3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o <tytso@xxxxxxx> commit c7df4a1ecb8579838ec8c56b2bb6a6716e974f37 upstream. If the file system is corrupted such that a file's i_links_count is too small, then it's possible that when unlinking that file, i_nlink will already be zero. Previously we were working around this kind of corruption by forcing i_nlink to one; but we were doing this before trying to delete the directory entry --- and if the file system is corrupted enough that ext4_delete_entry() fails, then we exit with i_nlink elevated, and this causes the orphan inode list handling to be FUBAR'ed, such that when we unmount the file system, the orphan inode list can get corrupted. A better way to fix this is to simply skip trying to call drop_nlink() if i_nlink is already zero, thus moving the check to the place where it makes the most sense. https://bugzilla.kernel.org/show_bug.cgi?id=205433 Link: https://lore.kernel.org/r/20191112032903.8828-1-tytso@xxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx> [bwh: Backported to 3.16: Log message and function are different] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2830,19 +2830,18 @@ static int ext4_unlink(struct inode *dir if (IS_DIRSYNC(dir)) ext4_handle_sync(handle); - if (!inode->i_nlink) { - ext4_warning(inode->i_sb, - "Deleting nonexistent file (%lu), %d", - inode->i_ino, inode->i_nlink); - set_nlink(inode, 1); - } retval = ext4_delete_entry(handle, dir, de, bh); if (retval) goto end_unlink; dir->i_ctime = dir->i_mtime = ext4_current_time(dir); ext4_update_dx_flag(dir); ext4_mark_inode_dirty(handle, dir); - drop_nlink(inode); + if (inode->i_nlink == 0) + ext4_warning(inode->i_sb, + "Deleting nonexistent file (%lu), %d", + inode->i_ino, inode->i_nlink); + else + drop_nlink(inode); if (!inode->i_nlink) ext4_orphan_add(handle, inode); inode->i_ctime = ext4_current_time(inode);
