diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2021-08-20 23:44:17 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-22 11:41:16 +0200 |
| commit | 69d82df68fbc5e368820123200d7b88f6c058350 (patch) | |
| tree | e5ff87948630801a87382ff16395951238d21acd /fs | |
| parent | cbc3014d0d917ba60a8ca3938316ef022ef11f8a (diff) | |
ext4: fix race writing to an inline_data file while its xattrs are changing
commit a54c4613dac1500b40e4ab55199f7c51f028e848 upstream.
The location of the system.data extended attribute can change whenever
xattr_sem is not taken. So we need to recalculate the i_inline_off
field since it mgiht have changed between ext4_write_begin() and
ext4_write_end().
This means that caching i_inline_off is probably not helpful, so in
the long run we should probably get rid of it and shrink the in-memory
ext4 inode slightly, but let's fix the race the simple way for now.
Cc: stable@kernel.org
Fixes: f19d5870cbf72 ("ext4: add normal write support for inline data")
Reported-by: syzbot+13146364637c7363a7de@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/inline.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c index df585267d3c2..6f5e292e86f7 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -746,6 +746,12 @@ int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len, ext4_write_lock_xattr(inode, &no_expand); BUG_ON(!ext4_has_inline_data(inode)); + /* + * ei->i_inline_off may have changed since ext4_write_begin() + * called ext4_try_to_write_inline_data() + */ + (void) ext4_find_inline_data_nolock(inode); + kaddr = kmap_atomic(page); ext4_write_inline_data(inode, &iloc, kaddr, pos, len); kunmap_atomic(kaddr); |