ext4: add lockdep annotations for i_data_sem for ea_inode's

Treat i_data_sem for ea_inodes as being in their own lockdep class to
avoid lockdep complaints about ext4_setattr's use of inode_lock() on
normal inodes potentially causing lock ordering with i_data_sem on
ea_inodes in ext4_xattr_inode_write().  However, ea_inodes will be
operated on by ext4_setattr(), so this isn't a problem.

Cc: stable@kernel.org
Link: https://syzkaller.appspot.com/bug?extid=298c5d8fb4a128bc27b0
Reported-by: syzbot+298c5d8fb4a128bc27b0@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230524034951.779531-5-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9525c52b78dc5c112451c8ddc8cb35c5920b08a2..8104a21b001ae3b9ea3e20f27e36642c73b30248 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -918,11 +918,13 @@ do {                                                                             \
  *                       where the second inode has larger inode number
  *                       than the first
  *  I_DATA_SEM_QUOTA  - Used for quota inodes only
+ *  I_DATA_SEM_EA     - Used for ea_inodes only
  */
 enum {
        I_DATA_SEM_NORMAL = 0,
        I_DATA_SEM_OTHER,
        I_DATA_SEM_QUOTA,
+       I_DATA_SEM_EA
 };
 
 

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index ff7ab63c5b4f0aee55c49f26d2d4ab97efcc8432..13d7f17a9c8cce74442e07aa1c67adb2133c737c 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -121,7 +121,11 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 #ifdef CONFIG_LOCKDEP
 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 {
+       struct ext4_inode_info *ei = EXT4_I(ea_inode);
+
        lockdep_set_subclass(&ea_inode->i_rwsem, 1);
+       (void) ei;      /* shut up clang warning if !CONFIG_LOCKDEP */
+       lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
 }
 #endif