| Message ID | 20190801010944.364767635@linutronix.de |
|---|---|
| State | New |
| Headers | show |
| Series | fs: Substitute bit-spinlocks for PREEMPT_RT and debugging | expand |
On Thu 01-08-19 03:01:31, Thomas Gleixner wrote: > 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> > Cc: linux-ext4@vger.kernel.org > Cc: "Theodore Ts'o" <tytso@mit.edu> > Cc: Jan Kara <jack@suse.com> Nice simplification. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > V2: New patch > --- > fs/jbd2/transaction.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > --- a/fs/jbd2/transaction.c > +++ b/fs/jbd2/transaction.c > @@ -2196,7 +2196,8 @@ static int journal_unmap_buffer(journal_ > * 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 */ > @@ -2204,10 +2205,6 @@ static int journal_unmap_buffer(journal_ > 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) > @@ -2329,7 +2326,6 @@ static int journal_unmap_buffer(journal_ > */ > 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); > >
--- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -2196,7 +2196,8 @@ static int journal_unmap_buffer(journal_ * 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 */ @@ -2204,10 +2205,6 @@ static int journal_unmap_buffer(journal_ 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) @@ -2329,7 +2326,6 @@ static int journal_unmap_buffer(journal_ */ 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);
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> Cc: linux-ext4@vger.kernel.org Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan Kara <jack@suse.com> --- V2: New patch --- fs/jbd2/transaction.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)