Btrfs: Retry metadata reads in the face of checksum failures
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 94ff87d..59bdf04 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -156,7 +156,6 @@
memcpy(&found, result, BTRFS_CRC32_SIZE);
read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
- WARN_ON(1);
printk("btrfs: %s checksum verify failed on %llu "
"wanted %X found %X from_this_trans %d "
"level %d\n",
@@ -171,6 +170,40 @@
return 0;
}
+static int btree_read_extent_buffer_pages(struct btrfs_root *root,
+ struct extent_buffer *eb,
+ u64 start)
+{
+ struct extent_io_tree *io_tree;
+ int ret;
+ int num_copies = 0;
+ int mirror_num = 0;
+
+ io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
+ while (1) {
+ ret = read_extent_buffer_pages(io_tree, eb, start, 1,
+ btree_get_extent, mirror_num);
+ if (!ret) {
+ if (mirror_num)
+printk("good read %Lu mirror %d total %d\n", eb->start, mirror_num, num_copies);
+ return ret;
+ }
+ num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
+ eb->start, eb->len);
+printk("failed to read %Lu mirror %d total %d\n", eb->start, mirror_num, num_copies);
+ if (num_copies == 1) {
+printk("reading %Lu failed only one copy\n", eb->start);
+ return ret;
+ }
+ mirror_num++;
+ if (mirror_num > num_copies) {
+printk("bailing at mirror %d of %d\n", mirror_num, num_copies);
+ return ret;
+ }
+ }
+printk("read extent buffer page last\n");
+ return -EIO;
+}
int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
{
@@ -180,6 +213,8 @@
int found_level;
unsigned long len;
struct extent_buffer *eb;
+ int ret;
+
tree = &BTRFS_I(page->mapping->host)->io_tree;
if (page->private == EXTENT_PAGE_PRIVATE)
@@ -191,8 +226,8 @@
WARN_ON(1);
}
eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
- read_extent_buffer_pages(tree, eb, start + PAGE_CACHE_SIZE, 1,
- btree_get_extent);
+ ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE);
+ BUG_ON(ret);
btrfs_clear_buffer_defrag(eb);
found_start = btrfs_header_bytenr(eb);
if (found_start != start) {
@@ -240,7 +275,7 @@
unsigned long len;
struct extent_buffer *eb;
struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
- int ret;
+ int ret = 0;
tree = &BTRFS_I(page->mapping->host)->io_tree;
if (page->private == EXTENT_PAGE_PRIVATE)
@@ -252,25 +287,26 @@
WARN_ON(1);
}
eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
- read_extent_buffer_pages(tree, eb, start + PAGE_CACHE_SIZE, 1,
- btree_get_extent);
+
btrfs_clear_buffer_defrag(eb);
found_start = btrfs_header_bytenr(eb);
if (found_start != start) {
- printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
- start, found_start, len);
- WARN_ON(1);
+printk("bad start on %Lu found %Lu\n", eb->start, found_start);
+ ret = -EIO;
goto err;
}
if (eb->first_page != page) {
printk("bad first page %lu %lu\n", eb->first_page->index,
page->index);
WARN_ON(1);
+ ret = -EIO;
goto err;
}
found_level = btrfs_header_level(eb);
ret = csum_tree_block(root, eb, 1);
+ if (ret)
+ ret = -EIO;
end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
end = eb->start + end - 1;
@@ -278,7 +314,7 @@
err:
free_extent_buffer(eb);
out:
- return 0;
+ return ret;
}
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
@@ -329,7 +365,8 @@
return 0;
}
-static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio)
+static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
+ int mirror_num)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 offset;
@@ -338,7 +375,7 @@
offset = bio->bi_sector << 9;
if (rw & (1 << BIO_RW)) {
- return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio);
+ return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num);
}
ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
@@ -349,7 +386,7 @@
submit_bio(rw, bio);
return 0;
}
- return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio);
+ return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num);
}
static int btree_writepage(struct page *page, struct writeback_control *wbc)
@@ -459,7 +496,7 @@
if (!buf)
return 0;
read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
- buf, 0, 0, btree_get_extent);
+ buf, 0, 0, btree_get_extent, 0);
free_extent_buffer(buf);
return ret;
}
@@ -522,8 +559,7 @@
if (!buf)
return NULL;
- ret = read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0,
- 1, btree_get_extent);
+ ret = btree_read_extent_buffer_pages(root, buf, 0);
if (ret == 0) {
buf->flags |= EXTENT_UPTODATE;
@@ -1366,10 +1402,8 @@
int btrfs_read_buffer(struct extent_buffer *buf)
{
struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
- struct inode *btree_inode = root->fs_info->btree_inode;
int ret;
- ret = read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
- buf, 0, 1, btree_get_extent);
+ ret = btree_read_extent_buffer_pages(root, buf, 0);
if (ret == 0) {
buf->flags |= EXTENT_UPTODATE;
}