Messages in this thread | | | Subject | Re: [PATCH] jfs: clear PAGECACHE_TAG_DIRTY for no-write pages | From | Dave Kleikamp <> | Date | Fri, 28 Dec 2007 22:50:59 -0600 |
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On Sat, 2007-12-29 at 10:21 +0800, Fengguang Wu wrote: > On Fri, Dec 28, 2007 at 10:53:14AM -0600, Dave Kleikamp wrote: > > > > --- > > > > diff -Nurp linux-2.6.24-rc6-git5/fs/jfs/jfs_metapage.c linux/fs/jfs/jfs_metapage.c > > --- linux-2.6.24-rc6-git5/fs/jfs/jfs_metapage.c 2007-12-28 10:28:33.000000000 -0600 > > +++ linux/fs/jfs/jfs_metapage.c 2007-12-28 10:37:30.000000000 -0600 > > @@ -360,6 +360,7 @@ static int metapage_writepage(struct pag > > struct metapage *mp; > > int redirty = 0; > > sector_t lblock; > > + int nr_underway = 0; > > sector_t pblock; > > sector_t next_block = 0; > > sector_t page_start; > > @@ -371,6 +372,7 @@ static int metapage_writepage(struct pag > > (PAGE_CACHE_SHIFT - inode->i_blkbits); > > BUG_ON(!PageLocked(page)); > > BUG_ON(PageWriteback(page)); > > This line should be moved below: > > + set_page_writeback(page);
No. set_page_writeback() needs to be called before submit_bio() is called.
I don't think there is any harm in calling set_page_writeback(), redirty_page_for_writeback() and end_page_writeback() in the case where there is no I/O to submit, and some dirty data cannot be written. It is consistent with what happens in __block_write_full_page().
It's also possible that some part of the page was written, and another part cannot be, causing the page to be redirtied.
> > > > for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { > > mp = page_to_mp(page, offset); > > @@ -413,11 +415,10 @@ static int metapage_writepage(struct pag > > if (!bio->bi_size) > > goto dump_bio; > > submit_bio(WRITE, bio); > > + nr_underway++; > > bio = NULL; > > - } else { > > - set_page_writeback(page); > > + } else > > inc_io(page); > > - } > > xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits; > > pblock = metapage_get_blocks(inode, lblock, &xlen); > > if (!pblock) { > > @@ -449,12 +450,16 @@ static int metapage_writepage(struct pag > > goto dump_bio; > > > > submit_bio(WRITE, bio); > > + nr_underway++; > > } > > if (redirty) > > redirty_page_for_writepage(wbc, page); > + else > + set_page_writeback(page); > > > > unlock_page(page); > > > > + if (nr_underway == 0) > + if (nr_underway == 0 && redirty == 0) > > > + end_page_writeback(page); > > + > > return 0; > > add_failed: > > /* We should never reach here, since we're only adding one vec */ > > Otherwise looks pretty good. > > Reviewed-by: Fengguang Wu <wfg@mail.ustc.edu.cn> > -- David Kleikamp IBM Linux Technology Center
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