Commit d84560f7 authored Aug 09, 2019 by Thomas Gleixner Committed by Theodore Ts'o Oct 21, 2019

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>

parent 4f5cafb5

fs/jbd2/transaction.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -2199,7 +2199,8 @@ static int journal_unmap_buffer(journal_t journal, struct buffer_head bh,
		* holding the page lock. --sct
		*/

		if (!buffer_jbd(bh))
		jh = jbd2_journal_grab_journal_head(bh);
		if (!jh)
		goto zap_buffer_unlocked;

		/* 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);
		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
		* transaction adding inode to orphan list (let's call it T)
		@@ -2332,7 +2329,6 @@ zap_buffer:
		*/
		jh->b_modified = 0;
		jbd2_journal_put_journal_head(jh);
		zap_buffer_no_jh:
		spin_unlock(&journal->j_list_lock);
		jbd_unlock_bh_state(bh);
		write_unlock(&journal->j_state_lock);

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