ext4: Convert to new freezing mechanism

[~andy/linux] / fs / ext4 / super.c

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index eb7aa3e4ef05caf136f24e0565a28e6d1e0a1539..9cc9bfd5176b130b12754a7940147481700910d7 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -332,33 +332,17 @@ static void ext4_put_nojournal(handle_t *handle)
  * journal_end calls result in the superblock being marked dirty, so
  * that sync() will call the filesystem's write_super callback if
  * appropriate.
- *
- * To avoid j_barrier hold in userspace when a user calls freeze(),
- * ext4 prevents a new handle from being started by s_frozen, which
- * is in an upper layer.
  */
 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
 {
        journal_t *journal;
-       handle_t  *handle;
 
        trace_ext4_journal_start(sb, nblocks, _RET_IP_);
        if (sb->s_flags & MS_RDONLY)
                return ERR_PTR(-EROFS);
 
+       WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
        journal = EXT4_SB(sb)->s_journal;
-       handle = ext4_journal_current_handle();
-
-       /*
-        * If a handle has been started, it should be allowed to
-        * finish, otherwise deadlock could happen between freeze
-        * and others(e.g. truncate) due to the restart of the
-        * journal handle if the filesystem is forzen and active
-        * handles are not stopped.
-        */
-       if (!handle)
-               vfs_check_frozen(sb, SB_FREEZE_TRANS);
-
        if (!journal)
                return ext4_get_nojournal();
        /*
@@ -2723,6 +2707,7 @@ static int ext4_run_li_request(struct ext4_li_request *elr)
        sb = elr->lr_super;
        ngroups = EXT4_SB(sb)->s_groups_count;
 
+       sb_start_write(sb);
        for (group = elr->lr_next_group; group < ngroups; group++) {
                gdp = ext4_get_group_desc(sb, group, NULL);
                if (!gdp) {
@@ -2749,6 +2734,7 @@ static int ext4_run_li_request(struct ext4_li_request *elr)
                elr->lr_next_sched = jiffies + elr->lr_timeout;
                elr->lr_next_group = group + 1;
        }
+       sb_end_write(sb);
 
        return ret;
 }
@@ -4302,10 +4288,8 @@ int ext4_force_commit(struct super_block *sb)
                return 0;
 
        journal = EXT4_SB(sb)->s_journal;
-       if (journal) {
-               vfs_check_frozen(sb, SB_FREEZE_TRANS);
+       if (journal)
                ret = ext4_journal_force_commit(journal);
-       }
 
        return ret;
 }
@@ -4325,6 +4309,11 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
 
        trace_ext4_sync_fs(sb, wait);
        flush_workqueue(sbi->dio_unwritten_wq);
+       /*
+        * Writeback quota in non-journalled quota case - journalled quota has
+        * no dirty dquots
+        */
+       dquot_writeback_dquots(sb, -1);
        if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
                if (wait)
                        jbd2_log_wait_commit(sbi->s_journal, target);
@@ -4337,9 +4326,8 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
  * gives us a chance to flush the journal completely and mark the fs clean.
  *
  * Note that only this function cannot bring a filesystem to be in a clean
- * state independently, because ext4 prevents a new handle from being started
- * by @sb->s_frozen, which stays in an upper layer.  It thus needs help from
- * the upper layer.
+ * state independently. It relies on upper layer to stop all data & metadata
+ * modifications.
  */
 static int ext4_freeze(struct super_block *sb)
 {
@@ -4366,7 +4354,7 @@ static int ext4_freeze(struct super_block *sb)
        EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
        error = ext4_commit_super(sb, 1);
 out:
-       /* we rely on s_frozen to stop further updates */
+       /* we rely on upper layer to stop further updates */
        jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
        return error;
 }