct kiocb *, char __user *, size_t, loff_t);
@@ -48,7 +49,7 @@ 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_flock(struct file *filp, int cmd, struct file_lock *fl);





struct file_operations nfs_file_operations = {

struct file_operations nfs_file_operations = {

	.llseek		= remote_llseek,

	.llseek		= nfs_file_llseek,

	.read		= do_sync_read,

	.read		= do_sync_read,

	.write		= do_sync_write,

	.write		= do_sync_write,

	.aio_read		= nfs_file_read,

	.aio_read		= nfs_file_read,
@@ -114,6 +115,45 @@ nfs_file_release(struct inode *inode, struct file *filp) 
	return NFS_PROTO(inode)->file_release(inode, filp);

	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;

	return nfs_revalidate_inode(server, inode);

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 == 2) {

		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);

}



/*

/*

 * Flush all dirty pages, and check for write errors.

 * Flush all dirty pages, and check for write errors.

 *

 *