linux_dsm_epyc7002/fs/ext4
Tahsin Erdogan 33d201e027 ext4: fix lockdep warning about recursive inode locking
Setting a large xattr value may require writing the attribute contents
to an external inode. In this case we may need to lock the xattr inode
along with the parent inode. This doesn't pose a deadlock risk because
xattr inodes are not directly visible to the user and their access is
restricted.

Assign a lockdep subclass to xattr inode's lock.

 ============================================
 WARNING: possible recursive locking detected
 4.12.0-rc1+ #740 Not tainted
 --------------------------------------------
 python/1822 is trying to acquire lock:
  (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff804912ca>] ext4_xattr_set_entry+0x65a/0x7b0

 but task is already holding lock:
  (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803d6687>] vfs_setxattr+0x57/0xb0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&sb->s_type->i_mutex_key#15);
   lock(&sb->s_type->i_mutex_key#15);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 4 locks held by python/1822:
  #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff803d0eef>] mnt_want_write+0x1f/0x50
  #1:  (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803d6687>] vfs_setxattr+0x57/0xb0
  #2:  (jbd2_handle){.+.+..}, at: [<ffffffff80493f40>] start_this_handle+0xf0/0x420
  #3:  (&ei->xattr_sem){++++..}, at: [<ffffffff804920ba>] ext4_xattr_set_handle+0x9a/0x4f0

 stack backtrace:
 CPU: 0 PID: 1822 Comm: python Not tainted 4.12.0-rc1+ #740
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 Call Trace:
  dump_stack+0x67/0x9e
  __lock_acquire+0x5f3/0x1750
  lock_acquire+0xb5/0x1d0
  down_write+0x2c/0x60
  ext4_xattr_set_entry+0x65a/0x7b0
  ext4_xattr_block_set+0x1b2/0x9b0
  ext4_xattr_set_handle+0x322/0x4f0
  ext4_xattr_set+0x144/0x1a0
  ext4_xattr_user_set+0x34/0x40
  __vfs_setxattr+0x66/0x80
  __vfs_setxattr_noperm+0x69/0x1c0
  vfs_setxattr+0xa2/0xb0
  setxattr+0x12e/0x150
  path_setxattr+0x87/0xb0
  SyS_setxattr+0xf/0x20
  entry_SYSCALL_64_fastpath+0x18/0xad

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-06-21 21:17:10 -04:00
..
acl.c ext4: fix quota charging for shared xattr blocks 2017-05-24 18:24:07 -04:00
acl.h ext2/3/4: use generic posix ACL infrastructure 2014-01-25 23:58:19 -05:00
balloc.c The major change this cycle is deleting ext4's copy of the file system 2016-07-26 18:35:55 -07:00
bitmap.c ext4: remove unused header files 2015-04-02 23:47:42 -04:00
block_validity.c ext4: add missing KERN_CONT to a few more debugging uses 2016-10-15 09:57:31 -04:00
dir.c ext4: remove unused variable 2016-09-30 02:14:56 -04:00
ext4_extents.h ext4: fix misspellings in comments. 2016-03-09 23:49:05 -05:00
ext4_jbd2.c ext4: add shutdown bit and check for it 2017-02-05 01:28:48 -05:00
ext4_jbd2.h ext4: add largedir feature 2017-06-21 21:09:57 -04:00
ext4.h ext4: xattr-in-inode support 2017-06-21 21:10:32 -04:00
extents_status.c scripts/spelling.txt: add "comsume(r)" pattern and fix typo instances 2017-02-27 18:43:47 -08:00
extents_status.h ext4: move procfs registration code to fs/ext4/sysfs.c 2015-09-23 12:46:17 -04:00
extents.c ext4: fix fdatasync(2) after extent manipulation operations 2017-05-29 13:24:55 -04:00
file.c ext4: fix off-by-one on max nr_pages in ext4_find_unwritten_pgoff() 2017-05-24 18:02:20 -04:00
fsmap.c ext4: support GETFSMAP ioctls 2017-04-30 00:36:53 -04:00
fsmap.h ext4: support GETFSMAP ioctls 2017-04-30 00:36:53 -04:00
fsync.c ext4: add shutdown bit and check for it 2017-02-05 01:28:48 -05:00
hash.c ext4: move halfmd4 into hash.c directly 2017-02-02 11:52:14 -05:00
ialloc.c ext4: xattr-in-inode support 2017-06-21 21:10:32 -04:00
indirect.c ext4: refactor direct IO code 2016-05-13 00:44:16 -04:00
inline.c ext4: xattr-in-inode support 2017-06-21 21:10:32 -04:00
inode.c ext4: fix lockdep warning about recursive inode locking 2017-06-21 21:17:10 -04:00
ioctl.c Add GETFSMAP support; some performance improvements for very large 2017-05-08 11:30:05 -07:00
Kconfig dax: fix build warnings with FS_DAX and !FS_IOMAP 2017-01-24 16:26:14 -08:00
Makefile ext4: support GETFSMAP ioctls 2017-04-30 00:36:53 -04:00
mballoc.c ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors 2017-05-21 22:35:23 -04:00
mballoc.h ext4: support GETFSMAP ioctls 2017-04-30 00:36:53 -04:00
migrate.c ext4: fix misspellings in comments. 2016-03-09 23:49:05 -05:00
mmp.c block,fs: use REQ_* flags directly 2016-11-01 09:43:26 -06:00
move_extent.c Fix a memory leak on an error path, and two races when modifying 2017-03-26 10:29:21 -07:00
namei.c ext4: add largedir feature 2017-06-21 21:09:57 -04:00
page-io.c ext4: replace BUG_ON with WARN_ONCE in ext4_end_bio() 2017-04-30 20:08:05 -04:00
readpage.c Merge branch 'akpm' (patches from Andrew) 2016-07-26 19:55:54 -07:00
resize.c ext4: rename s_resize_flags to s_ext4_flags 2017-02-05 01:27:48 -05:00
super.c ext4: fix quota charging for shared xattr blocks 2017-05-24 18:24:07 -04:00
symlink.c ext4: Add statx support 2017-04-03 01:05:58 -04:00
sysfs.c ext4: constify static data that is never modified 2017-04-29 23:47:50 -04:00
truncate.h ext4: fix races between page faults and hole punching 2015-12-07 14:28:03 -05:00
xattr_security.c switch xattr_handler->set() to passing dentry and inode separately 2016-05-27 15:39:43 -04:00
xattr_trusted.c switch xattr_handler->set() to passing dentry and inode separately 2016-05-27 15:39:43 -04:00
xattr_user.c switch xattr_handler->set() to passing dentry and inode separately 2016-05-27 15:39:43 -04:00
xattr.c ext4: fix lockdep warning about recursive inode locking 2017-06-21 21:17:10 -04:00
xattr.h ext4: fix lockdep warning about recursive inode locking 2017-06-21 21:17:10 -04:00