linux/fs/ext4
Jiaying Zhang 8c0bec2151 ext4: remove i_mutex lock in ext4_evict_inode to fix lockdep complaining
The i_mutex lock and flush_completed_IO() added by commit 2581fdc810
in ext4_evict_inode() causes lockdep complaining about potential
deadlock in several places.  In most/all of these LOCKDEP complaints
it looks like it's a false positive, since many of the potential
circular locking cases can't take place by the time the
ext4_evict_inode() is called; but since at the very least it may mask
real problems, we need to address this.

This change removes the flush_completed_IO() and i_mutex lock in
ext4_evict_inode().  Instead, we take a different approach to resolve
the software lockup that commit 2581fdc810 intends to fix.  Rather
than having ext4-dio-unwritten thread wait for grabing the i_mutex
lock of an inode, we use mutex_trylock() instead, and simply requeue
the work item if we fail to grab the inode's i_mutex lock.

This should speed up work queue processing in general and also
prevents the following deadlock scenario: During page fault,
shrink_icache_memory is called that in turn evicts another inode B.
Inode B has some pending io_end work so it calls ext4_ioend_wait()
that waits for inode B's i_ioend_count to become zero.  However, inode
B's ioend work was queued behind some of inode A's ioend work on the
same cpu's ext4-dio-unwritten workqueue.  As the ext4-dio-unwritten
thread on that cpu is processing inode A's ioend work, it tries to
grab inode A's i_mutex lock.  Since the i_mutex lock of inode A is
still hold before the page fault happened, we enter a deadlock.

Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-08-31 11:50:51 -04:00
..
Kconfig ext4: Don't ask about supporting ext2/3 in ext4 if ext4 is not configured 2009-12-21 10:54:09 -05:00
Makefile ext4: move ext4_ind_* functions from inode.c to indirect.c 2011-06-27 19:40:50 -04:00
acl.c switch posix_acl_equiv_mode() to umode_t * 2011-08-01 02:10:06 -04:00
acl.h fs: take the ACL checks to common code 2011-07-25 14:30:23 -04:00
balloc.c ext4: refactor duplicated block placement code 2011-06-28 10:01:31 -04:00
bitmap.c ext4: Change unsigned long to unsigned int 2008-11-05 00:14:04 -05:00
block_validity.c ext4: move ext4_ind_* functions from inode.c to indirect.c 2011-06-27 19:40:50 -04:00
dir.c ext4: Use ext4_error_file() to print the pathname to the corrupted inode 2011-01-10 12:10:55 -05:00
ext4.h ext4: remove i_mutex lock in ext4_evict_inode to fix lockdep complaining 2011-08-31 11:50:51 -04:00
ext4_extents.h ext4: use FIEMAP_EXTENT_LAST flag for last extent in fiemap 2011-06-06 00:06:52 -04:00
ext4_jbd2.c ext4: remove unneeded ext4_journal_get_undo_access 2011-05-09 10:58:45 -04:00
ext4_jbd2.h ext4: Fix ext4_should_writeback_data() for no-journal mode 2011-08-13 11:25:18 -04:00
extents.c ext4: Fix overflow caused by missing cast in ext4_fallocate() 2011-07-27 22:11:20 -04:00
file.c fs: take the ACL checks to common code 2011-07-25 14:30:23 -04:00
fsync.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2011-08-01 13:56:03 -10:00
hash.c ext4: Add support for non-native signed/unsigned htree hash algorithms 2008-10-28 13:21:44 -04:00
ialloc.c ext4: use the correct error exit path in ext4_init_inode_table() 2011-08-01 06:32:19 -04:00
indirect.c ext4: flush any pending end_io requests before DIO reads w/dioread_nolock 2011-08-19 19:13:32 -04:00
inode.c ext4: remove i_mutex lock in ext4_evict_inode to fix lockdep complaining 2011-08-31 11:50:51 -04:00
ioctl.c ext4: prevent parallel resizers by atomic bit ops 2011-07-26 21:35:44 -04:00
mballoc.c ext4: prevent memory leaks from ext4_mb_init_backend() on error path 2011-08-01 17:41:46 -04:00
mballoc.h ext4: remove ac_repeats from ext4_allocation_context 2011-07-23 16:18:55 -04:00
migrate.c ext4: set extents flag when migrating file to use extents 2011-05-03 09:34:42 -04:00
mmp.c ext4: add support for multiple mount protection 2011-05-24 18:31:25 -04:00
move_extent.c ext4: Fix max file size and logical block counting of extent format file 2011-06-06 00:05:17 -04:00
namei.c ext4: Properly count journal credits for long symlinks 2011-08-11 17:23:40 -07:00
page-io.c ext4: remove i_mutex lock in ext4_evict_inode to fix lockdep complaining 2011-08-31 11:50:51 -04:00
resize.c ext4: use ext4_kvzalloc()/ext4_kvmalloc() for s_group_desc and s_group_info 2011-08-01 08:45:38 -04:00
super.c ext4: call ext4_ioend_wait and ext4_flush_completed_IO in ext4_evict_inode 2011-08-13 12:17:13 -04:00
symlink.c ext4: symlink must be handled via filesystem specific operation 2010-05-16 02:00:00 -04:00
truncate.h ext4: move common truncate functions to header file 2011-06-27 19:16:04 -04:00
xattr.c ext4: add flag to ext4_has_free_blocks 2011-05-25 07:41:26 -04:00
xattr.h fs/vfs/security: pass last path component to LSM on inode creation 2011-02-01 11:12:29 -05:00
xattr_security.c fs/vfs/security: pass last path component to LSM on inode creation 2011-02-01 11:12:29 -05:00
xattr_trusted.c ext4: constify xattr_handler 2010-05-21 18:31:19 -04:00
xattr_user.c ext4: constify xattr_handler 2010-05-21 18:31:19 -04:00