iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

xfs: xfs_cluster_write is redundant

Browse Source 
xfs_cluster_write() is not necessary now that xfs_vm_writepages()
aggregates writepage calls across a single mapping. This means we no
longer need to do page lookups in xfs_cluster_write, so writeback
only needs to look up th epage cache once per page being written.
This also removes a large amount of mostly duplicate code between
xfs_do_writepage() and xfs_convert_page().

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner 2016-02-15 17:21:31 +11:00 committed by Dave Chinner
parent fbcc025613
commit ad68972acb
1 changed files with 6 additions and 208 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

214
fs/xfs/xfs_aops.c
View File

@ -650,179 +650,6 @@ xfs_check_page_type(
return false;
}
/*
* Allocate & map buffers for page given the extent map. Write it out.
* except for the original page of a writepage, this is called on
* delalloc/unwritten pages only, for the original page it is possible
* that the page has no mapping at all.
*/
STATIC int
xfs_convert_page(
struct inode *inode,
struct page *page,
loff_t tindex,
struct xfs_writepage_ctx *wpc,
struct writeback_control *wbc)
{
struct buffer_head *bh, *head;
xfs_off_t end_offset;
unsigned long p_offset;
int len, page_dirty;
int count = 0, done = 0, uptodate = 1;
xfs_off_t offset = page_offset(page);
if (page->index != tindex)
goto fail;
if (!trylock_page(page))
goto fail;
if (PageWriteback(page))
goto fail_unlock_page;
if (page->mapping != inode->i_mapping)
goto fail_unlock_page;
if (!xfs_check_page_type(page, wpc->ioend->io_type, false))
goto fail_unlock_page;
/*
* page_dirty is initially a count of buffers on the page before
* EOF and is decremented as we move each into a cleanable state.
*
* Derivation:
*
* End offset is the highest offset that this page should represent.
* If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
* will evaluate non-zero and be less than PAGE_CACHE_SIZE and
* hence give us the correct page_dirty count. On any other page,
* it will be zero and in that case we need page_dirty to be the
* count of buffers on the page.
*/
end_offset = min_t(unsigned long long,
(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
i_size_read(inode));
/*
* If the current map does not span the entire page we are about to try
* to write, then give up. The only way we can write a page that spans
* multiple mappings in a single writeback iteration is via the
* xfs_vm_writepage() function. Data integrity writeback requires the
* entire page to be written in a single attempt, otherwise the part of
* the page we don't write here doesn't get written as part of the data
* integrity sync.
*
* For normal writeback, we also don't attempt to write partial pages
* here as it simply means that write_cache_pages() will see it under
* writeback and ignore the page until some point in the future, at
* which time this will be the only page in the file that needs
* writeback. Hence for more optimal IO patterns, we should always
* avoid partial page writeback due to multiple mappings on a page here.
*/
if (!xfs_imap_valid(inode, &wpc->imap, end_offset))
goto fail_unlock_page;
len = 1 << inode->i_blkbits;
p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
PAGE_CACHE_SIZE);
p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
page_dirty = p_offset / len;
/*
* The moment we find a buffer that doesn't match our current type
* specification or can't be written, abort the loop and start
* writeback. As per the above xfs_imap_valid() check, only
* xfs_vm_writepage() can handle partial page writeback fully - we are
* limited here to the buffers that are contiguous with the current
* ioend, and hence a buffer we can't write breaks that contiguity and
* we have to defer the rest of the IO to xfs_vm_writepage().
*/
bh = head = page_buffers(page);
do {
if (offset >= end_offset)
break;
if (!buffer_uptodate(bh))
uptodate = 0;
if (!(PageUptodate(page) || buffer_uptodate(bh))) {
done = 1;
break;
}
if (buffer_unwritten(bh) || buffer_delay(bh) ||
buffer_mapped(bh)) {
if (buffer_unwritten(bh))
wpc->io_type = XFS_IO_UNWRITTEN;
else if (buffer_delay(bh))
wpc->io_type = XFS_IO_DELALLOC;
else
wpc->io_type = XFS_IO_OVERWRITE;
/*
* imap should always be valid because of the above
* partial page end_offset check on the imap.
*/
ASSERT(xfs_imap_valid(inode, &wpc->imap, offset));
lock_buffer(bh);
if (wpc->io_type != XFS_IO_OVERWRITE)
xfs_map_at_offset(inode, bh, &wpc->imap, offset);
xfs_add_to_ioend(inode, bh, offset, wpc);
page_dirty--;
count++;
} else {
done = 1;
break;
}
} while (offset += len, (bh = bh->b_this_page) != head);
if (uptodate && bh == head)
SetPageUptodate(page);
if (count) {
if (--wbc->nr_to_write <= 0 &&
wbc->sync_mode == WB_SYNC_NONE)
done = 1;
}
xfs_start_page_writeback(page, !page_dirty, count);
return done;
fail_unlock_page:
unlock_page(page);
fail:
return 1;
}
/*
* Convert & write out a cluster of pages in the same extent as defined
* by mp and following the start page.
*/
STATIC void
xfs_cluster_write(
struct inode *inode,
pgoff_t tindex,
struct xfs_writepage_ctx *wpc,
struct writeback_control *wbc,
pgoff_t tlast)
{
struct pagevec pvec;
int done = 0, i;
pagevec_init(&pvec, 0);
while (!done && tindex <= tlast) {
unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
break;
for (i = 0; i < pagevec_count(&pvec); i++) {
done = xfs_convert_page(inode, pvec.pages[i], tindex++,
wpc, wbc);
if (done)
break;
}
pagevec_release(&pvec);
cond_resched();
}
}
STATIC void
xfs_vm_invalidatepage(
struct page *page,
@ -939,7 +766,7 @@ xfs_do_writepage(
struct buffer_head *bh, *head;
loff_t offset;
__uint64_t end_offset;
pgoff_t end_index, last_index;
pgoff_t end_index;
ssize_t len;
int err, uptodate = 1;
int count = 0;
@ -969,12 +796,9 @@ xfs_do_writepage(
if (WARN_ON_ONCE(current->flags & PF_FSTRANS))
goto redirty;
/* Is this page beyond the end of the file? */
offset = i_size_read(inode);
end_index = offset >> PAGE_CACHE_SHIFT;
last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
/*
* Is this page beyond the end of the file?
*
* The page index is less than the end_index, adjust the end_offset
* to the highest offset that this page should represent.
* -----------------------------------------------------
@ -985,6 +809,8 @@ xfs_do_writepage(
* | desired writeback range | see else |
* ---------------------------------^------------------|
*/
offset = i_size_read(inode);
end_index = offset >> PAGE_CACHE_SHIFT;
if (page->index < end_index)
end_offset = (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT;
else {
@ -1113,35 +939,7 @@ xfs_do_writepage(
xfs_start_page_writeback(page, 1, count);
/* if there is no IO to be submitted for this page, we are done */
if (!count)
return 0;
ASSERT(wpc->iohead);
ASSERT(err == 0);
/*
* Any errors from this point onwards need tobe reported through the IO
* completion path as we have marked the initial page as under writeback
* and unlocked it.
*/
if (wpc->imap_valid) {
xfs_off_t end_index;
end_index = wpc->imap.br_startoff + wpc->imap.br_blockcount;
/* to bytes */
end_index <<= inode->i_blkbits;
/* to pages */
end_index = (end_index - 1) >> PAGE_CACHE_SHIFT;
/* check against file size */
if (end_index > last_index)
end_index = last_index;
xfs_cluster_write(inode, page->index + 1, wpc, wbc, end_index);
}
ASSERT(wpc->iohead || !count);
return 0;
error: