From 2201c590dd6e802795e21e69e3c152c519f1568e Mon Sep 17 00:00:00 2001
From: Seiji Aguchi <seiji.aguchi@hds.com>
Date: Mon, 20 Feb 2012 17:53:01 -0500
Subject: jbd2: add drop_transaction/update_superblock_end tracepoints

This patch adds trace_jbd2_drop_transaction and
trace_jbd2_update_superblock_end because there are similar tracepoints
in jbd and they are needed in jbd2 as well.

Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c | 2 ++
 fs/jbd2/journal.c    | 2 ++
 2 files changed, 4 insertions(+)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index d49d202903fb..453c9068b7d7 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -797,5 +797,7 @@ void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transact
 	J_ASSERT(journal->j_committing_transaction != transaction);
 	J_ASSERT(journal->j_running_transaction != transaction);
 
+	trace_jbd2_drop_transaction(journal, transaction);
+
 	jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
 }
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index c0a5f9f1b127..93a595c69616 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1185,6 +1185,8 @@ void jbd2_journal_update_superblock(journal_t *journal, int wait)
 	} else
 		write_dirty_buffer(bh, WRITE);
 
+	trace_jbd2_update_superblock_end(journal, wait);
+
 out:
 	/* If we have just flushed the log (by marking s_start==0), then
 	 * any future commit will have to be careful to update the
-- 
cgit v1.2.3


From 15291164b22a357cb211b618adfef4fa82fc0de3 Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@redhat.com>
Date: Mon, 20 Feb 2012 17:53:01 -0500
Subject: jbd2: clear BH_Delay & BH_Unwritten in journal_unmap_buffer

journal_unmap_buffer()'s zap_buffer: code clears a lot of buffer head
state ala discard_buffer(), but does not touch _Delay or _Unwritten as
discard_buffer() does.

This can be problematic in some areas of the ext4 code which assume
that if they have found a buffer marked unwritten or delay, then it's
a live one.  Perhaps those spots should check whether it is mapped
as well, but if jbd2 is going to tear down a buffer, let's really
tear it down completely.

Without this I get some fsx failures on sub-page-block filesystems
up until v3.2, at which point 4e96b2dbbf1d7e81f22047a50f862555a6cb87cb
and 189e868fa8fdca702eb9db9d8afc46b5cb9144c9 make the failures go
away, because buried within that large change is some more flag
clearing.  I still think it's worth doing in jbd2, since
->invalidatepage leads here directly, and it's the right place
to clear away these flags.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
---
 fs/jbd2/transaction.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 35ae096bed5d..526533062548 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1949,6 +1949,8 @@ zap_buffer_unlocked:
 	clear_buffer_mapped(bh);
 	clear_buffer_req(bh);
 	clear_buffer_new(bh);
+	clear_buffer_delay(bh);
+	clear_buffer_unwritten(bh);
 	bh->b_bdev = NULL;
 	return may_free;
 }
-- 
cgit v1.2.3


From 0c2022eccb01630c037f2024531e9ff1afbe1564 Mon Sep 17 00:00:00 2001
From: Yongqiang Yang <xiaoqiangnk@gmail.com>
Date: Mon, 20 Feb 2012 17:53:02 -0500
Subject: jbd2: allocate transaction from separate slab cache

There is normally only a handful of these active at any one time, but
putting them in a separate slab cache makes debugging memory
corruption problems easier.  Manish Katiyar also wanted this make it
easier to test memory failure scenarios in the jbd2 layer.

Cc: Manish Katiyar <mkatiyar@gmail.com>
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c  |  2 +-
 fs/jbd2/commit.c      |  2 +-
 fs/jbd2/journal.c     |  3 +++
 fs/jbd2/transaction.c | 36 +++++++++++++++++++++++++++++++++---
 include/linux/jbd2.h  |  5 +++++
 5 files changed, 43 insertions(+), 5 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 453c9068b7d7..253e91890e71 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -722,7 +722,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 				    transaction->t_tid, stats);
 
 	__jbd2_journal_drop_transaction(journal, transaction);
-	kfree(transaction);
+	jbd2_journal_free_transaction(transaction);
 
 	/* Just in case anybody was waiting for more transactions to be
            checkpointed... */
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 5069b8475150..8adc5d460f56 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -1048,7 +1048,7 @@ restart_loop:
 	jbd_debug(1, "JBD2: commit %d complete, head %d\n",
 		  journal->j_commit_sequence, journal->j_tail_sequence);
 	if (to_free)
-		kfree(commit_transaction);
+		jbd2_journal_free_transaction(commit_transaction);
 
 	wake_up(&journal->j_wait_done_commit);
 }
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 93a595c69616..aa8f5986f8da 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2361,6 +2361,8 @@ static int __init journal_init_caches(void)
 		ret = journal_init_jbd2_journal_head_cache();
 	if (ret == 0)
 		ret = journal_init_handle_cache();
+	if (ret == 0)
+		ret = jbd2_journal_init_transaction_cache();
 	return ret;
 }
 
@@ -2369,6 +2371,7 @@ static void jbd2_journal_destroy_caches(void)
 	jbd2_journal_destroy_revoke_caches();
 	jbd2_journal_destroy_jbd2_journal_head_cache();
 	jbd2_journal_destroy_handle_cache();
+	jbd2_journal_destroy_transaction_cache();
 	jbd2_journal_destroy_slabs();
 }
 
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 526533062548..d0a8b017b281 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -33,6 +33,35 @@
 static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
 static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
 
+static struct kmem_cache *transaction_cache;
+int __init jbd2_journal_init_transaction_cache(void)
+{
+	J_ASSERT(!transaction_cache);
+	transaction_cache = kmem_cache_create("jbd2_transaction_s",
+					sizeof(transaction_t),
+					0,
+					SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
+					NULL);
+	if (transaction_cache)
+		return 0;
+	return -ENOMEM;
+}
+
+void jbd2_journal_destroy_transaction_cache(void)
+{
+	if (transaction_cache) {
+		kmem_cache_destroy(transaction_cache);
+		transaction_cache = NULL;
+	}
+}
+
+void jbd2_journal_free_transaction(transaction_t *transaction)
+{
+	if (unlikely(ZERO_OR_NULL_PTR(transaction)))
+		return;
+	kmem_cache_free(transaction_cache, transaction);
+}
+
 /*
  * jbd2_get_transaction: obtain a new transaction_t object.
  *
@@ -133,7 +162,8 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
 
 alloc_transaction:
 	if (!journal->j_running_transaction) {
-		new_transaction = kzalloc(sizeof(*new_transaction), gfp_mask);
+		new_transaction = kmem_cache_alloc(transaction_cache,
+						   gfp_mask | __GFP_ZERO);
 		if (!new_transaction) {
 			/*
 			 * If __GFP_FS is not present, then we may be
@@ -162,7 +192,7 @@ repeat:
 	if (is_journal_aborted(journal) ||
 	    (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
 		read_unlock(&journal->j_state_lock);
-		kfree(new_transaction);
+		jbd2_journal_free_transaction(new_transaction);
 		return -EROFS;
 	}
 
@@ -284,7 +314,7 @@ repeat:
 	read_unlock(&journal->j_state_lock);
 
 	lock_map_acquire(&handle->h_lockdep_map);
-	kfree(new_transaction);
+	jbd2_journal_free_transaction(new_transaction);
 	return 0;
 }
 
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 5557baefed60..46eef77e6ab8 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1020,6 +1020,11 @@ jbd2_journal_write_metadata_buffer(transaction_t	  *transaction,
 /* Transaction locking */
 extern void		__wait_on_journal (journal_t *);
 
+/* Transaction cache support */
+extern void jbd2_journal_destroy_transaction_cache(void);
+extern int  jbd2_journal_init_transaction_cache(void);
+extern void jbd2_journal_free_transaction(transaction_t *);
+
 /*
  * Journal locking.
  *
-- 
cgit v1.2.3


From 4185a2ac422c7fc76a77a3eb2c38ce19eeaae563 Mon Sep 17 00:00:00 2001
From: Yongqiang Yang <xiaoqiangnk@gmail.com>
Date: Mon, 20 Feb 2012 17:53:03 -0500
Subject: jbd2: rename functions which initialize slab caches

This patch renames functions initializing the slab caches for the
journal head and handle structures to so they are consistent with the
names of the corresponding functions which destroys those slab caches.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/journal.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index aa8f5986f8da..47e341100c2c 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2017,7 +2017,7 @@ static struct kmem_cache *jbd2_journal_head_cache;
 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
 #endif
 
-static int journal_init_jbd2_journal_head_cache(void)
+static int jbd2_journal_init_journal_head_cache(void)
 {
 	int retval;
 
@@ -2035,7 +2035,7 @@ static int journal_init_jbd2_journal_head_cache(void)
 	return retval;
 }
 
-static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
+static void jbd2_journal_destroy_journal_head_cache(void)
 {
 	if (jbd2_journal_head_cache) {
 		kmem_cache_destroy(jbd2_journal_head_cache);
@@ -2323,7 +2323,7 @@ static void __exit jbd2_remove_jbd_stats_proc_entry(void)
 
 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
 
-static int __init journal_init_handle_cache(void)
+static int __init jbd2_journal_init_handle_cache(void)
 {
 	jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
 	if (jbd2_handle_cache == NULL) {
@@ -2358,9 +2358,9 @@ static int __init journal_init_caches(void)
 
 	ret = jbd2_journal_init_revoke_caches();
 	if (ret == 0)
-		ret = journal_init_jbd2_journal_head_cache();
+		ret = jbd2_journal_init_journal_head_cache();
 	if (ret == 0)
-		ret = journal_init_handle_cache();
+		ret = jbd2_journal_init_handle_cache();
 	if (ret == 0)
 		ret = jbd2_journal_init_transaction_cache();
 	return ret;
@@ -2369,7 +2369,7 @@ static int __init journal_init_caches(void)
 static void jbd2_journal_destroy_caches(void)
 {
 	jbd2_journal_destroy_revoke_caches();
-	jbd2_journal_destroy_jbd2_journal_head_cache();
+	jbd2_journal_destroy_journal_head_cache();
 	jbd2_journal_destroy_handle_cache();
 	jbd2_journal_destroy_transaction_cache();
 	jbd2_journal_destroy_slabs();
-- 
cgit v1.2.3


From 9c0e00e5ce0d23e3e0a93f99ae8e94398e32a2d2 Mon Sep 17 00:00:00 2001
From: Yongqiang Yang <xiaoqiangnk@gmail.com>
Date: Mon, 20 Feb 2012 17:53:03 -0500
Subject: jbd2: use KMEM_CACHE instead of kmem_cache_create()

Use the KMEM_CACHE helper macro instead of kmem_cache_create().

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/revoke.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index 30b2867d6cc9..6973705d6a3d 100644
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -208,17 +208,13 @@ int __init jbd2_journal_init_revoke_caches(void)
 	J_ASSERT(!jbd2_revoke_record_cache);
 	J_ASSERT(!jbd2_revoke_table_cache);
 
-	jbd2_revoke_record_cache = kmem_cache_create("jbd2_revoke_record",
-					   sizeof(struct jbd2_revoke_record_s),
-					   0,
-					   SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
-					   NULL);
+	jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
+					SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
 	if (!jbd2_revoke_record_cache)
 		goto record_cache_failure;
 
-	jbd2_revoke_table_cache = kmem_cache_create("jbd2_revoke_table",
-					   sizeof(struct jbd2_revoke_table_s),
-					   0, SLAB_TEMPORARY, NULL);
+	jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
+					     SLAB_TEMPORARY);
 	if (!jbd2_revoke_table_cache)
 		goto table_cache_failure;
 	return 0;
-- 
cgit v1.2.3


From 43e625d84fa7daca0ad46f1dbc965b04fd204afe Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@redhat.com>
Date: Mon, 20 Feb 2012 17:53:04 -0500
Subject: ext4: remove the journal=update mount option

The V2 journal format was introduced around ten years ago,
for ext3. It seems highly unlikely that anyone will need this
migration option for ext4.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 Documentation/filesystems/ext4.txt |  3 --
 fs/ext4/super.c                    | 26 +----------------
 fs/jbd2/journal.c                  | 57 --------------------------------------
 3 files changed, 1 insertion(+), 85 deletions(-)

(limited to 'fs/jbd2')

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 10ec4639f152..09d5f32ea156 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -144,9 +144,6 @@ journal_async_commit	Commit block can be written to disk without waiting
 			mount the device. This will enable 'journal_checksum'
 			internally.
 
-journal=update		Update the ext4 file system's journal to the current
-			format.
-
 journal_dev=devnum	When the external journal device's major/minor numbers
 			have changed, this option allows the user to specify
 			the new journal location.  The journal device is
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3e697ec7feca..9420c50c5c6a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1336,8 +1336,7 @@ enum {
 	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
 	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
 	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
-	Opt_journal_update, Opt_journal_dev,
-	Opt_journal_checksum, Opt_journal_async_commit,
+	Opt_journal_dev, Opt_journal_checksum, Opt_journal_async_commit,
 	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
 	Opt_data_err_abort, Opt_data_err_ignore,
 	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
@@ -1379,7 +1378,6 @@ static const match_table_t tokens = {
 	{Opt_commit, "commit=%u"},
 	{Opt_min_batch_time, "min_batch_time=%u"},
 	{Opt_max_batch_time, "max_batch_time=%u"},
-	{Opt_journal_update, "journal=update"},
 	{Opt_journal_dev, "journal_dev=%u"},
 	{Opt_journal_checksum, "journal_checksum"},
 	{Opt_journal_async_commit, "journal_async_commit"},
@@ -1629,19 +1627,6 @@ static int parse_options(char *options, struct super_block *sb,
 			ext4_msg(sb, KERN_ERR, "(no)acl options not supported");
 			break;
 #endif
-		case Opt_journal_update:
-			/* @@@ FIXME */
-			/* Eventually we will want to be able to create
-			   a journal file here.  For now, only allow the
-			   user to specify an existing inode to be the
-			   journal file. */
-			if (is_remount) {
-				ext4_msg(sb, KERN_ERR,
-					 "Cannot specify journal on remount");
-				return 0;
-			}
-			set_opt(sb, UPDATE_JOURNAL);
-			break;
 		case Opt_journal_dev:
 			if (is_remount) {
 				ext4_msg(sb, KERN_ERR,
@@ -4109,15 +4094,6 @@ static int ext4_load_journal(struct super_block *sb,
 	if (!(journal->j_flags & JBD2_BARRIER))
 		ext4_msg(sb, KERN_INFO, "barriers disabled");
 
-	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
-		err = jbd2_journal_update_format(journal);
-		if (err)  {
-			ext4_msg(sb, KERN_ERR, "error updating journal");
-			jbd2_journal_destroy(journal);
-			return err;
-		}
-	}
-
 	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
 		err = jbd2_journal_wipe(journal, !really_read_only);
 	if (!err) {
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 47e341100c2c..cfb36d99f7a4 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -71,7 +71,6 @@ EXPORT_SYMBOL(jbd2_journal_revoke);
 
 EXPORT_SYMBOL(jbd2_journal_init_dev);
 EXPORT_SYMBOL(jbd2_journal_init_inode);
-EXPORT_SYMBOL(jbd2_journal_update_format);
 EXPORT_SYMBOL(jbd2_journal_check_used_features);
 EXPORT_SYMBOL(jbd2_journal_check_available_features);
 EXPORT_SYMBOL(jbd2_journal_set_features);
@@ -96,7 +95,6 @@ EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
 EXPORT_SYMBOL(jbd2_inode_cache);
 
-static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
 static void __journal_abort_soft (journal_t *journal, int errno);
 static int jbd2_journal_create_slab(size_t slab_size);
 
@@ -1551,61 +1549,6 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
 }
 EXPORT_SYMBOL(jbd2_journal_clear_features);
 
-/**
- * int jbd2_journal_update_format () - Update on-disk journal structure.
- * @journal: Journal to act on.
- *
- * Given an initialised but unloaded journal struct, poke about in the
- * on-disk structure to update it to the most recent supported version.
- */
-int jbd2_journal_update_format (journal_t *journal)
-{
-	journal_superblock_t *sb;
-	int err;
-
-	err = journal_get_superblock(journal);
-	if (err)
-		return err;
-
-	sb = journal->j_superblock;
-
-	switch (be32_to_cpu(sb->s_header.h_blocktype)) {
-	case JBD2_SUPERBLOCK_V2:
-		return 0;
-	case JBD2_SUPERBLOCK_V1:
-		return journal_convert_superblock_v1(journal, sb);
-	default:
-		break;
-	}
-	return -EINVAL;
-}
-
-static int journal_convert_superblock_v1(journal_t *journal,
-					 journal_superblock_t *sb)
-{
-	int offset, blocksize;
-	struct buffer_head *bh;
-
-	printk(KERN_WARNING
-		"JBD2: Converting superblock from version 1 to 2.\n");
-
-	/* Pre-initialise new fields to zero */
-	offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
-	blocksize = be32_to_cpu(sb->s_blocksize);
-	memset(&sb->s_feature_compat, 0, blocksize-offset);
-
-	sb->s_nr_users = cpu_to_be32(1);
-	sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
-	journal->j_format_version = 2;
-
-	bh = journal->j_sb_buffer;
-	BUFFER_TRACE(bh, "marking dirty");
-	mark_buffer_dirty(bh);
-	sync_dirty_buffer(bh);
-	return 0;
-}
-
-
 /**
  * int jbd2_journal_flush () - Flush journal
  * @journal: Journal to act on.
-- 
cgit v1.2.3


From 24bcc89c7e7c64982e6192b4952a0a92379fc341 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 15:41:04 -0400
Subject: jbd2: split updating of journal superblock and marking journal empty

There are three case of updating journal superblock. In the first case, we want
to mark journal as empty (setting s_sequence to 0), in the second case we want
to update log tail, in the third case we want to update s_errno. Split these
cases into separate functions. It makes the code slightly more straightforward
and later patches will make the distinction even more important.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c        |   2 +-
 fs/jbd2/commit.c            |   2 +-
 fs/jbd2/journal.c           | 163 ++++++++++++++++++++++++++------------------
 include/linux/jbd2.h        |   2 +-
 include/trace/events/jbd2.h |  12 ++--
 5 files changed, 102 insertions(+), 79 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 253e91890e71..19dcd0b86bca 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -550,7 +550,7 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
 	    (journal->j_flags & JBD2_BARRIER))
 		blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
 	if (!(journal->j_flags & JBD2_ABORT))
-		jbd2_journal_update_superblock(journal, 1);
+		jbd2_journal_update_sb_log_tail(journal);
 	return 0;
 }
 
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 8adc5d460f56..19371a8a9015 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -340,7 +340,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	/* Do we need to erase the effects of a prior jbd2_journal_flush? */
 	if (journal->j_flags & JBD2_FLUSHED) {
 		jbd_debug(3, "super block updated\n");
-		jbd2_journal_update_superblock(journal, 1);
+		jbd2_journal_update_sb_log_tail(journal);
 	} else {
 		jbd_debug(3, "superblock not updated\n");
 	}
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index cfb36d99f7a4..6e75fbd75bad 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1110,40 +1110,30 @@ static int journal_reset(journal_t *journal)
 
 	journal->j_max_transaction_buffers = journal->j_maxlen / 4;
 
-	/* Add the dynamic fields and write it to disk. */
-	jbd2_journal_update_superblock(journal, 1);
-	return jbd2_journal_start_thread(journal);
-}
-
-/**
- * void jbd2_journal_update_superblock() - Update journal sb on disk.
- * @journal: The journal to update.
- * @wait: Set to '0' if you don't want to wait for IO completion.
- *
- * Update a journal's dynamic superblock fields and write it to disk,
- * optionally waiting for the IO to complete.
- */
-void jbd2_journal_update_superblock(journal_t *journal, int wait)
-{
-	journal_superblock_t *sb = journal->j_superblock;
-	struct buffer_head *bh = journal->j_sb_buffer;
-
 	/*
 	 * As a special case, if the on-disk copy is already marked as needing
-	 * no recovery (s_start == 0) and there are no outstanding transactions
-	 * in the filesystem, then we can safely defer the superblock update
-	 * until the next commit by setting JBD2_FLUSHED.  This avoids
+	 * no recovery (s_start == 0), then we can safely defer the superblock
+	 * update until the next commit by setting JBD2_FLUSHED.  This avoids
 	 * attempting a write to a potential-readonly device.
 	 */
-	if (sb->s_start == 0 && journal->j_tail_sequence ==
-				journal->j_transaction_sequence) {
+	if (sb->s_start == 0) {
 		jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
 			"(start %ld, seq %d, errno %d)\n",
 			journal->j_tail, journal->j_tail_sequence,
 			journal->j_errno);
-		goto out;
+		journal->j_flags |= JBD2_FLUSHED;
+	} else {
+		/* Add the dynamic fields and write it to disk. */
+		jbd2_journal_update_sb_log_tail(journal);
 	}
+	return jbd2_journal_start_thread(journal);
+}
 
+static void jbd2_write_superblock(journal_t *journal)
+{
+	struct buffer_head *bh = journal->j_sb_buffer;
+
+	trace_jbd2_write_superblock(journal);
 	if (buffer_write_io_error(bh)) {
 		/*
 		 * Oh, dear.  A previous attempt to write the journal
@@ -1160,49 +1150,98 @@ void jbd2_journal_update_superblock(journal_t *journal, int wait)
 		set_buffer_uptodate(bh);
 	}
 
+	BUFFER_TRACE(bh, "marking dirty");
+	mark_buffer_dirty(bh);
+	sync_dirty_buffer(bh);
+	if (buffer_write_io_error(bh)) {
+		printk(KERN_ERR "JBD2: I/O error detected "
+		       "when updating journal superblock for %s.\n",
+		       journal->j_devname);
+		clear_buffer_write_io_error(bh);
+		set_buffer_uptodate(bh);
+	}
+}
+
+/**
+ * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
+ * @journal: The journal to update.
+ *
+ * Update a journal's superblock information about log tail and write it to
+ * disk, waiting for the IO to complete.
+ */
+void jbd2_journal_update_sb_log_tail(journal_t *journal)
+{
+	journal_superblock_t *sb = journal->j_superblock;
+
 	read_lock(&journal->j_state_lock);
-	jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d, errno %d)\n",
-		  journal->j_tail, journal->j_tail_sequence, journal->j_errno);
+	jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d)\n",
+		  journal->j_tail, journal->j_tail_sequence);
 
 	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
 	sb->s_start    = cpu_to_be32(journal->j_tail);
-	sb->s_errno    = cpu_to_be32(journal->j_errno);
 	read_unlock(&journal->j_state_lock);
 
-	BUFFER_TRACE(bh, "marking dirty");
-	mark_buffer_dirty(bh);
-	if (wait) {
-		sync_dirty_buffer(bh);
-		if (buffer_write_io_error(bh)) {
-			printk(KERN_ERR "JBD2: I/O error detected "
-			       "when updating journal superblock for %s.\n",
-			       journal->j_devname);
-			clear_buffer_write_io_error(bh);
-			set_buffer_uptodate(bh);
-		}
-	} else
-		write_dirty_buffer(bh, WRITE);
+	jbd2_write_superblock(journal);
 
-	trace_jbd2_update_superblock_end(journal, wait);
+	/* Log is no longer empty */
+	write_lock(&journal->j_state_lock);
+	WARN_ON(!sb->s_sequence);
+	journal->j_flags &= ~JBD2_FLUSHED;
+	write_unlock(&journal->j_state_lock);
+}
 
-out:
-	/* If we have just flushed the log (by marking s_start==0), then
-	 * any future commit will have to be careful to update the
-	 * superblock again to re-record the true start of the log. */
+/**
+ * jbd2_mark_journal_empty() - Mark on disk journal as empty.
+ * @journal: The journal to update.
+ *
+ * Update a journal's dynamic superblock fields to show that journal is empty.
+ * Write updated superblock to disk waiting for IO to complete.
+ */
+static void jbd2_mark_journal_empty(journal_t *journal)
+{
+	journal_superblock_t *sb = journal->j_superblock;
+
+	read_lock(&journal->j_state_lock);
+	jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
+		  journal->j_tail_sequence);
+
+	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
+	sb->s_start    = cpu_to_be32(0);
+	read_unlock(&journal->j_state_lock);
+
+	jbd2_write_superblock(journal);
 
+	/* Log is no longer empty */
 	write_lock(&journal->j_state_lock);
-	if (sb->s_start)
-		journal->j_flags &= ~JBD2_FLUSHED;
-	else
-		journal->j_flags |= JBD2_FLUSHED;
+	journal->j_flags |= JBD2_FLUSHED;
 	write_unlock(&journal->j_state_lock);
 }
 
+
+/**
+ * jbd2_journal_update_sb_errno() - Update error in the journal.
+ * @journal: The journal to update.
+ *
+ * Update a journal's errno.  Write updated superblock to disk waiting for IO
+ * to complete.
+ */
+static void jbd2_journal_update_sb_errno(journal_t *journal)
+{
+	journal_superblock_t *sb = journal->j_superblock;
+
+	read_lock(&journal->j_state_lock);
+	jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
+		  journal->j_errno);
+	sb->s_errno    = cpu_to_be32(journal->j_errno);
+	read_unlock(&journal->j_state_lock);
+
+	jbd2_write_superblock(journal);
+}
+
 /*
  * Read the superblock for a given journal, performing initial
  * validation of the format.
  */
-
 static int journal_get_superblock(journal_t *journal)
 {
 	struct buffer_head *bh;
@@ -1395,15 +1434,10 @@ int jbd2_journal_destroy(journal_t *journal)
 	spin_unlock(&journal->j_list_lock);
 
 	if (journal->j_sb_buffer) {
-		if (!is_journal_aborted(journal)) {
-			/* We can now mark the journal as empty. */
-			journal->j_tail = 0;
-			journal->j_tail_sequence =
-				++journal->j_transaction_sequence;
-			jbd2_journal_update_superblock(journal, 1);
-		} else {
+		if (!is_journal_aborted(journal))
+			jbd2_mark_journal_empty(journal);
+		else
 			err = -EIO;
-		}
 		brelse(journal->j_sb_buffer);
 	}
 
@@ -1562,7 +1596,6 @@ int jbd2_journal_flush(journal_t *journal)
 {
 	int err = 0;
 	transaction_t *transaction = NULL;
-	unsigned long old_tail;
 
 	write_lock(&journal->j_state_lock);
 
@@ -1604,14 +1637,8 @@ int jbd2_journal_flush(journal_t *journal)
 	 * the magic code for a fully-recovered superblock.  Any future
 	 * commits of data to the journal will restore the current
 	 * s_start value. */
+	jbd2_mark_journal_empty(journal);
 	write_lock(&journal->j_state_lock);
-	old_tail = journal->j_tail;
-	journal->j_tail = 0;
-	write_unlock(&journal->j_state_lock);
-	jbd2_journal_update_superblock(journal, 1);
-	write_lock(&journal->j_state_lock);
-	journal->j_tail = old_tail;
-
 	J_ASSERT(!journal->j_running_transaction);
 	J_ASSERT(!journal->j_committing_transaction);
 	J_ASSERT(!journal->j_checkpoint_transactions);
@@ -1652,7 +1679,7 @@ int jbd2_journal_wipe(journal_t *journal, int write)
 
 	err = jbd2_journal_skip_recovery(journal);
 	if (write)
-		jbd2_journal_update_superblock(journal, 1);
+		jbd2_mark_journal_empty(journal);
 
  no_recovery:
 	return err;
@@ -1702,7 +1729,7 @@ static void __journal_abort_soft (journal_t *journal, int errno)
 	__jbd2_journal_abort_hard(journal);
 
 	if (errno)
-		jbd2_journal_update_superblock(journal, 1);
+		jbd2_journal_update_sb_errno(journal);
 }
 
 /**
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 46eef77e6ab8..5f05c77438e5 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1087,7 +1087,7 @@ extern int	   jbd2_journal_destroy    (journal_t *);
 extern int	   jbd2_journal_recover    (journal_t *journal);
 extern int	   jbd2_journal_wipe       (journal_t *, int);
 extern int	   jbd2_journal_skip_recovery	(journal_t *);
-extern void	   jbd2_journal_update_superblock	(journal_t *, int);
+extern void	   jbd2_journal_update_sb_log_tail	(journal_t *);
 extern void	   __jbd2_journal_abort_hard	(journal_t *);
 extern void	   jbd2_journal_abort      (journal_t *, int);
 extern int	   jbd2_journal_errno      (journal_t *);
diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h
index ae59bc207d70..e05a362bf3f1 100644
--- a/include/trace/events/jbd2.h
+++ b/include/trace/events/jbd2.h
@@ -236,25 +236,21 @@ TRACE_EVENT(jbd2_cleanup_journal_tail,
 		  __entry->block_nr, __entry->freed)
 );
 
-TRACE_EVENT(jbd2_update_superblock_end,
+TRACE_EVENT(jbd2_write_superblock,
 
-	TP_PROTO(journal_t *journal, int wait),
+	TP_PROTO(journal_t *journal),
 
-	TP_ARGS(journal, wait),
+	TP_ARGS(journal),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,  dev			)
-		__field(	int,    wait			)
 	),
 
 	TP_fast_assign(
 		__entry->dev		= journal->j_fs_dev->bd_dev;
-		__entry->wait		= wait;
 	),
 
-	TP_printk("dev %d,%d wait %d",
-		  MAJOR(__entry->dev), MINOR(__entry->dev),
-		  __entry->wait)
+	TP_printk("dev %d,%d", MAJOR(__entry->dev), MINOR(__entry->dev))
 );
 
 #endif /* _TRACE_JBD2_H */
-- 
cgit v1.2.3


From a78bb11d7acd525623c6a0c2ff4e213d527573fa Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 15:43:04 -0400
Subject: jbd2: protect all log tail updates with j_checkpoint_mutex

There are some log tail updates that are not protected by j_checkpoint_mutex.
Some of these are harmless because they happen during startup or shutdown but
updates in jbd2_journal_commit_transaction() and jbd2_journal_flush() can
really race with other log tail updates (e.g. someone doing
jbd2_journal_flush() with someone running jbd2_cleanup_journal_tail()). So
protect all log tail updates with j_checkpoint_mutex.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/commit.c  |  2 ++
 fs/jbd2/journal.c | 19 ++++++++++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 19371a8a9015..6705717d9b7f 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -340,7 +340,9 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	/* Do we need to erase the effects of a prior jbd2_journal_flush? */
 	if (journal->j_flags & JBD2_FLUSHED) {
 		jbd_debug(3, "super block updated\n");
+		mutex_lock(&journal->j_checkpoint_mutex);
 		jbd2_journal_update_sb_log_tail(journal);
+		mutex_unlock(&journal->j_checkpoint_mutex);
 	} else {
 		jbd_debug(3, "superblock not updated\n");
 	}
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 6e75fbd75bad..fc5f2acc9f18 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1123,8 +1123,11 @@ static int journal_reset(journal_t *journal)
 			journal->j_errno);
 		journal->j_flags |= JBD2_FLUSHED;
 	} else {
+		/* Lock here to make assertions happy... */
+		mutex_lock(&journal->j_checkpoint_mutex);
 		/* Add the dynamic fields and write it to disk. */
 		jbd2_journal_update_sb_log_tail(journal);
+		mutex_unlock(&journal->j_checkpoint_mutex);
 	}
 	return jbd2_journal_start_thread(journal);
 }
@@ -1173,6 +1176,7 @@ void jbd2_journal_update_sb_log_tail(journal_t *journal)
 {
 	journal_superblock_t *sb = journal->j_superblock;
 
+	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
 	read_lock(&journal->j_state_lock);
 	jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d)\n",
 		  journal->j_tail, journal->j_tail_sequence);
@@ -1201,6 +1205,7 @@ static void jbd2_mark_journal_empty(journal_t *journal)
 {
 	journal_superblock_t *sb = journal->j_superblock;
 
+	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
 	read_lock(&journal->j_state_lock);
 	jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
 		  journal->j_tail_sequence);
@@ -1434,9 +1439,11 @@ int jbd2_journal_destroy(journal_t *journal)
 	spin_unlock(&journal->j_list_lock);
 
 	if (journal->j_sb_buffer) {
-		if (!is_journal_aborted(journal))
+		if (!is_journal_aborted(journal)) {
+			mutex_lock(&journal->j_checkpoint_mutex);
 			jbd2_mark_journal_empty(journal);
-		else
+			mutex_unlock(&journal->j_checkpoint_mutex);
+		} else
 			err = -EIO;
 		brelse(journal->j_sb_buffer);
 	}
@@ -1630,6 +1637,7 @@ int jbd2_journal_flush(journal_t *journal)
 	if (is_journal_aborted(journal))
 		return -EIO;
 
+	mutex_lock(&journal->j_checkpoint_mutex);
 	jbd2_cleanup_journal_tail(journal);
 
 	/* Finally, mark the journal as really needing no recovery.
@@ -1638,6 +1646,7 @@ int jbd2_journal_flush(journal_t *journal)
 	 * commits of data to the journal will restore the current
 	 * s_start value. */
 	jbd2_mark_journal_empty(journal);
+	mutex_unlock(&journal->j_checkpoint_mutex);
 	write_lock(&journal->j_state_lock);
 	J_ASSERT(!journal->j_running_transaction);
 	J_ASSERT(!journal->j_committing_transaction);
@@ -1678,8 +1687,12 @@ int jbd2_journal_wipe(journal_t *journal, int write)
 		write ? "Clearing" : "Ignoring");
 
 	err = jbd2_journal_skip_recovery(journal);
-	if (write)
+	if (write) {
+		/* Lock to make assertions happy... */
+		mutex_lock(&journal->j_checkpoint_mutex);
 		jbd2_mark_journal_empty(journal);
+		mutex_unlock(&journal->j_checkpoint_mutex);
+	}
 
  no_recovery:
 	return err;
-- 
cgit v1.2.3


From 79feb521a44705262d15cc819a4117a447b11ea7 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 22:22:54 -0400
Subject: jbd2: issue cache flush after checkpointing even with internal
 journal

When we reach jbd2_cleanup_journal_tail(), there is no guarantee that
checkpointed buffers are on a stable storage - especially if buffers were
written out by jbd2_log_do_checkpoint(), they are likely to be only in disk's
caches. Thus when we update journal superblock effectively removing old
transaction from journal, this write of superblock can get to stable storage
before those checkpointed buffers which can result in filesystem corruption
after a crash. Thus we must unconditionally issue a cache flush before we
update journal superblock in these cases.

A similar problem can also occur if journal superblock is written only in
disk's caches, other transaction starts reusing space of the transaction
cleaned from the log and power failure happens. Subsequent journal replay would
still try to replay the old transaction but some of it's blocks may be already
overwritten by the new transaction. For this reason we must use WRITE_FUA when
updating log tail and we must first write new log tail to disk and update
in-memory information only after that.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c        |  75 ++++--------------------
 fs/jbd2/commit.c            |  11 +++-
 fs/jbd2/journal.c           | 138 +++++++++++++++++++++++++++++++++++++-------
 fs/jbd2/recovery.c          |   5 +-
 include/linux/jbd2.h        |   6 +-
 include/trace/events/jbd2.h |  11 ++--
 6 files changed, 155 insertions(+), 91 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 19dcd0b86bca..7f7ee5b90402 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -478,79 +478,28 @@ out:
 
 int jbd2_cleanup_journal_tail(journal_t *journal)
 {
-	transaction_t * transaction;
 	tid_t		first_tid;
-	unsigned long	blocknr, freed;
+	unsigned long	blocknr;
 
 	if (is_journal_aborted(journal))
 		return 1;
 
-	/* OK, work out the oldest transaction remaining in the log, and
-	 * the log block it starts at.
-	 *
-	 * If the log is now empty, we need to work out which is the
-	 * next transaction ID we will write, and where it will
-	 * start. */
-
-	write_lock(&journal->j_state_lock);
-	spin_lock(&journal->j_list_lock);
-	transaction = journal->j_checkpoint_transactions;
-	if (transaction) {
-		first_tid = transaction->t_tid;
-		blocknr = transaction->t_log_start;
-	} else if ((transaction = journal->j_committing_transaction) != NULL) {
-		first_tid = transaction->t_tid;
-		blocknr = transaction->t_log_start;
-	} else if ((transaction = journal->j_running_transaction) != NULL) {
-		first_tid = transaction->t_tid;
-		blocknr = journal->j_head;
-	} else {
-		first_tid = journal->j_transaction_sequence;
-		blocknr = journal->j_head;
-	}
-	spin_unlock(&journal->j_list_lock);
-	J_ASSERT(blocknr != 0);
-
-	/* If the oldest pinned transaction is at the tail of the log
-           already then there's not much we can do right now. */
-	if (journal->j_tail_sequence == first_tid) {
-		write_unlock(&journal->j_state_lock);
+	if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
 		return 1;
-	}
-
-	/* OK, update the superblock to recover the freed space.
-	 * Physical blocks come first: have we wrapped beyond the end of
-	 * the log?  */
-	freed = blocknr - journal->j_tail;
-	if (blocknr < journal->j_tail)
-		freed = freed + journal->j_last - journal->j_first;
-
-	trace_jbd2_cleanup_journal_tail(journal, first_tid, blocknr, freed);
-	jbd_debug(1,
-		  "Cleaning journal tail from %d to %d (offset %lu), "
-		  "freeing %lu\n",
-		  journal->j_tail_sequence, first_tid, blocknr, freed);
-
-	journal->j_free += freed;
-	journal->j_tail_sequence = first_tid;
-	journal->j_tail = blocknr;
-	write_unlock(&journal->j_state_lock);
+	J_ASSERT(blocknr != 0);
 
 	/*
-	 * If there is an external journal, we need to make sure that
-	 * any data blocks that were recently written out --- perhaps
-	 * by jbd2_log_do_checkpoint() --- are flushed out before we
-	 * drop the transactions from the external journal.  It's
-	 * unlikely this will be necessary, especially with a
-	 * appropriately sized journal, but we need this to guarantee
-	 * correctness.  Fortunately jbd2_cleanup_journal_tail()
-	 * doesn't get called all that often.
+	 * We need to make sure that any blocks that were recently written out
+	 * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before
+	 * we drop the transactions from the journal. It's unlikely this will
+	 * be necessary, especially with an appropriately sized journal, but we
+	 * need this to guarantee correctness.  Fortunately
+	 * jbd2_cleanup_journal_tail() doesn't get called all that often.
 	 */
-	if ((journal->j_fs_dev != journal->j_dev) &&
-	    (journal->j_flags & JBD2_BARRIER))
+	if (journal->j_flags & JBD2_BARRIER)
 		blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
-	if (!(journal->j_flags & JBD2_ABORT))
-		jbd2_journal_update_sb_log_tail(journal);
+
+	__jbd2_update_log_tail(journal, first_tid, blocknr);
 	return 0;
 }
 
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 6705717d9b7f..b89ef84786a7 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -341,7 +341,16 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	if (journal->j_flags & JBD2_FLUSHED) {
 		jbd_debug(3, "super block updated\n");
 		mutex_lock(&journal->j_checkpoint_mutex);
-		jbd2_journal_update_sb_log_tail(journal);
+		/*
+		 * We hold j_checkpoint_mutex so tail cannot change under us.
+		 * We don't need any special data guarantees for writing sb
+		 * since journal is empty and it is ok for write to be
+		 * flushed only with transaction commit.
+		 */
+		jbd2_journal_update_sb_log_tail(journal,
+						journal->j_tail_sequence,
+						journal->j_tail,
+						WRITE_SYNC);
 		mutex_unlock(&journal->j_checkpoint_mutex);
 	} else {
 		jbd_debug(3, "superblock not updated\n");
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index fc5f2acc9f18..c5ff177400ff 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -742,6 +742,85 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
 	return jbd2_journal_add_journal_head(bh);
 }
 
+/*
+ * Return tid of the oldest transaction in the journal and block in the journal
+ * where the transaction starts.
+ *
+ * If the journal is now empty, return which will be the next transaction ID
+ * we will write and where will that transaction start.
+ *
+ * The return value is 0 if journal tail cannot be pushed any further, 1 if
+ * it can.
+ */
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+			      unsigned long *block)
+{
+	transaction_t *transaction;
+	int ret;
+
+	read_lock(&journal->j_state_lock);
+	spin_lock(&journal->j_list_lock);
+	transaction = journal->j_checkpoint_transactions;
+	if (transaction) {
+		*tid = transaction->t_tid;
+		*block = transaction->t_log_start;
+	} else if ((transaction = journal->j_committing_transaction) != NULL) {
+		*tid = transaction->t_tid;
+		*block = transaction->t_log_start;
+	} else if ((transaction = journal->j_running_transaction) != NULL) {
+		*tid = transaction->t_tid;
+		*block = journal->j_head;
+	} else {
+		*tid = journal->j_transaction_sequence;
+		*block = journal->j_head;
+	}
+	ret = tid_gt(*tid, journal->j_tail_sequence);
+	spin_unlock(&journal->j_list_lock);
+	read_unlock(&journal->j_state_lock);
+
+	return ret;
+}
+
+/*
+ * Update information in journal structure and in on disk journal superblock
+ * about log tail. This function does not check whether information passed in
+ * really pushes log tail further. It's responsibility of the caller to make
+ * sure provided log tail information is valid (e.g. by holding
+ * j_checkpoint_mutex all the time between computing log tail and calling this
+ * function as is the case with jbd2_cleanup_journal_tail()).
+ *
+ * Requires j_checkpoint_mutex
+ */
+void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+	unsigned long freed;
+
+	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+
+	/*
+	 * We cannot afford for write to remain in drive's caches since as
+	 * soon as we update j_tail, next transaction can start reusing journal
+	 * space and if we lose sb update during power failure we'd replay
+	 * old transaction with possibly newly overwritten data.
+	 */
+	jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
+	write_lock(&journal->j_state_lock);
+	freed = block - journal->j_tail;
+	if (block < journal->j_tail)
+		freed += journal->j_last - journal->j_first;
+
+	trace_jbd2_update_log_tail(journal, tid, block, freed);
+	jbd_debug(1,
+		  "Cleaning journal tail from %d to %d (offset %lu), "
+		  "freeing %lu\n",
+		  journal->j_tail_sequence, tid, block, freed);
+
+	journal->j_free += freed;
+	journal->j_tail_sequence = tid;
+	journal->j_tail = block;
+	write_unlock(&journal->j_state_lock);
+}
+
 struct jbd2_stats_proc_session {
 	journal_t *journal;
 	struct transaction_stats_s *stats;
@@ -1125,18 +1204,30 @@ static int journal_reset(journal_t *journal)
 	} else {
 		/* Lock here to make assertions happy... */
 		mutex_lock(&journal->j_checkpoint_mutex);
-		/* Add the dynamic fields and write it to disk. */
-		jbd2_journal_update_sb_log_tail(journal);
+		/*
+		 * Update log tail information. We use WRITE_FUA since new
+		 * transaction will start reusing journal space and so we
+		 * must make sure information about current log tail is on
+		 * disk before that.
+		 */
+		jbd2_journal_update_sb_log_tail(journal,
+						journal->j_tail_sequence,
+						journal->j_tail,
+						WRITE_FUA);
 		mutex_unlock(&journal->j_checkpoint_mutex);
 	}
 	return jbd2_journal_start_thread(journal);
 }
 
-static void jbd2_write_superblock(journal_t *journal)
+static void jbd2_write_superblock(journal_t *journal, int write_op)
 {
 	struct buffer_head *bh = journal->j_sb_buffer;
+	int ret;
 
-	trace_jbd2_write_superblock(journal);
+	trace_jbd2_write_superblock(journal, write_op);
+	if (!(journal->j_flags & JBD2_BARRIER))
+		write_op &= ~(REQ_FUA | REQ_FLUSH);
+	lock_buffer(bh);
 	if (buffer_write_io_error(bh)) {
 		/*
 		 * Oh, dear.  A previous attempt to write the journal
@@ -1152,40 +1243,45 @@ static void jbd2_write_superblock(journal_t *journal)
 		clear_buffer_write_io_error(bh);
 		set_buffer_uptodate(bh);
 	}
-
-	BUFFER_TRACE(bh, "marking dirty");
-	mark_buffer_dirty(bh);
-	sync_dirty_buffer(bh);
+	get_bh(bh);
+	bh->b_end_io = end_buffer_write_sync;
+	ret = submit_bh(write_op, bh);
+	wait_on_buffer(bh);
 	if (buffer_write_io_error(bh)) {
-		printk(KERN_ERR "JBD2: I/O error detected "
-		       "when updating journal superblock for %s.\n",
-		       journal->j_devname);
 		clear_buffer_write_io_error(bh);
 		set_buffer_uptodate(bh);
+		ret = -EIO;
+	}
+	if (ret) {
+		printk(KERN_ERR "JBD2: Error %d detected when updating "
+		       "journal superblock for %s.\n", ret,
+		       journal->j_devname);
 	}
 }
 
 /**
  * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
  * @journal: The journal to update.
+ * @tail_tid: TID of the new transaction at the tail of the log
+ * @tail_block: The first block of the transaction at the tail of the log
+ * @write_op: With which operation should we write the journal sb
  *
  * Update a journal's superblock information about log tail and write it to
  * disk, waiting for the IO to complete.
  */
-void jbd2_journal_update_sb_log_tail(journal_t *journal)
+void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
+				     unsigned long tail_block, int write_op)
 {
 	journal_superblock_t *sb = journal->j_superblock;
 
 	BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
-	read_lock(&journal->j_state_lock);
-	jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d)\n",
-		  journal->j_tail, journal->j_tail_sequence);
+	jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
+		  tail_block, tail_tid);
 
-	sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
-	sb->s_start    = cpu_to_be32(journal->j_tail);
-	read_unlock(&journal->j_state_lock);
+	sb->s_sequence = cpu_to_be32(tail_tid);
+	sb->s_start    = cpu_to_be32(tail_block);
 
-	jbd2_write_superblock(journal);
+	jbd2_write_superblock(journal, write_op);
 
 	/* Log is no longer empty */
 	write_lock(&journal->j_state_lock);
@@ -1214,7 +1310,7 @@ static void jbd2_mark_journal_empty(journal_t *journal)
 	sb->s_start    = cpu_to_be32(0);
 	read_unlock(&journal->j_state_lock);
 
-	jbd2_write_superblock(journal);
+	jbd2_write_superblock(journal, WRITE_FUA);
 
 	/* Log is no longer empty */
 	write_lock(&journal->j_state_lock);
@@ -1240,7 +1336,7 @@ static void jbd2_journal_update_sb_errno(journal_t *journal)
 	sb->s_errno    = cpu_to_be32(journal->j_errno);
 	read_unlock(&journal->j_state_lock);
 
-	jbd2_write_superblock(journal);
+	jbd2_write_superblock(journal, WRITE_SYNC);
 }
 
 /*
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index da6d7baf1390..c1a03354a22f 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -21,6 +21,7 @@
 #include <linux/jbd2.h>
 #include <linux/errno.h>
 #include <linux/crc32.h>
+#include <linux/blkdev.h>
 #endif
 
 /*
@@ -265,7 +266,9 @@ int jbd2_journal_recover(journal_t *journal)
 	err2 = sync_blockdev(journal->j_fs_dev);
 	if (!err)
 		err = err2;
-
+	/* Make sure all replayed data is on permanent storage */
+	if (journal->j_flags & JBD2_BARRIER)
+		blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
 	return err;
 }
 
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 5f05c77438e5..876a7d87192b 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -971,6 +971,9 @@ extern void __journal_clean_data_list(transaction_t *transaction);
 /* Log buffer allocation */
 extern struct journal_head * jbd2_journal_get_descriptor_buffer(journal_t *);
 int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+			      unsigned long *block);
+void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
 
 /* Commit management */
 extern void jbd2_journal_commit_transaction(journal_t *);
@@ -1087,7 +1090,8 @@ extern int	   jbd2_journal_destroy    (journal_t *);
 extern int	   jbd2_journal_recover    (journal_t *journal);
 extern int	   jbd2_journal_wipe       (journal_t *, int);
 extern int	   jbd2_journal_skip_recovery	(journal_t *);
-extern void	   jbd2_journal_update_sb_log_tail	(journal_t *);
+extern void	   jbd2_journal_update_sb_log_tail	(journal_t *, tid_t,
+				unsigned long, int);
 extern void	   __jbd2_journal_abort_hard	(journal_t *);
 extern void	   jbd2_journal_abort      (journal_t *, int);
 extern int	   jbd2_journal_errno      (journal_t *);
diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h
index e05a362bf3f1..127993dbf322 100644
--- a/include/trace/events/jbd2.h
+++ b/include/trace/events/jbd2.h
@@ -207,7 +207,7 @@ TRACE_EVENT(jbd2_checkpoint_stats,
 		  __entry->forced_to_close, __entry->written, __entry->dropped)
 );
 
-TRACE_EVENT(jbd2_cleanup_journal_tail,
+TRACE_EVENT(jbd2_update_log_tail,
 
 	TP_PROTO(journal_t *journal, tid_t first_tid,
 		 unsigned long block_nr, unsigned long freed),
@@ -238,19 +238,22 @@ TRACE_EVENT(jbd2_cleanup_journal_tail,
 
 TRACE_EVENT(jbd2_write_superblock,
 
-	TP_PROTO(journal_t *journal),
+	TP_PROTO(journal_t *journal, int write_op),
 
-	TP_ARGS(journal),
+	TP_ARGS(journal, write_op),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,  dev			)
+		__field(	  int,  write_op		)
 	),
 
 	TP_fast_assign(
 		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->write_op	= write_op;
 	),
 
-	TP_printk("dev %d,%d", MAJOR(__entry->dev), MINOR(__entry->dev))
+	TP_printk("dev %d,%d write_op %x", MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->write_op)
 );
 
 #endif /* _TRACE_JBD2_H */
-- 
cgit v1.2.3


From 96c866782b5e0cbdcd8e4d921d0a893278430830 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 22:24:54 -0400
Subject: jbd2: fix BH_JWrite setting in checkpointing code

BH_JWrite bit should be set when buffer is written to the journal. So
checkpointing shouldn't set this bit when writing out buffer. This didn't
cause any observable bug since BH_JWrite bit is used only for debugging
purposes but it's good to have this consistent.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c | 2 --
 1 file changed, 2 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 7f7ee5b90402..546c3b300eef 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -266,7 +266,6 @@ __flush_batch(journal_t *journal, int *batch_count)
 
 	for (i = 0; i < *batch_count; i++) {
 		struct buffer_head *bh = journal->j_chkpt_bhs[i];
-		clear_buffer_jwrite(bh);
 		BUFFER_TRACE(bh, "brelse");
 		__brelse(bh);
 	}
@@ -340,7 +339,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
 		BUFFER_TRACE(bh, "queue");
 		get_bh(bh);
 		J_ASSERT_BH(bh, !buffer_jwrite(bh));
-		set_buffer_jwrite(bh);
 		journal->j_chkpt_bhs[*batch_count] = bh;
 		__buffer_relink_io(jh);
 		jbd_unlock_bh_state(bh);
-- 
cgit v1.2.3


From 5bebccf90127859085f6a020f08ff7f648e285a0 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 22:25:06 -0400
Subject: jbd2: declare __jbd2_journal_temp_unlink_buffer() static

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/transaction.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index d0a8b017b281..3eb326a54bf1 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1579,9 +1579,9 @@ __blist_del_buffer(struct journal_head **list, struct journal_head *jh)
  * of these pointers, it could go bad.  Generally the caller needs to re-read
  * the pointer from the transaction_t.
  *
- * Called under j_list_lock.  The journal may not be locked.
+ * Called under j_list_lock.
  */
-void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
+static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
 {
 	struct journal_head **list = NULL;
 	transaction_t *transaction;
-- 
cgit v1.2.3


From c254c9ec14d5c418c8f36ea7573edae2470a1dc1 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 22:27:44 -0400
Subject: jbd2: remove always true condition in __journal_try_to_free_buffer()

The check b_jlist == BJ_None in __journal_try_to_free_buffer() is
always true (__jbd2_journal_temp_unlink_buffer() also checks this in
an assertion) so just remove it.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/transaction.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 3eb326a54bf1..fd052a88e9ec 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1676,10 +1676,8 @@ __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
 	spin_lock(&journal->j_list_lock);
 	if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
 		/* written-back checkpointed metadata buffer */
-		if (jh->b_jlist == BJ_None) {
-			JBUFFER_TRACE(jh, "remove from checkpoint list");
-			__jbd2_journal_remove_checkpoint(jh);
-		}
+		JBUFFER_TRACE(jh, "remove from checkpoint list");
+		__jbd2_journal_remove_checkpoint(jh);
 	}
 	spin_unlock(&journal->j_list_lock);
 out:
-- 
cgit v1.2.3


From 932bb305ba2a01cd62809644d569f004e77a4355 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 22:45:25 -0400
Subject: jbd2: remove bh_state lock from checkpointing code

All accesses to checkpointing entries in journal_head are protected
by j_list_lock. Thus __jbd2_journal_remove_checkpoint() doesn't really
need bh_state lock.

Also the only part of journal head that the rest of checkpointing code
needs to check is jh->b_transaction which is safe to read under
j_list_lock.

So we can safely remove bh_state lock from all of checkpointing code which
makes it considerably prettier.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c         | 59 ++++++--------------------------------------
 include/linux/journal-head.h |  2 ++
 2 files changed, 9 insertions(+), 52 deletions(-)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 546c3b300eef..c78841ee81cf 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -88,14 +88,13 @@ static inline void __buffer_relink_io(struct journal_head *jh)
  * whole transaction.
  *
  * Requires j_list_lock
- * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
  */
 static int __try_to_free_cp_buf(struct journal_head *jh)
 {
 	int ret = 0;
 	struct buffer_head *bh = jh2bh(jh);
 
-	if (jh->b_jlist == BJ_None && !buffer_locked(bh) &&
+	if (jh->b_transaction == NULL && !buffer_locked(bh) &&
 	    !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
 		/*
 		 * Get our reference so that bh cannot be freed before
@@ -104,11 +103,8 @@ static int __try_to_free_cp_buf(struct journal_head *jh)
 		get_bh(bh);
 		JBUFFER_TRACE(jh, "remove from checkpoint list");
 		ret = __jbd2_journal_remove_checkpoint(jh) + 1;
-		jbd_unlock_bh_state(bh);
 		BUFFER_TRACE(bh, "release");
 		__brelse(bh);
-	} else {
-		jbd_unlock_bh_state(bh);
 	}
 	return ret;
 }
@@ -179,21 +175,6 @@ void __jbd2_log_wait_for_space(journal_t *journal)
 	}
 }
 
-/*
- * We were unable to perform jbd_trylock_bh_state() inside j_list_lock.
- * The caller must restart a list walk.  Wait for someone else to run
- * jbd_unlock_bh_state().
- */
-static void jbd_sync_bh(journal_t *journal, struct buffer_head *bh)
-	__releases(journal->j_list_lock)
-{
-	get_bh(bh);
-	spin_unlock(&journal->j_list_lock);
-	jbd_lock_bh_state(bh);
-	jbd_unlock_bh_state(bh);
-	put_bh(bh);
-}
-
 /*
  * Clean up transaction's list of buffers submitted for io.
  * We wait for any pending IO to complete and remove any clean
@@ -222,15 +203,9 @@ restart:
 	while (!released && transaction->t_checkpoint_io_list) {
 		jh = transaction->t_checkpoint_io_list;
 		bh = jh2bh(jh);
-		if (!jbd_trylock_bh_state(bh)) {
-			jbd_sync_bh(journal, bh);
-			spin_lock(&journal->j_list_lock);
-			goto restart;
-		}
 		get_bh(bh);
 		if (buffer_locked(bh)) {
 			spin_unlock(&journal->j_list_lock);
-			jbd_unlock_bh_state(bh);
 			wait_on_buffer(bh);
 			/* the journal_head may have gone by now */
 			BUFFER_TRACE(bh, "brelse");
@@ -246,7 +221,6 @@ restart:
 		 * it has been written out and so we can drop it from the list
 		 */
 		released = __jbd2_journal_remove_checkpoint(jh);
-		jbd_unlock_bh_state(bh);
 		__brelse(bh);
 	}
 
@@ -280,7 +254,6 @@ __flush_batch(journal_t *journal, int *batch_count)
  * be written out.
  *
  * Called with j_list_lock held and drops it if 1 is returned
- * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
  */
 static int __process_buffer(journal_t *journal, struct journal_head *jh,
 			    int *batch_count, transaction_t *transaction)
@@ -291,7 +264,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
 	if (buffer_locked(bh)) {
 		get_bh(bh);
 		spin_unlock(&journal->j_list_lock);
-		jbd_unlock_bh_state(bh);
 		wait_on_buffer(bh);
 		/* the journal_head may have gone by now */
 		BUFFER_TRACE(bh, "brelse");
@@ -303,7 +275,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
 
 		transaction->t_chp_stats.cs_forced_to_close++;
 		spin_unlock(&journal->j_list_lock);
-		jbd_unlock_bh_state(bh);
 		if (unlikely(journal->j_flags & JBD2_UNMOUNT))
 			/*
 			 * The journal thread is dead; so starting and
@@ -322,11 +293,9 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
 		if (unlikely(buffer_write_io_error(bh)))
 			ret = -EIO;
 		get_bh(bh);
-		J_ASSERT_JH(jh, !buffer_jbddirty(bh));
 		BUFFER_TRACE(bh, "remove from checkpoint");
 		__jbd2_journal_remove_checkpoint(jh);
 		spin_unlock(&journal->j_list_lock);
-		jbd_unlock_bh_state(bh);
 		__brelse(bh);
 	} else {
 		/*
@@ -341,7 +310,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
 		J_ASSERT_BH(bh, !buffer_jwrite(bh));
 		journal->j_chkpt_bhs[*batch_count] = bh;
 		__buffer_relink_io(jh);
-		jbd_unlock_bh_state(bh);
 		transaction->t_chp_stats.cs_written++;
 		(*batch_count)++;
 		if (*batch_count == JBD2_NR_BATCH) {
@@ -405,15 +373,7 @@ restart:
 		int retry = 0, err;
 
 		while (!retry && transaction->t_checkpoint_list) {
-			struct buffer_head *bh;
-
 			jh = transaction->t_checkpoint_list;
-			bh = jh2bh(jh);
-			if (!jbd_trylock_bh_state(bh)) {
-				jbd_sync_bh(journal, bh);
-				retry = 1;
-				break;
-			}
 			retry = __process_buffer(journal, jh, &batch_count,
 						 transaction);
 			if (retry < 0 && !result)
@@ -529,15 +489,12 @@ static int journal_clean_one_cp_list(struct journal_head *jh, int *released)
 	do {
 		jh = next_jh;
 		next_jh = jh->b_cpnext;
-		/* Use trylock because of the ranking */
-		if (jbd_trylock_bh_state(jh2bh(jh))) {
-			ret = __try_to_free_cp_buf(jh);
-			if (ret) {
-				freed++;
-				if (ret == 2) {
-					*released = 1;
-					return freed;
-				}
+		ret = __try_to_free_cp_buf(jh);
+		if (ret) {
+			freed++;
+			if (ret == 2) {
+				*released = 1;
+				return freed;
 			}
 		}
 		/*
@@ -620,9 +577,7 @@ out:
  * The function can free jh and bh.
  *
  * This function is called with j_list_lock held.
- * This function is called with jbd_lock_bh_state(jh2bh(jh))
  */
-
 int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 {
 	struct transaction_chp_stats_s *stats;
diff --git a/include/linux/journal-head.h b/include/linux/journal-head.h
index 423cb6d78ee0..c18b46f8aeeb 100644
--- a/include/linux/journal-head.h
+++ b/include/linux/journal-head.h
@@ -66,6 +66,8 @@ struct journal_head {
 	 * transaction (if there is one).  Only applies to buffers on a
 	 * transaction's data or metadata journaling list.
 	 * [j_list_lock] [jbd_lock_bh_state()]
+	 * Either of these locks is enough for reading, both are needed for
+	 * changes.
 	 */
 	transaction_t *b_transaction;
 
-- 
cgit v1.2.3


From 3339578f05787259917788f461f4196b7349c2a4 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 13 Mar 2012 22:45:38 -0400
Subject: jbd2: cleanup journal tail after transaction commit

Normally, we have to issue a cache flush before we can update journal tail in
journal superblock, effectively wiping out old transactions from the journal.
So use the fact that during transaction commit we issue cache flush anyway and
opportunistically push journal tail as far as we can. Since update of journal
superblock is still costly (we have to use WRITE_FUA), we update log tail only
if we can free significant amount of space.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 fs/jbd2/commit.c     | 32 ++++++++++++++++++++++++++++++++
 fs/jbd2/journal.c    | 13 +++++++++++++
 include/linux/jbd2.h |  1 +
 3 files changed, 46 insertions(+)

(limited to 'fs/jbd2')

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index b89ef84786a7..1dfcb207ea69 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -331,6 +331,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	struct buffer_head *cbh = NULL; /* For transactional checksums */
 	__u32 crc32_sum = ~0;
 	struct blk_plug plug;
+	/* Tail of the journal */
+	unsigned long first_block;
+	tid_t first_tid;
+	int update_tail;
 
 	/*
 	 * First job: lock down the current transaction and wait for
@@ -688,10 +692,30 @@ start_journal_io:
 		err = 0;
 	}
 
+	/*
+	 * Get current oldest transaction in the log before we issue flush
+	 * to the filesystem device. After the flush we can be sure that
+	 * blocks of all older transactions are checkpointed to persistent
+	 * storage and we will be safe to update journal start in the
+	 * superblock with the numbers we get here.
+	 */
+	update_tail =
+		jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
+
 	write_lock(&journal->j_state_lock);
+	if (update_tail) {
+		long freed = first_block - journal->j_tail;
+
+		if (first_block < journal->j_tail)
+			freed += journal->j_last - journal->j_first;
+		/* Update tail only if we free significant amount of space */
+		if (freed < journal->j_maxlen / 4)
+			update_tail = 0;
+	}
 	J_ASSERT(commit_transaction->t_state == T_COMMIT);
 	commit_transaction->t_state = T_COMMIT_DFLUSH;
 	write_unlock(&journal->j_state_lock);
+
 	/* 
 	 * If the journal is not located on the file system device,
 	 * then we must flush the file system device before we issue
@@ -842,6 +866,14 @@ wait_for_iobuf:
 	if (err)
 		jbd2_journal_abort(journal, err);
 
+	/*
+	 * Now disk caches for filesystem device are flushed so we are safe to
+	 * erase checkpointed transactions from the log by updating journal
+	 * superblock.
+	 */
+	if (update_tail)
+		jbd2_update_log_tail(journal, first_tid, first_block);
+
 	/* End of a transaction!  Finally, we can do checkpoint
            processing: any buffers committed as a result of this
            transaction can be removed from any checkpoint list it was on
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index c5ff177400ff..bda564f63864 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -821,6 +821,19 @@ void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
 	write_unlock(&journal->j_state_lock);
 }
 
+/*
+ * This is a variaon of __jbd2_update_log_tail which checks for validity of
+ * provided log tail and locks j_checkpoint_mutex. So it is safe against races
+ * with other threads updating log tail.
+ */
+void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+	mutex_lock(&journal->j_checkpoint_mutex);
+	if (tid_gt(tid, journal->j_tail_sequence))
+		__jbd2_update_log_tail(journal, tid, block);
+	mutex_unlock(&journal->j_checkpoint_mutex);
+}
+
 struct jbd2_stats_proc_session {
 	journal_t *journal;
 	struct transaction_stats_s *stats;
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 876a7d87192b..912c30a8ddb1 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -974,6 +974,7 @@ int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
 			      unsigned long *block);
 void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
+void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
 
 /* Commit management */
 extern void jbd2_journal_commit_transaction(journal_t *);
-- 
cgit v1.2.3