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Message-ID: <20190530175714.GB28719@jaegeuk-macbookpro.roam.corp.google.com>
Date: Thu, 30 May 2019 10:57:14 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH v2] f2fs: add a rw_sem to cover quota flag changes
thread 1: thread 2:
writeback checkpoint
set QUOTA_NEED_FLUSH
clear QUOTA_NEED_FLUSH
f2fs_dquot_commit
dquot_commit
clear_dquot_dirty
f2fs_quota_sync
dquot_writeback_dquots
nothing to commit
commit_dqblk
quota_write
f2fs_quota_write
waiting for f2fs_lock_op()
pass __need_flush_quota
(no F2FS_DIRTY_QDATA)
-> up-to-date quota is not written
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
v2 from v1:
- avoid deadlock.
- shorten the loop path
fs/f2fs/checkpoint.c | 40 ++++++++++++++++++++--------------------
fs/f2fs/f2fs.h | 1 +
fs/f2fs/super.c | 27 ++++++++++++++++++++++-----
3 files changed, 43 insertions(+), 25 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 89825261d474..66f29907fc0e 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1131,17 +1131,26 @@ static void __prepare_cp_block(struct f2fs_sb_info *sbi)
static bool __need_flush_quota(struct f2fs_sb_info *sbi)
{
+ bool ret;
+
if (!is_journalled_quota(sbi))
return false;
- if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
- return false;
- if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
- return false;
- if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_FLUSH))
- return true;
- if (get_pages(sbi, F2FS_DIRTY_QDATA))
+
+ if (!down_write_trylock(&sbi->quota_sem))
return true;
- return false;
+
+ if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
+ ret = false;
+ else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
+ ret = false;
+ else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_FLUSH))
+ ret = true;
+ else if (get_pages(sbi, F2FS_DIRTY_QDATA))
+ ret = true;
+ else
+ ret = false;
+ up_write(&sbi->quota_sem);
+ return ret;
}
/*
@@ -1160,14 +1169,16 @@ static int block_operations(struct f2fs_sb_info *sbi)
blk_start_plug(&plug);
retry_flush_quotas:
+ f2fs_lock_all(sbi);
if (__need_flush_quota(sbi)) {
int locked;
if (++cnt > DEFAULT_RETRY_QUOTA_FLUSH_COUNT) {
set_sbi_flag(sbi, SBI_QUOTA_SKIP_FLUSH);
- f2fs_lock_all(sbi);
goto retry_flush_dents;
}
+
+ f2fs_unlock_all(sbi);
clear_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
/* only failed during mount/umount/freeze/quotactl */
@@ -1175,11 +1186,6 @@ static int block_operations(struct f2fs_sb_info *sbi)
f2fs_quota_sync(sbi->sb, -1);
if (locked)
up_read(&sbi->sb->s_umount);
- }
-
- f2fs_lock_all(sbi);
- if (__need_flush_quota(sbi)) {
- f2fs_unlock_all(sbi);
cond_resched();
goto retry_flush_quotas;
}
@@ -1201,12 +1207,6 @@ static int block_operations(struct f2fs_sb_info *sbi)
*/
down_write(&sbi->node_change);
- if (__need_flush_quota(sbi)) {
- up_write(&sbi->node_change);
- f2fs_unlock_all(sbi);
- goto retry_flush_quotas;
- }
-
if (get_pages(sbi, F2FS_DIRTY_IMETA)) {
up_write(&sbi->node_change);
f2fs_unlock_all(sbi);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9b3d9977cd1e..692c0922f5b2 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1250,6 +1250,7 @@ struct f2fs_sb_info {
block_t unusable_block_count; /* # of blocks saved by last cp */
unsigned int nquota_files; /* # of quota sysfile */
+ struct rw_semaphore quota_sem; /* blocking cp for flags */
/* # of pages, see count_type */
atomic_t nr_pages[NR_COUNT_TYPE];
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1dc02101e5e5..7a6d70d8e851 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1946,7 +1946,10 @@ int f2fs_quota_sync(struct super_block *sb, int type)
int cnt;
int ret;
+ down_read(&sbi->quota_sem);
ret = dquot_writeback_dquots(sb, type);
+ up_read(&sbi->quota_sem);
+
if (ret)
goto out;
@@ -2076,32 +2079,40 @@ static void f2fs_truncate_quota_inode_pages(struct super_block *sb)
static int f2fs_dquot_commit(struct dquot *dquot)
{
+ struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb);
int ret;
+ down_read(&sbi->quota_sem);
ret = dquot_commit(dquot);
if (ret < 0)
- set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR);
+ set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+ up_read(&sbi->quota_sem);
return ret;
}
static int f2fs_dquot_acquire(struct dquot *dquot)
{
+ struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb);
int ret;
+ down_read(&sbi->quota_sem);
ret = dquot_acquire(dquot);
if (ret < 0)
- set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR);
-
+ set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+ up_read(&sbi->quota_sem);
return ret;
}
static int f2fs_dquot_release(struct dquot *dquot)
{
+ struct f2fs_sb_info *sbi = F2FS_SB(dquot->dq_sb);
int ret;
+ down_read(&sbi->quota_sem);
ret = dquot_release(dquot);
if (ret < 0)
- set_sbi_flag(F2FS_SB(dquot->dq_sb), SBI_QUOTA_NEED_REPAIR);
+ set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+ up_read(&sbi->quota_sem);
return ret;
}
@@ -2111,22 +2122,27 @@ static int f2fs_dquot_mark_dquot_dirty(struct dquot *dquot)
struct f2fs_sb_info *sbi = F2FS_SB(sb);
int ret;
+ down_read(&sbi->quota_sem);
ret = dquot_mark_dquot_dirty(dquot);
/* if we are using journalled quota */
if (is_journalled_quota(sbi))
set_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
+ up_read(&sbi->quota_sem);
return ret;
}
static int f2fs_dquot_commit_info(struct super_block *sb, int type)
{
+ struct f2fs_sb_info *sbi = F2FS_SB(sb);
int ret;
+ down_read(&sbi->quota_sem);
ret = dquot_commit_info(sb, type);
if (ret < 0)
- set_sbi_flag(F2FS_SB(sb), SBI_QUOTA_NEED_REPAIR);
+ set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR);
+ up_read(&sbi->quota_sem);
return ret;
}
@@ -3235,6 +3251,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
}
init_rwsem(&sbi->cp_rwsem);
+ init_rwsem(&sbi->quota_sem);
init_waitqueue_head(&sbi->cp_wait);
init_sb_info(sbi);
--
2.19.0.605.g01d371f741-goog
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