korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-26 13:44:15 +08:00
Code Issues Packages Projects Releases Wiki Activity

buffer: Rewrite nobh_truncate_page() to use folios

Browse Source 
- Calculate iblock directly instead of using a while loop
 - Move has_buffers to the end to remove a backwards jump
 - Use __filemap_get_folio() instead of grab_cache_page(), which
   removes a spurious FGP_ACCESSED flag.
 - Eliminate length and pos variables
 - Use folio APIs where they exist

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-04-28 23:59:15 -04:00
parent 2ebdd1df31
commit 6c2ae0d5db
1 changed files with 27 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
fs/buffer.c
View File

@ -2791,44 +2791,28 @@ int nobh_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;
struct inode *inode = mapping->host;
struct page *page;
unsigned blocksize = i_blocksize(inode);
struct folio *folio;
struct buffer_head map_bh;
size_t offset;
sector_t iblock;
int err;
blocksize = i_blocksize(inode);
length = offset & (blocksize - 1);
/* Block boundary? Nothing to do */
if (!length)
if (!(from & (blocksize - 1)))
return 0;
length = blocksize - length;
iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);
page = grab_cache_page(mapping, index);
folio = __filemap_get_folio(mapping, index, FGP_LOCK | FGP_CREAT,
mapping_gfp_mask(mapping));
err = -ENOMEM;
if (!page)
if (!folio)
goto out;
if (page_has_buffers(page)) {
has_buffers:
unlock_page(page);
put_page(page);
return block_truncate_page(mapping, from, get_block);
}
/* Find the buffer that contains "offset" */
pos = blocksize;
while (offset >= pos) {
iblock++;
pos += blocksize;
}
if (folio_buffers(folio))
goto has_buffers;
iblock = from >> inode->i_blkbits;
map_bh.b_size = blocksize;
map_bh.b_state = 0;
err = get_block(inode, iblock, &map_bh, 0);
@ -2839,29 +2823,35 @@ has_buffers:
goto unlock;
/* Ok, it's mapped. Make sure it's up-to-date */
if (!PageUptodate(page)) {
err = mapping->a_ops->readpage(NULL, page);
if (!folio_test_uptodate(folio)) {
err = mapping->a_ops->readpage(NULL, &folio->page);
if (err) {
put_page(page);
folio_put(folio);
goto out;
}
lock_page(page);
if (!PageUptodate(page)) {
folio_lock(folio);
if (!folio_test_uptodate(folio)) {
err = -EIO;
goto unlock;
}
if (page_has_buffers(page))
if (folio_buffers(folio))
goto has_buffers;
}
zero_user(page, offset, length);
set_page_dirty(page);
offset = offset_in_folio(folio, from);
folio_zero_segment(folio, offset, round_up(offset, blocksize));
folio_mark_dirty(folio);
err = 0;
unlock:
unlock_page(page);
put_page(page);
folio_unlock(folio);
folio_put(folio);
out:
return err;
has_buffers:
folio_unlock(folio);
folio_put(folio);
return block_truncate_page(mapping, from, get_block);
}
EXPORT_SYMBOL(nobh_truncate_page);