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authorWengang Wang <wen.gang.wang@oracle.com>2021-04-09 23:27:29 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-10 00:54:23 +0300
commit90bd070aae6c4fb5d302f9c4b9c88be60c8197ec (patch)
tree780aa6b672ed9ff3e9901d4c69398bd87edbce54 /fs/ocfs2/aops.c
parent9562fd132985ea9185388a112e50f2a51557827d (diff)
downloadlinux-90bd070aae6c4fb5d302f9c4b9c88be60c8197ec.tar.xz
ocfs2: fix deadlock between setattr and dio_end_io_write
The following deadlock is detected: truncate -> setattr path is waiting for pending direct IO to be done (inode->i_dio_count become zero) with inode->i_rwsem held (down_write). PID: 14827 TASK: ffff881686a9af80 CPU: 20 COMMAND: "ora_p005_hrltd9" #0 __schedule at ffffffff818667cc #1 schedule at ffffffff81866de6 #2 inode_dio_wait at ffffffff812a2d04 #3 ocfs2_setattr at ffffffffc05f322e [ocfs2] #4 notify_change at ffffffff812a5a09 #5 do_truncate at ffffffff812808f5 #6 do_sys_ftruncate.constprop.18 at ffffffff81280cf2 #7 sys_ftruncate at ffffffff81280d8e #8 do_syscall_64 at ffffffff81003949 #9 entry_SYSCALL_64_after_hwframe at ffffffff81a001ad dio completion path is going to complete one direct IO (decrement inode->i_dio_count), but before that it hung at locking inode->i_rwsem: #0 __schedule+700 at ffffffff818667cc #1 schedule+54 at ffffffff81866de6 #2 rwsem_down_write_failed+536 at ffffffff8186aa28 #3 call_rwsem_down_write_failed+23 at ffffffff8185a1b7 #4 down_write+45 at ffffffff81869c9d #5 ocfs2_dio_end_io_write+180 at ffffffffc05d5444 [ocfs2] #6 ocfs2_dio_end_io+85 at ffffffffc05d5a85 [ocfs2] #7 dio_complete+140 at ffffffff812c873c #8 dio_aio_complete_work+25 at ffffffff812c89f9 #9 process_one_work+361 at ffffffff810b1889 #10 worker_thread+77 at ffffffff810b233d #11 kthread+261 at ffffffff810b7fd5 #12 ret_from_fork+62 at ffffffff81a0035e Thus above forms ABBA deadlock. The same deadlock was mentioned in upstream commit 28f5a8a7c033 ("ocfs2: should wait dio before inode lock in ocfs2_setattr()"). It seems that that commit only removed the cluster lock (the victim of above dead lock) from the ABBA deadlock party. End-user visible effects: Process hang in truncate -> ocfs2_setattr path and other processes hang at ocfs2_dio_end_io_write path. This is to fix the deadlock itself. It removes inode_lock() call from dio completion path to remove the deadlock and add ip_alloc_sem lock in setattr path to synchronize the inode modifications. [wen.gang.wang@oracle.com: remove the "had_alloc_lock" as suggested] Link: https://lkml.kernel.org/r/20210402171344.1605-1-wen.gang.wang@oracle.com Link: https://lkml.kernel.org/r/20210331203654.3911-1-wen.gang.wang@oracle.com Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2/aops.c')
-rw-r--r--fs/ocfs2/aops.c11
1 files changed, 1 insertions, 10 deletions
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 3bfb4147895a..ad20403b383f 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2295,7 +2295,7 @@ static int ocfs2_dio_end_io_write(struct inode *inode,
struct ocfs2_alloc_context *meta_ac = NULL;
handle_t *handle = NULL;
loff_t end = offset + bytes;
- int ret = 0, credits = 0, locked = 0;
+ int ret = 0, credits = 0;
ocfs2_init_dealloc_ctxt(&dealloc);
@@ -2306,13 +2306,6 @@ static int ocfs2_dio_end_io_write(struct inode *inode,
!dwc->dw_orphaned)
goto out;
- /* ocfs2_file_write_iter will get i_mutex, so we need not lock if we
- * are in that context. */
- if (dwc->dw_writer_pid != task_pid_nr(current)) {
- inode_lock(inode);
- locked = 1;
- }
-
ret = ocfs2_inode_lock(inode, &di_bh, 1);
if (ret < 0) {
mlog_errno(ret);
@@ -2393,8 +2386,6 @@ out:
if (meta_ac)
ocfs2_free_alloc_context(meta_ac);
ocfs2_run_deallocs(osb, &dealloc);
- if (locked)
- inode_unlock(inode);
ocfs2_dio_free_write_ctx(inode, dwc);
return ret;