From ede7dc7fa0af619afc08995776eadb9ff3b0a711 Mon Sep 17 00:00:00 2001
From: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Date: Thu, 5 Nov 2020 19:58:54 -0800
Subject: jbd2: rename j_maxlen to j_total_len and add
 jbd2_journal_max_txn_bufs

The on-disk superblock field sb->s_maxlen represents the total size of
the journal including the fast commit area and is no more the max
number of blocks available for a transaction. The maximum number of
blocks available to a transaction is reduced by the number of fast
commit blocks. So, this patch renames j_maxlen to j_total_len to
better represent its intent. Also, it adds a function to calculate max
number of bufs available for a transaction.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-6-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 include/linux/jbd2.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 1d5566af48ac..e0b6b53eae64 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -988,9 +988,9 @@ struct journal_s
 	struct block_device	*j_fs_dev;
 
 	/**
-	 * @j_maxlen: Total maximum capacity of the journal region on disk.
+	 * @j_total_len: Total maximum capacity of the journal region on disk.
 	 */
-	unsigned int		j_maxlen;
+	unsigned int		j_total_len;
 
 	/**
 	 * @j_reserved_credits:
@@ -1624,6 +1624,11 @@ int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
 int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
 int jbd2_fc_release_bufs(journal_t *journal);
 
+static inline int jbd2_journal_get_max_txn_bufs(journal_t *journal)
+{
+	return (journal->j_total_len - journal->j_fc_wbufsize) / 4;
+}
+
 /*
  * is_journal_abort
  *
-- 
cgit v1.3-14-g43fede


From a1e5e465b31d6015fccb359d99053b39e5180466 Mon Sep 17 00:00:00 2001
From: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Date: Thu, 5 Nov 2020 19:58:55 -0800
Subject: ext4: clean up the JBD2 API that initializes fast commits

This patch removes jbd2_fc_init() API and its related functions to
simplify enabling fast commits. With this change, the number of fast
commit blocks to use is solely determined by the JBD2 layer. So, we
move the default value for minimum number of fast commit blocks from
ext4/fast_commit.h to include/linux/jbd2.h. However, whether or not to
use fast commits is determined by the file system. The file system
just sets the fast commit feature using
jbd2_journal_set_features(). JBD2 layer then determines how many
blocks to use for fast commits (based on the value found in the JBD2
superblock).

Note that the JBD2 feature flag of fast commits is just an indication
that there are fast commit blocks present on disk. It doesn't tell
JBD2 layer about the intent of the file system of whether to it wants
to use fast commit or not. That's why, we blindly clear the fast
commit flag in journal_reset() after the recovery is done.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-7-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/fast_commit.c | 14 --------
 fs/ext4/fast_commit.h |  3 --
 fs/ext4/super.c       |  8 +++++
 fs/jbd2/journal.c     | 96 ++++++++++++++++++++++++++++++---------------------
 include/linux/jbd2.h  |  2 +-
 5 files changed, 65 insertions(+), 58 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 9399e9cccb7e..bab60c5d5095 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -2091,8 +2091,6 @@ static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
 
 void ext4_fc_init(struct super_block *sb, journal_t *journal)
 {
-	int num_fc_blocks;
-
 	/*
 	 * We set replay callback even if fast commit disabled because we may
 	 * could still have fast commit blocks that need to be replayed even if
@@ -2102,18 +2100,6 @@ void ext4_fc_init(struct super_block *sb, journal_t *journal)
 	if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
 		return;
 	journal->j_fc_cleanup_callback = ext4_fc_cleanup;
-	if (!buffer_uptodate(journal->j_sb_buffer)
-		&& ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO,
-					true)) {
-		ext4_msg(sb, KERN_ERR, "I/O error on journal");
-		return;
-	}
-	num_fc_blocks = be32_to_cpu(journal->j_superblock->s_num_fc_blks);
-	if (jbd2_fc_init(journal, num_fc_blocks ? num_fc_blocks :
-					EXT4_NUM_FC_BLKS)) {
-		pr_warn("Error while enabling fast commits, turning off.");
-		ext4_clear_feature_fast_commit(sb);
-	}
 }
 
 const char *fc_ineligible_reasons[] = {
diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h
index 140fbb6af19e..1d96e0ac8138 100644
--- a/fs/ext4/fast_commit.h
+++ b/fs/ext4/fast_commit.h
@@ -3,9 +3,6 @@
 #ifndef __FAST_COMMIT_H__
 #define __FAST_COMMIT_H__
 
-/* Number of blocks in journal area to allocate for fast commits */
-#define EXT4_NUM_FC_BLKS		256
-
 /* Fast commit tags */
 #define EXT4_FC_TAG_ADD_RANGE		0x0001
 #define EXT4_FC_TAG_DEL_RANGE		0x0002
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8a6dd433bb70..ba02d7c86fb3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4857,6 +4857,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (test_opt2(sb, JOURNAL_FAST_COMMIT) &&
+		!jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
+					  JBD2_FEATURE_INCOMPAT_FAST_COMMIT)) {
+		ext4_msg(sb, KERN_ERR,
+			"Failed to set fast commit journal feature");
+		goto failed_mount_wq;
+	}
+
 	/* We have now updated the journal if required, so we can
 	 * validate the data journaling mode. */
 	switch (test_opt(sb, DATA_FLAGS)) {
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index c3c768248527..500152f0421a 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1352,19 +1352,12 @@ static journal_t *journal_init_common(struct block_device *bdev,
 	/* We need enough buffers to write out full descriptor block. */
 	n = journal->j_blocksize / jbd2_min_tag_size();
 	journal->j_wbufsize = n;
+	journal->j_fc_wbuf = NULL;
 	journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
 					GFP_KERNEL);
 	if (!journal->j_wbuf)
 		goto err_cleanup;
 
-	if (journal->j_fc_wbufsize > 0) {
-		journal->j_fc_wbuf = kmalloc_array(journal->j_fc_wbufsize,
-					sizeof(struct buffer_head *),
-					GFP_KERNEL);
-		if (!journal->j_fc_wbuf)
-			goto err_cleanup;
-	}
-
 	bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
 	if (!bh) {
 		pr_err("%s: Cannot get buffer for journal superblock\n",
@@ -1378,23 +1371,11 @@ static journal_t *journal_init_common(struct block_device *bdev,
 
 err_cleanup:
 	kfree(journal->j_wbuf);
-	kfree(journal->j_fc_wbuf);
 	jbd2_journal_destroy_revoke(journal);
 	kfree(journal);
 	return NULL;
 }
 
-int jbd2_fc_init(journal_t *journal, int num_fc_blks)
-{
-	journal->j_fc_wbufsize = num_fc_blks;
-	journal->j_fc_wbuf = kmalloc_array(journal->j_fc_wbufsize,
-				sizeof(struct buffer_head *), GFP_KERNEL);
-	if (!journal->j_fc_wbuf)
-		return -ENOMEM;
-	return 0;
-}
-EXPORT_SYMBOL(jbd2_fc_init);
-
 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
  *
  * Create a journal structure assigned some fixed set of disk blocks to
@@ -1512,16 +1493,7 @@ static int journal_reset(journal_t *journal)
 	}
 
 	journal->j_first = first;
-
-	if (jbd2_has_feature_fast_commit(journal) &&
-	    journal->j_fc_wbufsize > 0) {
-		journal->j_fc_last = last;
-		journal->j_last = last - journal->j_fc_wbufsize;
-		journal->j_fc_first = journal->j_last + 1;
-		journal->j_fc_off = 0;
-	} else {
-		journal->j_last = last;
-	}
+	journal->j_last = last;
 
 	journal->j_head = journal->j_first;
 	journal->j_tail = journal->j_first;
@@ -1533,6 +1505,13 @@ static int journal_reset(journal_t *journal)
 
 	journal->j_max_transaction_buffers = jbd2_journal_get_max_txn_bufs(journal);
 
+	/*
+	 * Now that journal recovery is done, turn fast commits off here. This
+	 * way, if fast commit was enabled before the crash but if now FS has
+	 * disabled it, we don't enable fast commits.
+	 */
+	jbd2_clear_feature_fast_commit(journal);
+
 	/*
 	 * As a special case, if the on-disk copy is already marked as needing
 	 * no recovery (s_start == 0), then we can safely defer the superblock
@@ -1872,6 +1851,7 @@ static int load_superblock(journal_t *journal)
 {
 	int err;
 	journal_superblock_t *sb;
+	int num_fc_blocks;
 
 	err = journal_get_superblock(journal);
 	if (err)
@@ -1883,15 +1863,17 @@ static int load_superblock(journal_t *journal)
 	journal->j_tail = be32_to_cpu(sb->s_start);
 	journal->j_first = be32_to_cpu(sb->s_first);
 	journal->j_errno = be32_to_cpu(sb->s_errno);
+	journal->j_last = be32_to_cpu(sb->s_maxlen);
 
-	if (jbd2_has_feature_fast_commit(journal) &&
-	    journal->j_fc_wbufsize > 0) {
+	if (jbd2_has_feature_fast_commit(journal)) {
 		journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
-		journal->j_last = journal->j_fc_last - journal->j_fc_wbufsize;
+		num_fc_blocks = be32_to_cpu(sb->s_num_fc_blks);
+		if (!num_fc_blocks)
+			num_fc_blocks = JBD2_MIN_FC_BLOCKS;
+		if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
+			journal->j_last = journal->j_fc_last - num_fc_blocks;
 		journal->j_fc_first = journal->j_last + 1;
 		journal->j_fc_off = 0;
-	} else {
-		journal->j_last = be32_to_cpu(sb->s_maxlen);
 	}
 
 	return 0;
@@ -1954,9 +1936,6 @@ int jbd2_journal_load(journal_t *journal)
 	 */
 	journal->j_flags &= ~JBD2_ABORT;
 
-	if (journal->j_fc_wbufsize > 0)
-		jbd2_journal_set_features(journal, 0, 0,
-					  JBD2_FEATURE_INCOMPAT_FAST_COMMIT);
 	/* OK, we've finished with the dynamic journal bits:
 	 * reinitialise the dynamic contents of the superblock in memory
 	 * and reset them on disk. */
@@ -2040,8 +2019,7 @@ int jbd2_journal_destroy(journal_t *journal)
 		jbd2_journal_destroy_revoke(journal);
 	if (journal->j_chksum_driver)
 		crypto_free_shash(journal->j_chksum_driver);
-	if (journal->j_fc_wbufsize > 0)
-		kfree(journal->j_fc_wbuf);
+	kfree(journal->j_fc_wbuf);
 	kfree(journal->j_wbuf);
 	kfree(journal);
 
@@ -2116,6 +2094,37 @@ int jbd2_journal_check_available_features(journal_t *journal, unsigned long comp
 	return 0;
 }
 
+static int
+jbd2_journal_initialize_fast_commit(journal_t *journal)
+{
+	journal_superblock_t *sb = journal->j_superblock;
+	unsigned long long num_fc_blks;
+
+	num_fc_blks = be32_to_cpu(sb->s_num_fc_blks);
+	if (num_fc_blks == 0)
+		num_fc_blks = JBD2_MIN_FC_BLOCKS;
+	if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
+		return -ENOSPC;
+
+	/* Are we called twice? */
+	WARN_ON(journal->j_fc_wbuf != NULL);
+	journal->j_fc_wbuf = kmalloc_array(num_fc_blks,
+				sizeof(struct buffer_head *), GFP_KERNEL);
+	if (!journal->j_fc_wbuf)
+		return -ENOMEM;
+
+	journal->j_fc_wbufsize = num_fc_blks;
+	journal->j_fc_last = journal->j_last;
+	journal->j_last = journal->j_fc_last - num_fc_blks;
+	journal->j_fc_first = journal->j_last + 1;
+	journal->j_fc_off = 0;
+	journal->j_free = journal->j_last - journal->j_first;
+	journal->j_max_transaction_buffers =
+		jbd2_journal_get_max_txn_bufs(journal);
+
+	return 0;
+}
+
 /**
  * int jbd2_journal_set_features() - Mark a given journal feature in the superblock
  * @journal: Journal to act on.
@@ -2159,6 +2168,13 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
 
 	sb = journal->j_superblock;
 
+	if (incompat & JBD2_FEATURE_INCOMPAT_FAST_COMMIT) {
+		if (jbd2_journal_initialize_fast_commit(journal)) {
+			pr_err("JBD2: Cannot enable fast commits.\n");
+			return 0;
+		}
+	}
+
 	/* Load the checksum driver if necessary */
 	if ((journal->j_chksum_driver == NULL) &&
 	    INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index e0b6b53eae64..b2caf7bbd8e5 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -68,6 +68,7 @@ extern void *jbd2_alloc(size_t size, gfp_t flags);
 extern void jbd2_free(void *ptr, size_t size);
 
 #define JBD2_MIN_JOURNAL_BLOCKS 1024
+#define JBD2_MIN_FC_BLOCKS	256
 
 #ifdef __KERNEL__
 
@@ -1614,7 +1615,6 @@ extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
 extern int jbd2_cleanup_journal_tail(journal_t *);
 
 /* Fast commit related APIs */
-int jbd2_fc_init(journal_t *journal, int num_fc_blks);
 int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
 int jbd2_fc_end_commit(journal_t *journal);
 int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid);
-- 
cgit v1.3-14-g43fede


From c460e5edc85a063ec9cb60addff93d00ed378701 Mon Sep 17 00:00:00 2001
From: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Date: Thu, 5 Nov 2020 19:58:57 -0800
Subject: jbd2: don't use state lock during commit path

Variables journal->j_fc_off, journal->j_fc_wbuf are accessed during
commit path. Since today we allow only one process to perform a fast
commit, there is no need take state lock before accessing these
variables. This patch removes these locks and adds comments to
describe this.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-9-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/jbd2/journal.c    |  6 ------
 include/linux/jbd2.h | 10 ++++++----
 2 files changed, 6 insertions(+), 10 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 500152f0421a..778ea50fc8d1 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -865,7 +865,6 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
 	int fc_off;
 
 	*bh_out = NULL;
-	write_lock(&journal->j_state_lock);
 
 	if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) {
 		fc_off = journal->j_fc_off;
@@ -874,7 +873,6 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
 	} else {
 		ret = -EINVAL;
 	}
-	write_unlock(&journal->j_state_lock);
 
 	if (ret)
 		return ret;
@@ -909,9 +907,7 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
 	struct buffer_head *bh;
 	int i, j_fc_off;
 
-	read_lock(&journal->j_state_lock);
 	j_fc_off = journal->j_fc_off;
-	read_unlock(&journal->j_state_lock);
 
 	/*
 	 * Wait in reverse order to minimize chances of us being woken up before
@@ -939,9 +935,7 @@ int jbd2_fc_release_bufs(journal_t *journal)
 	struct buffer_head *bh;
 	int i, j_fc_off;
 
-	read_lock(&journal->j_state_lock);
 	j_fc_off = journal->j_fc_off;
-	read_unlock(&journal->j_state_lock);
 
 	/*
 	 * Wait in reverse order to minimize chances of us being woken up before
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index b2caf7bbd8e5..5f0ef6380b0c 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -945,8 +945,9 @@ struct journal_s
 	/**
 	 * @j_fc_off:
 	 *
-	 * Number of fast commit blocks currently allocated.
-	 * [j_state_lock].
+	 * Number of fast commit blocks currently allocated. Accessed only
+	 * during fast commit. Currently only process can do fast commit, so
+	 * this field is not protected by any lock.
 	 */
 	unsigned long		j_fc_off;
 
@@ -1109,8 +1110,9 @@ struct journal_s
 	struct buffer_head	**j_wbuf;
 
 	/**
-	 * @j_fc_wbuf: Array of fast commit bhs for
-	 * jbd2_journal_commit_transaction.
+	 * @j_fc_wbuf: Array of fast commit bhs for fast commit. Accessed only
+	 * during a fast commit. Currently only process can do fast commit, so
+	 * this field is not protected by any lock.
 	 */
 	struct buffer_head	**j_fc_wbuf;
 
-- 
cgit v1.3-14-g43fede


From 0bce577bf9cae13ae32d391432d0030e3f67fc1d Mon Sep 17 00:00:00 2001
From: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Date: Thu, 5 Nov 2020 19:58:58 -0800
Subject: jbd2: don't pass tid to jbd2_fc_end_commit_fallback()

In jbd2_fc_end_commit_fallback(), we know which tid to commit. There's
no need for caller to pass it.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-10-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/fast_commit.c |  2 +-
 fs/jbd2/journal.c     | 12 +++++++++---
 include/linux/jbd2.h  |  2 +-
 3 files changed, 11 insertions(+), 5 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index bab60c5d5095..e69c580fa91e 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1143,7 +1143,7 @@ out:
 		"Fast commit ended with blks = %d, reason = %d, subtid - %d",
 		nblks, reason, subtid);
 	if (reason == EXT4_FC_REASON_FC_FAILED)
-		return jbd2_fc_end_commit_fallback(journal, commit_tid);
+		return jbd2_fc_end_commit_fallback(journal);
 	if (reason == EXT4_FC_REASON_FC_START_FAILED ||
 		reason == EXT4_FC_REASON_INELIGIBLE)
 		return jbd2_complete_transaction(journal, commit_tid);
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 778ea50fc8d1..59166e299cde 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -777,13 +777,19 @@ static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
 
 int jbd2_fc_end_commit(journal_t *journal)
 {
-	return __jbd2_fc_end_commit(journal, 0, 0);
+	return __jbd2_fc_end_commit(journal, 0, false);
 }
 EXPORT_SYMBOL(jbd2_fc_end_commit);
 
-int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid)
+int jbd2_fc_end_commit_fallback(journal_t *journal)
 {
-	return __jbd2_fc_end_commit(journal, tid, 1);
+	tid_t tid;
+
+	read_lock(&journal->j_state_lock);
+	tid = journal->j_running_transaction ?
+		journal->j_running_transaction->t_tid : 0;
+	read_unlock(&journal->j_state_lock);
+	return __jbd2_fc_end_commit(journal, tid, true);
 }
 EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
 
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 5f0ef6380b0c..1c49fd62ff2e 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1619,7 +1619,7 @@ extern int jbd2_cleanup_journal_tail(journal_t *);
 /* Fast commit related APIs */
 int jbd2_fc_begin_commit(journal_t *journal, tid_t tid);
 int jbd2_fc_end_commit(journal_t *journal);
-int jbd2_fc_end_commit_fallback(journal_t *journal, tid_t tid);
+int jbd2_fc_end_commit_fallback(journal_t *journal);
 int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
 int jbd2_submit_inode_data(struct jbd2_inode *jinode);
 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
-- 
cgit v1.3-14-g43fede


From 2bf31d94423c8ae3ff58e38a115b177df6940399 Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Date: Mon, 16 Nov 2020 11:18:08 +0100
Subject: jbd2: fix kernel-doc markups

Kernel-doc markup should use this format:
        identifier - description

They should not have any type before that, as otherwise
the parser won't do the right thing.

Also, some identifiers have different names between their
prototypes and the kernel-doc markup.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/72f5c6628f5f278d67625f60893ffbc2ca28d46e.1605521731.git.mchehab+huawei@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/jbd2/journal.c     | 34 ++++++++++++++++++----------------
 fs/jbd2/transaction.c | 31 ++++++++++++++++---------------
 include/linux/jbd2.h  |  2 +-
 3 files changed, 35 insertions(+), 32 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0c3d5e3b24b2..188f79d76988 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -566,12 +566,14 @@ static int __jbd2_journal_force_commit(journal_t *journal)
 }
 
 /**
- * Force and wait upon a commit if the calling process is not within
- * transaction.  This is used for forcing out undo-protected data which contains
- * bitmaps, when the fs is running out of space.
+ * jbd2_journal_force_commit_nested - Force and wait upon a commit if the
+ * calling process is not within transaction.
  *
  * @journal: journal to force
  * Returns true if progress was made.
+ *
+ * This is used for forcing out undo-protected data which contains
+ * bitmaps, when the fs is running out of space.
  */
 int jbd2_journal_force_commit_nested(journal_t *journal)
 {
@@ -582,7 +584,7 @@ int jbd2_journal_force_commit_nested(journal_t *journal)
 }
 
 /**
- * int journal_force_commit() - force any uncommitted transactions
+ * jbd2_journal_force_commit() - force any uncommitted transactions
  * @journal: journal to force
  *
  * Caller want unconditional commit. We can only force the running transaction
@@ -1881,7 +1883,7 @@ static int load_superblock(journal_t *journal)
 
 
 /**
- * int jbd2_journal_load() - Read journal from disk.
+ * jbd2_journal_load() - Read journal from disk.
  * @journal: Journal to act on.
  *
  * Given a journal_t structure which tells us which disk blocks contain
@@ -1951,7 +1953,7 @@ recovery_error:
 }
 
 /**
- * void jbd2_journal_destroy() - Release a journal_t structure.
+ * jbd2_journal_destroy() - Release a journal_t structure.
  * @journal: Journal to act on.
  *
  * Release a journal_t structure once it is no longer in use by the
@@ -2028,7 +2030,7 @@ int jbd2_journal_destroy(journal_t *journal)
 
 
 /**
- *int jbd2_journal_check_used_features() - Check if features specified are used.
+ * jbd2_journal_check_used_features() - Check if features specified are used.
  * @journal: Journal to check.
  * @compat: bitmask of compatible features
  * @ro: bitmask of features that force read-only mount
@@ -2063,7 +2065,7 @@ int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
 }
 
 /**
- * int jbd2_journal_check_available_features() - Check feature set in journalling layer
+ * jbd2_journal_check_available_features() - Check feature set in journalling layer
  * @journal: Journal to check.
  * @compat: bitmask of compatible features
  * @ro: bitmask of features that force read-only mount
@@ -2126,7 +2128,7 @@ jbd2_journal_initialize_fast_commit(journal_t *journal)
 }
 
 /**
- * int jbd2_journal_set_features() - Mark a given journal feature in the superblock
+ * jbd2_journal_set_features() - Mark a given journal feature in the superblock
  * @journal: Journal to act on.
  * @compat: bitmask of compatible features
  * @ro: bitmask of features that force read-only mount
@@ -2217,7 +2219,7 @@ int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
 }
 
 /*
- * jbd2_journal_clear_features () - Clear a given journal feature in the
+ * jbd2_journal_clear_features() - Clear a given journal feature in the
  * 				    superblock
  * @journal: Journal to act on.
  * @compat: bitmask of compatible features
@@ -2246,7 +2248,7 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
 EXPORT_SYMBOL(jbd2_journal_clear_features);
 
 /**
- * int jbd2_journal_flush () - Flush journal
+ * jbd2_journal_flush() - Flush journal
  * @journal: Journal to act on.
  *
  * Flush all data for a given journal to disk and empty the journal.
@@ -2321,7 +2323,7 @@ out:
 }
 
 /**
- * int jbd2_journal_wipe() - Wipe journal contents
+ * jbd2_journal_wipe() - Wipe journal contents
  * @journal: Journal to act on.
  * @write: flag (see below)
  *
@@ -2362,7 +2364,7 @@ int jbd2_journal_wipe(journal_t *journal, int write)
 }
 
 /**
- * void jbd2_journal_abort () - Shutdown the journal immediately.
+ * jbd2_journal_abort () - Shutdown the journal immediately.
  * @journal: the journal to shutdown.
  * @errno:   an error number to record in the journal indicating
  *           the reason for the shutdown.
@@ -2453,7 +2455,7 @@ void jbd2_journal_abort(journal_t *journal, int errno)
 }
 
 /**
- * int jbd2_journal_errno () - returns the journal's error state.
+ * jbd2_journal_errno() - returns the journal's error state.
  * @journal: journal to examine.
  *
  * This is the errno number set with jbd2_journal_abort(), the last
@@ -2477,7 +2479,7 @@ int jbd2_journal_errno(journal_t *journal)
 }
 
 /**
- * int jbd2_journal_clear_err () - clears the journal's error state
+ * jbd2_journal_clear_err() - clears the journal's error state
  * @journal: journal to act on.
  *
  * An error must be cleared or acked to take a FS out of readonly
@@ -2497,7 +2499,7 @@ int jbd2_journal_clear_err(journal_t *journal)
 }
 
 /**
- * void jbd2_journal_ack_err() - Ack journal err.
+ * jbd2_journal_ack_err() - Ack journal err.
  * @journal: journal to act on.
  *
  * An error must be cleared or acked to take a FS out of readonly
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index d54f04674e8e..9396666b7314 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -519,7 +519,7 @@ EXPORT_SYMBOL(jbd2__journal_start);
 
 
 /**
- * handle_t *jbd2_journal_start() - Obtain a new handle.
+ * jbd2_journal_start() - Obtain a new handle.
  * @journal: Journal to start transaction on.
  * @nblocks: number of block buffer we might modify
  *
@@ -566,7 +566,7 @@ void jbd2_journal_free_reserved(handle_t *handle)
 EXPORT_SYMBOL(jbd2_journal_free_reserved);
 
 /**
- * int jbd2_journal_start_reserved() - start reserved handle
+ * jbd2_journal_start_reserved() - start reserved handle
  * @handle: handle to start
  * @type: for handle statistics
  * @line_no: for handle statistics
@@ -620,7 +620,7 @@ int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
 EXPORT_SYMBOL(jbd2_journal_start_reserved);
 
 /**
- * int jbd2_journal_extend() - extend buffer credits.
+ * jbd2_journal_extend() - extend buffer credits.
  * @handle:  handle to 'extend'
  * @nblocks: nr blocks to try to extend by.
  * @revoke_records: number of revoke records to try to extend by.
@@ -745,7 +745,7 @@ static void stop_this_handle(handle_t *handle)
 }
 
 /**
- * int jbd2_journal_restart() - restart a handle .
+ * jbd2__journal_restart() - restart a handle .
  * @handle:  handle to restart
  * @nblocks: nr credits requested
  * @revoke_records: number of revoke record credits requested
@@ -815,7 +815,7 @@ int jbd2_journal_restart(handle_t *handle, int nblocks)
 EXPORT_SYMBOL(jbd2_journal_restart);
 
 /**
- * void jbd2_journal_lock_updates () - establish a transaction barrier.
+ * jbd2_journal_lock_updates () - establish a transaction barrier.
  * @journal:  Journal to establish a barrier on.
  *
  * This locks out any further updates from being started, and blocks
@@ -874,7 +874,7 @@ void jbd2_journal_lock_updates(journal_t *journal)
 }
 
 /**
- * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier
+ * jbd2_journal_unlock_updates () - release barrier
  * @journal:  Journal to release the barrier on.
  *
  * Release a transaction barrier obtained with jbd2_journal_lock_updates().
@@ -1182,7 +1182,8 @@ out:
 }
 
 /**
- * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
+ * jbd2_journal_get_write_access() - notify intent to modify a buffer
+ *				     for metadata (not data) update.
  * @handle: transaction to add buffer modifications to
  * @bh:     bh to be used for metadata writes
  *
@@ -1226,7 +1227,7 @@ int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
  * unlocked buffer beforehand. */
 
 /**
- * int jbd2_journal_get_create_access () - notify intent to use newly created bh
+ * jbd2_journal_get_create_access () - notify intent to use newly created bh
  * @handle: transaction to new buffer to
  * @bh: new buffer.
  *
@@ -1306,7 +1307,7 @@ out:
 }
 
 /**
- * int jbd2_journal_get_undo_access() -  Notify intent to modify metadata with
+ * jbd2_journal_get_undo_access() -  Notify intent to modify metadata with
  *     non-rewindable consequences
  * @handle: transaction
  * @bh: buffer to undo
@@ -1383,7 +1384,7 @@ out:
 }
 
 /**
- * void jbd2_journal_set_triggers() - Add triggers for commit writeout
+ * jbd2_journal_set_triggers() - Add triggers for commit writeout
  * @bh: buffer to trigger on
  * @type: struct jbd2_buffer_trigger_type containing the trigger(s).
  *
@@ -1425,7 +1426,7 @@ void jbd2_buffer_abort_trigger(struct journal_head *jh,
 }
 
 /**
- * int jbd2_journal_dirty_metadata() -  mark a buffer as containing dirty metadata
+ * jbd2_journal_dirty_metadata() -  mark a buffer as containing dirty metadata
  * @handle: transaction to add buffer to.
  * @bh: buffer to mark
  *
@@ -1593,7 +1594,7 @@ out:
 }
 
 /**
- * void jbd2_journal_forget() - bforget() for potentially-journaled buffers.
+ * jbd2_journal_forget() - bforget() for potentially-journaled buffers.
  * @handle: transaction handle
  * @bh:     bh to 'forget'
  *
@@ -1762,7 +1763,7 @@ drop:
 }
 
 /**
- * int jbd2_journal_stop() - complete a transaction
+ * jbd2_journal_stop() - complete a transaction
  * @handle: transaction to complete.
  *
  * All done for a particular handle.
@@ -2080,7 +2081,7 @@ out:
 }
 
 /**
- * int jbd2_journal_try_to_free_buffers() - try to free page buffers.
+ * jbd2_journal_try_to_free_buffers() - try to free page buffers.
  * @journal: journal for operation
  * @page: to try and free
  *
@@ -2411,7 +2412,7 @@ zap_buffer_unlocked:
 }
 
 /**
- * void jbd2_journal_invalidatepage()
+ * jbd2_journal_invalidatepage()
  * @journal: journal to use for flush...
  * @page:    page to flush
  * @offset:  start of the range to invalidate
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 1c49fd62ff2e..578ff196b3ce 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -401,7 +401,7 @@ static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
 #define JI_WAIT_DATA (1 << __JI_WAIT_DATA)
 
 /**
- * struct jbd_inode - The jbd_inode type is the structure linking inodes in
+ * struct jbd2_inode - The jbd_inode type is the structure linking inodes in
  * ordered mode present in a transaction so that we can sync them during commit.
  */
 struct jbd2_inode {
-- 
cgit v1.3-14-g43fede


From 50a4952fd67b7f7f551e82ac07c51c1a7a74d474 Mon Sep 17 00:00:00 2001
From: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
Date: Thu, 15 Oct 2020 15:24:52 +0200
Subject: Updated locking documentation for transaction_t

We used LockDoc to derive locking rules for each member
of struct transaction_t.
Based on those results, we extended the existing documentation
by more members of struct transaction_t, and updated the existing
documentation.

Link: https://lore.kernel.org/r/10cfbef1-994c-c604-f8a6-b1042fcc622f@tu-dortmund.de
Signed-off-by: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
Signed-off-by: Horst Schirmeier <horst.schirmeier@tu-dortmund.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 include/linux/jbd2.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 578ff196b3ce..d2a4860feb72 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -538,6 +538,7 @@ struct transaction_chp_stats_s {
  * The transaction keeps track of all of the buffers modified by a
  * running transaction, and all of the buffers committed but not yet
  * flushed to home for finished transactions.
+ * (Locking Documentation improved by LockDoc)
  */
 
 /*
@@ -658,12 +659,12 @@ struct transaction_s
 	unsigned long		t_start;
 
 	/*
-	 * When commit was requested
+	 * When commit was requested [j_state_lock]
 	 */
 	unsigned long		t_requested;
 
 	/*
-	 * Checkpointing stats [j_checkpoint_sem]
+	 * Checkpointing stats [j_list_lock]
 	 */
 	struct transaction_chp_stats_s t_chp_stats;
 
-- 
cgit v1.3-14-g43fede


From 9bd23c31f392bda88618008f27fd52ee9e0fac38 Mon Sep 17 00:00:00 2001
From: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Date: Fri, 20 Nov 2020 12:22:32 -0800
Subject: jbd2: add a helper to find out number of fast commit blocks

Add a helper to read number of fast commit blocks from jbd2 superblock
and also rename the JBD2_MIN_FC_BLKS to
JBD2_DEFAULT_FAST_COMMIT_BLOCKS since this constant is just the
default number of fast commit blocks to use in case number of fast
commit blocks isn't set in jbd2 superblock.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201120202232.2240293-2-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/jbd2/journal.c    | 8 ++------
 include/linux/jbd2.h | 9 ++++++++-
 2 files changed, 10 insertions(+), 7 deletions(-)

(limited to 'include/linux/jbd2.h')

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 188f79d76988..2dc944442802 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1869,9 +1869,7 @@ static int load_superblock(journal_t *journal)
 
 	if (jbd2_has_feature_fast_commit(journal)) {
 		journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
-		num_fc_blocks = be32_to_cpu(sb->s_num_fc_blks);
-		if (!num_fc_blocks)
-			num_fc_blocks = JBD2_MIN_FC_BLOCKS;
+		num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
 		if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
 			journal->j_last = journal->j_fc_last - num_fc_blocks;
 		journal->j_fc_first = journal->j_last + 1;
@@ -2102,9 +2100,7 @@ jbd2_journal_initialize_fast_commit(journal_t *journal)
 	journal_superblock_t *sb = journal->j_superblock;
 	unsigned long long num_fc_blks;
 
-	num_fc_blks = be32_to_cpu(sb->s_num_fc_blks);
-	if (num_fc_blks == 0)
-		num_fc_blks = JBD2_MIN_FC_BLOCKS;
+	num_fc_blks = jbd2_journal_get_num_fc_blks(sb);
 	if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
 		return -ENOSPC;
 
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index d2a4860feb72..99d3cd051ac3 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -68,7 +68,7 @@ extern void *jbd2_alloc(size_t size, gfp_t flags);
 extern void jbd2_free(void *ptr, size_t size);
 
 #define JBD2_MIN_JOURNAL_BLOCKS 1024
-#define JBD2_MIN_FC_BLOCKS	256
+#define JBD2_DEFAULT_FAST_COMMIT_BLOCKS 256
 
 #ifdef __KERNEL__
 
@@ -1692,6 +1692,13 @@ static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
 	return journal->j_chksum_driver != NULL;
 }
 
+static inline int jbd2_journal_get_num_fc_blks(journal_superblock_t *jsb)
+{
+	int num_fc_blocks = be32_to_cpu(jsb->s_num_fc_blks);
+
+	return num_fc_blocks ? num_fc_blocks : JBD2_DEFAULT_FAST_COMMIT_BLOCKS;
+}
+
 /*
  * Return number of free blocks in the log. Must be called under j_state_lock.
  */
-- 
cgit v1.3-14-g43fede