buffer: convert block_truncate_page() to use a folio

Support large folios in block_truncate_page() and avoid three hidden calls
to compound_head().

[willy@infradead.org: fix check of filemap_grab_folio() return value]
  Link: https://lkml.kernel.org/r/ZItZOt+XxV12HtzL@casper.infradead.org
Link: https://lkml.kernel.org/r/20230612210141.730128-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-06-12 22:01:41 +01:00 committed by Andrew Morton
parent eee25182a8
commit 6d68f644b9

View file

@ -2598,17 +2598,16 @@ int block_truncate_page(struct address_space *mapping,
loff_t from, get_block_t *get_block)
{
pgoff_t index = from >> PAGE_SHIFT;
unsigned offset = from & (PAGE_SIZE-1);
unsigned blocksize;
sector_t iblock;
unsigned length, pos;
size_t offset, length, pos;
struct inode *inode = mapping->host;
struct page *page;
struct folio *folio;
struct buffer_head *bh;
int err = 0;
blocksize = i_blocksize(inode);
length = offset & (blocksize - 1);
length = from & (blocksize - 1);
/* Block boundary? Nothing to do */
if (!length)
@ -2617,15 +2616,18 @@ int block_truncate_page(struct address_space *mapping,
length = blocksize - length;
iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);
page = grab_cache_page(mapping, index);
if (!page)
return -ENOMEM;
folio = filemap_grab_folio(mapping, index);
if (IS_ERR(folio))
return PTR_ERR(folio);
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
bh = folio_buffers(folio);
if (!bh) {
folio_create_empty_buffers(folio, blocksize, 0);
bh = folio_buffers(folio);
}
/* Find the buffer that contains "offset" */
bh = page_buffers(page);
offset = offset_in_folio(folio, from);
pos = blocksize;
while (offset >= pos) {
bh = bh->b_this_page;
@ -2644,7 +2646,7 @@ int block_truncate_page(struct address_space *mapping,
}
/* Ok, it's mapped. Make sure it's up-to-date */
if (PageUptodate(page))
if (folio_test_uptodate(folio))
set_buffer_uptodate(bh);
if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) {
@ -2654,12 +2656,12 @@ int block_truncate_page(struct address_space *mapping,
goto unlock;
}
zero_user(page, offset, length);
folio_zero_range(folio, offset, length);
mark_buffer_dirty(bh);
unlock:
unlock_page(page);
put_page(page);
folio_unlock(folio);
folio_put(folio);
return err;
}