For the subpagesize-blocksize scenario, This patch adds the ability to write a
single extent buffer to the disk.
Signed-off-by: Chandan Rajendra <chan...@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 5d23935..7f88dbd 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3495,32 +3495,53 @@ 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);
}
@@ -3531,27 +3552,25 @@ 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;
@@ -3638,13 +3657,14 @@ 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;
@@ -3652,14 +3672,52 @@ 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);
}
@@ -3676,22 +3734,23 @@ 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;
@@ -3702,13 +3761,14 @@ 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;
@@ -3728,12 +3788,85 @@ 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,
@@ -3744,6 +3877,7 @@ 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;
@@ -3770,7 +3904,7 @@ 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++) {
@@ -3802,30 +3936,79 @@ 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
--
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