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Date: Tue, 28 May 2013 13:18:57 +0400
From: Dmitry Monakhov <dmonakhov@...nvz.org>
To: linux-ext4@...r.kernel.org
Cc: jack@...e.cz, Dmitry Monakhov <dmonakhov@...nvz.org>
Subject: [PATCH 2/6] ext4: fix data integrity for ext4_sync_fs
Inode's data or non journaled quota may be written w/o jounral so we _must_
send a barrier at the end of ext4_sync_fs. But it can be skipped if journal
commit will do it for us.
Also fix data integrity for nojournal mode.
changes from v1:
skip barrier for async mode
Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
---
fs/ext4/super.c | 35 ++++++++++++++++++++++++++++++++++-
include/linux/jbd2.h | 15 +++++++++++++++
2 files changed, 49 insertions(+), 1 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dbc7c09..edc716d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -69,6 +69,7 @@ static void ext4_mark_recovery_complete(struct super_block *sb,
static void ext4_clear_journal_err(struct super_block *sb,
struct ext4_super_block *es);
static int ext4_sync_fs(struct super_block *sb, int wait);
+static int ext4_sync_fs_nojournal(struct super_block *sb, int wait);
static int ext4_remount(struct super_block *sb, int *flags, char *data);
static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
static int ext4_unfreeze(struct super_block *sb);
@@ -1096,6 +1097,7 @@ static const struct super_operations ext4_nojournal_sops = {
.dirty_inode = ext4_dirty_inode,
.drop_inode = ext4_drop_inode,
.evict_inode = ext4_evict_inode,
+ .sync_fs = ext4_sync_fs_nojournal,
.put_super = ext4_put_super,
.statfs = ext4_statfs,
.remount_fs = ext4_remount,
@@ -4520,6 +4522,7 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
{
int ret = 0;
tid_t target;
+ bool needs_barrier = false;
struct ext4_sb_info *sbi = EXT4_SB(sb);
trace_ext4_sync_fs(sb, wait);
@@ -4529,10 +4532,40 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
* no dirty dquots
*/
dquot_writeback_dquots(sb, -1);
+ /*
+ * Data writeback is possible w/o journal transaction, so barrier must
+ * being sent at the end of the function. But we can skip it if
+ * transaction_commit will do it for us.
+ */
+ target = jbd2_get_latest_transaction(sbi->s_journal);
+ if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
+ !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
+ needs_barrier = true;
+
if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
if (wait)
- jbd2_log_wait_commit(sbi->s_journal, target);
+ ret = jbd2_log_wait_commit(sbi->s_journal, target);
+ }
+ if (needs_barrier) {
+ int err;
+ err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+ if (!ret)
+ ret = err;
}
+
+ return ret;
+}
+
+static int ext4_sync_fs_nojournal(struct super_block *sb, int wait)
+{
+ int ret = 0;
+
+ trace_ext4_sync_fs(sb, wait);
+ flush_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
+ dquot_writeback_dquots(sb, -1);
+ if (wait && test_opt(sb, BARRIER))
+ ret = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+
return ret;
}
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index c9e1ab6..ed974fd 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1319,6 +1319,21 @@ static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
return *(u32 *)desc.ctx;
}
+/* Return most recent uncommitted transaction */
+static inline tid_t jbd2_get_latest_transaction(journal_t *journal)
+{
+ tid_t tid;
+
+ read_lock(&journal->j_state_lock);
+ tid = journal->j_commit_request;
+ if (journal->j_running_transaction) {
+ tid = journal->j_running_transaction->t_tid;
+ } else if (!journal->j_commit_sequence)
+ tid = journal->j_commit_sequence;
+ read_unlock(&journal->j_state_lock);
+ return tid;
+}
+
#ifdef __KERNEL__
#define buffer_trace_init(bh) do {} while (0)
--
1.7.1
--
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