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Date: Sun, 16 Oct 2022 16:29:50 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Gang He <ghe@...e.com>
Cc: Joseph Qi <joseph.qi@...ux.alibaba.com>, mark@...heh.com,
jlbec@...lplan.org, Wengang Wang <wen.gang.wang@...cle.com>,
linux-kernel@...r.kernel.org, ocfs2-devel@....oracle.com
Subject: Re: [Ocfs2-devel] [PATCH] ocfs2: reflink deadlock when clone file
to the same directory simultaneously
On Thu, 26 Aug 2021 13:56:16 +0800 Gang He <ghe@...e.com> wrote:
> So, I will send a new patch to fix this deadlock problem via dlmglue layer.
> For this patch, I want to change the patch comments as a reflink
> improvement patch.
Did this ever happen? I've been sitting on this patch for ages.
From: Gang He <ghe@...e.com>
Subject: ocfs2: reflink deadlock when clone file to the same directory simultaneously
Running reflink from multiple nodes simultaneously to clone a file to the
same directory probably triggers a deadlock issue. For example, there is
a three node ocfs2 cluster, each node mounts the ocfs2 file system to
/mnt/shared, and run the reflink command from each node repeatedly, like
reflink "/mnt/shared/test" \
"/mnt/shared/.snapshots/test.`date +%m%d%H%M%S`.`hostname`"
then, reflink command process will be hung on each node, and you
can't list this file system directory.
The problematic reflink command process is blocked at one node,
task:reflink state:D stack: 0 pid: 1283 ppid: 4154
Call Trace:
__schedule+0x2fd/0x750
schedule+0x2f/0xa0
schedule_timeout+0x1cc/0x310
? ocfs2_control_cfu+0x50/0x50 [ocfs2_stack_user]
? 0xffffffffc0e3e000
wait_for_completion+0xba/0x140
? wake_up_q+0xa0/0xa0
__ocfs2_cluster_lock.isra.41+0x3b5/0x820 [ocfs2]
? ocfs2_inode_lock_full_nested+0x1fc/0x960 [ocfs2]
ocfs2_inode_lock_full_nested+0x1fc/0x960 [ocfs2]
ocfs2_init_security_and_acl+0xbe/0x1d0 [ocfs2]
ocfs2_reflink+0x436/0x4c0 [ocfs2]
? ocfs2_reflink_ioctl+0x2ca/0x360 [ocfs2]
ocfs2_reflink_ioctl+0x2ca/0x360 [ocfs2]
ocfs2_ioctl+0x25e/0x670 [ocfs2]
do_vfs_ioctl+0xa0/0x680
ksys_ioctl+0x70/0x80
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x5b/0x1e0
The other reflink command processes are blocked at other nodes,
task:reflink state:D stack: 0 pid:29759 ppid: 4088
Call Trace:
__schedule+0x2fd/0x750
schedule+0x2f/0xa0
schedule_timeout+0x1cc/0x310
? ocfs2_control_cfu+0x50/0x50 [ocfs2_stack_user]
? 0xffffffffc0b19000
wait_for_completion+0xba/0x140
? wake_up_q+0xa0/0xa0
__ocfs2_cluster_lock.isra.41+0x3b5/0x820 [ocfs2]
? ocfs2_inode_lock_full_nested+0x1fc/0x960 [ocfs2]
ocfs2_inode_lock_full_nested+0x1fc/0x960 [ocfs2]
ocfs2_mv_orphaned_inode_to_new+0x87/0x7e0 [ocfs2]
ocfs2_reflink+0x335/0x4c0 [ocfs2]
? ocfs2_reflink_ioctl+0x2ca/0x360 [ocfs2]
ocfs2_reflink_ioctl+0x2ca/0x360 [ocfs2]
ocfs2_ioctl+0x25e/0x670 [ocfs2]
do_vfs_ioctl+0xa0/0x680
ksys_ioctl+0x70/0x80
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x5b/0x1e0
or
task:reflink state:D stack: 0 pid:18465 ppid: 4156
Call Trace:
__schedule+0x302/0x940
? usleep_range+0x80/0x80
schedule+0x46/0xb0
schedule_timeout+0xff/0x140
? ocfs2_control_cfu+0x50/0x50 [ocfs2_stack_user]
? 0xffffffffc0c3b000
__wait_for_common+0xb9/0x170
__ocfs2_cluster_lock.constprop.0+0x1d6/0x860 [ocfs2]
? ocfs2_wait_for_recovery+0x49/0xd0 [ocfs2]
? ocfs2_inode_lock_full_nested+0x30f/0xa50 [ocfs2]
ocfs2_inode_lock_full_nested+0x30f/0xa50 [ocfs2]
ocfs2_inode_lock_tracker+0xf2/0x2b0 [ocfs2]
? dput+0x32/0x2f0
ocfs2_permission+0x45/0xe0 [ocfs2]
inode_permission+0xcc/0x170
link_path_walk.part.0.constprop.0+0x2a2/0x380
? path_init+0x2c1/0x3f0
path_parentat+0x3c/0x90
filename_parentat+0xc1/0x1d0
? filename_lookup+0x138/0x1c0
filename_create+0x43/0x160
ocfs2_reflink_ioctl+0xe6/0x380 [ocfs2]
ocfs2_ioctl+0x1ea/0x2c0 [ocfs2]
? do_sys_openat2+0x81/0x150
__x64_sys_ioctl+0x82/0xb0
do_syscall_64+0x61/0xb0
The deadlock is caused by multiple acquiring the destination directory
inode dlm lock in ocfs2_reflink function, we should acquire this directory
inode dlm lock at the beginning, and hold this dlm lock until end of the
function.
Link: https://lkml.kernel.org/r/20210729110230.18983-1-ghe@suse.com
Signed-off-by: Gang He <ghe@...e.com>
Cc: Mark Fasheh <mark@...heh.com>
Cc: Joel Becker <jlbec@...lplan.org>
Cc: Junxiao Bi <junxiao.bi@...cle.com>
Cc: Joseph Qi <jiangqi903@...il.com>
Cc: Changwei Ge <gechangwei@...e.cn>
Cc: Gang He <ghe@...e.com>
Cc: Jun Piao <piaojun@...wei.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
fs/ocfs2/namei.c | 32 +++++++++++++-------------------
fs/ocfs2/namei.h | 2 ++
fs/ocfs2/refcounttree.c | 15 +++++++++++----
fs/ocfs2/xattr.c | 12 +-----------
fs/ocfs2/xattr.h | 1 +
5 files changed, 28 insertions(+), 34 deletions(-)
--- a/fs/ocfs2/namei.c~ocfs2-reflink-deadlock-when-clone-file-to-the-same-directory-simultaneously
+++ a/fs/ocfs2/namei.c
@@ -2490,6 +2490,7 @@ out:
}
int ocfs2_create_inode_in_orphan(struct inode *dir,
+ struct buffer_head **dir_bh,
int mode,
struct inode **new_inode)
{
@@ -2598,13 +2599,16 @@ leave:
brelse(new_di_bh);
- if (!status)
- *new_inode = inode;
-
ocfs2_free_dir_lookup_result(&orphan_insert);
- ocfs2_inode_unlock(dir, 1);
- brelse(parent_di_bh);
+ if (!status) {
+ *new_inode = inode;
+ *dir_bh = parent_di_bh;
+ } else {
+ ocfs2_inode_unlock(dir, 1);
+ brelse(parent_di_bh);
+ }
+
return status;
}
@@ -2761,11 +2765,11 @@ bail:
}
int ocfs2_mv_orphaned_inode_to_new(struct inode *dir,
+ struct buffer_head *dir_bh,
struct inode *inode,
struct dentry *dentry)
{
int status = 0;
- struct buffer_head *parent_di_bh = NULL;
handle_t *handle = NULL;
struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
struct ocfs2_dinode *dir_di, *di;
@@ -2779,14 +2783,7 @@ int ocfs2_mv_orphaned_inode_to_new(struc
(unsigned long long)OCFS2_I(dir)->ip_blkno,
(unsigned long long)OCFS2_I(inode)->ip_blkno);
- status = ocfs2_inode_lock(dir, &parent_di_bh, 1);
- if (status < 0) {
- if (status != -ENOENT)
- mlog_errno(status);
- return status;
- }
-
- dir_di = (struct ocfs2_dinode *) parent_di_bh->b_data;
+ dir_di = (struct ocfs2_dinode *) dir_bh->b_data;
if (!dir_di->i_links_count) {
/* can't make a file in a deleted directory. */
status = -ENOENT;
@@ -2799,7 +2796,7 @@ int ocfs2_mv_orphaned_inode_to_new(struc
goto leave;
/* get a spot inside the dir. */
- status = ocfs2_prepare_dir_for_insert(osb, dir, parent_di_bh,
+ status = ocfs2_prepare_dir_for_insert(osb, dir, dir_bh,
dentry->d_name.name,
dentry->d_name.len, &lookup);
if (status < 0) {
@@ -2863,7 +2860,7 @@ int ocfs2_mv_orphaned_inode_to_new(struc
ocfs2_journal_dirty(handle, di_bh);
status = ocfs2_add_entry(handle, dentry, inode,
- OCFS2_I(inode)->ip_blkno, parent_di_bh,
+ OCFS2_I(inode)->ip_blkno, dir_bh,
&lookup);
if (status < 0) {
mlog_errno(status);
@@ -2887,10 +2884,7 @@ orphan_unlock:
iput(orphan_dir_inode);
leave:
- ocfs2_inode_unlock(dir, 1);
-
brelse(di_bh);
- brelse(parent_di_bh);
brelse(orphan_dir_bh);
ocfs2_free_dir_lookup_result(&lookup);
--- a/fs/ocfs2/namei.h~ocfs2-reflink-deadlock-when-clone-file-to-the-same-directory-simultaneously
+++ a/fs/ocfs2/namei.h
@@ -24,6 +24,7 @@ int ocfs2_orphan_del(struct ocfs2_super
struct buffer_head *orphan_dir_bh,
bool dio);
int ocfs2_create_inode_in_orphan(struct inode *dir,
+ struct buffer_head **dir_bh,
int mode,
struct inode **new_inode);
int ocfs2_add_inode_to_orphan(struct ocfs2_super *osb,
@@ -32,6 +33,7 @@ int ocfs2_del_inode_from_orphan(struct o
struct inode *inode, struct buffer_head *di_bh,
int update_isize, loff_t end);
int ocfs2_mv_orphaned_inode_to_new(struct inode *dir,
+ struct buffer_head *dir_bh,
struct inode *new_inode,
struct dentry *new_dentry);
--- a/fs/ocfs2/refcounttree.c~ocfs2-reflink-deadlock-when-clone-file-to-the-same-directory-simultaneously
+++ a/fs/ocfs2/refcounttree.c
@@ -4222,7 +4222,7 @@ static int ocfs2_reflink(struct dentry *
{
int error, had_lock;
struct inode *inode = d_inode(old_dentry);
- struct buffer_head *old_bh = NULL;
+ struct buffer_head *old_bh = NULL, *dir_bh = NULL;
struct inode *new_orphan_inode = NULL;
struct ocfs2_lock_holder oh;
@@ -4230,7 +4230,7 @@ static int ocfs2_reflink(struct dentry *
return -EOPNOTSUPP;
- error = ocfs2_create_inode_in_orphan(dir, inode->i_mode,
+ error = ocfs2_create_inode_in_orphan(dir, &dir_bh, inode->i_mode,
&new_orphan_inode);
if (error) {
mlog_errno(error);
@@ -4276,13 +4276,15 @@ static int ocfs2_reflink(struct dentry *
/* If the security isn't preserved, we need to re-initialize them. */
if (!preserve) {
- error = ocfs2_init_security_and_acl(dir, new_orphan_inode,
+ error = ocfs2_init_security_and_acl(dir, dir_bh,
+ new_orphan_inode,
&new_dentry->d_name);
if (error)
mlog_errno(error);
}
if (!error) {
- error = ocfs2_mv_orphaned_inode_to_new(dir, new_orphan_inode,
+ error = ocfs2_mv_orphaned_inode_to_new(dir, dir_bh,
+ new_orphan_inode,
new_dentry);
if (error)
mlog_errno(error);
@@ -4300,6 +4302,11 @@ out:
iput(new_orphan_inode);
}
+ if (dir_bh) {
+ ocfs2_inode_unlock(dir, 1);
+ brelse(dir_bh);
+ }
+
return error;
}
--- a/fs/ocfs2/xattr.c~ocfs2-reflink-deadlock-when-clone-file-to-the-same-directory-simultaneously
+++ a/fs/ocfs2/xattr.c
@@ -7203,16 +7203,13 @@ out:
/*
* Initialize security and acl for a already created inode.
* Used for reflink a non-preserve-security file.
- *
- * It uses common api like ocfs2_xattr_set, so the caller
- * must not hold any lock expect i_rwsem.
*/
int ocfs2_init_security_and_acl(struct inode *dir,
+ struct buffer_head *dir_bh,
struct inode *inode,
const struct qstr *qstr)
{
int ret = 0;
- struct buffer_head *dir_bh = NULL;
ret = ocfs2_init_security_get(inode, dir, qstr, NULL);
if (ret) {
@@ -7220,17 +7217,10 @@ int ocfs2_init_security_and_acl(struct i
goto leave;
}
- ret = ocfs2_inode_lock(dir, &dir_bh, 0);
- if (ret) {
- mlog_errno(ret);
- goto leave;
- }
ret = ocfs2_init_acl(NULL, inode, dir, NULL, dir_bh, NULL, NULL);
if (ret)
mlog_errno(ret);
- ocfs2_inode_unlock(dir, 0);
- brelse(dir_bh);
leave:
return ret;
}
--- a/fs/ocfs2/xattr.h~ocfs2-reflink-deadlock-when-clone-file-to-the-same-directory-simultaneously
+++ a/fs/ocfs2/xattr.h
@@ -83,6 +83,7 @@ int ocfs2_reflink_xattrs(struct inode *o
struct buffer_head *new_bh,
bool preserve_security);
int ocfs2_init_security_and_acl(struct inode *dir,
+ struct buffer_head *dir_bh,
struct inode *inode,
const struct qstr *qstr);
#endif /* OCFS2_XATTR_H */
_
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