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authorTrond Myklebust <Trond.Myklebust@netapp.com>2005-06-13 11:14:01 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-13 10:33:02 -0700
commit980802e311088fda56c16650589faa4597c695fb (patch)
tree37092823ea5ad1203253ee5e54e7c9631df4087d /fs/nfs/file.c
parentc22fa3acbc2ef79ea57217643f6cd6d226963069 (diff)
downloadop-kernel-dev-980802e311088fda56c16650589faa4597c695fb.zip
op-kernel-dev-980802e311088fda56c16650589faa4597c695fb.tar.gz
[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: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/nfs/file.c')
-rw-r--r--fs/nfs/file.c42
1 files changed, 41 insertions, 1 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index f06eee6..55c9075 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -37,6 +37,7 @@
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_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);
@@ -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);
struct file_operations nfs_file_operations = {
- .llseek = remote_llseek,
+ .llseek = nfs_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.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);
}
+/**
+ * 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.
*
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