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@kernel.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 8374d47..a28eac2 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1133,17 +1133,24 @@ 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;
 }
 
 /*
@@ -1162,26 +1169,22 @@ 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;
        }
@@ -1203,12 +1206,6 @@ retry_flush_dents:
         */
        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 611cb76..a3c506b 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1255,6 +1255,7 @@ 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 d8b8f3a..3acc38f 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1924,6 +1924,18 @@ int f2fs_quota_sync(struct super_block *sb, int type)
        int cnt;
        int ret;
 
+       /*
+        * do_quotactl
+        *  f2fs_quota_sync
+        *  down_read(quota_sem)
+        *  dquot_writeback_dquots()
+        *  f2fs_dquot_commit
+        *                            block_operation
+        *                            down_read(quota_sem)
+        */
+       f2fs_lock_op(sbi);
+
+       down_read(&sbi->quota_sem);
        ret = dquot_writeback_dquots(sb, type);
        if (ret)
                goto out;
@@ -1961,6 +1973,8 @@ 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);
+       f2fs_unlock_op(sbi);
        return ret;
 }
 
@@ -2052,32 +2066,40 @@ 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;
 }
 
@@ -2087,22 +2109,27 @@ 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;
 }
 
@@ -3176,6 +3203,7 @@ try_onemore:
        }
 
        init_rwsem(&sbi->cp_rwsem);
+       init_rwsem(&sbi->quota_sem);
        init_waitqueue_head(&sbi->cp_wait);
        init_sb_info(sbi);