mirror of
https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
synced 2026-10-29 03:01:39 -04:00
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
commit
1da177e4c3
17291 changed files with 6718755 additions and 0 deletions
772
fs/mpage.c
Normal file
772
fs/mpage.c
Normal file
|
|
@ -0,0 +1,772 @@
|
|||
/*
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||||
* fs/mpage.c
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*
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||||
* Copyright (C) 2002, Linus Torvalds.
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*
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||||
* Contains functions related to preparing and submitting BIOs which contain
|
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* multiple pagecache pages.
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*
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* 15May2002 akpm@zip.com.au
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* Initial version
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* 27Jun2002 axboe@suse.de
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* use bio_add_page() to build bio's just the right size
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*/
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||||
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||||
#include <linux/kernel.h>
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||||
#include <linux/module.h>
|
||||
#include <linux/mm.h>
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#include <linux/kdev_t.h>
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#include <linux/bio.h>
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/blkdev.h>
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#include <linux/highmem.h>
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#include <linux/prefetch.h>
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#include <linux/mpage.h>
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#include <linux/writeback.h>
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#include <linux/backing-dev.h>
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#include <linux/pagevec.h>
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|
||||
/*
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||||
* I/O completion handler for multipage BIOs.
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||||
*
|
||||
* The mpage code never puts partial pages into a BIO (except for end-of-file).
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* If a page does not map to a contiguous run of blocks then it simply falls
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||||
* back to block_read_full_page().
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*
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||||
* Why is this? If a page's completion depends on a number of different BIOs
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* which can complete in any order (or at the same time) then determining the
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||||
* status of that page is hard. See end_buffer_async_read() for the details.
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* There is no point in duplicating all that complexity.
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||||
*/
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static int mpage_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
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||||
{
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||||
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
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struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
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|
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if (bio->bi_size)
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return 1;
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do {
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struct page *page = bvec->bv_page;
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if (--bvec >= bio->bi_io_vec)
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prefetchw(&bvec->bv_page->flags);
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if (uptodate) {
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SetPageUptodate(page);
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} else {
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||||
ClearPageUptodate(page);
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SetPageError(page);
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||||
}
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unlock_page(page);
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||||
} while (bvec >= bio->bi_io_vec);
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bio_put(bio);
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return 0;
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}
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static int mpage_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
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||||
{
|
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const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
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struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
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if (bio->bi_size)
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return 1;
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do {
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struct page *page = bvec->bv_page;
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if (--bvec >= bio->bi_io_vec)
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prefetchw(&bvec->bv_page->flags);
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if (!uptodate)
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SetPageError(page);
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end_page_writeback(page);
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} while (bvec >= bio->bi_io_vec);
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bio_put(bio);
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return 0;
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}
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struct bio *mpage_bio_submit(int rw, struct bio *bio)
|
||||
{
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||||
bio->bi_end_io = mpage_end_io_read;
|
||||
if (rw == WRITE)
|
||||
bio->bi_end_io = mpage_end_io_write;
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||||
submit_bio(rw, bio);
|
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return NULL;
|
||||
}
|
||||
|
||||
static struct bio *
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||||
mpage_alloc(struct block_device *bdev,
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||||
sector_t first_sector, int nr_vecs,
|
||||
unsigned int __nocast gfp_flags)
|
||||
{
|
||||
struct bio *bio;
|
||||
|
||||
bio = bio_alloc(gfp_flags, nr_vecs);
|
||||
|
||||
if (bio == NULL && (current->flags & PF_MEMALLOC)) {
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||||
while (!bio && (nr_vecs /= 2))
|
||||
bio = bio_alloc(gfp_flags, nr_vecs);
|
||||
}
|
||||
|
||||
if (bio) {
|
||||
bio->bi_bdev = bdev;
|
||||
bio->bi_sector = first_sector;
|
||||
}
|
||||
return bio;
|
||||
}
|
||||
|
||||
/*
|
||||
* support function for mpage_readpages. The fs supplied get_block might
|
||||
* return an up to date buffer. This is used to map that buffer into
|
||||
* the page, which allows readpage 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_page(struct page *page, struct buffer_head *bh, int page_block)
|
||||
{
|
||||
struct inode *inode = page->mapping->host;
|
||||
struct buffer_head *page_bh, *head;
|
||||
int block = 0;
|
||||
|
||||
if (!page_has_buffers(page)) {
|
||||
/*
|
||||
* don't make any buffers if there is only one buffer on
|
||||
* the page and the page just needs to be set up to date
|
||||
*/
|
||||
if (inode->i_blkbits == PAGE_CACHE_SHIFT &&
|
||||
buffer_uptodate(bh)) {
|
||||
SetPageUptodate(page);
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||||
return;
|
||||
}
|
||||
create_empty_buffers(page, 1 << inode->i_blkbits, 0);
|
||||
}
|
||||
head = page_buffers(page);
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page_bh = head;
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do {
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if (block == page_block) {
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||||
page_bh->b_state = bh->b_state;
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||||
page_bh->b_bdev = bh->b_bdev;
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||||
page_bh->b_blocknr = bh->b_blocknr;
|
||||
break;
|
||||
}
|
||||
page_bh = page_bh->b_this_page;
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||||
block++;
|
||||
} while (page_bh != head);
|
||||
}
|
||||
|
||||
/**
|
||||
* mpage_readpages - populate an address space with some pages, and
|
||||
* start reads against them.
|
||||
*
|
||||
* @mapping: the address_space
|
||||
* @pages: The address of a list_head which contains the target pages. These
|
||||
* pages have their ->index populated and are otherwise uninitialised.
|
||||
*
|
||||
* The page at @pages->prev has the lowest file offset, and reads should be
|
||||
* issued in @pages->prev to @pages->next order.
|
||||
*
|
||||
* @nr_pages: The number of pages at *@pages
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||||
* @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_CACHE_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.
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||||
*/
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||||
static struct bio *
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||||
do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
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||||
sector_t *last_block_in_bio, get_block_t get_block)
|
||||
{
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||||
struct inode *inode = page->mapping->host;
|
||||
const unsigned blkbits = inode->i_blkbits;
|
||||
const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits;
|
||||
const unsigned blocksize = 1 << blkbits;
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sector_t block_in_file;
|
||||
sector_t last_block;
|
||||
sector_t blocks[MAX_BUF_PER_PAGE];
|
||||
unsigned page_block;
|
||||
unsigned first_hole = blocks_per_page;
|
||||
struct block_device *bdev = NULL;
|
||||
struct buffer_head bh;
|
||||
int length;
|
||||
int fully_mapped = 1;
|
||||
|
||||
if (page_has_buffers(page))
|
||||
goto confused;
|
||||
|
||||
block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits);
|
||||
last_block = (i_size_read(inode) + blocksize - 1) >> blkbits;
|
||||
|
||||
bh.b_page = page;
|
||||
for (page_block = 0; page_block < blocks_per_page;
|
||||
page_block++, block_in_file++) {
|
||||
bh.b_state = 0;
|
||||
if (block_in_file < last_block) {
|
||||
if (get_block(inode, block_in_file, &bh, 0))
|
||||
goto confused;
|
||||
}
|
||||
|
||||
if (!buffer_mapped(&bh)) {
|
||||
fully_mapped = 0;
|
||||
if (first_hole == blocks_per_page)
|
||||
first_hole = page_block;
|
||||
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_page copies the data
|
||||
* we just collected from get_block into the page's buffers
|
||||
* so readpage doesn't have to repeat the get_block call
|
||||
*/
|
||||
if (buffer_uptodate(&bh)) {
|
||||
map_buffer_to_page(page, &bh, page_block);
|
||||
goto confused;
|
||||
}
|
||||
|
||||
if (first_hole != blocks_per_page)
|
||||
goto confused; /* hole -> non-hole */
|
||||
|
||||
/* Contiguous blocks? */
|
||||
if (page_block && blocks[page_block-1] != bh.b_blocknr-1)
|
||||
goto confused;
|
||||
blocks[page_block] = bh.b_blocknr;
|
||||
bdev = bh.b_bdev;
|
||||
}
|
||||
|
||||
if (first_hole != blocks_per_page) {
|
||||
char *kaddr = kmap_atomic(page, KM_USER0);
|
||||
memset(kaddr + (first_hole << blkbits), 0,
|
||||
PAGE_CACHE_SIZE - (first_hole << blkbits));
|
||||
flush_dcache_page(page);
|
||||
kunmap_atomic(kaddr, KM_USER0);
|
||||
if (first_hole == 0) {
|
||||
SetPageUptodate(page);
|
||||
unlock_page(page);
|
||||
goto out;
|
||||
}
|
||||
} else if (fully_mapped) {
|
||||
SetPageMappedToDisk(page);
|
||||
}
|
||||
|
||||
/*
|
||||
* This page will go to BIO. Do we need to send this BIO off first?
|
||||
*/
|
||||
if (bio && (*last_block_in_bio != blocks[0] - 1))
|
||||
bio = mpage_bio_submit(READ, bio);
|
||||
|
||||
alloc_new:
|
||||
if (bio == NULL) {
|
||||
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
|
||||
min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
|
||||
GFP_KERNEL);
|
||||
if (bio == NULL)
|
||||
goto confused;
|
||||
}
|
||||
|
||||
length = first_hole << blkbits;
|
||||
if (bio_add_page(bio, page, length, 0) < length) {
|
||||
bio = mpage_bio_submit(READ, bio);
|
||||
goto alloc_new;
|
||||
}
|
||||
|
||||
if (buffer_boundary(&bh) || (first_hole != blocks_per_page))
|
||||
bio = mpage_bio_submit(READ, bio);
|
||||
else
|
||||
*last_block_in_bio = blocks[blocks_per_page - 1];
|
||||
out:
|
||||
return bio;
|
||||
|
||||
confused:
|
||||
if (bio)
|
||||
bio = mpage_bio_submit(READ, bio);
|
||||
if (!PageUptodate(page))
|
||||
block_read_full_page(page, get_block);
|
||||
else
|
||||
unlock_page(page);
|
||||
goto out;
|
||||
}
|
||||
|
||||
int
|
||||
mpage_readpages(struct address_space *mapping, struct list_head *pages,
|
||||
unsigned nr_pages, get_block_t get_block)
|
||||
{
|
||||
struct bio *bio = NULL;
|
||||
unsigned page_idx;
|
||||
sector_t last_block_in_bio = 0;
|
||||
struct pagevec lru_pvec;
|
||||
|
||||
pagevec_init(&lru_pvec, 0);
|
||||
for (page_idx = 0; page_idx < nr_pages; page_idx++) {
|
||||
struct page *page = list_entry(pages->prev, struct page, lru);
|
||||
|
||||
prefetchw(&page->flags);
|
||||
list_del(&page->lru);
|
||||
if (!add_to_page_cache(page, mapping,
|
||||
page->index, GFP_KERNEL)) {
|
||||
bio = do_mpage_readpage(bio, page,
|
||||
nr_pages - page_idx,
|
||||
&last_block_in_bio, get_block);
|
||||
if (!pagevec_add(&lru_pvec, page))
|
||||
__pagevec_lru_add(&lru_pvec);
|
||||
} else {
|
||||
page_cache_release(page);
|
||||
}
|
||||
}
|
||||
pagevec_lru_add(&lru_pvec);
|
||||
BUG_ON(!list_empty(pages));
|
||||
if (bio)
|
||||
mpage_bio_submit(READ, bio);
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(mpage_readpages);
|
||||
|
||||
/*
|
||||
* This isn't called much at all
|
||||
*/
|
||||
int mpage_readpage(struct page *page, get_block_t get_block)
|
||||
{
|
||||
struct bio *bio = NULL;
|
||||
sector_t last_block_in_bio = 0;
|
||||
|
||||
bio = do_mpage_readpage(bio, page, 1,
|
||||
&last_block_in_bio, get_block);
|
||||
if (bio)
|
||||
mpage_bio_submit(READ, bio);
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(mpage_readpage);
|
||||
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
static struct bio *
|
||||
__mpage_writepage(struct bio *bio, struct page *page, get_block_t get_block,
|
||||
sector_t *last_block_in_bio, int *ret, struct writeback_control *wbc,
|
||||
writepage_t writepage_fn)
|
||||
{
|
||||
struct address_space *mapping = page->mapping;
|
||||
struct inode *inode = page->mapping->host;
|
||||
const unsigned blkbits = inode->i_blkbits;
|
||||
unsigned long end_index;
|
||||
const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits;
|
||||
sector_t last_block;
|
||||
sector_t block_in_file;
|
||||
sector_t blocks[MAX_BUF_PER_PAGE];
|
||||
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;
|
||||
int length;
|
||||
struct buffer_head map_bh;
|
||||
loff_t i_size = i_size_read(inode);
|
||||
|
||||
if (page_has_buffers(page)) {
|
||||
struct buffer_head *head = page_buffers(page);
|
||||
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
|
||||
* __set_page_dirty_buffers -> 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 != blocks[page_block-1] + 1)
|
||||
goto confused;
|
||||
}
|
||||
blocks[page_block++] = bh->b_blocknr;
|
||||
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_page(). If this address_space is also
|
||||
* using mpage_readpages then this can rarely happen.
|
||||
*/
|
||||
goto confused;
|
||||
}
|
||||
|
||||
/*
|
||||
* The page has no buffers: map it to disk
|
||||
*/
|
||||
BUG_ON(!PageUptodate(page));
|
||||
block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits);
|
||||
last_block = (i_size - 1) >> blkbits;
|
||||
map_bh.b_page = page;
|
||||
for (page_block = 0; page_block < blocks_per_page; ) {
|
||||
|
||||
map_bh.b_state = 0;
|
||||
if (get_block(inode, block_in_file, &map_bh, 1))
|
||||
goto confused;
|
||||
if (buffer_new(&map_bh))
|
||||
unmap_underlying_metadata(map_bh.b_bdev,
|
||||
map_bh.b_blocknr);
|
||||
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 != blocks[page_block-1] + 1)
|
||||
goto confused;
|
||||
}
|
||||
blocks[page_block++] = map_bh.b_blocknr;
|
||||
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:
|
||||
end_index = i_size >> PAGE_CACHE_SHIFT;
|
||||
if (page->index >= end_index) {
|
||||
/*
|
||||
* The page straddles i_size. It must be zeroed out on each
|
||||
* and every writepage invokation 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."
|
||||
*/
|
||||
unsigned offset = i_size & (PAGE_CACHE_SIZE - 1);
|
||||
char *kaddr;
|
||||
|
||||
if (page->index > end_index || !offset)
|
||||
goto confused;
|
||||
kaddr = kmap_atomic(page, KM_USER0);
|
||||
memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
|
||||
flush_dcache_page(page);
|
||||
kunmap_atomic(kaddr, KM_USER0);
|
||||
}
|
||||
|
||||
/*
|
||||
* This page will go to BIO. Do we need to send this BIO off first?
|
||||
*/
|
||||
if (bio && *last_block_in_bio != blocks[0] - 1)
|
||||
bio = mpage_bio_submit(WRITE, bio);
|
||||
|
||||
alloc_new:
|
||||
if (bio == NULL) {
|
||||
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
|
||||
bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH);
|
||||
if (bio == NULL)
|
||||
goto confused;
|
||||
}
|
||||
|
||||
/*
|
||||
* 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)
|
||||
*/
|
||||
length = first_unmapped << blkbits;
|
||||
if (bio_add_page(bio, page, length, 0) < length) {
|
||||
bio = mpage_bio_submit(WRITE, bio);
|
||||
goto alloc_new;
|
||||
}
|
||||
|
||||
/*
|
||||
* OK, 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.
|
||||
*/
|
||||
if (page_has_buffers(page)) {
|
||||
struct buffer_head *head = page_buffers(page);
|
||||
struct buffer_head *bh = head;
|
||||
unsigned buffer_counter = 0;
|
||||
|
||||
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 readpage would fail to serialize with the bh
|
||||
* and it would read from disk before we reach the platter.
|
||||
*/
|
||||
if (buffer_heads_over_limit && PageUptodate(page))
|
||||
try_to_free_buffers(page);
|
||||
}
|
||||
|
||||
BUG_ON(PageWriteback(page));
|
||||
set_page_writeback(page);
|
||||
unlock_page(page);
|
||||
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 {
|
||||
*last_block_in_bio = blocks[blocks_per_page - 1];
|
||||
}
|
||||
goto out;
|
||||
|
||||
confused:
|
||||
if (bio)
|
||||
bio = mpage_bio_submit(WRITE, bio);
|
||||
|
||||
if (writepage_fn) {
|
||||
*ret = (*writepage_fn)(page, wbc);
|
||||
} else {
|
||||
*ret = -EAGAIN;
|
||||
goto out;
|
||||
}
|
||||
/*
|
||||
* The caller has a ref on the inode, so *mapping is stable
|
||||
*/
|
||||
if (*ret) {
|
||||
if (*ret == -ENOSPC)
|
||||
set_bit(AS_ENOSPC, &mapping->flags);
|
||||
else
|
||||
set_bit(AS_EIO, &mapping->flags);
|
||||
}
|
||||
out:
|
||||
return bio;
|
||||
}
|
||||
|
||||
/**
|
||||
* mpage_writepages - walk the list of dirty pages of the given
|
||||
* address space and 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.
|
||||
* If this is NULL then use a_ops->writepage. Otherwise, go
|
||||
* direct-to-BIO.
|
||||
*
|
||||
* This is a library function, which implements the writepages()
|
||||
* address_space_operation.
|
||||
*
|
||||
* If a page is already under I/O, generic_writepages() skips it, even
|
||||
* if it's dirty. This is desirable behaviour for memory-cleaning writeback,
|
||||
* but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
|
||||
* and msync() need to guarantee that all the data which was dirty at the time
|
||||
* the call was made get new I/O started against them. If wbc->sync_mode is
|
||||
* WB_SYNC_ALL then we were called for data integrity and we must wait for
|
||||
* existing IO to complete.
|
||||
*/
|
||||
int
|
||||
mpage_writepages(struct address_space *mapping,
|
||||
struct writeback_control *wbc, get_block_t get_block)
|
||||
{
|
||||
return __mpage_writepages(mapping, wbc, get_block,
|
||||
mapping->a_ops->writepage);
|
||||
}
|
||||
|
||||
int
|
||||
__mpage_writepages(struct address_space *mapping,
|
||||
struct writeback_control *wbc, get_block_t get_block,
|
||||
writepage_t writepage_fn)
|
||||
{
|
||||
struct backing_dev_info *bdi = mapping->backing_dev_info;
|
||||
struct bio *bio = NULL;
|
||||
sector_t last_block_in_bio = 0;
|
||||
int ret = 0;
|
||||
int done = 0;
|
||||
int (*writepage)(struct page *page, struct writeback_control *wbc);
|
||||
struct pagevec pvec;
|
||||
int nr_pages;
|
||||
pgoff_t index;
|
||||
pgoff_t end = -1; /* Inclusive */
|
||||
int scanned = 0;
|
||||
int is_range = 0;
|
||||
|
||||
if (wbc->nonblocking && bdi_write_congested(bdi)) {
|
||||
wbc->encountered_congestion = 1;
|
||||
return 0;
|
||||
}
|
||||
|
||||
writepage = NULL;
|
||||
if (get_block == NULL)
|
||||
writepage = mapping->a_ops->writepage;
|
||||
|
||||
pagevec_init(&pvec, 0);
|
||||
if (wbc->sync_mode == WB_SYNC_NONE) {
|
||||
index = mapping->writeback_index; /* Start from prev offset */
|
||||
} else {
|
||||
index = 0; /* whole-file sweep */
|
||||
scanned = 1;
|
||||
}
|
||||
if (wbc->start || wbc->end) {
|
||||
index = wbc->start >> PAGE_CACHE_SHIFT;
|
||||
end = wbc->end >> PAGE_CACHE_SHIFT;
|
||||
is_range = 1;
|
||||
scanned = 1;
|
||||
}
|
||||
retry:
|
||||
while (!done && (index <= end) &&
|
||||
(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
|
||||
PAGECACHE_TAG_DIRTY,
|
||||
min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
|
||||
unsigned i;
|
||||
|
||||
scanned = 1;
|
||||
for (i = 0; i < nr_pages; i++) {
|
||||
struct page *page = pvec.pages[i];
|
||||
|
||||
/*
|
||||
* At this point we hold neither mapping->tree_lock nor
|
||||
* lock on the page itself: the page may be truncated or
|
||||
* invalidated (changing page->mapping to NULL), or even
|
||||
* swizzled back from swapper_space to tmpfs file
|
||||
* mapping
|
||||
*/
|
||||
|
||||
lock_page(page);
|
||||
|
||||
if (unlikely(page->mapping != mapping)) {
|
||||
unlock_page(page);
|
||||
continue;
|
||||
}
|
||||
|
||||
if (unlikely(is_range) && page->index > end) {
|
||||
done = 1;
|
||||
unlock_page(page);
|
||||
continue;
|
||||
}
|
||||
|
||||
if (wbc->sync_mode != WB_SYNC_NONE)
|
||||
wait_on_page_writeback(page);
|
||||
|
||||
if (PageWriteback(page) ||
|
||||
!clear_page_dirty_for_io(page)) {
|
||||
unlock_page(page);
|
||||
continue;
|
||||
}
|
||||
|
||||
if (writepage) {
|
||||
ret = (*writepage)(page, wbc);
|
||||
if (ret) {
|
||||
if (ret == -ENOSPC)
|
||||
set_bit(AS_ENOSPC,
|
||||
&mapping->flags);
|
||||
else
|
||||
set_bit(AS_EIO,
|
||||
&mapping->flags);
|
||||
}
|
||||
} else {
|
||||
bio = __mpage_writepage(bio, page, get_block,
|
||||
&last_block_in_bio, &ret, wbc,
|
||||
writepage_fn);
|
||||
}
|
||||
if (ret || (--(wbc->nr_to_write) <= 0))
|
||||
done = 1;
|
||||
if (wbc->nonblocking && bdi_write_congested(bdi)) {
|
||||
wbc->encountered_congestion = 1;
|
||||
done = 1;
|
||||
}
|
||||
}
|
||||
pagevec_release(&pvec);
|
||||
cond_resched();
|
||||
}
|
||||
if (!scanned && !done) {
|
||||
/*
|
||||
* We hit the last page and there is more work to be done: wrap
|
||||
* back to the start of the file
|
||||
*/
|
||||
scanned = 1;
|
||||
index = 0;
|
||||
goto retry;
|
||||
}
|
||||
if (!is_range)
|
||||
mapping->writeback_index = index;
|
||||
if (bio)
|
||||
mpage_bio_submit(WRITE, bio);
|
||||
return ret;
|
||||
}
|
||||
EXPORT_SYMBOL(mpage_writepages);
|
||||
EXPORT_SYMBOL(__mpage_writepages);
|
||||
|
||||
int mpage_writepage(struct page *page, get_block_t get_block,
|
||||
struct writeback_control *wbc)
|
||||
{
|
||||
int ret = 0;
|
||||
struct bio *bio;
|
||||
sector_t last_block_in_bio = 0;
|
||||
|
||||
bio = __mpage_writepage(NULL, page, get_block,
|
||||
&last_block_in_bio, &ret, wbc, NULL);
|
||||
if (bio)
|
||||
mpage_bio_submit(WRITE, bio);
|
||||
|
||||
return ret;
|
||||
}
|
||||
EXPORT_SYMBOL(mpage_writepage);
|
||||
Loading…
Reference in a new issue