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| author | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2011-04-13 10:31:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-04-22 08:50:00 -0700 |
| commit | 165ed2c6017e420a5b640b918162b7729c5ef3ab (patch) | |
| tree | d12a04c4c8e1f5e329ca11dda2244eb3b1e27821 | |
| parent | 6f70a0f2754aa565b1b05366e454929d4086d2a8 (diff) | |
| download | lwn-165ed2c6017e420a5b640b918162b7729c5ef3ab.tar.gz lwn-165ed2c6017e420a5b640b918162b7729c5ef3ab.zip | |
UBIFS: fix oops when R/O file-system is fsync'ed
commit 78530bf7f2559b317c04991b52217c1608d5a58d upstream.
This patch fixes severe UBIFS bug: UBIFS oopses when we 'fsync()' an
file on R/O-mounter file-system. We (the UBIFS authors) incorrectly
thought that VFS would not propagate 'fsync()' down to the file-system
if it is read-only, but this is not the case.
It is easy to exploit this bug using the following simple perl script:
use strict;
use File::Sync qw(fsync sync);
die "File path is not specified" if not defined $ARGV[0];
my $path = $ARGV[0];
open FILE, "<", "$path" or die "Cannot open $path: $!";
fsync(\*FILE) or die "cannot fsync $path: $!";
close FILE or die "Cannot close $path: $!";
Thanks to Reuben Dowle <Reuben.Dowle@navico.com> for reporting about this
issue.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reported-by: Reuben Dowle <Reuben.Dowle@navico.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/ubifs/file.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 16a6444330ec..98ae58cdbd41 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1311,6 +1311,9 @@ int ubifs_fsync(struct file *file, struct dentry *dentry, int datasync) dbg_gen("syncing inode %lu", inode->i_ino); + if (inode->i_sb->s_flags & MS_RDONLY) + return 0; + /* * VFS has already synchronized dirty pages for this inode. Synchronize * the inode unless this is a 'datasync()' call. |