if (--bvec >= bio->bi_io_vec)
prefetchw(&bvec->bv_page->flags);
- if (!uptodate)
+ if (!uptodate){
SetPageError(page);
+ if (page->mapping)
+ set_bit(AS_EIO, &page->mapping->flags);
+ }
end_page_writeback(page);
} while (bvec >= bio->bi_io_vec);
bio_put(bio);
return 0;
}
-struct bio *mpage_bio_submit(int rw, struct bio *bio)
+static struct bio *mpage_bio_submit(int rw, struct bio *bio)
{
bio->bi_end_io = mpage_end_io_read;
if (rw == WRITE)
static struct bio *
mpage_alloc(struct block_device *bdev,
- sector_t first_sector, int nr_vecs, int gfp_flags)
+ sector_t first_sector, int nr_vecs,
+ gfp_t gfp_flags)
{
struct bio *bio;
} 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
- * @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.
- */
static struct bio *
do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
sector_t *last_block_in_bio, get_block_t get_block)
if (page_has_buffers(page))
goto confused;
- block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits);
+ block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
last_block = (i_size_read(inode) + blocksize - 1) >> blkbits;
bh.b_page = page;
alloc_new:
if (bio == NULL) {
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
- nr_pages, GFP_KERNEL);
+ min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
+ GFP_KERNEL);
if (bio == NULL)
goto confused;
}
goto out;
}
+/**
+ * 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
+ * @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.
+ */
int
mpage_readpages(struct address_space *mapping, struct list_head *pages,
unsigned nr_pages, get_block_t get_block)
* 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)
+__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;
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);
* 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_read(inode) - 1) >> blkbits;
+ block_in_file = (sector_t)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; ) {
first_unmapped = page_block;
- end_index = i_size_read(inode) >> PAGE_CACHE_SHIFT;
+page_is_mapped:
+ end_index = i_size >> PAGE_CACHE_SHIFT;
if (page->index >= end_index) {
- unsigned offset = i_size_read(inode) & (PAGE_CACHE_SIZE - 1);
+ /*
+ * 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)
kunmap_atomic(kaddr, KM_USER0);
}
-page_is_mapped:
-
/*
* This page will go to BIO. Do we need to send this BIO off first?
*/
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.
bh = bh->b_this_page;
} while (bh != head);
- if (buffer_heads_over_limit)
+ /*
+ * 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);
}
- length = first_unmapped << blkbits;
- if (bio_add_page(bio, page, length, 0) < length) {
- bio = mpage_bio_submit(WRITE, bio);
- goto alloc_new;
- }
-
BUG_ON(PageWriteback(page));
set_page_writeback(page);
unlock_page(page);
confused:
if (bio)
bio = mpage_bio_submit(WRITE, bio);
- *ret = page->mapping->a_ops->writepage(page, wbc);
+
+ 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
*/
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;
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 && (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
- PAGECACHE_TAG_DIRTY, PAGEVEC_SIZE))) {
+ 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;
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 (page->mapping != mapping || PageWriteback(page) ||
+ if (PageWriteback(page) ||
!clear_page_dirty_for_io(page)) {
unlock_page(page);
continue;
&mapping->flags);
}
} else {
- bio = mpage_writepage(bio, page, get_block,
- &last_block_in_bio, &ret, wbc);
+ bio = __mpage_writepage(bio, page, get_block,
+ &last_block_in_bio, &ret, wbc,
+ page->mapping->a_ops->writepage);
}
+ if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE))
+ unlock_page(page);
if (ret || (--(wbc->nr_to_write) <= 0))
done = 1;
if (wbc->nonblocking && bdi_write_congested(bdi)) {
index = 0;
goto retry;
}
- mapping->writeback_index = index;
+ if (!is_range)
+ mapping->writeback_index = index;
if (bio)
mpage_bio_submit(WRITE, bio);
return ret;
}
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);
git://git.onelab.eu / linux-2.6.git / blobdiff