Shaohua Li
2011-Jan-19 01:15 UTC
[PATCH v3 5/5] validate extent_buffer if it''s readahead in btrfs
do validation for extent_buffer if it''s skipped before
With metadata readahead, we slightly change the behavior. Before it, we allocate
an extent_buffer (so set page->private), do metadata read and
btree_readpage_end_io_hook() will do validation. After it, we directly do
metadata readahead, and since in this case page hasn''t ->private,
btree_readpage_end_io_hook() will not do validation. This patch fixes this.
It addes a new flag to indicate if a buffer is validated. If not and even
the buffer is uptodated, we will do a validation.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
---
fs/btrfs/disk-io.c | 71 ++++++++++++++++++++++++++++++-------------------
fs/btrfs/disk-io.h | 2 +
fs/btrfs/extent-tree.c | 1
fs/btrfs/extent_io.c | 14 ++++++++-
fs/btrfs/extent_io.h | 1
5 files changed, 60 insertions(+), 29 deletions(-)
Index: linux/fs/btrfs/disk-io.c
==================================================================---
linux.orig/fs/btrfs/disk-io.c 2011-01-18 10:53:07.000000000 +0800
+++ linux/fs/btrfs/disk-io.c 2011-01-18 11:16:41.000000000 +0800
@@ -424,12 +424,53 @@ void btrfs_set_buffer_lockdep_class(stru
}
#endif
+int btree_validate_extent_buffer(struct btrfs_root *root,
+ struct extent_buffer *eb)
+{
+ u64 found_start;
+ int found_level;
+ int ret = 0;
+
+ if (!test_bit(EXTENT_BUFFER_UNCHECKED, &eb->bflags))
+ return 0;
+
+ found_start = btrfs_header_bytenr(eb);
+ if (found_start != eb->start) {
+ if (printk_ratelimit()) {
+ printk(KERN_INFO "btrfs bad tree block start "
+ "%llu %llu\n",
+ (unsigned long long)found_start,
+ (unsigned long long)eb->start);
+ }
+ ret = -EIO;
+ goto err;
+ }
+
+ if (check_tree_block_fsid(root, eb)) {
+ if (printk_ratelimit()) {
+ printk(KERN_INFO "btrfs bad fsid on block %llu\n",
+ (unsigned long long)eb->start);
+ }
+ ret = -EIO;
+ goto err;
+ }
+ found_level = btrfs_header_level(eb);
+
+ btrfs_set_buffer_lockdep_class(eb, found_level);
+
+ ret = csum_tree_block(root, eb, 1);
+ if (ret)
+ ret = -EIO;
+err:
+ if (ret == 0)
+ clear_bit(EXTENT_BUFFER_UNCHECKED, &eb->bflags);
+ return ret;
+}
+
static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
struct extent_state *state)
{
struct extent_io_tree *tree;
- u64 found_start;
- int found_level;
unsigned long len;
struct extent_buffer *eb;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
@@ -450,17 +491,6 @@ static int btree_readpage_end_io_hook(st
goto out;
}
- found_start = btrfs_header_bytenr(eb);
- if (found_start != start) {
- if (printk_ratelimit()) {
- printk(KERN_INFO "btrfs bad tree block start "
- "%llu %llu\n",
- (unsigned long long)found_start,
- (unsigned long long)eb->start);
- }
- ret = -EIO;
- goto err;
- }
if (eb->first_page != page) {
printk(KERN_INFO "btrfs bad first page %lu %lu\n",
eb->first_page->index, page->index);
@@ -468,21 +498,8 @@ static int btree_readpage_end_io_hook(st
ret = -EIO;
goto err;
}
- if (check_tree_block_fsid(root, eb)) {
- if (printk_ratelimit()) {
- printk(KERN_INFO "btrfs bad fsid on block %llu\n",
- (unsigned long long)eb->start);
- }
- ret = -EIO;
- goto err;
- }
- found_level = btrfs_header_level(eb);
-
- btrfs_set_buffer_lockdep_class(eb, found_level);
- ret = csum_tree_block(root, eb, 1);
- if (ret)
- ret = -EIO;
+ ret = btree_validate_extent_buffer(root, eb);
end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
end = eb->start + end - 1;
Index: linux/fs/btrfs/disk-io.h
==================================================================---
linux.orig/fs/btrfs/disk-io.h 2011-01-18 10:53:07.000000000 +0800
+++ linux/fs/btrfs/disk-io.h 2011-01-18 10:57:54.000000000 +0800
@@ -36,6 +36,8 @@ static inline u64 btrfs_sb_offset(int mi
struct btrfs_device;
struct btrfs_fs_devices;
+int btree_validate_extent_buffer(struct btrfs_root *root,
+ struct extent_buffer *eb);
struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
u32 blocksize, u64 parent_transid);
int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
Index: linux/fs/btrfs/extent_io.c
==================================================================---
linux.orig/fs/btrfs/extent_io.c 2011-01-18 10:53:07.000000000 +0800
+++ linux/fs/btrfs/extent_io.c 2011-01-18 10:57:54.000000000 +0800
@@ -14,6 +14,7 @@
#include "extent_map.h"
#include "compat.h"
#include "ctree.h"
+#include "disk-io.h"
#include "btrfs_inode.h"
static struct kmem_cache *extent_state_cache;
@@ -3194,6 +3195,7 @@ struct extent_buffer *alloc_extent_buffe
uptodate = 0;
unlock_page(p);
}
+ set_bit(EXTENT_BUFFER_UNCHECKED, &eb->bflags);
if (uptodate)
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
@@ -3424,9 +3426,10 @@ int read_extent_buffer_pages(struct exte
unsigned long num_pages;
struct bio *bio = NULL;
unsigned long bio_flags = 0;
+ struct btrfs_root *root = BTRFS_I(tree->mapping->host)->root;
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
- return 0;
+ goto out;
if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
EXTENT_UPTODATE, 1, NULL)) {
@@ -3491,8 +3494,10 @@ int read_extent_buffer_pages(struct exte
ret = -EIO;
}
- if (!ret)
+ if (!ret) {
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
+ goto out;
+ }
return ret;
unlock_exit:
@@ -3503,6 +3508,11 @@ unlock_exit:
unlock_page(page);
locked_pages--;
}
+out:
+ if (!ret && test_bit(EXTENT_BUFFER_UNCHECKED, &eb->bflags)
&&
+ test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
+ return btree_validate_extent_buffer(root, eb);
+
return ret;
}
Index: linux/fs/btrfs/extent_io.h
==================================================================---
linux.orig/fs/btrfs/extent_io.h 2011-01-18 10:53:07.000000000 +0800
+++ linux/fs/btrfs/extent_io.h 2011-01-18 10:57:54.000000000 +0800
@@ -31,6 +31,7 @@
#define EXTENT_BUFFER_UPTODATE 0
#define EXTENT_BUFFER_BLOCKING 1
#define EXTENT_BUFFER_DIRTY 2
+#define EXTENT_BUFFER_UNCHECKED 3
/* these are flags for extent_clear_unlock_delalloc */
#define EXTENT_CLEAR_UNLOCK_PAGE 0x1
Index: linux/fs/btrfs/extent-tree.c
==================================================================---
linux.orig/fs/btrfs/extent-tree.c 2011-01-18 10:53:07.000000000 +0800
+++ linux/fs/btrfs/extent-tree.c 2011-01-18 10:57:54.000000000 +0800
@@ -5606,6 +5606,7 @@ struct extent_buffer *btrfs_init_new_buf
clean_tree_block(trans, root, buf);
btrfs_set_lock_blocking(buf);
+ clear_bit(EXTENT_BUFFER_UNCHECKED, &buf->bflags);
btrfs_set_buffer_uptodate(buf);
if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
--
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