In the case of subpage-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 <chan...@linux.vnet.ibm.com>
---
fs/btrfs/disk-io.c | 52 ++++++++-------------
fs/btrfs/disk-io.h | 3 ++
fs/btrfs/extent_io.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++----
3 files changed, 142 insertions(+), 41 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 299f353..b09d3e3 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -612,29 +612,36 @@ 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 address_space *mapping =
(io_bio->bio).bi_io_vec->bv_page->mapping;
+ struct extent_buffer_head *ebh;
struct extent_buffer *eb;
- struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
+ struct btrfs_root *root = BTRFS_I(mapping->host)->root;
struct btrfs_fs_info *fs_info = root->fs_info;
- int ret = 0;
+ u64 found_start;
+ int found_level;
int reads_done;
-
- if (!page->private)
- goto out;
+ int ret = 0;
eb = (struct extent_buffer *)page->private;
+ do {
+ if ((eb->start <= start) && (eb->start + eb->len - 1 > start))
+ break;
+ } while ((eb = eb->eb_next) != NULL);
+
+ ASSERT(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_head(eb)->io_bvecs);
+ reads_done = atomic_dec_and_test(&ebh->io_bvecs);
if (!reads_done)
goto err;
@@ -690,30 +697,13 @@ err:
btree_readahead_hook(fs_info, eb, eb->start, ret);
if (ret) {
- /*
- * our io error hook is going to dec the io pages
- * again, we have to make sure it has something
- * to decrement
- */
atomic_inc(&eb_head(eb)->io_bvecs);
clear_extent_buffer_uptodate(eb);
}
- free_extent_buffer(eb);
-out:
- return ret;
-}
-static int btree_io_failed_hook(struct page *page, int failed_mirror)
-{
- struct extent_buffer *eb;
+ free_extent_buffer(eb);
- eb = (struct extent_buffer *)page->private;
- set_bit(EXTENT_BUFFER_READ_ERR, &eb->ebflags);
- eb->read_mirror = failed_mirror;
- atomic_dec(&eb_head(eb)->io_bvecs);
- if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->ebflags))
- btree_readahead_hook(eb_head(eb)->fs_info, eb, eb->start, -EIO);
- return -EIO; /* we fixed nothing */
+ return ret;
}
static void end_workqueue_bio(struct bio *bio)
@@ -4534,8 +4524,6 @@ static int btrfs_cleanup_transaction(struct btrfs_root
*root)
}
static const 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 acba821..a81ff8d 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -113,6 +113,9 @@ 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 080baf7..a425f90 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"
@@ -2207,7 +2208,7 @@ int repair_eb_io_failure(struct btrfs_root *root, struct
extent_buffer *eb,
struct page *p = eb_head(eb)->pages[i];
ret = repair_io_failure(root->fs_info->btree_inode, start,
- PAGE_SIZE, start, p,
+ eb->len, start, p,
start - page_offset(p), mirror_num);
if (ret)
break;
@@ -3794,6 +3795,80 @@ lock_extent_buffer_for_io(struct extent_buffer *eb,
return ret;
}
+static void end_bio_extent_buffer_readpage(struct bio *bio)
+{
+ 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 extent_buffer *eb;
+ struct btrfs_root *root;
+ struct bio_vec *bvec;
+ struct page *page;
+ int uptodate = !bio->bi_error;
+ u64 start;
+ u64 end;
+ int mirror;
+ int ret;
+ int i;
+
+ bio_for_each_segment_all(bvec, bio, i) {
+ page = bvec->bv_page;
+ root = BTRFS_I(page->mapping->host)->root;
+
+ start = page_offset(page) + bvec->bv_offset;
+ end = start + bvec->bv_len - 1;
+
+ if (!page->private) {
+ unlock_page(page);
+ clear_extent_bit(tree, start, end,
+ EXTENT_LOCKED, 1, 0, NULL,
+ GFP_ATOMIC);
+ continue;
+ }
+
+ eb = (struct extent_buffer *)page->private;
+
+ 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_READ_ERR, &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->fs_info, eb,
eb->start,
+ -EIO);
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+
+ unlock_page(page);
+ clear_extent_bit(tree, start, end,
+ EXTENT_LOCKED, 1, 0, NULL, GFP_ATOMIC);
+ }
+
+ bio_put(bio);
+}
+
static void end_extent_buffer_writeback(struct extent_buffer *eb)
{
clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->ebflags);
@@ -5535,6 +5610,8 @@ 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;
+ struct btrfs_fs_info *fs_info;
unsigned long i;
unsigned long start_i;
struct page *page;
@@ -5550,6 +5627,9 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->ebflags))
return 0;
+ inode = tree->mapping->host;
+ fs_info = BTRFS_I(inode)->root->fs_info;
+
if (start) {
WARN_ON(start < eb->start);
start_i = (start >> PAGE_SHIFT) -
@@ -5562,10 +5642,17 @@ int read_extent_buffer_pages(struct extent_io_tree
*tree,
for (i = start_i; i < num_pages; i++) {
page = eb_head(eb)->pages[i];
if (wait == WAIT_NONE) {
- if (!trylock_page(page))
+ if (!trylock_page(page)) {
goto unlock_exit;
+ } else {
+ if (PageWriteback(page)) {
+ unlock_page(page);
+ goto unlock_exit;
+ }
+ }
} else {
lock_page(page);
+ wait_on_page_writeback(page);
}
locked_pages++;
if (!PageUptodate(page)) {
@@ -5586,14 +5673,36 @@ int read_extent_buffer_pages(struct extent_io_tree
*tree,
page = eb_head(eb)->pages[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_SIZE) {
+ lock_extent_bits(tree, eb->start, eb->start +
eb->len - 1,
+ NULL);
+ err = submit_extent_page(READ | REQ_META, tree,
+ NULL, 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, false);
+ } else {
+ lock_extent_bits(tree, page_offset(page),
+ page_offset(page) + PAGE_SIZE -
1,
+ NULL);
+ err = submit_extent_page(READ | REQ_META, tree,
+ NULL, page,
+ page_offset(page) >> 9,
+ PAGE_SIZE, 0,
+
fs_info->fs_devices->latest_bdev,
+ &bio, -1,
+
end_bio_extent_buffer_readpage,
+ mirror_num, bio_flags,
+ bio_flags, false);
+ }
if (err) {
ret = err;
/*
- * We use &bio in above __extent_read_full_page,
+ * We use &bio in above submit_extent_page,
* so we ensure that if it returns error, the
* current page fails to add itself to bio.
*
@@ -5619,10 +5728,11 @@ int read_extent_buffer_pages(struct extent_io_tree
*tree,
for (i = start_i; i < num_pages; i++) {
page = eb_head(eb)->pages[i];
wait_on_page_locked(page);
- if (!PageUptodate(page))
- ret = -EIO;
}
+ if (!extent_buffer_uptodate(eb))
+ ret = -EIO;
+
return ret;
unlock_exit:
--
2.5.5
--
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