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Message-ID: <20190604183619.GA8507@jaegeuk-macbookpro.roam.corp.google.com>
Date: Tue, 4 Jun 2019 11:36:19 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v3] f2fs: add a rw_sem to cover quota flag
changes
Two paths to update quota and f2fs_lock_op:
1.
- lock_op
| - quota_update
`- unlock_op
2.
- quota_update
- lock_op
`- unlock_op
But, we need to make a transaction on quota_update + lock_op in #2 case.
So, this patch introduces:
1. lock_op
2. down_write
3. check __need_flush
4. up_write
5. if there is dirty quota entries, flush them
6. otherwise, good to go
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
v3 from v2:
- refactor to fix quota corruption issue
: it seems that the previous scenario is not real and no deadlock case was
encountered.
fs/f2fs/checkpoint.c | 41 +++++++++++++++++++----------------------
fs/f2fs/f2fs.h | 1 +
fs/f2fs/super.c | 26 +++++++++++++++++++++-----
3 files changed, 41 insertions(+), 27 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 89825261d474..43f65f0962e5 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1131,17 +1131,24 @@ static void __prepare_cp_block(struct f2fs_sb_info *sbi)
static bool __need_flush_quota(struct f2fs_sb_info *sbi)
{
+ bool ret = false;
+
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))
- return true;
- return false;
+
+ down_write(&sbi->quota_sem);
+ 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)) {
+ clear_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
+ ret = true;
+ } else if (get_pages(sbi, F2FS_DIRTY_QDATA)) {
+ ret = true;
+ }
+ up_write(&sbi->quota_sem);
+ return ret;
}
/*
@@ -1160,26 +1167,22 @@ 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);
+ set_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
goto retry_flush_dents;
}
- clear_sbi_flag(sbi, SBI_QUOTA_NEED_FLUSH);
+ 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)
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 +1204,6 @@ 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 9674a85154b2..9bd2bf0f559b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1253,6 +1253,7 @@ 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 15d7e30bfc72..5a318399a2fa 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1964,6 +1964,7 @@ 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);
if (ret)
goto out;
@@ -2001,6 +2002,7 @@ int f2fs_quota_sync(struct super_block *sb, int type)
out:
if (ret)
set_sbi_flag(F2FS_SB(sb), SBI_QUOTA_NEED_REPAIR);
+ up_read(&sbi->quota_sem);
return ret;
}
@@ -2094,32 +2096,40 @@ 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;
}
@@ -2129,22 +2139,27 @@ 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;
}
@@ -3253,6 +3268,7 @@ 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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