From: Andrew Morton Port a090d9132c1e53e3517111123680c15afb25c0a4 into ext2: All modifications of ->i_flags in inodes that might be visible to somebody else must be under ->i_mutex. That patch fixes ext2 ioctl() setting S_APPEND. Cc: Al Viro Signed-off-by: Andrew Morton --- fs/ext2/ioctl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff -puN fs/ext2/ioctl.c~protect-ext2-ioctl-modifying-append_only-immutable-etc-with-i_mutex fs/ext2/ioctl.c --- a/fs/ext2/ioctl.c~protect-ext2-ioctl-modifying-append_only-immutable-etc-with-i_mutex +++ a/fs/ext2/ioctl.c @@ -44,6 +44,7 @@ int ext2_ioctl (struct inode * inode, st if (!S_ISDIR(inode->i_mode)) flags &= ~EXT2_DIRSYNC_FL; + mutex_lock(&inode->i_mutex); oldflags = ei->i_flags; /* @@ -53,13 +54,16 @@ int ext2_ioctl (struct inode * inode, st * This test looks nicer. Thanks to Pauline Middelink */ if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) { - if (!capable(CAP_LINUX_IMMUTABLE)) + if (!capable(CAP_LINUX_IMMUTABLE)) { + mutex_unlock(&inode->i_mutex); return -EPERM; + } } flags = flags & EXT2_FL_USER_MODIFIABLE; flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE; ei->i_flags = flags; + mutex_unlock(&inode->i_mutex); ext2_set_inode_flags(inode); inode->i_ctime = CURRENT_TIME_SEC; _