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Message-ID: <20250206064451.3088028-1-chao@kernel.org>
Date: Thu, 6 Feb 2025 14:44:51 +0800
From: Chao Yu <chao@...nel.org>
To: jaegeuk@...nel.org
Cc: linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org,
Chao Yu <chao@...nel.org>
Subject: [PATCH] f2fs: quota: fix to avoid warning in dquot_writeback_dquots()
F2FS-fs (dm-59): checkpoint=enable has some unwritten data.
------------[ cut here ]------------
WARNING: CPU: 6 PID: 8013 at fs/quota/dquot.c:691 dquot_writeback_dquots+0x2fc/0x308
pc : dquot_writeback_dquots+0x2fc/0x308
lr : f2fs_quota_sync+0xcc/0x1c4
Call trace:
dquot_writeback_dquots+0x2fc/0x308
f2fs_quota_sync+0xcc/0x1c4
f2fs_write_checkpoint+0x3d4/0x9b0
f2fs_issue_checkpoint+0x1bc/0x2c0
f2fs_sync_fs+0x54/0x150
f2fs_do_sync_file+0x2f8/0x814
__f2fs_ioctl+0x1960/0x3244
f2fs_ioctl+0x54/0xe0
__arm64_sys_ioctl+0xa8/0xe4
invoke_syscall+0x58/0x114
checkpoint and f2fs_remount may race as below, resulting triggering warning
in dquot_writeback_dquots().
atomic write remount
- do_remount
- down_write(&sb->s_umount);
- f2fs_remount
- ioctl
- f2fs_do_sync_file
- f2fs_sync_fs
- f2fs_write_checkpoint
- block_operations
- locked = down_read_trylock(&sbi->sb->s_umount)
: fail to lock due to the write lock was held by remount
- up_write(&sb->s_umount);
- f2fs_quota_sync
- dquot_writeback_dquots
- WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount))
: trigger warning because s_umount lock was unlocked by remount
If checkpoint comes from mount/umount/remount/freeze/quotactl, caller of
checkpoint has already held s_umount lock, calling dquot_writeback_dquots()
in the context should be safe.
So let's record task to sbi->umount_lock_holder, so that checkpoint can
know whether the lock has held in the context or not by checking current
w/ it.
In addition, in order to misrepresent caller of checkpoint, we should not
allow to trigger async checkpoint for those callers: mount/umount/remount/
freeze/quotactl.
Fixes: af033b2aa8a8 ("f2fs: guarantee journalled quota data by checkpoint")
Signed-off-by: Chao Yu <chao@...nel.org>
---
fs/f2fs/checkpoint.c | 17 ++++++++-----
fs/f2fs/f2fs.h | 3 ++-
fs/f2fs/super.c | 59 +++++++++++++++++++++++++++++++++++---------
3 files changed, 60 insertions(+), 19 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index efda9a022981..baff639ac0c4 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1237,7 +1237,8 @@ static int block_operations(struct f2fs_sb_info *sbi)
retry_flush_quotas:
f2fs_lock_all(sbi);
if (__need_flush_quota(sbi)) {
- int locked;
+ bool need_lock = sbi->umount_lock_holder != current;
+ bool locked = false;
if (++cnt > DEFAULT_RETRY_QUOTA_FLUSH_COUNT) {
set_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH);
@@ -1246,10 +1247,13 @@ static int block_operations(struct f2fs_sb_info *sbi)
}
f2fs_unlock_all(sbi);
- /* only failed during mount/umount/freeze/quotactl */
- locked = down_read_trylock(&sbi->sb->s_umount);
- f2fs_quota_sync(sbi->sb, -1);
- if (locked)
+ /* don't grab s_umount lock during mount/umount/remount/freeze/quotactl */
+ if (need_lock && !down_read_trylock(&sbi->sb->s_umount)) {
+ cond_resched();
+ goto retry_flush_quotas;
+ }
+ f2fs_do_quota_sync(sbi->sb, -1);
+ if (need_lock)
up_read(&sbi->sb->s_umount);
cond_resched();
goto retry_flush_quotas;
@@ -1867,7 +1871,8 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi)
struct cp_control cpc;
cpc.reason = __get_cp_reason(sbi);
- if (!test_opt(sbi, MERGE_CHECKPOINT) || cpc.reason != CP_SYNC) {
+ if (!test_opt(sbi, MERGE_CHECKPOINT) || cpc.reason != CP_SYNC ||
+ sbi->umount_lock_holder == current) {
int ret;
f2fs_down_write(&sbi->gc_lock);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 62b7fed1514a..7174dea641e9 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1670,6 +1670,7 @@ struct f2fs_sb_info {
unsigned int nquota_files; /* # of quota sysfile */
struct f2fs_rwsem quota_sem; /* blocking cp for flags */
+ struct task_struct *umount_lock_holder; /* s_umount lock holder */
/* # of pages, see count_type */
atomic_t nr_pages[NR_COUNT_TYPE];
@@ -3652,7 +3653,7 @@ int f2fs_inode_dirtied(struct inode *inode, bool sync);
void f2fs_inode_synced(struct inode *inode);
int f2fs_dquot_initialize(struct inode *inode);
int f2fs_enable_quota_files(struct f2fs_sb_info *sbi, bool rdonly);
-int f2fs_quota_sync(struct super_block *sb, int type);
+int f2fs_do_quota_sync(struct super_block *sb, int type);
loff_t max_file_blocks(struct inode *inode);
void f2fs_quota_off_umount(struct super_block *sb);
void f2fs_save_errors(struct f2fs_sb_info *sbi, unsigned char flag);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index ef639a6d82e5..cb9d7b6fa3ad 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1740,22 +1740,28 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
static int f2fs_freeze(struct super_block *sb)
{
+ struct f2fs_sb_info *sbi = F2FS_SB(sb);
+
if (f2fs_readonly(sb))
return 0;
/* IO error happened before */
- if (unlikely(f2fs_cp_error(F2FS_SB(sb))))
+ if (unlikely(f2fs_cp_error(sbi)))
return -EIO;
/* must be clean, since sync_filesystem() was already called */
- if (is_sbi_flag_set(F2FS_SB(sb), SBI_IS_DIRTY))
+ if (is_sbi_flag_set(sbi, SBI_IS_DIRTY))
return -EINVAL;
+ sbi->umount_lock_holder = current;
+
/* Let's flush checkpoints and stop the thread. */
- f2fs_flush_ckpt_thread(F2FS_SB(sb));
+ f2fs_flush_ckpt_thread(sbi);
+
+ sbi->umount_lock_holder = NULL;
/* to avoid deadlock on f2fs_evict_inode->SB_FREEZE_FS */
- set_sbi_flag(F2FS_SB(sb), SBI_IS_FREEZING);
+ set_sbi_flag(sbi, SBI_IS_FREEZING);
return 0;
}
@@ -2332,6 +2338,8 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
org_mount_opt = sbi->mount_opt;
old_sb_flags = sb->s_flags;
+ sbi->umount_lock_holder = current;
+
#ifdef CONFIG_QUOTA
org_mount_opt.s_jquota_fmt = F2FS_OPTION(sbi).s_jquota_fmt;
for (i = 0; i < MAXQUOTAS; i++) {
@@ -2555,6 +2563,8 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
limit_reserve_root(sbi);
*flags = (*flags & ~SB_LAZYTIME) | (sb->s_flags & SB_LAZYTIME);
+
+ sbi->umount_lock_holder = NULL;
return 0;
restore_checkpoint:
if (need_enable_checkpoint) {
@@ -2595,6 +2605,8 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
#endif
sbi->mount_opt = org_mount_opt;
sb->s_flags = old_sb_flags;
+
+ sbi->umount_lock_holder = NULL;
return err;
}
@@ -2911,7 +2923,7 @@ static int f2fs_quota_sync_file(struct f2fs_sb_info *sbi, int type)
return ret;
}
-int f2fs_quota_sync(struct super_block *sb, int type)
+int f2fs_do_quota_sync(struct super_block *sb, int type)
{
struct f2fs_sb_info *sbi = F2FS_SB(sb);
struct quota_info *dqopt = sb_dqopt(sb);
@@ -2959,6 +2971,16 @@ int f2fs_quota_sync(struct super_block *sb, int type)
return ret;
}
+static int f2fs_quota_sync(struct super_block *sb, int type)
+{
+ int ret;
+
+ F2FS_SB(sb)->umount_lock_holder = current;
+ ret = f2fs_do_quota_sync(sb, type);
+ F2FS_SB(sb)->umount_lock_holder = NULL;
+ return ret;
+}
+
static int f2fs_quota_on(struct super_block *sb, int type, int format_id,
const struct path *path)
{
@@ -2974,30 +2996,33 @@ static int f2fs_quota_on(struct super_block *sb, int type, int format_id,
if (path->dentry->d_sb != sb)
return -EXDEV;
- err = f2fs_quota_sync(sb, type);
+ F2FS_SB(sb)->umount_lock_holder = current;
+
+ err = f2fs_do_quota_sync(sb, type);
if (err)
- return err;
+ goto out;
inode = d_inode(path->dentry);
err = filemap_fdatawrite(inode->i_mapping);
if (err)
- return err;
+ goto out;
err = filemap_fdatawait(inode->i_mapping);
if (err)
- return err;
+ goto out;
err = dquot_quota_on(sb, type, format_id, path);
if (err)
- return err;
+ goto out;
inode_lock(inode);
F2FS_I(inode)->i_flags |= F2FS_QUOTA_DEFAULT_FL;
f2fs_set_inode_flags(inode);
inode_unlock(inode);
f2fs_mark_inode_dirty_sync(inode, false);
-
+out:
+ F2FS_SB(sb)->umount_lock_holder = NULL;
return 0;
}
@@ -3009,7 +3034,7 @@ static int __f2fs_quota_off(struct super_block *sb, int type)
if (!inode || !igrab(inode))
return dquot_quota_off(sb, type);
- err = f2fs_quota_sync(sb, type);
+ err = f2fs_do_quota_sync(sb, type);
if (err)
goto out_put;
@@ -3032,6 +3057,8 @@ static int f2fs_quota_off(struct super_block *sb, int type)
struct f2fs_sb_info *sbi = F2FS_SB(sb);
int err;
+ F2FS_SB(sb)->umount_lock_holder = current;
+
err = __f2fs_quota_off(sb, type);
/*
@@ -3041,6 +3068,9 @@ static int f2fs_quota_off(struct super_block *sb, int type)
*/
if (is_journalled_quota(sbi))
set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+
+ F2FS_SB(sb)->umount_lock_holder = NULL;
+
return err;
}
@@ -4715,6 +4745,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto free_compress_inode;
+ sbi->umount_lock_holder = current;
#ifdef CONFIG_QUOTA
/* Enable quota usage during mount */
if (f2fs_sb_has_quota_ino(sbi) && !f2fs_readonly(sb)) {
@@ -4841,6 +4872,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
f2fs_update_time(sbi, CP_TIME);
f2fs_update_time(sbi, REQ_TIME);
clear_sbi_flag(sbi, SBI_CP_DISABLED_QUICK);
+
+ sbi->umount_lock_holder = NULL;
return 0;
sync_free_meta:
@@ -4945,6 +4978,8 @@ static void kill_f2fs_super(struct super_block *sb)
struct f2fs_sb_info *sbi = F2FS_SB(sb);
if (sb->s_root) {
+ sbi->umount_lock_holder = current;
+
set_sbi_flag(sbi, SBI_IS_CLOSE);
f2fs_stop_gc_thread(sbi);
f2fs_stop_discard_thread(sbi);
--
2.48.1.502.g6dc24dfdaf-goog
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