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jbd2: Simplify journal_unmap_buffer() 

journal_unmap_buffer() checks first whether the buffer head is a journal.
If so it takes locks and then invokes jbd2_journal_grab_journal_head()
followed by another check whether this is journal head buffer.

The double checking is pointless.

Replace the initial check with jbd2_journal_grab_journal_head() which
alredy checks whether the buffer head is actually a journal.

Allows also early access to the journal head pointer for the upcoming
conversion of state lock to a regular spinlock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20190809124233.13277-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Thomas Gleixner 2019-08-09 14:42:27 +02:00 committed by Theodore Ts'o
parent 4f5cafb5cb
commit d84560f74d
1 changed files with 2 additions and 6 deletions
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8
fs/jbd2/transaction.c
View File

@ -2199,7 +2199,8 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
* holding the page lock. --sct * holding the page lock. --sct
*/ */
if (!buffer_jbd(bh)) jh = jbd2_journal_grab_journal_head(bh);
if (!jh)
goto zap_buffer_unlocked; goto zap_buffer_unlocked;
/* OK, we have data buffer in journaled mode */ /* OK, we have data buffer in journaled mode */
@ -2207,10 +2208,6 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
jbd_lock_bh_state(bh); jbd_lock_bh_state(bh);
spin_lock(&journal->j_list_lock); spin_lock(&journal->j_list_lock);
jh = jbd2_journal_grab_journal_head(bh);
if (!jh)
goto zap_buffer_no_jh;
/* /*
* We cannot remove the buffer from checkpoint lists until the * We cannot remove the buffer from checkpoint lists until the
* transaction adding inode to orphan list (let's call it T) * transaction adding inode to orphan list (let's call it T)
@ -2332,7 +2329,6 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
*/ */
jh->b_modified = 0; jh->b_modified = 0;
jbd2_journal_put_journal_head(jh); jbd2_journal_put_journal_head(jh);
zap_buffer_no_jh:
spin_unlock(&journal->j_list_lock); spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh); jbd_unlock_bh_state(bh);
write_unlock(&journal->j_state_lock); write_unlock(&journal->j_state_lock);