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In the current implementation of unaligned aio+dio, lock order behave as follow: in user process context: -> call io_submit() -> get i_mutex <== window1 -> get ip_unaligned_aio -> submit direct io to block device -> release i_mutex -> io_submit() return in dio work queue context(the work queue is created in __blockdev_direct_IO): -> release ip_unaligned_aio <== window2 -> get i_mutex -> clear unwritten flag & change i_size -> release i_mutex There is a limitation to the thread number of dio work queue. 256 at default. If all 256 thread are in the above 'window2' stage, and there is a user process in the 'window1' stage, the system will became deadlock. Since the user process hold i_mutex to wait ip_unaligned_aio lock, while there is a direct bio hold ip_unaligned_aio mutex who is waiting for a dio work queue thread to be schedule. But all the dio work queue thread is waiting for i_mutex lock in 'window2'. This case only happened in a test which send a large number(more than 256) of aio at one io_submit() call. My design is to remove ip_unaligned_aio lock. Change it to a sync io instead. Just like ip_unaligned_aio lock, serialize the unaligned aio dio. [akpm@linux-foundation.org: remove OCFS2_IOCB_UNALIGNED_IO, per Junxiao Bi] Signed-off-by: Ryan Ding <ryan.ding@oracle.com> Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com> Cc: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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cluster | ||
dlm | ||
dlmfs | ||
acl.c | ||
acl.h | ||
alloc.c | ||
alloc.h | ||
aops.c | ||
aops.h | ||
blockcheck.c | ||
blockcheck.h | ||
buffer_head_io.c | ||
buffer_head_io.h | ||
dcache.c | ||
dcache.h | ||
dir.c | ||
dir.h | ||
dlmglue.c | ||
dlmglue.h | ||
export.c | ||
export.h | ||
extent_map.c | ||
extent_map.h | ||
file.c | ||
file.h | ||
filecheck.c | ||
filecheck.h | ||
heartbeat.c | ||
heartbeat.h | ||
inode.c | ||
inode.h | ||
ioctl.c | ||
ioctl.h | ||
journal.c | ||
journal.h | ||
Kconfig | ||
localalloc.c | ||
localalloc.h | ||
locks.c | ||
locks.h | ||
Makefile | ||
mmap.c | ||
mmap.h | ||
move_extents.c | ||
move_extents.h | ||
namei.c | ||
namei.h | ||
ocfs1_fs_compat.h | ||
ocfs2_fs.h | ||
ocfs2_ioctl.h | ||
ocfs2_lockid.h | ||
ocfs2_lockingver.h | ||
ocfs2_trace.h | ||
ocfs2.h | ||
quota_global.c | ||
quota_local.c | ||
quota.h | ||
refcounttree.c | ||
refcounttree.h | ||
reservations.c | ||
reservations.h | ||
resize.c | ||
resize.h | ||
slot_map.c | ||
slot_map.h | ||
stack_o2cb.c | ||
stack_user.c | ||
stackglue.c | ||
stackglue.h | ||
suballoc.c | ||
suballoc.h | ||
super.c | ||
super.h | ||
symlink.c | ||
symlink.h | ||
sysfile.c | ||
sysfile.h | ||
uptodate.c | ||
uptodate.h | ||
xattr.c | ||
xattr.h |