From: Theodore Ts'o tytso@mit.edu
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 --- fs/ext4/inline.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -756,6 +756,12 @@ int ext4_write_inline_data_end(struct in 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);