Based on original patch from Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
For the subpagesize-blocksize scenario, a page can contain multiple
blocks. This patch handles this case.
This patch adds the new EXTENT_READ_IO extent state bit to reliably unlock
pages in readpage's end bio function.
Signed-off-by: Chandan Rajendra <chan...@linux.vnet.ibm.com>
---
fs/btrfs/extent_io.c | 182 ++++++++++++++++++++++++---------------------------
fs/btrfs/extent_io.h | 5 +-
2 files changed, 89 insertions(+), 98 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a389820..c98dfd8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1951,14 +1951,23 @@ int test_range_bit(struct extent_io_tree *tree, u64
start, u64 end,
* helper function to set a given page up to date if all the
* extents in the tree for that page are up to date
*/
-static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
+static void check_page_uptodate(struct extent_io_tree *tree, struct page *page,
+ struct extent_state *cached)
{
u64 start = page_offset(page);
u64 end = start + PAGE_CACHE_SIZE - 1;
- if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
+ if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, cached))
SetPageUptodate(page);
}
+static int page_read_complete(struct extent_io_tree *tree, struct page *page)
+{
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+
+ return !test_range_bit(tree, start, end, EXTENT_READ_IO, 0, NULL);
+}
+
/*
* When IO fails, either with EIO or csum verification fails, we
* try other mirrors that might have a good copy of the data. This
@@ -2275,7 +2284,9 @@ static int bio_readpage_error(struct bio *failed_bio, u64
phy_offset,
* a) deliver good data to the caller
* b) correct the bad sectors on disk
*/
- if (failed_bio->bi_vcnt > 1) {
+ if ((failed_bio->bi_vcnt > 1)
+ || (failed_bio->bi_io_vec->bv_len
+ > BTRFS_I(inode)->root->sectorsize)) {
/*
* to fulfill b), we need to know the exact failing sectors, as
* we don't want to rewrite any more than the failed ones. thus,
@@ -2422,18 +2433,6 @@ static void end_bio_extent_writepage(struct bio *bio,
int err)
bio_put(bio);
}
-static void
-endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
- int uptodate)
-{
- struct extent_state *cached = NULL;
- u64 end = start + len - 1;
-
- if (uptodate && tree->track_uptodate)
- set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
- unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
-}
-
/*
* after a readpage IO is done, we need to:
* clear the uptodate bits on error
@@ -2450,14 +2449,15 @@ static void end_bio_extent_readpage(struct bio *bio,
int err)
struct bio_vec *bvec;
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+ struct extent_state *cached = NULL;
struct extent_io_tree *tree;
+ unsigned long flags;
u64 offset = 0;
u64 start;
u64 end;
- u64 len;
- u64 extent_start = 0;
- u64 extent_len = 0;
+ int nr_sectors;
int mirror;
+ int unlock;
int ret;
int i;
@@ -2467,54 +2467,31 @@ static void end_bio_extent_readpage(struct bio *bio,
int err)
bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;
struct inode *inode = page->mapping->host;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
"mirror=%lu\n", (u64)bio->bi_iter.bi_sector, err,
io_bio->mirror_num);
tree = &BTRFS_I(inode)->io_tree;
- /* We always issue full-page reads, but if some block
- * in a page fails to read, blk_update_request() will
- * advance bv_offset and adjust bv_len to compensate.
- * Print a warning for nonzero offsets, and an error
- * if they don't add up to a full page. */
- if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
- if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
-
btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
- "partial page read in btrfs with offset %u
and length %u",
- bvec->bv_offset, bvec->bv_len);
- else
-
btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
- "incomplete page read in btrfs with offset
%u and "
- "length %u",
- bvec->bv_offset, bvec->bv_len);
- }
-
- start = page_offset(page);
- end = start + bvec->bv_offset + bvec->bv_len - 1;
- len = bvec->bv_len;
-
+ start = page_offset(page) + bvec->bv_offset;
+ end = start + bvec->bv_len - 1;
+ nr_sectors = bvec->bv_len >> inode->i_sb->s_blocksize_bits;
mirror = io_bio->mirror_num;
- if (likely(uptodate && tree->ops &&
- tree->ops->readpage_end_io_hook)) {
+
+next_block:
+ if (likely(uptodate)) {
ret = tree->ops->readpage_end_io_hook(io_bio, offset,
- page, start, end,
- mirror);
+ page, start,
+ start +
root->sectorsize - 1,
+ mirror);
if (ret)
uptodate = 0;
else
clean_io_failure(start, page);
}
- if (likely(uptodate))
- goto readpage_ok;
-
- if (tree->ops && tree->ops->readpage_io_failed_hook) {
- ret = tree->ops->readpage_io_failed_hook(page, mirror);
- if (!ret && !err &&
- test_bit(BIO_UPTODATE, &bio->bi_flags))
- uptodate = 1;
- } else {
+ if (!uptodate) {
/*
* The generic bio_readpage_error handles errors the
* following way: If possible, new read requests are
@@ -2525,60 +2502,64 @@ static void end_bio_extent_readpage(struct bio *bio,
int err)
* can't handle the error it will return -EIO and we
* remain responsible for that page.
*/
- ret = bio_readpage_error(bio, offset, page, start, end,
- mirror);
+ ret = bio_readpage_error(bio, offset, page,
+ start, start + root->sectorsize
- 1,
+ mirror);
if (ret == 0) {
- uptodate =
- test_bit(BIO_UPTODATE, &bio->bi_flags);
+ uptodate = test_bit(BIO_UPTODATE,
&bio->bi_flags);
if (err)
uptodate = 0;
- continue;
+ offset += root->sectorsize;
+ if (--nr_sectors) {
+ start += root->sectorsize;
+ goto next_block;
+ } else {
+ continue;
+ }
}
}
-readpage_ok:
- if (likely(uptodate)) {
- loff_t i_size = i_size_read(inode);
- pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
- unsigned offset;
-
- /* Zero out the end if this page straddles i_size */
- offset = i_size & (PAGE_CACHE_SIZE-1);
- if (page->index == end_index && offset)
- zero_user_segment(page, offset,
PAGE_CACHE_SIZE);
- SetPageUptodate(page);
+
+ if (uptodate) {
+ set_extent_uptodate(tree, start,
+ start + root->sectorsize - 1,
+ &cached, GFP_ATOMIC);
+ check_page_uptodate(tree, page, cached);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
- unlock_page(page);
- offset += len;
-
- if (unlikely(!uptodate)) {
- if (extent_len) {
- endio_readpage_release_extent(tree,
- extent_start,
- extent_len, 1);
- extent_start = 0;
- extent_len = 0;
- }
- endio_readpage_release_extent(tree, start,
- end - start + 1, 0);
- } else if (!extent_len) {
- extent_start = start;
- extent_len = end + 1 - start;
- } else if (extent_start + extent_len == start) {
- extent_len += end + 1 - start;
- } else {
- endio_readpage_release_extent(tree, extent_start,
- extent_len, uptodate);
- extent_start = start;
- extent_len = end + 1 - start;
+
+ offset += root->sectorsize;
+
+ if (--nr_sectors) {
+ clear_extent_bit(tree, start, start + root->sectorsize
- 1,
+ EXTENT_READ_IO, 0, 0, &cached, GFP_ATOMIC);
+ clear_extent_bit(tree, start, start + root->sectorsize
- 1,
+ EXTENT_LOCKED, 1, 0, &cached,
GFP_ATOMIC);
+ start += root->sectorsize;
+ goto next_block;
}
+
+ WARN_ON(!PagePrivate(page));
+
+ local_irq_save(flags);
+ bit_spin_lock(EXTENT_PAGE_UPTODATE_LOCK, &page->private);
+
+ clear_extent_bit(tree, start, start + root->sectorsize - 1,
+ EXTENT_READ_IO, 0, 0, &cached, GFP_ATOMIC);
+
+ unlock = page_read_complete(tree, page);
+
+ bit_spin_unlock(EXTENT_PAGE_UPTODATE_LOCK, &page->private);
+ local_irq_restore(flags);
+
+ clear_extent_bit(tree, start, start + root->sectorsize - 1,
+ EXTENT_LOCKED, 1, 0, &cached, GFP_ATOMIC);
+
+ if (unlock)
+ unlock_page(page);
}
- if (extent_len)
- endio_readpage_release_extent(tree, extent_start, extent_len,
- uptodate);
if (io_bio->end_io)
io_bio->end_io(io_bio, err);
bio_put(bio);
@@ -2799,6 +2780,7 @@ static int __do_readpage(struct extent_io_tree *tree,
unsigned long *bio_flags, int rw)
{
struct inode *inode = page->mapping->host;
+ struct extent_state *cached = NULL;
u64 start = page_offset(page);
u64 page_end = start + PAGE_CACHE_SIZE - 1;
u64 end;
@@ -2918,7 +2900,7 @@ static int __do_readpage(struct extent_io_tree *tree,
/* the get_extent function already copied into the page */
if (test_range_bit(tree, cur, cur_end,
EXTENT_UPTODATE, 1, NULL)) {
- check_page_uptodate(tree, page);
+ check_page_uptodate(tree, page, NULL);
if (!parent_locked)
unlock_extent(tree, cur, cur + iosize - 1);
cur = cur + iosize;
@@ -2938,6 +2920,10 @@ static int __do_readpage(struct extent_io_tree *tree,
}
pnr -= page->index;
+
+ set_extent_bit(tree, cur, cur + iosize - 1, EXTENT_READ_IO,
+ NULL, &cached, GFP_NOFS);
+
ret = submit_extent_page(rw, tree, page,
sector, disk_io_size, pg_offset,
bdev, bio, pnr,
@@ -2949,8 +2935,12 @@ static int __do_readpage(struct extent_io_tree *tree,
*bio_flags = this_bio_flag;
} else {
SetPageError(page);
+ clear_extent_bit(tree, cur, cur + iosize - 1,
+ EXTENT_READ_IO, 0, 0, &cached,
+ GFP_NOFS);
if (!parent_locked)
- unlock_extent(tree, cur, cur + iosize - 1);
+ unlock_extent_cached(tree, cur, cur + iosize -
1,
+ &cached, GFP_NOFS);
}
cur = cur + iosize;
pg_offset += iosize;
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index ccc264e..4d019c0 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -20,6 +20,7 @@
#define EXTENT_NEED_WAIT (1 << 13)
#define EXTENT_DAMAGED (1 << 14)
#define EXTENT_NORESERVE (1 << 15)
+#define EXTENT_READ_IO (1 << 16)
#define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
#define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC)
@@ -56,8 +57,8 @@
* page->private values. Every page that is controlled by the extent
* map has page->private set to one.
*/
-#define EXTENT_PAGE_PRIVATE 1
-#define EXTENT_PAGE_PRIVATE_FIRST_PAGE 3
+#define EXTENT_PAGE_PRIVATE (1 << 0)
+#define EXTENT_PAGE_UPTODATE_LOCK (1 << 1)
struct extent_state;
struct btrfs_root;
--
2.1.0
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