* [RFC PATCH V2 1/8] Btrfs: subpagesize-blocksize: Get rid of whole page reads.
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 2/8] Btrfs: subpagesize-blocksize: Get rid of whole page writes Chandan Rajendra
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandan Rajendra, linux-btrfs, aneesh.kumar
Based on original patch from Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
bio_vec->{bv_offset, bv_len} cannot be relied upon by the end bio functions
to track the file offset range operated on by the bio. Hence this patch adds
two new members to 'struct btrfs_io_bio' to track the file offset range.
This patch also brings back check_page_locked() to reliably unlock pages in
readpage's end bio function.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/extent_io.c | 200 ++++++++++++++++++++++-----------------------------
fs/btrfs/volumes.h | 3 +
2 files changed, 90 insertions(+), 113 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fbe501d..fa28545 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1943,15 +1943,29 @@ 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);
}
/*
+ * helper function to unlock a page if all the extents in the tree
+ * for that page are unlocked
+ */
+static void check_page_locked(struct extent_io_tree *tree, struct page *page)
+{
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+
+ if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
+ unlock_page(page);
+ }
+}
+
* When IO fails, either with EIO or csum verification fails, we
* try other mirrors that might have a good copy of the data. This
* io_failure_record is used to record state as we go through all the
@@ -2173,6 +2187,7 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
struct bio *bio;
struct btrfs_io_bio *btrfs_failed_bio;
struct btrfs_io_bio *btrfs_bio;
+ int nr_sectors;
int num_copies;
int ret;
int read_mode;
@@ -2267,7 +2282,8 @@ 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) {
+ nr_sectors = btrfs_io_bio(failed_bio)->len >> inode->i_sb->s_blocksize_bits;
+ if (nr_sectors > 1) {
/*
* 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,
@@ -2314,6 +2330,8 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
bio->bi_sector = failrec->logical >> 9;
bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
bio->bi_size = 0;
+ btrfs_io_bio(bio)->start_offset = start;
+ btrfs_io_bio(bio)->len = end - start + 1;
btrfs_failed_bio = btrfs_io_bio(failed_bio);
if (btrfs_failed_bio->csum) {
@@ -2414,18 +2432,6 @@ 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
@@ -2440,76 +2446,50 @@ endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
static void end_bio_extent_readpage(struct bio *bio, int err)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
- struct bio_vec *bvec = bio->bi_io_vec;
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+ struct bio_vec *bvec = bio->bi_io_vec;
+ struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct address_space *mapping;
+ struct extent_state *cached = NULL;
struct extent_io_tree *tree;
- u64 offset = 0;
+ struct btrfs_root *root;
+ struct inode *inode;
+ struct page *page;
u64 start;
- u64 end;
+ u64 offset = 0;
u64 len;
- u64 extent_start = 0;
- u64 extent_len = 0;
+ int nr_sectors;
int mirror;
int ret;
- if (err)
- uptodate = 0;
+ mapping = bio->bi_io_vec->bv_page->mapping;
+ inode = mapping->host;
+ root = BTRFS_I(inode)->root;
+ tree = &BTRFS_I(inode)->io_tree;
- do {
- struct page *page = bvec->bv_page;
- struct inode *inode = page->mapping->host;
-
- pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
- "mirror=%lu\n", (u64)bio->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 = btrfs_io_bio(bio)->start_offset;
+ len = btrfs_io_bio(bio)->len;
+ mirror = io_bio->mirror_num;
- start = page_offset(page);
- end = start + bvec->bv_offset + bvec->bv_len - 1;
- len = bvec->bv_len;
+ nr_sectors = len >> inode->i_sb->s_blocksize_bits;
+ BUG_ON(!nr_sectors);
- if (++bvec <= bvec_end)
- prefetchw(&bvec->bv_page->flags);
+ do {
+ BUG_ON(bvec > bvec_end);
+ page = bvec->bv_page;
- mirror = io_bio->mirror_num;
- if (likely(uptodate && tree->ops &&
- tree->ops->readpage_end_io_hook)) {
+ if (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
@@ -2520,63 +2500,38 @@ 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;
+ goto next_block;
}
}
-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;
- }
- } while (bvec <= bvec_end);
- if (extent_len)
- endio_readpage_release_extent(tree, extent_start, extent_len,
- uptodate);
+ unlock_extent(tree, start, start + root->sectorsize - 1);
+ check_page_locked(tree, page);
+next_block:
+ offset += root->sectorsize;
+ start += root->sectorsize;
+ if ((page_offset(page) + PAGE_CACHE_SIZE) == start)
+ ++bvec;
+ } while (--nr_sectors);
+
if (io_bio->end_io)
io_bio->end_io(io_bio, err);
- bio_put(bio);
}
/*
@@ -2700,6 +2655,18 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
else
contig = bio_end_sector(bio) == sector;
+ if (contig) {
+ /*
+ * Check whether we are contig if file offsets.
+ * We should mostly be for readpage/readpages
+ * We need to do this because we use btrfs_io_bio
+ * start_offset and len to unlock in endio routines.
+ */
+ if ((page_offset(page) + offset) !=
+ (btrfs_io_bio(bio)->start_offset +
+ btrfs_io_bio(bio)->len))
+ contig = 0;
+ }
if (prev_bio_flags != bio_flags || !contig ||
merge_bio(rw, tree, page, offset, page_size, bio, bio_flags) ||
bio_add_page(bio, page, page_size, offset) < page_size) {
@@ -2709,6 +2676,11 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
return ret;
bio = NULL;
} else {
+ /*
+ * update btrfs_io_bio len. So that we can unlock
+ * correctly in end_io callback.
+ */
+ btrfs_io_bio(bio)->len += page_size;
return 0;
}
}
@@ -2724,6 +2696,8 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
bio_add_page(bio, page, page_size, offset);
bio->bi_end_io = end_io_func;
bio->bi_private = tree;
+ btrfs_io_bio(bio)->start_offset = page_offset(page) + offset;
+ btrfs_io_bio(bio)->len = page_size;
if (bio_ret)
*bio_ret = bio;
@@ -2914,7 +2888,7 @@ 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;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 80754f9..fb2dbdc 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -173,6 +173,9 @@ struct btrfs_io_bio {
u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
u8 *csum_allocated;
btrfs_io_bio_end_io_t *end_io;
+ /* Track file offset range operated on by the bio.*/
+ u64 start_offset;
+ u64 len;
struct bio bio;
};
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 2/8] Btrfs: subpagesize-blocksize: Get rid of whole page writes.
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 1/8] Btrfs: subpagesize-blocksize: Get rid of whole page reads Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 3/8] Btrfs: subpagesize-blocksize: __btrfs_buffered_write: Reserve/release extents aligned to block size Chandan Rajendra
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandan Rajendra, linux-btrfs, aneesh.kumar
This commit brings back functions that set/clear EXTENT_WRITEBACK bits. These
are required to reliably clear PG_writeback page flag.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/extent_io.c | 147 +++++++++++++++++++++++++++++++++++----------------
fs/btrfs/extent_io.h | 2 +-
fs/btrfs/inode.c | 45 ++++++++++++----
3 files changed, 136 insertions(+), 58 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fa28545..20d8bdc 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1293,6 +1293,20 @@ int clear_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
cached_state, mask);
}
+static int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
+ struct extent_state **cached_state, gfp_t mask)
+{
+ return set_extent_bit(tree, start, end, EXTENT_WRITEBACK, NULL,
+ cached_state, mask);
+}
+
+static int clear_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
+ struct extent_state **cached_state, gfp_t mask)
+{
+ return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0,
+ cached_state, mask);
+}
+
/*
* either insert or lock state struct between start and end use mask to tell
* us if waiting is desired.
@@ -1399,6 +1413,7 @@ static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
page_cache_release(page);
index++;
}
+ set_extent_writeback(tree, start, end, NULL, GFP_NOFS);
return 0;
}
@@ -1966,6 +1981,16 @@ static void check_page_locked(struct extent_io_tree *tree, struct page *page)
}
}
+static void check_page_writeback(struct extent_io_tree *tree, struct page *page)
+{
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+
+ if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0, NULL))
+ end_page_writeback(page);
+}
+
+/*
* When IO fails, either with EIO or csum verification fails, we
* try other mirrors that might have a good copy of the data. This
* io_failure_record is used to record state as we go through all the
@@ -2359,27 +2384,69 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
}
/* lots and lots of room for performance fixes in the end_bio funcs */
-
-int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
+void end_extents_write(struct inode *inode, int err, u64 start, u64 end)
{
+ struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
int uptodate = (err == 0);
- struct extent_io_tree *tree;
+ pgoff_t index, end_index;
+ u64 page_start, page_end;
+ struct page *page;
int ret;
- tree = &BTRFS_I(page->mapping->host)->io_tree;
+ index = start >> PAGE_CACHE_SHIFT;
+ end_index = end >> PAGE_CACHE_SHIFT;
- if (tree->ops && tree->ops->writepage_end_io_hook) {
- ret = tree->ops->writepage_end_io_hook(page, start,
- end, NULL, uptodate);
- if (ret)
- uptodate = 0;
+ page_start = start;
+
+ while (index <= end_index) {
+ page = find_get_page(inode->i_mapping, index);
+ BUG_ON(!page);
+
+ page_end = min_t(u64, end, page_offset(page) + PAGE_CACHE_SIZE - 1);
+
+ if (tree->ops && tree->ops->writepage_end_io_hook) {
+ ret = tree->ops->writepage_end_io_hook(page,
+ page_start, page_end,
+ NULL, uptodate);
+ if (ret)
+ uptodate = 0;
+ }
+
+ page_start = page_end + 1;
+
+ ++index;
+
+ if (!uptodate) {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+
+ page_cache_release(page);
}
+}
+
+static void clear_extent_and_page_writeback(struct address_space *mapping,
+ struct extent_io_tree *tree,
+ struct btrfs_io_bio *io_bio)
+{
+ struct page *page;
+ pgoff_t index;
+ u64 offset, len;
- if (!uptodate) {
- ClearPageUptodate(page);
- SetPageError(page);
+ offset = io_bio->start_offset;
+ len = io_bio->len;
+
+ clear_extent_writeback(tree, offset, offset + len - 1, NULL,
+ GFP_ATOMIC);
+
+ index = offset >> PAGE_CACHE_SHIFT;
+ while (offset < io_bio->start_offset + len) {
+ page = find_get_page(mapping, index);
+ check_page_writeback(tree, page);
+ page_cache_release(page);
+ index++;
+ offset += page_offset(page) + PAGE_CACHE_SIZE - offset;
}
- return 0;
}
/*
@@ -2393,41 +2460,14 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
*/
static void end_bio_extent_writepage(struct bio *bio, int err)
{
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
- u64 start;
- u64 end;
-
- do {
- struct page *page = bvec->bv_page;
-
- /* 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 write 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 write 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;
-
- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
+ struct address_space *mapping = bio->bi_io_vec->bv_page->mapping;
+ struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
+ struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
- if (end_extent_writepage(page, err, start, end))
- continue;
+ end_extents_write(mapping->host, err, io_bio->start_offset,
+ io_bio->start_offset + io_bio->len - 1);
- end_page_writeback(page);
- } while (bvec >= bio->bi_io_vec);
+ clear_extent_and_page_writeback(mapping, tree, io_bio);
bio_put(bio);
}
@@ -3091,6 +3131,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
u64 last_byte = i_size_read(inode);
u64 block_start;
u64 iosize;
+ u64 unlock_start = start;
sector_t sector;
struct extent_state *cached_state = NULL;
struct extent_map *em;
@@ -3173,6 +3214,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
/* File system has been set read-only */
if (ret) {
SetPageError(page);
+ unlock_start = page_end + 1;
goto done;
}
/*
@@ -3208,10 +3250,14 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
goto done_unlocked;
}
}
+
+ lock_extent(tree, start, page_end);
+
if (tree->ops && tree->ops->writepage_start_hook) {
ret = tree->ops->writepage_start_hook(page, start,
page_end);
if (ret) {
+ unlock_extent(tree, start, page_end);
/* Fixup worker will requeue */
if (ret == -EBUSY)
wbc->pages_skipped++;
@@ -3232,9 +3278,11 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
end = page_end;
if (last_byte <= start) {
+ unlock_extent(tree, start, page_end);
if (tree->ops && tree->ops->writepage_end_io_hook)
tree->ops->writepage_end_io_hook(page, start,
page_end, NULL, 1);
+ unlock_start = page_end + 1;
goto done;
}
@@ -3242,9 +3290,11 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
while (cur <= end) {
if (cur >= last_byte) {
+ unlock_extent(tree, unlock_start, page_end);
if (tree->ops && tree->ops->writepage_end_io_hook)
tree->ops->writepage_end_io_hook(page, cur,
page_end, NULL, 1);
+ unlock_start = page_end + 1;
break;
}
em = epd->get_extent(inode, page, pg_offset, cur,
@@ -3272,6 +3322,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
*/
if (compressed || block_start == EXTENT_MAP_HOLE ||
block_start == EXTENT_MAP_INLINE) {
+ unlock_extent(tree, unlock_start, cur + iosize - 1);
/*
* end_io notification does not happen here for
* compressed extents
@@ -3291,6 +3342,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
cur += iosize;
pg_offset += iosize;
+ unlock_start = cur;
continue;
}
/* leave this out until we have a page_mkwrite call */
@@ -3337,6 +3389,9 @@ done:
set_page_writeback(page);
end_page_writeback(page);
}
+ if (unlock_start <= page_end)
+ unlock_extent(tree, unlock_start, page_end);
+
unlock_page(page);
done_unlocked:
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 58b27e5..42d0b74 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -341,7 +341,7 @@ struct btrfs_fs_info;
int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
u64 length, u64 logical, struct page *page,
int mirror_num);
-int end_extent_writepage(struct page *page, int err, u64 start, u64 end);
+void end_extents_write(struct inode *inode, int err, u64 start, u64 end);
int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
int mirror_num);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8dba152..16da8e3a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1797,7 +1797,7 @@ again:
ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
if (ret) {
mapping_set_error(page->mapping, ret);
- end_extent_writepage(page, ret, page_start, page_end);
+ end_extents_write(page->mapping->host, ret, page_start, page_end);
ClearPageChecked(page);
goto out;
}
@@ -2766,23 +2766,46 @@ static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_ordered_extent *ordered_extent = NULL;
struct btrfs_workers *workers;
+ u64 ordered_start, ordered_end;
+ int done;
trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
ClearPagePrivate2(page);
- if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
- end - start + 1, uptodate))
- return 0;
+loop:
+ ordered_extent = btrfs_lookup_ordered_range(inode, start,
+ start + end - 1);
+ if (!ordered_extent)
+ goto out;
- ordered_extent->work.func = finish_ordered_fn;
- ordered_extent->work.flags = 0;
+ ordered_start = max_t(u64, start, ordered_extent->file_offset);
+ ordered_end = min_t(u64, end,
+ ordered_extent->file_offset + ordered_extent->len - 1);
- if (btrfs_is_free_space_inode(inode))
- workers = &root->fs_info->endio_freespace_worker;
- else
- workers = &root->fs_info->endio_write_workers;
- btrfs_queue_worker(workers, &ordered_extent->work);
+ done = btrfs_dec_test_ordered_pending(inode, &ordered_extent,
+ ordered_start,
+ ordered_end - ordered_start + 1,
+ uptodate);
+ if (done) {
+ ordered_extent->work.func = finish_ordered_fn;
+ ordered_extent->work.flags = 0;
+ if (btrfs_is_free_space_inode(inode))
+ workers = &root->fs_info->endio_freespace_worker;
+ else
+ workers = &root->fs_info->endio_write_workers;
+
+ btrfs_queue_worker(workers, &ordered_extent->work);
+ }
+
+ btrfs_put_ordered_extent(ordered_extent);
+
+ start = ordered_end + 1;
+
+ if (start < end)
+ goto loop;
+
+out:
return 0;
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 3/8] Btrfs: subpagesize-blocksize: __btrfs_buffered_write: Reserve/release extents aligned to block size.
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 1/8] Btrfs: subpagesize-blocksize: Get rid of whole page reads Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 2/8] Btrfs: subpagesize-blocksize: Get rid of whole page writes Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 4/8] Btrfs: subpagesize-blocksize: Define extent_buffer_head Chandan Rajendra
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandan Rajendra, linux-btrfs, aneesh.kumar
Currently, the code reserves/releases extents in multiples of PAGE_CACHE_SIZE
units. Fix this.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/file.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 006af2f..541e227 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1339,18 +1339,21 @@ fail:
static noinline int
lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
size_t num_pages, loff_t pos,
+ size_t write_bytes,
u64 *lockstart, u64 *lockend,
struct extent_state **cached_state)
{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
u64 start_pos;
u64 last_pos;
int i;
int ret = 0;
- start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
- last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1;
+ start_pos = pos & ~((u64)root->sectorsize - 1);
+ last_pos = start_pos
+ + ALIGN(pos + write_bytes - start_pos, root->sectorsize) - 1;
- if (start_pos < inode->i_size) {
+ if (start_pos < inode->i_size) {
struct btrfs_ordered_extent *ordered;
lock_extent_bits(&BTRFS_I(inode)->io_tree,
start_pos, last_pos, 0, cached_state);
@@ -1468,6 +1471,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
while (iov_iter_count(i) > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
+ size_t sector_offset;
size_t write_bytes = min(iov_iter_count(i),
nrptrs * (size_t)PAGE_CACHE_SIZE -
offset);
@@ -1488,7 +1492,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
break;
}
- reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
+ sector_offset = pos & (root->sectorsize - 1);
+ reserve_bytes = ALIGN(write_bytes + sector_offset, root->sectorsize);
+
ret = btrfs_check_data_free_space(inode, reserve_bytes);
if (ret == -ENOSPC &&
(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
@@ -1503,7 +1509,9 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
num_pages = (write_bytes + offset +
PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
- reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
+
+ reserve_bytes = ALIGN(write_bytes + sector_offset,
+ root->sectorsize);
ret = 0;
} else {
ret = -ENOSPC;
@@ -1536,8 +1544,8 @@ again:
break;
ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages,
- pos, &lockstart, &lockend,
- &cached_state);
+ pos, write_bytes, &lockstart, &lockend,
+ &cached_state);
if (ret < 0) {
if (ret == -EAGAIN)
goto again;
@@ -1574,9 +1582,9 @@ again:
* we still have an outstanding extent for the chunk we actually
* managed to copy.
*/
- if (num_pages > dirty_pages) {
- release_bytes = (num_pages - dirty_pages) <<
- PAGE_CACHE_SHIFT;
+ if (write_bytes > copied) {
+ release_bytes = (write_bytes - copied)
+ & ~((u64)root->sectorsize - 1);
if (copied > 0) {
spin_lock(&BTRFS_I(inode)->lock);
BTRFS_I(inode)->outstanding_extents++;
@@ -1590,7 +1598,7 @@ again:
release_bytes);
}
- release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
+ release_bytes = ALIGN(copied + sector_offset, root->sectorsize);
if (copied > 0)
ret = btrfs_dirty_pages(root, inode, pages,
@@ -1609,7 +1617,7 @@ again:
if (only_release_metadata && copied > 0) {
u64 lockstart = round_down(pos, root->sectorsize);
u64 lockend = lockstart +
- (dirty_pages << PAGE_CACHE_SHIFT) - 1;
+ ALIGN(copied, root->sectorsize) - 1;
set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
lockend, EXTENT_NORESERVE, NULL,
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 4/8] Btrfs: subpagesize-blocksize: Define extent_buffer_head.
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
` (2 preceding siblings ...)
2014-06-11 11:32 ` [RFC PATCH V2 3/8] Btrfs: subpagesize-blocksize: __btrfs_buffered_write: Reserve/release extents aligned to block size Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 5/8] Btrfs: subpagesize-blocksize: Read tree blocks whose size is <PAGE_CACHE_SIZE Chandan Rajendra
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandra Seetharaman, linux-btrfs, aneesh.kumar, Chandan Rajendra
From: Chandra Seetharaman <sekharan@us.ibm.com>
In order to handle multiple extent buffers per page, first we need to create a
way to handle all the extent buffers that are attached to a page.
This patch creates a new data structure 'struct extent_buffer_head', and moves
fields that are common to all extent buffers in a page from 'struct extent
buffer' to 'struct extent_buffer_head'
Also, this patch moves EXTENT_BUFFER_TREE_REF, EXTENT_BUFFER_DUMMY and
EXTENT_BUFFER_IN_TREE flags from extent_buffer->ebflags to
extent_buffer_head->bflags.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/backref.c | 2 +-
fs/btrfs/ctree.c | 2 +-
fs/btrfs/ctree.h | 6 +-
fs/btrfs/disk-io.c | 46 ++++--
fs/btrfs/extent-tree.c | 6 +-
fs/btrfs/extent_io.c | 372 +++++++++++++++++++++++++++++--------------
fs/btrfs/extent_io.h | 46 ++++--
fs/btrfs/volumes.c | 2 +-
include/trace/events/btrfs.h | 2 +-
9 files changed, 326 insertions(+), 158 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index a88da72..603ae44 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1272,7 +1272,7 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
eb = path->nodes[0];
/* make sure we can use eb after releasing the path */
if (eb != eb_in) {
- atomic_inc(&eb->refs);
+ atomic_inc(&eb_head(eb)->refs);
btrfs_tree_read_lock(eb);
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
}
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index cbd3a7d..0d4ad91 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -169,7 +169,7 @@ struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
* the inc_not_zero dance and if it doesn't work then
* synchronize_rcu and try again.
*/
- if (atomic_inc_not_zero(&eb->refs)) {
+ if (atomic_inc_not_zero(&eb_head(eb)->refs)) {
rcu_read_unlock();
break;
}
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index dac6653..901ada2 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2138,14 +2138,16 @@ static inline void btrfs_set_token_##name(struct extent_buffer *eb, \
#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \
static inline u##bits btrfs_##name(struct extent_buffer *eb) \
{ \
- type *p = page_address(eb->pages[0]); \
+ type *p = page_address(eb_head(eb)->pages[0]) + \
+ (eb->start & (PAGE_CACHE_SIZE -1)); \
u##bits res = le##bits##_to_cpu(p->member); \
return res; \
} \
static inline void btrfs_set_##name(struct extent_buffer *eb, \
u##bits val) \
{ \
- type *p = page_address(eb->pages[0]); \
+ type *p = page_address(eb_head(eb)->pages[0]) + \
+ (eb->start & (PAGE_CACHE_SIZE -1)); \
p->member = cpu_to_le##bits(val); \
}
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index cc1b423..bda2157 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1018,13 +1018,21 @@ static int btree_set_page_dirty(struct page *page)
{
#ifdef DEBUG
struct extent_buffer *eb;
+ int i, dirty = 0;
BUG_ON(!PagePrivate(page));
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
- BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
- BUG_ON(!atomic_read(&eb->refs));
- btrfs_assert_tree_locked(eb);
+
+ do {
+ dirty = test_bit(EXTENT_BUFFER_DIRTY, &eb->ebflags);
+ if (dirty)
+ break;
+ } while ((eb = eb->eb_next) != NULL);
+
+ BUG_ON(!dirty);
+ BUG_ON(!atomic_read(&(eb_head(eb)->refs)));
+ btrfs_assert_tree_locked(&ebh->eb);
#endif
return __set_page_dirty_nobuffers(page);
}
@@ -1068,7 +1076,7 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
if (!buf)
return 0;
- set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
+ set_bit(EXTENT_BUFFER_READAHEAD, &buf->ebflags);
ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
btree_get_extent, mirror_num);
@@ -1077,7 +1085,7 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
return ret;
}
- if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
+ if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->ebflags)) {
free_extent_buffer(buf);
return -EIO;
} else if (extent_buffer_uptodate(buf)) {
@@ -1103,14 +1111,16 @@ struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
int btrfs_write_tree_block(struct extent_buffer *buf)
{
- return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
+ return filemap_fdatawrite_range(eb_head(buf)->pages[0]->mapping,
+ buf->start,
buf->start + buf->len - 1);
}
int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
{
- return filemap_fdatawait_range(buf->pages[0]->mapping,
- buf->start, buf->start + buf->len - 1);
+ return filemap_fdatawait_range(eb_head(buf)->pages[0]->mapping,
+ buf->start,
+ buf->start + buf->len - 1);
}
struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
@@ -1141,7 +1151,8 @@ void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
fs_info->running_transaction->transid) {
btrfs_assert_tree_locked(buf);
- if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
+ if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
+ &buf->ebflags)) {
__percpu_counter_add(&fs_info->dirty_metadata_bytes,
-buf->len,
fs_info->dirty_metadata_batch);
@@ -2613,7 +2624,8 @@ int open_ctree(struct super_block *sb,
btrfs_super_chunk_root(disk_super),
blocksize, generation);
if (!chunk_root->node ||
- !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
+ !test_bit(EXTENT_BUFFER_UPTODATE,
+ &chunk_root->node->ebflags)) {
printk(KERN_WARNING "BTRFS: failed to read chunk root on %s\n",
sb->s_id);
goto fail_tree_roots;
@@ -2652,7 +2664,8 @@ retry_root_backup:
btrfs_super_root(disk_super),
blocksize, generation);
if (!tree_root->node ||
- !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
+ !test_bit(EXTENT_BUFFER_UPTODATE,
+ &tree_root->node->ebflags)) {
printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
sb->s_id);
@@ -3642,7 +3655,7 @@ int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
int atomic)
{
int ret;
- struct inode *btree_inode = buf->pages[0]->mapping->host;
+ struct inode *btree_inode = eb_head(buf)->pages[0]->mapping->host;
ret = extent_buffer_uptodate(buf);
if (!ret)
@@ -3672,10 +3685,10 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
* enabled. Normal people shouldn't be marking dummy buffers as dirty
* outside of the sanity tests.
*/
- if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &buf->bflags)))
+ if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb_head(buf)->bflags)))
return;
#endif
- root = BTRFS_I(buf->pages[0]->mapping->host)->root;
+ root = BTRFS_I(eb_head(buf)->pages[0]->mapping->host)->root;
btrfs_assert_tree_locked(buf);
if (transid != root->fs_info->generation)
WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, "
@@ -3724,7 +3737,8 @@ void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
{
- struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
+ struct btrfs_root *root =
+ BTRFS_I(eb_head(buf)->pages[0]->mapping->host)->root;
return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
}
@@ -3962,7 +3976,7 @@ static int btrfs_destroy_marked_extents(struct btrfs_root *root,
wait_on_extent_buffer_writeback(eb);
if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
- &eb->bflags))
+ &eb->ebflags))
clear_extent_buffer_dirty(eb);
free_extent_buffer_stale(eb);
}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 32312e0..232d0a3 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5984,7 +5984,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
goto out;
}
- WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
+ WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->ebflags));
btrfs_add_free_space(cache, buf->start, buf->len);
btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
@@ -6001,7 +6001,7 @@ out:
* Deleting the buffer, clear the corrupt flag since it doesn't matter
* anymore.
*/
- clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
+ clear_bit(EXTENT_BUFFER_CORRUPT, &buf->ebflags);
btrfs_put_block_group(cache);
}
@@ -6887,7 +6887,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
btrfs_tree_lock(buf);
clean_tree_block(trans, root, buf);
- clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
+ clear_bit(EXTENT_BUFFER_STALE, &buf->ebflags);
btrfs_set_lock_blocking(buf);
btrfs_set_buffer_uptodate(buf);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 20d8bdc..fdc06a6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -56,6 +56,7 @@ void btrfs_leak_debug_check(void)
{
struct extent_state *state;
struct extent_buffer *eb;
+ struct extent_buffer_head *ebh;
while (!list_empty(&states)) {
state = list_entry(states.next, struct extent_state, leak_list);
@@ -68,12 +69,17 @@ void btrfs_leak_debug_check(void)
}
while (!list_empty(&buffers)) {
- eb = list_entry(buffers.next, struct extent_buffer, leak_list);
- printk(KERN_ERR "BTRFS: buffer leak start %llu len %lu "
- "refs %d\n",
- eb->start, eb->len, atomic_read(&eb->refs));
- list_del(&eb->leak_list);
- kmem_cache_free(extent_buffer_cache, eb);
+ ebh = list_entry(buffers.next, struct extent_buffer_head, leak_list);
+ printk(KERN_ERR "btrfs buffer leak ");
+
+ eb = &ebh->eb;
+ do {
+ printk(KERN_ERR "eb %p %llu:%lu ", eb, eb->start, eb->len);
+ } while ((eb = eb->eb_next) != NULL);
+
+ printk(KERN_ERR "refs %d\n", atomic_read(&ebh->refs));
+ list_del(&ebh->leak_list);
+ kmem_cache_free(extent_buffer_cache, ebh);
}
}
@@ -144,7 +150,7 @@ int __init extent_io_init(void)
return -ENOMEM;
extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
- sizeof(struct extent_buffer), 0,
+ sizeof(struct extent_buffer_head), 0,
SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
if (!extent_buffer_cache)
goto free_state_cache;
@@ -3409,7 +3415,7 @@ static int eb_wait(void *word)
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
{
- wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
+ wait_on_bit(&eb->ebflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
TASK_UNINTERRUPTIBLE);
}
@@ -4335,29 +4341,47 @@ out:
return ret;
}
-static void __free_extent_buffer(struct extent_buffer *eb)
+static void __free_extent_buffer(struct extent_buffer_head *ebh)
{
- btrfs_leak_debug_del(&eb->leak_list);
- kmem_cache_free(extent_buffer_cache, eb);
+ struct extent_buffer *eb, *next_eb;
+
+ btrfs_leak_debug_del(&ebh->leak_list);
+
+ eb = ebh->eb.eb_next;
+ while (eb) {
+ next_eb = eb->eb_next;
+ kfree(eb);
+ eb = next_eb;
+ }
+
+ kmem_cache_free(extent_buffer_cache, ebh);
}
static int extent_buffer_under_io(struct extent_buffer *eb)
{
- return (atomic_read(&eb->io_pages) ||
- test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
- test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+ struct extent_buffer_head *ebh = eb->ebh;
+ int dirty_or_writeback = 0;
+
+ for (eb = &ebh->eb; eb; eb = eb->eb_next) {
+ if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags)
+ || test_bit(EXTENT_BUFFER_DIRTY, &eb->ebflags))
+ dirty_or_writeback = 1;
+ }
+
+ return (atomic_read(&ebh->io_bvecs) || dirty_or_writeback);
}
/*
* Helper for releasing extent buffer page.
*/
-static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
+static noinline void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
unsigned long start_idx)
{
unsigned long index;
unsigned long num_pages;
struct page *page;
- int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
+ struct extent_buffer_head *ebh = eb_head(eb);
+ int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &ebh->bflags);
BUG_ON(extent_buffer_under_io(eb));
@@ -4367,6 +4391,8 @@ static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
return;
do {
+ struct extent_buffer *e;
+
index--;
page = extent_buffer_page(eb, index);
if (page && mapped) {
@@ -4379,8 +4405,10 @@ static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
* this eb.
*/
if (PagePrivate(page) &&
- page->private == (unsigned long)eb) {
- BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+ page->private == (unsigned long)(&ebh->eb)) {
+ for (e = &ebh->eb; !e; e = e->eb_next)
+ BUG_ON(test_bit(EXTENT_BUFFER_DIRTY,
+ &e->ebflags));
BUG_ON(PageDirty(page));
BUG_ON(PageWriteback(page));
/*
@@ -4408,22 +4436,18 @@ static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,
static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
{
btrfs_release_extent_buffer_page(eb, 0);
- __free_extent_buffer(eb);
+ __free_extent_buffer(eb_head(eb));
}
-static struct extent_buffer *
-__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
- unsigned long len, gfp_t mask)
+static void __init_extent_buffer(struct extent_buffer *eb,
+ struct extent_buffer_head *ebh,
+ u64 start,
+ unsigned long len)
{
- struct extent_buffer *eb = NULL;
-
- eb = kmem_cache_zalloc(extent_buffer_cache, mask);
- if (eb == NULL)
- return NULL;
eb->start = start;
eb->len = len;
- eb->fs_info = fs_info;
- eb->bflags = 0;
+ eb->ebh = ebh;
+ eb->eb_next = NULL;
rwlock_init(&eb->lock);
atomic_set(&eb->write_locks, 0);
atomic_set(&eb->read_locks, 0);
@@ -4434,12 +4458,26 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
eb->lock_nested = 0;
init_waitqueue_head(&eb->write_lock_wq);
init_waitqueue_head(&eb->read_lock_wq);
+}
+
+static struct extent_buffer *__alloc_extent_buffer(struct btrfs_fs_info *fs_info,
+ u64 start, unsigned long len,
+ gfp_t mask)
+{
+ struct extent_buffer_head *ebh = NULL;
+ struct extent_buffer *eb = NULL;
+ int i;
- btrfs_leak_debug_add(&eb->leak_list, &buffers);
+ ebh = kmem_cache_zalloc(extent_buffer_cache, mask);
+ if (ebh == NULL)
+ return NULL;
+ ebh->fs_info = fs_info;
+ ebh->bflags = 0;
+ btrfs_leak_debug_add(&ebh->leak_list, &buffers);
- spin_lock_init(&eb->refs_lock);
- atomic_set(&eb->refs, 1);
- atomic_set(&eb->io_pages, 0);
+ spin_lock_init(&ebh->refs_lock);
+ atomic_set(&ebh->refs, 1);
+ atomic_set(&ebh->io_bvecs, 0);
/*
* Sanity checks, currently the maximum is 64k covered by 16x 4k pages
@@ -4448,6 +4486,29 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
> MAX_INLINE_EXTENT_BUFFER_SIZE);
BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
+ if (len < PAGE_CACHE_SIZE) {
+ struct extent_buffer *cur_eb, *prev_eb;
+ int ebs_per_page = PAGE_CACHE_SIZE / len;
+ u64 st = start & ~(PAGE_CACHE_SIZE - 1);
+
+ prev_eb = NULL;
+ cur_eb = &ebh->eb;
+ for (i = 0; i < ebs_per_page; i++, st += len) {
+ if (prev_eb) {
+ cur_eb = kzalloc(sizeof(*eb), mask);
+ prev_eb->eb_next = cur_eb;
+ }
+ __init_extent_buffer(cur_eb, ebh, st, len);
+ prev_eb = cur_eb;
+ if (st == start)
+ eb = cur_eb;
+ }
+ BUG_ON(!eb);
+ } else {
+ eb = &ebh->eb;
+ __init_extent_buffer(eb, ebh, start, len);
+ }
+
return eb;
}
@@ -4468,15 +4529,16 @@ struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
btrfs_release_extent_buffer(new);
return NULL;
}
- attach_extent_buffer_page(new, p);
+ attach_extent_buffer_page(&(eb_head(new)->eb), p);
WARN_ON(PageDirty(p));
SetPageUptodate(p);
- new->pages[i] = p;
+ eb_head(new)->pages[i] = p;
}
+ set_bit(EXTENT_BUFFER_UPTODATE, &new->ebflags);
+ set_bit(EXTENT_BUFFER_DUMMY, &eb_head(new)->bflags);
+
copy_extent_buffer(new, src, 0, 0, src->len);
- set_bit(EXTENT_BUFFER_UPTODATE, &new->bflags);
- set_bit(EXTENT_BUFFER_DUMMY, &new->bflags);
return new;
}
@@ -4492,19 +4554,19 @@ struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len)
return NULL;
for (i = 0; i < num_pages; i++) {
- eb->pages[i] = alloc_page(GFP_NOFS);
- if (!eb->pages[i])
+ eb_head(eb)->pages[i] = alloc_page(GFP_NOFS);
+ if (!eb_head(eb)->pages[i])
goto err;
}
set_extent_buffer_uptodate(eb);
btrfs_set_header_nritems(eb, 0);
- set_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
+ set_bit(EXTENT_BUFFER_DUMMY, &eb_head(eb)->bflags);
return eb;
err:
for (; i > 0; i--)
- __free_page(eb->pages[i - 1]);
- __free_extent_buffer(eb);
+ __free_page(eb_head(eb)->pages[i - 1]);
+ __free_extent_buffer(eb_head(eb));
return NULL;
}
@@ -4531,14 +4593,15 @@ static void check_buffer_tree_ref(struct extent_buffer *eb)
* So bump the ref count first, then set the bit. If someone
* beat us to it, drop the ref we added.
*/
- refs = atomic_read(&eb->refs);
- if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
+ refs = atomic_read(&eb_head(eb)->refs);
+ if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF,
+ &eb_head(eb)->bflags))
return;
- spin_lock(&eb->refs_lock);
- if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
- atomic_inc(&eb->refs);
- spin_unlock(&eb->refs_lock);
+ spin_lock(&eb_head(eb)->refs_lock);
+ if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb_head(eb)->bflags))
+ atomic_inc(&eb_head(eb)->refs);
+ spin_unlock(&eb_head(eb)->refs_lock);
}
static void mark_extent_buffer_accessed(struct extent_buffer *eb)
@@ -4557,15 +4620,24 @@ static void mark_extent_buffer_accessed(struct extent_buffer *eb)
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
+ struct extent_buffer_head *ebh;
struct extent_buffer *eb;
rcu_read_lock();
- eb = radix_tree_lookup(&fs_info->buffer_radix,
- start >> PAGE_CACHE_SHIFT);
- if (eb && atomic_inc_not_zero(&eb->refs)) {
+ ebh = radix_tree_lookup(&fs_info->buffer_radix,
+ start >> PAGE_CACHE_SHIFT);
+ if (ebh && atomic_inc_not_zero(&ebh->refs)) {
rcu_read_unlock();
- mark_extent_buffer_accessed(eb);
- return eb;
+
+ eb = &ebh->eb;
+ do {
+ if (eb->start == start) {
+ mark_extent_buffer_accessed(eb);
+ return eb;
+ }
+ } while ((eb = eb->eb_next) != NULL);
+
+ BUG();
}
rcu_read_unlock();
@@ -4578,7 +4650,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
unsigned long num_pages = num_extent_pages(start, len);
unsigned long i;
unsigned long index = start >> PAGE_CACHE_SHIFT;
- struct extent_buffer *eb;
+ struct extent_buffer *eb, *cur_eb;
struct extent_buffer *exists = NULL;
struct page *p;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
@@ -4608,12 +4680,18 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
* overwrite page->private.
*/
exists = (struct extent_buffer *)p->private;
- if (atomic_inc_not_zero(&exists->refs)) {
+ if (atomic_inc_not_zero(&eb_head(exists)->refs)) {
spin_unlock(&mapping->private_lock);
unlock_page(p);
page_cache_release(p);
- mark_extent_buffer_accessed(exists);
- goto free_eb;
+ do {
+ if (exists->start == start) {
+ mark_extent_buffer_accessed(exists);
+ goto free_eb;
+ }
+ } while ((exists = exists->eb_next) != NULL);
+
+ BUG();
}
/*
@@ -4624,11 +4702,11 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
WARN_ON(PageDirty(p));
page_cache_release(p);
}
- attach_extent_buffer_page(eb, p);
+ attach_extent_buffer_page(&(eb_head(eb)->eb), p);
spin_unlock(&mapping->private_lock);
WARN_ON(PageDirty(p));
mark_page_accessed(p);
- eb->pages[i] = p;
+ eb_head(eb)->pages[i] = p;
if (!PageUptodate(p))
uptodate = 0;
@@ -4637,16 +4715,22 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
* and why we unlock later
*/
}
- if (uptodate)
- set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ if (uptodate) {
+ cur_eb = &(eb_head(eb)->eb);
+ do {
+ set_bit(EXTENT_BUFFER_UPTODATE, &cur_eb->ebflags);
+ } while ((cur_eb = cur_eb->eb_next) != NULL);
+ }
again:
ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
- if (ret)
+ if (ret) {
+ exists = NULL;
goto free_eb;
+ }
spin_lock(&fs_info->buffer_lock);
ret = radix_tree_insert(&fs_info->buffer_radix,
- start >> PAGE_CACHE_SHIFT, eb);
+ start >> PAGE_CACHE_SHIFT, eb_head(eb));
spin_unlock(&fs_info->buffer_lock);
radix_tree_preload_end();
if (ret == -EEXIST) {
@@ -4658,7 +4742,7 @@ again:
}
/* add one reference for the tree */
check_buffer_tree_ref(eb);
- set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
+ set_bit(EXTENT_BUFFER_IN_TREE, &eb_head(eb)->bflags);
/*
* there is a race where release page may have
@@ -4669,108 +4753,125 @@ again:
* after the extent buffer is in the radix tree so
* it doesn't get lost
*/
- SetPageChecked(eb->pages[0]);
+ SetPageChecked(eb_head(eb)->pages[0]);
for (i = 1; i < num_pages; i++) {
p = extent_buffer_page(eb, i);
ClearPageChecked(p);
unlock_page(p);
}
- unlock_page(eb->pages[0]);
+ unlock_page(eb_head(eb)->pages[0]);
return eb;
free_eb:
for (i = 0; i < num_pages; i++) {
- if (eb->pages[i])
- unlock_page(eb->pages[i]);
+ if (eb_head(eb)->pages[i])
+ unlock_page(eb_head(eb)->pages[i]);
}
- WARN_ON(!atomic_dec_and_test(&eb->refs));
+ WARN_ON(!atomic_dec_and_test(&eb_head(eb)->refs));
btrfs_release_extent_buffer(eb);
return exists;
}
static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
{
- struct extent_buffer *eb =
- container_of(head, struct extent_buffer, rcu_head);
+ struct extent_buffer_head *ebh =
+ container_of(head, struct extent_buffer_head, rcu_head);
- __free_extent_buffer(eb);
+ __free_extent_buffer(ebh);
}
/* Expects to have eb->eb_lock already held */
-static int release_extent_buffer(struct extent_buffer *eb)
+static int release_extent_buffer(struct extent_buffer_head *ebh)
{
- WARN_ON(atomic_read(&eb->refs) == 0);
- if (atomic_dec_and_test(&eb->refs)) {
- if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
- struct btrfs_fs_info *fs_info = eb->fs_info;
+ WARN_ON(atomic_read(&ebh->refs) == 0);
+ if (atomic_dec_and_test(&ebh->refs)) {
+ if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &ebh->bflags)) {
+ struct btrfs_fs_info *fs_info = ebh->fs_info;
- spin_unlock(&eb->refs_lock);
+ spin_unlock(&ebh->refs_lock);
spin_lock(&fs_info->buffer_lock);
radix_tree_delete(&fs_info->buffer_radix,
- eb->start >> PAGE_CACHE_SHIFT);
+ ebh->eb.start >> PAGE_CACHE_SHIFT);
spin_unlock(&fs_info->buffer_lock);
} else {
- spin_unlock(&eb->refs_lock);
+ spin_unlock(&ebh->refs_lock);
}
/* Should be safe to release our pages at this point */
- btrfs_release_extent_buffer_page(eb, 0);
- call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
+ btrfs_release_extent_buffer_page(&ebh->eb, 0);
+ call_rcu(&ebh->rcu_head, btrfs_release_extent_buffer_rcu);
return 1;
}
- spin_unlock(&eb->refs_lock);
+ spin_unlock(&ebh->refs_lock);
return 0;
}
void free_extent_buffer(struct extent_buffer *eb)
{
+ struct extent_buffer_head *ebh;
int refs;
int old;
if (!eb)
return;
+ ebh = eb_head(eb);
while (1) {
- refs = atomic_read(&eb->refs);
+ refs = atomic_read(&ebh->refs);
if (refs <= 3)
break;
- old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
+ old = atomic_cmpxchg(&ebh->refs, refs, refs - 1);
if (old == refs)
return;
}
- spin_lock(&eb->refs_lock);
- if (atomic_read(&eb->refs) == 2 &&
- test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))
- atomic_dec(&eb->refs);
+ spin_lock(&ebh->refs_lock);
+ if (atomic_read(&ebh->refs) == 2 &&
+ test_bit(EXTENT_BUFFER_DUMMY, &ebh->bflags))
+ atomic_dec(&ebh->refs);
- if (atomic_read(&eb->refs) == 2 &&
- test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
+ if (atomic_read(&ebh->refs) == 2 &&
+ test_bit(EXTENT_BUFFER_STALE, &eb->ebflags) &&
!extent_buffer_under_io(eb) &&
- test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
- atomic_dec(&eb->refs);
+ test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &ebh->bflags))
+ atomic_dec(&ebh->refs);
/*
* I know this is terrible, but it's temporary until we stop tracking
* the uptodate bits and such for the extent buffers.
*/
- release_extent_buffer(eb);
+ release_extent_buffer(ebh);
}
void free_extent_buffer_stale(struct extent_buffer *eb)
{
+ struct extent_buffer_head *ebh;
if (!eb)
return;
- spin_lock(&eb->refs_lock);
- set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
+ ebh = eb_head(eb);
+ spin_lock(&ebh->refs_lock);
+
+ set_bit(EXTENT_BUFFER_STALE, &eb->ebflags);
+ if (atomic_read(&ebh->refs) == 2 && !extent_buffer_under_io(eb) &&
+ test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &ebh->bflags))
+ atomic_dec(&ebh->refs);
+
+ release_extent_buffer(ebh);
+}
+
+static int page_ebs_clean(struct extent_buffer_head *ebh)
+{
+ struct extent_buffer *eb = &ebh->eb;;
+
+ do {
+ if (test_bit(EXTENT_BUFFER_DIRTY, &eb->ebflags))
+ return 0;
+ } while ((eb = eb->eb_next) != NULL);
- if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
- test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
- atomic_dec(&eb->refs);
- release_extent_buffer(eb);
+ return 1;
}
void clear_extent_buffer_dirty(struct extent_buffer *eb)
@@ -4781,6 +4882,9 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb)
num_pages = num_extent_pages(eb->start, eb->len);
+ if (eb->len < PAGE_CACHE_SIZE && !page_ebs_clean(eb_head(eb)))
+ return;
+
for (i = 0; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
if (!PageDirty(page))
@@ -4800,7 +4904,7 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb)
ClearPageError(page);
unlock_page(page);
}
- WARN_ON(atomic_read(&eb->refs) == 0);
+ WARN_ON(atomic_read(&eb_head(eb)->refs) == 0);
}
int set_extent_buffer_dirty(struct extent_buffer *eb)
@@ -4811,11 +4915,11 @@ int set_extent_buffer_dirty(struct extent_buffer *eb)
check_buffer_tree_ref(eb);
- was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
+ was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->ebflags);
num_pages = num_extent_pages(eb->start, eb->len);
- WARN_ON(atomic_read(&eb->refs) == 0);
- WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
+ WARN_ON(atomic_read(&eb_head(eb)->refs) == 0);
+ WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb_head(eb)->bflags));
for (i = 0; i < num_pages; i++)
set_page_dirty(extent_buffer_page(eb, i));
@@ -4828,7 +4932,9 @@ int clear_extent_buffer_uptodate(struct extent_buffer *eb)
struct page *page;
unsigned long num_pages;
- clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ if (!eb || !eb_head(eb))
+ return 0;
+ clear_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags);
num_pages = num_extent_pages(eb->start, eb->len);
for (i = 0; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
@@ -4840,22 +4946,43 @@ int clear_extent_buffer_uptodate(struct extent_buffer *eb)
int set_extent_buffer_uptodate(struct extent_buffer *eb)
{
+ struct extent_buffer_head *ebh;
unsigned long i;
struct page *page;
unsigned long num_pages;
+ int uptodate;
- set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
- num_pages = num_extent_pages(eb->start, eb->len);
- for (i = 0; i < num_pages; i++) {
- page = extent_buffer_page(eb, i);
- SetPageUptodate(page);
+ ebh = eb->ebh;
+
+ set_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags);
+ if (eb->len < PAGE_CACHE_SIZE) {
+ eb = &(eb_head(eb)->eb);
+ uptodate = 1;
+ do {
+ if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags)) {
+ uptodate = 0;
+ break;
+ }
+ } while ((eb = eb->eb_next) != NULL);
+
+ if (uptodate) {
+ page = extent_buffer_page(&ebh->eb, 0);
+ SetPageUptodate(page);
+ }
+ } else {
+ num_pages = num_extent_pages(eb->start, eb->len);
+ for (i = 0; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ SetPageUptodate(page);
+ }
}
+
return 0;
}
int extent_buffer_uptodate(struct extent_buffer *eb)
{
- return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ return test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags);
}
int read_extent_buffer_pages(struct extent_io_tree *tree,
@@ -5075,9 +5202,10 @@ void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
+ WARN_ON(!test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags));
+
while (len > 0) {
page = extent_buffer_page(eb, i);
- WARN_ON(!PageUptodate(page));
cur = min(len, PAGE_CACHE_SIZE - offset);
kaddr = page_address(page);
@@ -5102,12 +5230,12 @@ void memset_extent_buffer(struct extent_buffer *eb, char c,
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
+ WARN_ON(!test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags));
offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
while (len > 0) {
page = extent_buffer_page(eb, i);
- WARN_ON(!PageUptodate(page));
cur = min(len, PAGE_CACHE_SIZE - offset);
kaddr = page_address(page);
@@ -5136,9 +5264,10 @@ void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
offset = (start_offset + dst_offset) &
(PAGE_CACHE_SIZE - 1);
+ WARN_ON(!test_bit(EXTENT_BUFFER_UPTODATE, &dst->ebflags));
+
while (len > 0) {
page = extent_buffer_page(dst, i);
- WARN_ON(!PageUptodate(page));
cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
@@ -5275,6 +5404,7 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
int try_release_extent_buffer(struct page *page)
{
+ struct extent_buffer_head *ebh;
struct extent_buffer *eb;
/*
@@ -5290,14 +5420,15 @@ int try_release_extent_buffer(struct page *page)
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
+ ebh = eb->ebh;
/*
* This is a little awful but should be ok, we need to make sure that
* the eb doesn't disappear out from under us while we're looking at
* this page.
*/
- spin_lock(&eb->refs_lock);
- if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
- spin_unlock(&eb->refs_lock);
+ spin_lock(&ebh->refs_lock);
+ if (atomic_read(&ebh->refs) != 1 || extent_buffer_under_io(eb)) {
+ spin_unlock(&ebh->refs_lock);
spin_unlock(&page->mapping->private_lock);
return 0;
}
@@ -5307,10 +5438,11 @@ int try_release_extent_buffer(struct page *page)
* If tree ref isn't set then we know the ref on this eb is a real ref,
* so just return, this page will likely be freed soon anyway.
*/
- if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
- spin_unlock(&eb->refs_lock);
+ if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &ebh->bflags)) {
+ spin_unlock(&ebh->refs_lock);
return 0;
}
- return release_extent_buffer(eb);
+ return release_extent_buffer(ebh);
}
+
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 42d0b74..75a01fd 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -123,19 +123,17 @@ struct extent_state {
#define INLINE_EXTENT_BUFFER_PAGES 16
#define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_CACHE_SIZE)
+
+/* Forward declaration */
+struct extent_buffer_head;
+
struct extent_buffer {
u64 start;
unsigned long len;
- unsigned long map_start;
- unsigned long map_len;
- unsigned long bflags;
- struct btrfs_fs_info *fs_info;
- spinlock_t refs_lock;
- atomic_t refs;
- atomic_t io_pages;
+ unsigned long ebflags;
+ struct extent_buffer_head *ebh;
+ struct extent_buffer *eb_next;
int read_mirror;
- struct rcu_head rcu_head;
- pid_t lock_owner;
/* count of read lock holders on the extent buffer */
atomic_t write_locks;
@@ -146,6 +144,8 @@ struct extent_buffer {
atomic_t spinning_writers;
int lock_nested;
+ pid_t lock_owner;
+
/* protects write locks */
rwlock_t lock;
@@ -159,7 +159,19 @@ struct extent_buffer {
*/
wait_queue_head_t read_lock_wq;
wait_queue_head_t lock_wq;
+};
+
+struct extent_buffer_head {
+ unsigned long bflags;
+ struct btrfs_fs_info *fs_info;
+ spinlock_t refs_lock;
+ atomic_t refs;
+ atomic_t io_bvecs;
+ struct rcu_head rcu_head;
+
struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
+
+ struct extent_buffer eb;
#ifdef CONFIG_BTRFS_DEBUG
struct list_head leak_list;
#endif
@@ -176,6 +188,14 @@ static inline int extent_compress_type(unsigned long bio_flags)
return bio_flags >> EXTENT_BIO_FLAG_SHIFT;
}
+/*
+ * return the extent_buffer_head that contains the extent buffer provided.
+ */
+static inline struct extent_buffer_head *eb_head(struct extent_buffer *eb)
+{
+ return eb->ebh;
+
+}
struct extent_map_tree;
typedef struct extent_map *(get_extent_t)(struct inode *inode,
@@ -287,15 +307,15 @@ static inline unsigned long num_extent_pages(u64 start, u64 len)
(start >> PAGE_CACHE_SHIFT);
}
-static inline struct page *extent_buffer_page(struct extent_buffer *eb,
- unsigned long i)
+static inline struct page *extent_buffer_page(
+ struct extent_buffer *eb, unsigned long i)
{
- return eb->pages[i];
+ return eb_head(eb)->pages[i];
}
static inline void extent_buffer_get(struct extent_buffer *eb)
{
- atomic_inc(&eb->refs);
+ atomic_inc(&eb_head(eb)->refs);
}
int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 07629e9..1ec359b 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5936,7 +5936,7 @@ int btrfs_read_sys_array(struct btrfs_root *root)
* to silence the warning eg. on PowerPC 64.
*/
if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
- SetPageUptodate(sb->pages[0]);
+ SetPageUptodate(eb_head(sb)->pages[0]);
write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
array_size = btrfs_super_sys_array_size(super_copy);
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 3176cdc..5b79ac2 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -695,7 +695,7 @@ TRACE_EVENT(btrfs_cow_block,
TP_fast_assign(
__entry->root_objectid = root->root_key.objectid;
__entry->buf_start = buf->start;
- __entry->refs = atomic_read(&buf->refs);
+ __entry->refs = atomic_read(&eb_head(buf)->refs);
__entry->cow_start = cow->start;
__entry->buf_level = btrfs_header_level(buf);
__entry->cow_level = btrfs_header_level(cow);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 5/8] Btrfs: subpagesize-blocksize: Read tree blocks whose size is <PAGE_CACHE_SIZE.
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
` (3 preceding siblings ...)
2014-06-11 11:32 ` [RFC PATCH V2 4/8] Btrfs: subpagesize-blocksize: Define extent_buffer_head Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 6/8] Btrfs: subpagesize-blocksize: Write only dirty extent buffers belonging to a page Chandan Rajendra
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandan Rajendra, linux-btrfs, aneesh.kumar
In the case of subpagesize-blocksize, this patch makes it possible to read
only a single metadata block from the disk instead of all the metadata blocks
that map into a page.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/disk-io.c | 45 ++++++++---------
fs/btrfs/disk-io.h | 3 ++
fs/btrfs/extent_io.c | 135 +++++++++++++++++++++++++++++++++++++++++++--------
3 files changed, 137 insertions(+), 46 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index bda2157..b2c4e9d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -413,7 +413,7 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
int mirror_num = 0;
int failed_mirror = 0;
- clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
+ clear_bit(EXTENT_BUFFER_CORRUPT, &eb->ebflags);
io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
while (1) {
ret = read_extent_buffer_pages(io_tree, eb, start,
@@ -432,7 +432,7 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
* there is no reason to read the other copies, they won't be
* any less wrong.
*/
- if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
+ if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->ebflags))
break;
num_copies = btrfs_num_copies(root->fs_info,
@@ -564,12 +564,13 @@ static noinline int check_leaf(struct btrfs_root *root,
return 0;
}
-static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
- u64 phy_offset, struct page *page,
- u64 start, u64 end, int mirror)
+int verify_extent_buffer_read(struct btrfs_io_bio *io_bio,
+ struct page *page,
+ u64 start, u64 end, int mirror)
{
u64 found_start;
int found_level;
+ struct extent_buffer_head *ebh;
struct extent_buffer *eb;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
int ret = 0;
@@ -579,18 +580,26 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
goto out;
eb = (struct extent_buffer *)page->private;
+ do {
+ if ((eb->start <= start) && (eb->start + eb->len - 1 > start))
+ break;
+ } while ((eb = eb->eb_next) != NULL);
+
+ BUG_ON(!eb);
+
+ ebh = eb_head(eb);
/* the pending IO might have been the only thing that kept this buffer
* in memory. Make sure we have a ref for all this other checks
*/
extent_buffer_get(eb);
- reads_done = atomic_dec_and_test(&eb->io_pages);
+ reads_done = atomic_dec_and_test(&ebh->io_bvecs);
if (!reads_done)
goto err;
eb->read_mirror = mirror;
- if (test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
+ if (test_bit(EXTENT_BUFFER_IOERR, &eb->ebflags)) {
ret = -EIO;
goto err;
}
@@ -632,7 +641,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
* return -EIO.
*/
if (found_level == 0 && check_leaf(root, eb)) {
- set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
+ set_bit(EXTENT_BUFFER_CORRUPT, &eb->ebflags);
ret = -EIO;
}
@@ -640,7 +649,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
set_extent_buffer_uptodate(eb);
err:
if (reads_done &&
- test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
+ test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->ebflags))
btree_readahead_hook(root, eb, eb->start, ret);
if (ret) {
@@ -649,7 +658,7 @@ err:
* again, we have to make sure it has something
* to decrement
*/
- atomic_inc(&eb->io_pages);
+ atomic_inc(&eb_head(eb)->io_bvecs);
clear_extent_buffer_uptodate(eb);
}
free_extent_buffer(eb);
@@ -657,20 +666,6 @@ out:
return ret;
}
-static int btree_io_failed_hook(struct page *page, int failed_mirror)
-{
- struct extent_buffer *eb;
- struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
-
- eb = (struct extent_buffer *)page->private;
- set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
- eb->read_mirror = failed_mirror;
- atomic_dec(&eb->io_pages);
- if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
- btree_readahead_hook(root, eb, eb->start, -EIO);
- return -EIO; /* we fixed nothing */
-}
-
static void end_workqueue_bio(struct bio *bio, int err)
{
struct end_io_wq *end_io_wq = bio->bi_private;
@@ -4109,8 +4104,6 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
}
static struct extent_io_ops btree_extent_io_ops = {
- .readpage_end_io_hook = btree_readpage_end_io_hook,
- .readpage_io_failed_hook = btree_io_failed_hook,
.submit_bio_hook = btree_submit_bio_hook,
/* note we're sharing with inode.c for the merge bio hook */
.merge_bio_hook = btrfs_merge_bio_hook,
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 53059df..678a09b 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -110,6 +110,9 @@ static inline void btrfs_put_fs_root(struct btrfs_root *root)
kfree(root);
}
+int verify_extent_buffer_read(struct btrfs_io_bio *io_bio,
+ struct page *page,
+ u64 start, u64 end, int mirror);
void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
int atomic);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fdc06a6..c095575 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -14,6 +14,7 @@
#include "extent_io.h"
#include "extent_map.h"
#include "ctree.h"
+#include "disk-io.h"
#include "btrfs_inode.h"
#include "volumes.h"
#include "check-integrity.h"
@@ -2120,7 +2121,7 @@ int repair_eb_io_failure(struct btrfs_root *root, struct extent_buffer *eb,
for (i = 0; i < num_pages; i++) {
struct page *p = extent_buffer_page(eb, i);
- ret = repair_io_failure(root->fs_info, start, PAGE_CACHE_SIZE,
+ ret = repair_io_failure(root->fs_info, start, eb->len,
start, p, mirror_num);
if (ret)
break;
@@ -3476,17 +3477,88 @@ static int lock_extent_buffer_for_io(struct extent_buffer *eb,
num_pages = num_extent_pages(eb->start, eb->len);
for (i = 0; i < num_pages; i++) {
struct page *p = extent_buffer_page(eb, i);
+static void end_bio_extent_buffer_readpage(struct bio *bio, int err)
+{
+ struct address_space *mapping = bio->bi_io_vec->bv_page->mapping;
+ struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
+ struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+ struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bvec = bio->bi_io_vec;
+ struct extent_buffer *eb;
+ struct page *page = bvec->bv_page;
+ struct btrfs_root *root;
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ u64 start;
+ u64 end;
+ int mirror;
+ int ret;
- if (!trylock_page(p)) {
- if (!flush) {
- flush_write_bio(epd);
- flush = 1;
- }
- lock_page(p);
+ root = BTRFS_I(page->mapping->host)->root;
+
+ if (err)
+ uptodate = 0;
+
+ do {
+ page = bvec->bv_page;
+
+ if (!page->private) {
+ SetPageUptodate(page);
+ goto unlock;
}
- }
- return ret;
+ eb = (struct extent_buffer *)page->private;
+
+ start = io_bio->start_offset;
+ end = start + io_bio->len - 1;
+
+ do {
+ /*
+ read_extent_buffer_pages() does not start
+ I/O on PG_uptodate pages. Hence the bio may
+ map only part of the extent buffer.
+ */
+ if ((eb->start <= start) && (eb->start + eb->len - 1 > start))
+ break;
+ } while ((eb = eb->eb_next) != NULL);
+
+ BUG_ON(!eb);
+
+ mirror = io_bio->mirror_num;
+
+ if (uptodate) {
+ ret = verify_extent_buffer_read(io_bio, page, start,
+ end, mirror);
+ if (ret)
+ uptodate = 0;
+ }
+
+ if (!uptodate) {
+ set_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
+ eb->read_mirror = mirror;
+ atomic_dec(&eb_head(eb)->io_bvecs);
+ if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD,
+ &eb->ebflags))
+ btree_readahead_hook(root, eb, eb->start,
+ -EIO);
+ ClearPageUptodate(page);
+ SetPageError(page);
+ goto unlock;
+ }
+
+unlock:
+ unlock_page(page);
+ ++bvec;
+ } while (bvec <= bvec_end);
+
+ /*
+ We don't need to add a check to see if
+ extent_io_tree->track_uptodate is set or not, Since
+ this function only deals with extent buffers.
+ */
+ unlock_extent(tree, io_bio->start_offset,
+ io_bio->start_offset + io_bio->len - 1);
+
+ bio_put(bio);
}
static void end_extent_buffer_writeback(struct extent_buffer *eb)
@@ -4989,6 +5061,9 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
struct extent_buffer *eb, u64 start, int wait,
get_extent_t *get_extent, int mirror_num)
{
+ struct inode *inode = tree->mapping->host;
+ struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
+ struct extent_state *cached_state = NULL;
unsigned long i;
unsigned long start_i;
struct page *page;
@@ -5001,7 +5076,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
struct bio *bio = NULL;
unsigned long bio_flags = 0;
- if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
+ if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags))
return 0;
if (start) {
@@ -5029,21 +5104,34 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
}
if (all_uptodate) {
if (start_i == 0)
- set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ set_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags);
goto unlock_exit;
}
- clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ clear_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
eb->read_mirror = 0;
- atomic_set(&eb->io_pages, num_reads);
+ atomic_set(&eb_head(eb)->io_bvecs, num_reads);
+ lock_extent_bits(tree, eb->start, eb->start + eb->len - 1, 0,
+ &cached_state);
for (i = start_i; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
if (!PageUptodate(page)) {
ClearPageError(page);
- err = __extent_read_full_page(tree, page,
- get_extent, &bio,
- mirror_num, &bio_flags,
- READ | REQ_META);
+ if (eb->len < PAGE_CACHE_SIZE) {
+ err = submit_extent_page(READ | REQ_META, tree,
+ page, eb->start >> 9,
+ eb->len, eb->start - page_offset(page),
+ fs_info->fs_devices->latest_bdev,
+ &bio, -1, end_bio_extent_buffer_readpage,
+ mirror_num, bio_flags, bio_flags);
+ } else {
+ err = submit_extent_page(READ | REQ_META, tree,
+ page, page_offset(page) >> 9,
+ PAGE_CACHE_SIZE, 0,
+ fs_info->fs_devices->latest_bdev,
+ &bio, -1, end_bio_extent_buffer_readpage,
+ mirror_num, bio_flags, bio_flags);
+ }
if (err)
ret = err;
} else {
@@ -5061,11 +5149,18 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
if (ret || wait != WAIT_COMPLETE)
return ret;
- for (i = start_i; i < num_pages; i++) {
- page = extent_buffer_page(eb, i);
+ if (eb->len < PAGE_CACHE_SIZE) {
+ page = extent_buffer_page(eb, 0);
wait_on_page_locked(page);
- if (!PageUptodate(page))
+ if (!extent_buffer_uptodate(eb))
ret = -EIO;
+ } else {
+ for (i = start_i; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ wait_on_page_locked(page);
+ if (!PageUptodate(page))
+ ret = -EIO;
+ }
}
return ret;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 6/8] Btrfs: subpagesize-blocksize: Write only dirty extent buffers belonging to a page
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
` (4 preceding siblings ...)
2014-06-11 11:32 ` [RFC PATCH V2 5/8] Btrfs: subpagesize-blocksize: Read tree blocks whose size is <PAGE_CACHE_SIZE Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 7/8] Btrfs: subpagesize-blocksize: Allow mounting filesystems where sectorsize != PAGE_SIZE Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 8/8] Btrfs: subpagesize-blocksize: Compute and look up csums based on sectorsized blocks Chandan Rajendra
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandan Rajendra, linux-btrfs, aneesh.kumar
For the subpagesize-blocksize scenario, This patch adds the ability to write a
single extent buffer to the disk.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/disk-io.c | 20 ++--
fs/btrfs/extent_io.c | 277 ++++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 243 insertions(+), 54 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b2c4e9d..28a45f6 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -466,17 +466,23 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
{
- u64 start = page_offset(page);
- u64 found_start;
struct extent_buffer *eb;
+ u64 found_start;
eb = (struct extent_buffer *)page->private;
- if (page != eb->pages[0])
+ if (page != eb_head(eb)->pages[0])
return 0;
- found_start = btrfs_header_bytenr(eb);
- if (WARN_ON(found_start != start || !PageUptodate(page)))
- return 0;
- csum_tree_block(root, eb, 0);
+ do {
+ if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags))
+ continue;
+ if (WARN_ON(!test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags)))
+ continue;
+ found_start = btrfs_header_bytenr(eb);
+ if (WARN_ON(found_start != eb->start))
+ return 0;
+ csum_tree_block(root, eb, 0);
+ } while ((eb = eb->eb_next) != NULL);
+
return 0;
}
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c095575..507ef5b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3420,32 +3420,53 @@ void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
TASK_UNINTERRUPTIBLE);
}
-static int lock_extent_buffer_for_io(struct extent_buffer *eb,
- struct btrfs_fs_info *fs_info,
- struct extent_page_data *epd)
+static void lock_extent_buffer_pages(struct extent_buffer_head *ebh,
+ struct extent_page_data *epd)
{
+ struct extent_buffer *eb = &ebh->eb;
unsigned long i, num_pages;
- int flush = 0;
+
+ num_pages = num_extent_pages(eb->start, eb->len);
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = extent_buffer_page(eb, i);
+
+ if (!trylock_page(p)) {
+ flush_write_bio(epd);
+ lock_page(p);
+ }
+ }
+
+ return;
+}
+
+static int lock_extent_buffer_for_io(struct extent_buffer *eb,
+ struct btrfs_fs_info *fs_info,
+ struct extent_page_data *epd)
+{
+ int dirty;
int ret = 0;
if (!btrfs_try_tree_write_lock(eb)) {
- flush = 1;
flush_write_bio(epd);
btrfs_tree_lock(eb);
}
- if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
+ if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags)) {
+ dirty = test_bit(EXTENT_BUFFER_DIRTY, &eb->ebflags);
btrfs_tree_unlock(eb);
- if (!epd->sync_io)
- return 0;
- if (!flush) {
- flush_write_bio(epd);
- flush = 1;
+ if (!epd->sync_io) {
+ if (!dirty)
+ return 1;
+ else
+ return 2;
}
+
+ flush_write_bio(epd);
+
while (1) {
wait_on_extent_buffer_writeback(eb);
btrfs_tree_lock(eb);
- if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
+ if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags))
break;
btrfs_tree_unlock(eb);
}
@@ -3456,27 +3477,25 @@ static int lock_extent_buffer_for_io(struct extent_buffer *eb,
* under IO since we can end up having no IO bits set for a short period
* of time.
*/
- spin_lock(&eb->refs_lock);
- if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
- set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
- spin_unlock(&eb->refs_lock);
+ spin_lock(&eb_head(eb)->refs_lock);
+ if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->ebflags)) {
+ set_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags);
+ spin_unlock(&eb_head(eb)->refs_lock);
btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
__percpu_counter_add(&fs_info->dirty_metadata_bytes,
-eb->len,
fs_info->dirty_metadata_batch);
- ret = 1;
+ ret = 0;
} else {
- spin_unlock(&eb->refs_lock);
+ spin_unlock(&eb_head(eb)->refs_lock);
+ ret = 1;
}
btrfs_tree_unlock(eb);
- if (!ret)
- return ret;
+ return ret;
+}
- num_pages = num_extent_pages(eb->start, eb->len);
- for (i = 0; i < num_pages; i++) {
- struct page *p = extent_buffer_page(eb, i);
static void end_bio_extent_buffer_readpage(struct bio *bio, int err)
{
struct address_space *mapping = bio->bi_io_vec->bv_page->mapping;
@@ -3563,13 +3582,14 @@ unlock:
static void end_extent_buffer_writeback(struct extent_buffer *eb)
{
- clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
+ clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags);
smp_mb__after_clear_bit();
- wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
+ wake_up_bit(&eb->ebflags, EXTENT_BUFFER_WRITEBACK);
}
-static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
+static void end_bio_subpagesize_blocksize_ebh_writepage(struct bio *bio, int err)
{
+ struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
int uptodate = err == 0;
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_buffer *eb;
@@ -3577,14 +3597,52 @@ static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
do {
struct page *page = bvec->bv_page;
+ eb = (struct extent_buffer *)page->private;
+ BUG_ON(!eb);
+
+ do {
+ if (!(eb->start >= io_bio->start_offset
+ && (eb->start + eb->len)
+ <= (io_bio->start_offset + io_bio->len))) {
+ continue;
+ }
+
+ done = atomic_dec_and_test(&eb_head(eb)->io_bvecs);
+
+ if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->ebflags)) {
+ set_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+
+ end_extent_buffer_writeback(eb);
+
+ if (done)
+ end_page_writeback(page);
+
+ } while ((eb = eb->eb_next) != NULL);
+
+ } while (--bvec >= bio->bi_io_vec);
+
+}
+
+static void end_bio_regular_ebh_writepage(struct bio *bio, int err)
+{
+ int uptodate = (err == 0);
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct extent_buffer *eb;
+ int done;
+
+ do {
+ struct page *page = bvec->bv_page;
bvec--;
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
- done = atomic_dec_and_test(&eb->io_pages);
+ done = atomic_dec_and_test(&eb_head(eb)->io_bvecs);
- if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
- set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->ebflags)) {
+ set_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
ClearPageUptodate(page);
SetPageError(page);
}
@@ -3601,22 +3659,23 @@ static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
}
-static int write_one_eb(struct extent_buffer *eb,
+static int write_regular_ebh(struct extent_buffer_head *ebh,
struct btrfs_fs_info *fs_info,
struct writeback_control *wbc,
struct extent_page_data *epd)
{
struct block_device *bdev = fs_info->fs_devices->latest_bdev;
struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
- u64 offset = eb->start;
+ struct extent_buffer *eb = &ebh->eb;
+ u64 offset = eb->start & ~(PAGE_CACHE_SIZE - 1);
unsigned long i, num_pages;
unsigned long bio_flags = 0;
int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
int ret = 0;
- clear_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ clear_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
num_pages = num_extent_pages(eb->start, eb->len);
- atomic_set(&eb->io_pages, num_pages);
+ atomic_set(&eb_head(eb)->io_bvecs, num_pages);
if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
bio_flags = EXTENT_BIO_TREE_LOG;
@@ -3627,13 +3686,14 @@ static int write_one_eb(struct extent_buffer *eb,
set_page_writeback(p);
ret = submit_extent_page(rw, tree, p, offset >> 9,
PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
- -1, end_bio_extent_buffer_writepage,
+ -1, end_bio_regular_ebh_writepage,
0, epd->bio_flags, bio_flags);
epd->bio_flags = bio_flags;
if (ret) {
- set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
+ set_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
SetPageError(p);
- if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
+ if (atomic_sub_and_test(num_pages - i,
+ &eb_head(eb)->io_bvecs))
end_extent_buffer_writeback(eb);
ret = -EIO;
break;
@@ -3653,12 +3713,85 @@ static int write_one_eb(struct extent_buffer *eb,
return ret;
}
+static int write_subpagesize_blocksize_ebh(struct extent_buffer_head *ebh,
+ struct btrfs_fs_info *fs_info,
+ struct writeback_control *wbc,
+ struct extent_page_data *epd,
+ unsigned long ebs_to_write)
+{
+ struct block_device *bdev = fs_info->fs_devices->latest_bdev;
+ struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
+ struct extent_buffer *eb;
+ struct page *p;
+ u64 offset;
+ unsigned long i;
+ unsigned long bio_flags = 0;
+ int rw = (epd->sync_io ? WRITE_SYNC : WRITE) | REQ_META;
+ int ret = 0, err = 0;
+
+ eb = &ebh->eb;
+ p = extent_buffer_page(eb, 0);
+ clear_page_dirty_for_io(p);
+ set_page_writeback(p);
+ i = 0;
+ do {
+ if (!test_bit(i++, &ebs_to_write))
+ continue;
+
+ clear_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
+ atomic_inc(&eb_head(eb)->io_bvecs);
+
+ if (btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID)
+ bio_flags = EXTENT_BIO_TREE_LOG;
+
+ offset = eb->start - page_offset(p);
+
+ ret = submit_extent_page(rw, tree, p, eb->start >> 9,
+ eb->len, offset,
+ bdev, &epd->bio, -1,
+ end_bio_subpagesize_blocksize_ebh_writepage,
+ 0, epd->bio_flags, bio_flags);
+ epd->bio_flags = bio_flags;
+ if (ret) {
+ set_bit(EXTENT_BUFFER_IOERR, &eb->ebflags);
+ SetPageError(p);
+ atomic_dec(&eb_head(eb)->io_bvecs);
+ end_extent_buffer_writeback(eb);
+ err = -EIO;
+ }
+ } while ((eb = eb->eb_next) != NULL);
+
+ if (!err) {
+ update_nr_written(p, wbc, 1);
+ }
+
+ unlock_page(p);
+
+ return ret;
+}
+
+static void redirty_extent_buffer_pages_for_writepage(struct extent_buffer *eb,
+ struct writeback_control *wbc)
+{
+ unsigned long i, num_pages;
+ struct page *p;
+
+ num_pages = num_extent_pages(eb->start, eb->len);
+ for (i = 0; i < num_pages; i++) {
+ p = extent_buffer_page(eb, i);
+ redirty_page_for_writepage(wbc, p);
+ }
+
+ return;
+}
+
int btree_write_cache_pages(struct address_space *mapping,
- struct writeback_control *wbc)
+ struct writeback_control *wbc)
{
struct extent_io_tree *tree = &BTRFS_I(mapping->host)->io_tree;
struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
- struct extent_buffer *eb, *prev_eb = NULL;
+ struct extent_buffer *eb;
+ struct extent_buffer_head *ebh, *prev_ebh = NULL;
struct extent_page_data epd = {
.bio = NULL,
.tree = tree,
@@ -3669,6 +3802,7 @@ int btree_write_cache_pages(struct address_space *mapping,
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
+ unsigned long ebs_to_write, dirty_ebs;
struct pagevec pvec;
int nr_pages;
pgoff_t index;
@@ -3695,7 +3829,7 @@ retry:
while (!done && !nr_to_write_done && (index <= end) &&
(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
- unsigned i;
+ unsigned i, j;
scanned = 1;
for (i = 0; i < nr_pages; i++) {
@@ -3727,30 +3861,79 @@ retry:
continue;
}
- if (eb == prev_eb) {
+ ebh = eb_head(eb);
+ if (ebh == prev_ebh) {
spin_unlock(&mapping->private_lock);
continue;
}
- ret = atomic_inc_not_zero(&eb->refs);
+ ret = atomic_inc_not_zero(&ebh->refs);
spin_unlock(&mapping->private_lock);
if (!ret)
continue;
- prev_eb = eb;
- ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
- if (!ret) {
+ prev_ebh = ebh;
+
+ j = 0;
+ ebs_to_write = dirty_ebs = 0;
+ eb = &ebh->eb;
+ do {
+ BUG_ON(j >= BITS_PER_LONG);
+
+ ret = lock_extent_buffer_for_io(eb, fs_info, &epd);
+ switch (ret) {
+ case 0:
+ /*
+ EXTENT_BUFFER_DIRTY was set and we were able to
+ clear it.
+ */
+ set_bit(j, &ebs_to_write);
+ break;
+ case 2:
+ /*
+ EXTENT_BUFFER_DIRTY was set, but we were unable
+ to clear EXTENT_BUFFER_WRITEBACK that was set
+ before we got the extent buffer locked.
+ */
+ set_bit(j, &dirty_ebs);
+ default:
+ /*
+ EXTENT_BUFFER_DIRTY wasn't set.
+ */
+ break;
+ }
+ ++j;
+ } while ((eb = eb->eb_next) != NULL);
+
+ ret = 0;
+
+ if (!ebs_to_write) {
free_extent_buffer(eb);
continue;
}
- ret = write_one_eb(eb, fs_info, wbc, &epd);
+ /*
+ Now that we know that atleast one of the extent buffer
+ belonging to the extent buffer head must be written to
+ the disk, lock the extent_buffer_head's pages.
+ */
+ lock_extent_buffer_pages(ebh, &epd);
+
+ if (ebh->eb.len < PAGE_CACHE_SIZE) {
+ ret = write_subpagesize_blocksize_ebh(ebh, fs_info, wbc, &epd, ebs_to_write);
+ if (dirty_ebs) {
+ redirty_extent_buffer_pages_for_writepage(&ebh->eb, wbc);
+ }
+ } else {
+ ret = write_regular_ebh(ebh, fs_info, wbc, &epd);
+ }
+
if (ret) {
done = 1;
- free_extent_buffer(eb);
+ free_extent_buffer(&ebh->eb);
break;
}
- free_extent_buffer(eb);
+ free_extent_buffer(&ebh->eb);
/*
* the filesystem may choose to bump up nr_to_write.
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 7/8] Btrfs: subpagesize-blocksize: Allow mounting filesystems where sectorsize != PAGE_SIZE
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
` (5 preceding siblings ...)
2014-06-11 11:32 ` [RFC PATCH V2 6/8] Btrfs: subpagesize-blocksize: Write only dirty extent buffers belonging to a page Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
2014-06-11 11:32 ` [RFC PATCH V2 8/8] Btrfs: subpagesize-blocksize: Compute and look up csums based on sectorsized blocks Chandan Rajendra
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandra Seetharaman, linux-btrfs, aneesh.kumar, Chandan Rajendra
From: Chandra Seetharaman <sekharan@us.ibm.com>
This patch allows mounting filesystems with blocksize smaller than the
PAGE_SIZE.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/disk-io.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 28a45f6..3bb7072 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2599,12 +2599,6 @@ int open_ctree(struct super_block *sb,
goto fail_sb_buffer;
}
- if (sectorsize != PAGE_SIZE) {
- printk(KERN_WARNING "BTRFS: Incompatible sector size(%lu) "
- "found on %s\n", (unsigned long)sectorsize, sb->s_id);
- goto fail_sb_buffer;
- }
-
mutex_lock(&fs_info->chunk_mutex);
ret = btrfs_read_sys_array(tree_root);
mutex_unlock(&fs_info->chunk_mutex);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [RFC PATCH V2 8/8] Btrfs: subpagesize-blocksize: Compute and look up csums based on sectorsized blocks.
2014-06-11 11:32 [RFC PATCH V2 0/8] Btrfs: Subpagesize-blocksize: Get rid of whole page I/O Chandan Rajendra
` (6 preceding siblings ...)
2014-06-11 11:32 ` [RFC PATCH V2 7/8] Btrfs: subpagesize-blocksize: Allow mounting filesystems where sectorsize != PAGE_SIZE Chandan Rajendra
@ 2014-06-11 11:32 ` Chandan Rajendra
7 siblings, 0 replies; 9+ messages in thread
From: Chandan Rajendra @ 2014-06-11 11:32 UTC (permalink / raw)
To: clm, jbacik, bo.li.liu, dsterba
Cc: Chandan Rajendra, linux-btrfs, aneesh.kumar
Checksums are applicable to sectorsize units. The current code uses
bio->bv_len units to compute and look up checksums. This works on machines
where sectorsize == PAGE_CACHE_SIZE. This patch makes the checksum
computation and look up code to work with sectorsize units.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/btrfs/file-item.c | 85 ++++++++++++++++++++++++++++++++--------------------
1 file changed, 52 insertions(+), 33 deletions(-)
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 9d84658..16deb87 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -172,6 +172,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
u64 item_start_offset = 0;
u64 item_last_offset = 0;
u64 disk_bytenr;
+ u64 page_bytes_left;
u32 diff;
int nblocks;
int bio_index = 0;
@@ -220,6 +221,8 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
disk_bytenr = (u64)bio->bi_sector << 9;
if (dio)
offset = logical_offset;
+
+ page_bytes_left = bvec->bv_len;
while (bio_index < bio->bi_vcnt) {
if (!dio)
offset = page_offset(bvec->bv_page) + bvec->bv_offset;
@@ -243,7 +246,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
if (BTRFS_I(inode)->root->root_key.objectid ==
BTRFS_DATA_RELOC_TREE_OBJECTID) {
set_extent_bits(io_tree, offset,
- offset + bvec->bv_len - 1,
+ offset + root->sectorsize - 1,
EXTENT_NODATASUM, GFP_NOFS);
} else {
btrfs_info(BTRFS_I(inode)->root->fs_info,
@@ -281,11 +284,17 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
found:
csum += count * csum_size;
nblocks -= count;
+
while (count--) {
- disk_bytenr += bvec->bv_len;
- offset += bvec->bv_len;
- bio_index++;
- bvec++;
+ disk_bytenr += root->sectorsize;
+ offset += root->sectorsize;
+ page_bytes_left -= root->sectorsize;
+ if (!page_bytes_left) {
+ bio_index++;
+ bvec++;
+ page_bytes_left = bvec->bv_len;
+ }
+
}
}
btrfs_free_path(path);
@@ -442,6 +451,8 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
struct bio_vec *bvec = bio->bi_io_vec;
int bio_index = 0;
int index;
+ int nr_sectors;
+ int i;
unsigned long total_bytes = 0;
unsigned long this_sum_bytes = 0;
u64 offset;
@@ -468,41 +479,49 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
if (!contig)
offset = page_offset(bvec->bv_page) + bvec->bv_offset;
- if (offset >= ordered->file_offset + ordered->len ||
- offset < ordered->file_offset) {
- unsigned long bytes_left;
- sums->len = this_sum_bytes;
- this_sum_bytes = 0;
- btrfs_add_ordered_sum(inode, ordered, sums);
- btrfs_put_ordered_extent(ordered);
+ data = kmap_atomic(bvec->bv_page);
- bytes_left = bio->bi_size - total_bytes;
+ nr_sectors = (bvec->bv_len + root->sectorsize - 1)
+ >> root->fs_info->sb->s_blocksize_bits;
+
+ for (i = 0; i < nr_sectors; i++) {
+ if (offset >= ordered->file_offset + ordered->len ||
+ offset < ordered->file_offset) {
+ unsigned long bytes_left;
+ sums->len = this_sum_bytes;
+ this_sum_bytes = 0;
+ btrfs_add_ordered_sum(inode, ordered, sums);
+ btrfs_put_ordered_extent(ordered);
+
+ bytes_left = bio->bi_size - total_bytes;
+
+ sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
+ GFP_NOFS);
+ BUG_ON(!sums); /* -ENOMEM */
+ sums->len = bytes_left;
+ ordered = btrfs_lookup_ordered_extent(inode, offset);
+ BUG_ON(!ordered); /* Logic error */
+ sums->bytenr = ((u64)bio->bi_sector << 9) +
+ total_bytes;
+ index = 0;
+ }
- sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
- GFP_NOFS);
- BUG_ON(!sums); /* -ENOMEM */
- sums->len = bytes_left;
- ordered = btrfs_lookup_ordered_extent(inode, offset);
- BUG_ON(!ordered); /* Logic error */
- sums->bytenr = ((u64)bio->bi_sector << 9) +
- total_bytes;
- index = 0;
+ sums->sums[index] = ~(u32)0;
+ sums->sums[index]
+ = btrfs_csum_data(data + bvec->bv_offset + (i * root->sectorsize),
+ sums->sums[index],
+ root->sectorsize);
+ btrfs_csum_final(sums->sums[index],
+ (char *)(sums->sums + index));
+ index++;
+ offset += root->sectorsize;
+ this_sum_bytes += root->sectorsize;
+ total_bytes += root->sectorsize;
}
- data = kmap_atomic(bvec->bv_page);
- sums->sums[index] = ~(u32)0;
- sums->sums[index] = btrfs_csum_data(data + bvec->bv_offset,
- sums->sums[index],
- bvec->bv_len);
kunmap_atomic(data);
- btrfs_csum_final(sums->sums[index],
- (char *)(sums->sums + index));
bio_index++;
- index++;
- total_bytes += bvec->bv_len;
- this_sum_bytes += bvec->bv_len;
- offset += bvec->bv_len;
bvec++;
}
this_sum_bytes = 0;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread