From: "J. Bruce Fields" Subject: Re: [PATCH 02/15 v2] jbd2: implement jbd2_journal_invalidatepage_range Date: Tue, 4 Sep 2012 10:52:13 -0400 Message-ID: <20120904145213.GA26656@fieldses.org> References: <1346451711-1931-1-git-send-email-lczerner@redhat.com> <1346451711-1931-3-git-send-email-lczerner@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, tytso@mit.edu, hughd@google.com, linux-mm@kvack.org To: Lukas Czerner Return-path: Received: from fieldses.org ([174.143.236.118]:40824 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756758Ab2IDOwP (ORCPT ); Tue, 4 Sep 2012 10:52:15 -0400 Content-Disposition: inline In-Reply-To: <1346451711-1931-3-git-send-email-lczerner@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Aug 31, 2012 at 06:21:38PM -0400, Lukas Czerner wrote: > mm now supports invalidatepage_range address space operation and there > are two file system using jbd2 also implementing punch hole feature > which can benefit from this. We need to implement the same thing for > jbd2 layer in order to allow those file system take benefit of this > functionality. > > With new function jbd2_journal_invalidatepage_range() we can now specify > length to invalidate, rather than assuming invalidate to the end of the > page. > > Signed-off-by: Lukas Czerner > --- > fs/jbd2/journal.c | 1 + > fs/jbd2/transaction.c | 19 +++++++++++++++++-- > include/linux/jbd2.h | 2 ++ > 3 files changed, 20 insertions(+), 2 deletions(-) > > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c > index e149b99..e4618e9 100644 > --- a/fs/jbd2/journal.c > +++ b/fs/jbd2/journal.c > @@ -86,6 +86,7 @@ EXPORT_SYMBOL(jbd2_journal_force_commit_nested); > EXPORT_SYMBOL(jbd2_journal_wipe); > EXPORT_SYMBOL(jbd2_journal_blocks_per_page); > EXPORT_SYMBOL(jbd2_journal_invalidatepage); > +EXPORT_SYMBOL(jbd2_journal_invalidatepage_range); > EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers); > EXPORT_SYMBOL(jbd2_journal_force_commit); > EXPORT_SYMBOL(jbd2_journal_file_inode); > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c > index fb1ab953..65c1374 100644 > --- a/fs/jbd2/transaction.c > +++ b/fs/jbd2/transaction.c > @@ -1993,10 +1993,20 @@ zap_buffer_unlocked: > * > */ > void jbd2_journal_invalidatepage(journal_t *journal, > - struct page *page, > - unsigned long offset) > + struct page *page, > + unsigned long offset) > +{ > + jbd2_journal_invalidatepage_range(journal, page, offset, > + PAGE_CACHE_SIZE - offset); > +} > + > +void jbd2_journal_invalidatepage_range(journal_t *journal, > + struct page *page, > + unsigned int offset, > + unsigned int length) > { > struct buffer_head *head, *bh, *next; > + unsigned int stop = offset + length; > unsigned int curr_off = 0; > int may_free = 1; > > @@ -2005,6 +2015,8 @@ void jbd2_journal_invalidatepage(journal_t *journal, > if (!page_has_buffers(page)) > return; > > + BUG_ON(stop > PAGE_CACHE_SIZE || stop < length); This misses e.g. length == (unsigned int)(-1), offset = 1. Could make it obvious with: BUG_ON(offset > PAGE_CACHE_SIZE || length > PAGE_CACHE_SIZE); BUG_ON(stop > PAGE_CACHE_SIZE); Or is that overkill? --b. > + > /* We will potentially be playing with lists other than just the > * data lists (especially for journaled data mode), so be > * cautious in our locking. */ > @@ -2014,6 +2026,9 @@ void jbd2_journal_invalidatepage(journal_t *journal, > unsigned int next_off = curr_off + bh->b_size; > next = bh->b_this_page; > > + if (next_off > stop) > + return; > + > if (offset <= curr_off) { > /* This block is wholly outside the truncation point */ > lock_buffer(bh); > diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h > index 3efc43f..21288fa 100644 > --- a/include/linux/jbd2.h > +++ b/include/linux/jbd2.h > @@ -1101,6 +1101,8 @@ extern int jbd2_journal_forget (handle_t *, struct buffer_head *); > extern void journal_sync_buffer (struct buffer_head *); > extern void jbd2_journal_invalidatepage(journal_t *, > struct page *, unsigned long); > +extern void jbd2_journal_invalidatepage_range(journal_t *, struct page *, > + unsigned int, unsigned int); > extern int jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t); > extern int jbd2_journal_stop(handle_t *); > extern int jbd2_journal_flush (journal_t *); > -- > 1.7.7.6 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html