diff options
| author | Scott Mayhew <smayhew@redhat.com> | 2014-01-17 15:12:05 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-13 13:55:33 -0800 |
| commit | 2591ac9037720a8d6de35734912ae5b86b011546 (patch) | |
| tree | 8b0420aeb8425dd5aa95652cc59e2b16324d0c8f /fs | |
| parent | f1e432ef9b915522fe16467221d86254ba6f9b5e (diff) | |
nfs: always make sure page is up-to-date before extending a write to cover the entire page
commit 263b4509ec4d47e0da3e753f85a39ea12d1eff24 upstream.
We should always make sure the cached page is up-to-date when we're
determining whether we can extend a write to cover the full page -- even
if we've received a write delegation from the server.
Commit c7559663 added logic to skip this check if we have a write
delegation, which can lead to data corruption such as the following
scenario if client B receives a write delegation from the NFS server:
Client A:
# echo 123456789 > /mnt/file
Client B:
# echo abcdefghi >> /mnt/file
# cat /mnt/file
0�D0�abcdefghi
Just because we hold a write delegation doesn't mean that we've read in
the entire page contents.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/write.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c index c1d548211c31..6a850381b23b 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -922,19 +922,20 @@ out: * extend the write to cover the entire page in order to avoid fragmentation * inefficiencies. * - * If the file is opened for synchronous writes or if we have a write delegation - * from the server then we can just skip the rest of the checks. + * If the file is opened for synchronous writes then we can just skip the rest + * of the checks. */ static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode) { if (file->f_flags & O_DSYNC) return 0; + if (!nfs_write_pageuptodate(page, inode)) + return 0; if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) return 1; - if (nfs_write_pageuptodate(page, inode) && (inode->i_flock == NULL || - (inode->i_flock->fl_start == 0 && + if (inode->i_flock == NULL || (inode->i_flock->fl_start == 0 && inode->i_flock->fl_end == OFFSET_MAX && - inode->i_flock->fl_type != F_RDLCK))) + inode->i_flock->fl_type != F_RDLCK)) return 1; return 0; } |