mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 18:41:23 +00:00
449813515d
Restore support for passing data lifetime information from filesystems to block drivers. This patch reverts commitb179c98f76
("block: Remove request.write_hint") and commitc75e707fe1
("block: remove the per-bio/request write hint"). This patch does not modify the size of struct bio because the new bi_write_hint member fills a hole in struct bio. pahole reports the following for struct bio on an x86_64 system with this patch applied: /* size: 112, cachelines: 2, members: 20 */ /* sum members: 110, holes: 1, sum holes: 2 */ /* last cacheline: 48 bytes */ Reviewed-by: Kanchan Joshi <joshi.k@samsung.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240202203926.2478590-7-bvanassche@acm.org Signed-off-by: Christian Brauner <brauner@kernel.org>
680 lines
18 KiB
C
680 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* fs/mpage.c
|
|
*
|
|
* Copyright (C) 2002, Linus Torvalds.
|
|
*
|
|
* Contains functions related to preparing and submitting BIOs which contain
|
|
* multiple pagecache pages.
|
|
*
|
|
* 15May2002 Andrew Morton
|
|
* Initial version
|
|
* 27Jun2002 axboe@suse.de
|
|
* use bio_add_page() to build bio's just the right size
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/kdev_t.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/prefetch.h>
|
|
#include <linux/mpage.h>
|
|
#include <linux/mm_inline.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/pagevec.h>
|
|
#include "internal.h"
|
|
|
|
/*
|
|
* I/O completion handler for multipage BIOs.
|
|
*
|
|
* The mpage code never puts partial pages into a BIO (except for end-of-file).
|
|
* If a page does not map to a contiguous run of blocks then it simply falls
|
|
* back to block_read_full_folio().
|
|
*
|
|
* Why is this? If a page's completion depends on a number of different BIOs
|
|
* which can complete in any order (or at the same time) then determining the
|
|
* status of that page is hard. See end_buffer_async_read() for the details.
|
|
* There is no point in duplicating all that complexity.
|
|
*/
|
|
static void mpage_read_end_io(struct bio *bio)
|
|
{
|
|
struct folio_iter fi;
|
|
int err = blk_status_to_errno(bio->bi_status);
|
|
|
|
bio_for_each_folio_all(fi, bio) {
|
|
if (err)
|
|
folio_set_error(fi.folio);
|
|
else
|
|
folio_mark_uptodate(fi.folio);
|
|
folio_unlock(fi.folio);
|
|
}
|
|
|
|
bio_put(bio);
|
|
}
|
|
|
|
static void mpage_write_end_io(struct bio *bio)
|
|
{
|
|
struct folio_iter fi;
|
|
int err = blk_status_to_errno(bio->bi_status);
|
|
|
|
bio_for_each_folio_all(fi, bio) {
|
|
if (err) {
|
|
folio_set_error(fi.folio);
|
|
mapping_set_error(fi.folio->mapping, err);
|
|
}
|
|
folio_end_writeback(fi.folio);
|
|
}
|
|
|
|
bio_put(bio);
|
|
}
|
|
|
|
static struct bio *mpage_bio_submit_read(struct bio *bio)
|
|
{
|
|
bio->bi_end_io = mpage_read_end_io;
|
|
guard_bio_eod(bio);
|
|
submit_bio(bio);
|
|
return NULL;
|
|
}
|
|
|
|
static struct bio *mpage_bio_submit_write(struct bio *bio)
|
|
{
|
|
bio->bi_end_io = mpage_write_end_io;
|
|
guard_bio_eod(bio);
|
|
submit_bio(bio);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* support function for mpage_readahead. The fs supplied get_block might
|
|
* return an up to date buffer. This is used to map that buffer into
|
|
* the page, which allows read_folio to avoid triggering a duplicate call
|
|
* to get_block.
|
|
*
|
|
* The idea is to avoid adding buffers to pages that don't already have
|
|
* them. So when the buffer is up to date and the page size == block size,
|
|
* this marks the page up to date instead of adding new buffers.
|
|
*/
|
|
static void map_buffer_to_folio(struct folio *folio, struct buffer_head *bh,
|
|
int page_block)
|
|
{
|
|
struct inode *inode = folio->mapping->host;
|
|
struct buffer_head *page_bh, *head;
|
|
int block = 0;
|
|
|
|
head = folio_buffers(folio);
|
|
if (!head) {
|
|
/*
|
|
* don't make any buffers if there is only one buffer on
|
|
* the folio and the folio just needs to be set up to date
|
|
*/
|
|
if (inode->i_blkbits == PAGE_SHIFT &&
|
|
buffer_uptodate(bh)) {
|
|
folio_mark_uptodate(folio);
|
|
return;
|
|
}
|
|
head = create_empty_buffers(folio, i_blocksize(inode), 0);
|
|
}
|
|
|
|
page_bh = head;
|
|
do {
|
|
if (block == page_block) {
|
|
page_bh->b_state = bh->b_state;
|
|
page_bh->b_bdev = bh->b_bdev;
|
|
page_bh->b_blocknr = bh->b_blocknr;
|
|
break;
|
|
}
|
|
page_bh = page_bh->b_this_page;
|
|
block++;
|
|
} while (page_bh != head);
|
|
}
|
|
|
|
struct mpage_readpage_args {
|
|
struct bio *bio;
|
|
struct folio *folio;
|
|
unsigned int nr_pages;
|
|
bool is_readahead;
|
|
sector_t last_block_in_bio;
|
|
struct buffer_head map_bh;
|
|
unsigned long first_logical_block;
|
|
get_block_t *get_block;
|
|
};
|
|
|
|
/*
|
|
* This is the worker routine which does all the work of mapping the disk
|
|
* blocks and constructs largest possible bios, submits them for IO if the
|
|
* blocks are not contiguous on the disk.
|
|
*
|
|
* We pass a buffer_head back and forth and use its buffer_mapped() flag to
|
|
* represent the validity of its disk mapping and to decide when to do the next
|
|
* get_block() call.
|
|
*/
|
|
static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
|
|
{
|
|
struct folio *folio = args->folio;
|
|
struct inode *inode = folio->mapping->host;
|
|
const unsigned blkbits = inode->i_blkbits;
|
|
const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
|
|
const unsigned blocksize = 1 << blkbits;
|
|
struct buffer_head *map_bh = &args->map_bh;
|
|
sector_t block_in_file;
|
|
sector_t last_block;
|
|
sector_t last_block_in_file;
|
|
sector_t first_block;
|
|
unsigned page_block;
|
|
unsigned first_hole = blocks_per_page;
|
|
struct block_device *bdev = NULL;
|
|
int length;
|
|
int fully_mapped = 1;
|
|
blk_opf_t opf = REQ_OP_READ;
|
|
unsigned nblocks;
|
|
unsigned relative_block;
|
|
gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL);
|
|
|
|
/* MAX_BUF_PER_PAGE, for example */
|
|
VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
|
|
|
|
if (args->is_readahead) {
|
|
opf |= REQ_RAHEAD;
|
|
gfp |= __GFP_NORETRY | __GFP_NOWARN;
|
|
}
|
|
|
|
if (folio_buffers(folio))
|
|
goto confused;
|
|
|
|
block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
|
|
last_block = block_in_file + args->nr_pages * blocks_per_page;
|
|
last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
|
|
if (last_block > last_block_in_file)
|
|
last_block = last_block_in_file;
|
|
page_block = 0;
|
|
|
|
/*
|
|
* Map blocks using the result from the previous get_blocks call first.
|
|
*/
|
|
nblocks = map_bh->b_size >> blkbits;
|
|
if (buffer_mapped(map_bh) &&
|
|
block_in_file > args->first_logical_block &&
|
|
block_in_file < (args->first_logical_block + nblocks)) {
|
|
unsigned map_offset = block_in_file - args->first_logical_block;
|
|
unsigned last = nblocks - map_offset;
|
|
|
|
first_block = map_bh->b_blocknr + map_offset;
|
|
for (relative_block = 0; ; relative_block++) {
|
|
if (relative_block == last) {
|
|
clear_buffer_mapped(map_bh);
|
|
break;
|
|
}
|
|
if (page_block == blocks_per_page)
|
|
break;
|
|
page_block++;
|
|
block_in_file++;
|
|
}
|
|
bdev = map_bh->b_bdev;
|
|
}
|
|
|
|
/*
|
|
* Then do more get_blocks calls until we are done with this folio.
|
|
*/
|
|
map_bh->b_folio = folio;
|
|
while (page_block < blocks_per_page) {
|
|
map_bh->b_state = 0;
|
|
map_bh->b_size = 0;
|
|
|
|
if (block_in_file < last_block) {
|
|
map_bh->b_size = (last_block-block_in_file) << blkbits;
|
|
if (args->get_block(inode, block_in_file, map_bh, 0))
|
|
goto confused;
|
|
args->first_logical_block = block_in_file;
|
|
}
|
|
|
|
if (!buffer_mapped(map_bh)) {
|
|
fully_mapped = 0;
|
|
if (first_hole == blocks_per_page)
|
|
first_hole = page_block;
|
|
page_block++;
|
|
block_in_file++;
|
|
continue;
|
|
}
|
|
|
|
/* some filesystems will copy data into the page during
|
|
* the get_block call, in which case we don't want to
|
|
* read it again. map_buffer_to_folio copies the data
|
|
* we just collected from get_block into the folio's buffers
|
|
* so read_folio doesn't have to repeat the get_block call
|
|
*/
|
|
if (buffer_uptodate(map_bh)) {
|
|
map_buffer_to_folio(folio, map_bh, page_block);
|
|
goto confused;
|
|
}
|
|
|
|
if (first_hole != blocks_per_page)
|
|
goto confused; /* hole -> non-hole */
|
|
|
|
/* Contiguous blocks? */
|
|
if (!page_block)
|
|
first_block = map_bh->b_blocknr;
|
|
else if (first_block + page_block != map_bh->b_blocknr)
|
|
goto confused;
|
|
nblocks = map_bh->b_size >> blkbits;
|
|
for (relative_block = 0; ; relative_block++) {
|
|
if (relative_block == nblocks) {
|
|
clear_buffer_mapped(map_bh);
|
|
break;
|
|
} else if (page_block == blocks_per_page)
|
|
break;
|
|
page_block++;
|
|
block_in_file++;
|
|
}
|
|
bdev = map_bh->b_bdev;
|
|
}
|
|
|
|
if (first_hole != blocks_per_page) {
|
|
folio_zero_segment(folio, first_hole << blkbits, PAGE_SIZE);
|
|
if (first_hole == 0) {
|
|
folio_mark_uptodate(folio);
|
|
folio_unlock(folio);
|
|
goto out;
|
|
}
|
|
} else if (fully_mapped) {
|
|
folio_set_mappedtodisk(folio);
|
|
}
|
|
|
|
/*
|
|
* This folio will go to BIO. Do we need to send this BIO off first?
|
|
*/
|
|
if (args->bio && (args->last_block_in_bio != first_block - 1))
|
|
args->bio = mpage_bio_submit_read(args->bio);
|
|
|
|
alloc_new:
|
|
if (args->bio == NULL) {
|
|
args->bio = bio_alloc(bdev, bio_max_segs(args->nr_pages), opf,
|
|
gfp);
|
|
if (args->bio == NULL)
|
|
goto confused;
|
|
args->bio->bi_iter.bi_sector = first_block << (blkbits - 9);
|
|
}
|
|
|
|
length = first_hole << blkbits;
|
|
if (!bio_add_folio(args->bio, folio, length, 0)) {
|
|
args->bio = mpage_bio_submit_read(args->bio);
|
|
goto alloc_new;
|
|
}
|
|
|
|
relative_block = block_in_file - args->first_logical_block;
|
|
nblocks = map_bh->b_size >> blkbits;
|
|
if ((buffer_boundary(map_bh) && relative_block == nblocks) ||
|
|
(first_hole != blocks_per_page))
|
|
args->bio = mpage_bio_submit_read(args->bio);
|
|
else
|
|
args->last_block_in_bio = first_block + blocks_per_page - 1;
|
|
out:
|
|
return args->bio;
|
|
|
|
confused:
|
|
if (args->bio)
|
|
args->bio = mpage_bio_submit_read(args->bio);
|
|
if (!folio_test_uptodate(folio))
|
|
block_read_full_folio(folio, args->get_block);
|
|
else
|
|
folio_unlock(folio);
|
|
goto out;
|
|
}
|
|
|
|
/**
|
|
* mpage_readahead - start reads against pages
|
|
* @rac: Describes which pages to read.
|
|
* @get_block: The filesystem's block mapper function.
|
|
*
|
|
* This function walks the pages and the blocks within each page, building and
|
|
* emitting large BIOs.
|
|
*
|
|
* If anything unusual happens, such as:
|
|
*
|
|
* - encountering a page which has buffers
|
|
* - encountering a page which has a non-hole after a hole
|
|
* - encountering a page with non-contiguous blocks
|
|
*
|
|
* then this code just gives up and calls the buffer_head-based read function.
|
|
* It does handle a page which has holes at the end - that is a common case:
|
|
* the end-of-file on blocksize < PAGE_SIZE setups.
|
|
*
|
|
* BH_Boundary explanation:
|
|
*
|
|
* There is a problem. The mpage read code assembles several pages, gets all
|
|
* their disk mappings, and then submits them all. That's fine, but obtaining
|
|
* the disk mappings may require I/O. Reads of indirect blocks, for example.
|
|
*
|
|
* So an mpage read of the first 16 blocks of an ext2 file will cause I/O to be
|
|
* submitted in the following order:
|
|
*
|
|
* 12 0 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16
|
|
*
|
|
* because the indirect block has to be read to get the mappings of blocks
|
|
* 13,14,15,16. Obviously, this impacts performance.
|
|
*
|
|
* So what we do it to allow the filesystem's get_block() function to set
|
|
* BH_Boundary when it maps block 11. BH_Boundary says: mapping of the block
|
|
* after this one will require I/O against a block which is probably close to
|
|
* this one. So you should push what I/O you have currently accumulated.
|
|
*
|
|
* This all causes the disk requests to be issued in the correct order.
|
|
*/
|
|
void mpage_readahead(struct readahead_control *rac, get_block_t get_block)
|
|
{
|
|
struct folio *folio;
|
|
struct mpage_readpage_args args = {
|
|
.get_block = get_block,
|
|
.is_readahead = true,
|
|
};
|
|
|
|
while ((folio = readahead_folio(rac))) {
|
|
prefetchw(&folio->flags);
|
|
args.folio = folio;
|
|
args.nr_pages = readahead_count(rac);
|
|
args.bio = do_mpage_readpage(&args);
|
|
}
|
|
if (args.bio)
|
|
mpage_bio_submit_read(args.bio);
|
|
}
|
|
EXPORT_SYMBOL(mpage_readahead);
|
|
|
|
/*
|
|
* This isn't called much at all
|
|
*/
|
|
int mpage_read_folio(struct folio *folio, get_block_t get_block)
|
|
{
|
|
struct mpage_readpage_args args = {
|
|
.folio = folio,
|
|
.nr_pages = 1,
|
|
.get_block = get_block,
|
|
};
|
|
|
|
args.bio = do_mpage_readpage(&args);
|
|
if (args.bio)
|
|
mpage_bio_submit_read(args.bio);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(mpage_read_folio);
|
|
|
|
/*
|
|
* Writing is not so simple.
|
|
*
|
|
* If the page has buffers then they will be used for obtaining the disk
|
|
* mapping. We only support pages which are fully mapped-and-dirty, with a
|
|
* special case for pages which are unmapped at the end: end-of-file.
|
|
*
|
|
* If the page has no buffers (preferred) then the page is mapped here.
|
|
*
|
|
* If all blocks are found to be contiguous then the page can go into the
|
|
* BIO. Otherwise fall back to the mapping's writepage().
|
|
*
|
|
* FIXME: This code wants an estimate of how many pages are still to be
|
|
* written, so it can intelligently allocate a suitably-sized BIO. For now,
|
|
* just allocate full-size (16-page) BIOs.
|
|
*/
|
|
|
|
struct mpage_data {
|
|
struct bio *bio;
|
|
sector_t last_block_in_bio;
|
|
get_block_t *get_block;
|
|
};
|
|
|
|
/*
|
|
* We have our BIO, so we can now mark the buffers clean. Make
|
|
* sure to only clean buffers which we know we'll be writing.
|
|
*/
|
|
static void clean_buffers(struct folio *folio, unsigned first_unmapped)
|
|
{
|
|
unsigned buffer_counter = 0;
|
|
struct buffer_head *bh, *head = folio_buffers(folio);
|
|
|
|
if (!head)
|
|
return;
|
|
bh = head;
|
|
|
|
do {
|
|
if (buffer_counter++ == first_unmapped)
|
|
break;
|
|
clear_buffer_dirty(bh);
|
|
bh = bh->b_this_page;
|
|
} while (bh != head);
|
|
|
|
/*
|
|
* we cannot drop the bh if the page is not uptodate or a concurrent
|
|
* read_folio would fail to serialize with the bh and it would read from
|
|
* disk before we reach the platter.
|
|
*/
|
|
if (buffer_heads_over_limit && folio_test_uptodate(folio))
|
|
try_to_free_buffers(folio);
|
|
}
|
|
|
|
static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
|
|
void *data)
|
|
{
|
|
struct mpage_data *mpd = data;
|
|
struct bio *bio = mpd->bio;
|
|
struct address_space *mapping = folio->mapping;
|
|
struct inode *inode = mapping->host;
|
|
const unsigned blkbits = inode->i_blkbits;
|
|
const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
|
|
sector_t last_block;
|
|
sector_t block_in_file;
|
|
sector_t first_block;
|
|
unsigned page_block;
|
|
unsigned first_unmapped = blocks_per_page;
|
|
struct block_device *bdev = NULL;
|
|
int boundary = 0;
|
|
sector_t boundary_block = 0;
|
|
struct block_device *boundary_bdev = NULL;
|
|
size_t length;
|
|
struct buffer_head map_bh;
|
|
loff_t i_size = i_size_read(inode);
|
|
int ret = 0;
|
|
struct buffer_head *head = folio_buffers(folio);
|
|
|
|
if (head) {
|
|
struct buffer_head *bh = head;
|
|
|
|
/* If they're all mapped and dirty, do it */
|
|
page_block = 0;
|
|
do {
|
|
BUG_ON(buffer_locked(bh));
|
|
if (!buffer_mapped(bh)) {
|
|
/*
|
|
* unmapped dirty buffers are created by
|
|
* block_dirty_folio -> mmapped data
|
|
*/
|
|
if (buffer_dirty(bh))
|
|
goto confused;
|
|
if (first_unmapped == blocks_per_page)
|
|
first_unmapped = page_block;
|
|
continue;
|
|
}
|
|
|
|
if (first_unmapped != blocks_per_page)
|
|
goto confused; /* hole -> non-hole */
|
|
|
|
if (!buffer_dirty(bh) || !buffer_uptodate(bh))
|
|
goto confused;
|
|
if (page_block) {
|
|
if (bh->b_blocknr != first_block + page_block)
|
|
goto confused;
|
|
} else {
|
|
first_block = bh->b_blocknr;
|
|
}
|
|
page_block++;
|
|
boundary = buffer_boundary(bh);
|
|
if (boundary) {
|
|
boundary_block = bh->b_blocknr;
|
|
boundary_bdev = bh->b_bdev;
|
|
}
|
|
bdev = bh->b_bdev;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
|
|
if (first_unmapped)
|
|
goto page_is_mapped;
|
|
|
|
/*
|
|
* Page has buffers, but they are all unmapped. The page was
|
|
* created by pagein or read over a hole which was handled by
|
|
* block_read_full_folio(). If this address_space is also
|
|
* using mpage_readahead then this can rarely happen.
|
|
*/
|
|
goto confused;
|
|
}
|
|
|
|
/*
|
|
* The page has no buffers: map it to disk
|
|
*/
|
|
BUG_ON(!folio_test_uptodate(folio));
|
|
block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
|
|
/*
|
|
* Whole page beyond EOF? Skip allocating blocks to avoid leaking
|
|
* space.
|
|
*/
|
|
if (block_in_file >= (i_size + (1 << blkbits) - 1) >> blkbits)
|
|
goto page_is_mapped;
|
|
last_block = (i_size - 1) >> blkbits;
|
|
map_bh.b_folio = folio;
|
|
for (page_block = 0; page_block < blocks_per_page; ) {
|
|
|
|
map_bh.b_state = 0;
|
|
map_bh.b_size = 1 << blkbits;
|
|
if (mpd->get_block(inode, block_in_file, &map_bh, 1))
|
|
goto confused;
|
|
if (!buffer_mapped(&map_bh))
|
|
goto confused;
|
|
if (buffer_new(&map_bh))
|
|
clean_bdev_bh_alias(&map_bh);
|
|
if (buffer_boundary(&map_bh)) {
|
|
boundary_block = map_bh.b_blocknr;
|
|
boundary_bdev = map_bh.b_bdev;
|
|
}
|
|
if (page_block) {
|
|
if (map_bh.b_blocknr != first_block + page_block)
|
|
goto confused;
|
|
} else {
|
|
first_block = map_bh.b_blocknr;
|
|
}
|
|
page_block++;
|
|
boundary = buffer_boundary(&map_bh);
|
|
bdev = map_bh.b_bdev;
|
|
if (block_in_file == last_block)
|
|
break;
|
|
block_in_file++;
|
|
}
|
|
BUG_ON(page_block == 0);
|
|
|
|
first_unmapped = page_block;
|
|
|
|
page_is_mapped:
|
|
/* Don't bother writing beyond EOF, truncate will discard the folio */
|
|
if (folio_pos(folio) >= i_size)
|
|
goto confused;
|
|
length = folio_size(folio);
|
|
if (folio_pos(folio) + length > i_size) {
|
|
/*
|
|
* The page straddles i_size. It must be zeroed out on each
|
|
* and every writepage invocation because it may be mmapped.
|
|
* "A file is mapped in multiples of the page size. For a file
|
|
* that is not a multiple of the page size, the remaining memory
|
|
* is zeroed when mapped, and writes to that region are not
|
|
* written out to the file."
|
|
*/
|
|
length = i_size - folio_pos(folio);
|
|
folio_zero_segment(folio, length, folio_size(folio));
|
|
}
|
|
|
|
/*
|
|
* This page will go to BIO. Do we need to send this BIO off first?
|
|
*/
|
|
if (bio && mpd->last_block_in_bio != first_block - 1)
|
|
bio = mpage_bio_submit_write(bio);
|
|
|
|
alloc_new:
|
|
if (bio == NULL) {
|
|
bio = bio_alloc(bdev, BIO_MAX_VECS,
|
|
REQ_OP_WRITE | wbc_to_write_flags(wbc),
|
|
GFP_NOFS);
|
|
bio->bi_iter.bi_sector = first_block << (blkbits - 9);
|
|
wbc_init_bio(wbc, bio);
|
|
bio->bi_write_hint = inode->i_write_hint;
|
|
}
|
|
|
|
/*
|
|
* Must try to add the page before marking the buffer clean or
|
|
* the confused fail path above (OOM) will be very confused when
|
|
* it finds all bh marked clean (i.e. it will not write anything)
|
|
*/
|
|
wbc_account_cgroup_owner(wbc, &folio->page, folio_size(folio));
|
|
length = first_unmapped << blkbits;
|
|
if (!bio_add_folio(bio, folio, length, 0)) {
|
|
bio = mpage_bio_submit_write(bio);
|
|
goto alloc_new;
|
|
}
|
|
|
|
clean_buffers(folio, first_unmapped);
|
|
|
|
BUG_ON(folio_test_writeback(folio));
|
|
folio_start_writeback(folio);
|
|
folio_unlock(folio);
|
|
if (boundary || (first_unmapped != blocks_per_page)) {
|
|
bio = mpage_bio_submit_write(bio);
|
|
if (boundary_block) {
|
|
write_boundary_block(boundary_bdev,
|
|
boundary_block, 1 << blkbits);
|
|
}
|
|
} else {
|
|
mpd->last_block_in_bio = first_block + blocks_per_page - 1;
|
|
}
|
|
goto out;
|
|
|
|
confused:
|
|
if (bio)
|
|
bio = mpage_bio_submit_write(bio);
|
|
|
|
/*
|
|
* The caller has a ref on the inode, so *mapping is stable
|
|
*/
|
|
ret = block_write_full_folio(folio, wbc, mpd->get_block);
|
|
mapping_set_error(mapping, ret);
|
|
out:
|
|
mpd->bio = bio;
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them
|
|
* @mapping: address space structure to write
|
|
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
|
|
* @get_block: the filesystem's block mapper function.
|
|
*
|
|
* This is a library function, which implements the writepages()
|
|
* address_space_operation.
|
|
*/
|
|
int
|
|
mpage_writepages(struct address_space *mapping,
|
|
struct writeback_control *wbc, get_block_t get_block)
|
|
{
|
|
struct mpage_data mpd = {
|
|
.get_block = get_block,
|
|
};
|
|
struct blk_plug plug;
|
|
int ret;
|
|
|
|
blk_start_plug(&plug);
|
|
ret = write_cache_pages(mapping, wbc, __mpage_writepage, &mpd);
|
|
if (mpd.bio)
|
|
mpage_bio_submit_write(mpd.bio);
|
|
blk_finish_plug(&plug);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(mpage_writepages);
|