Btrfs: Handle checksumming errors while reading data blocks
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8c2d5d0..48f1d1b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -385,6 +385,86 @@
return ret;
}
+struct io_failure_record {
+ struct page *page;
+ u64 start;
+ u64 len;
+ u64 logical;
+ int last_mirror;
+};
+
+int btrfs_readpage_io_failed_hook(struct bio *failed_bio,
+ struct page *page, u64 start, u64 end,
+ struct extent_state *state)
+{
+ struct io_failure_record *failrec = NULL;
+ u64 private;
+ struct extent_map *em;
+ struct inode *inode = page->mapping->host;
+ struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
+ struct bio *bio;
+ int num_copies;
+ int ret;
+ u64 logical;
+
+ ret = get_state_private(failure_tree, start, &private);
+ if (ret) {
+ size_t pg_offset = start - page_offset(page);
+ failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
+ if (!failrec)
+ return -ENOMEM;
+ failrec->start = start;
+ failrec->len = end - start + 1;
+ failrec->last_mirror = 0;
+
+ em = btrfs_get_extent(inode, NULL, pg_offset, start,
+ failrec->len, 0);
+
+ if (!em || IS_ERR(em)) {
+ kfree(failrec);
+ return -EIO;
+ }
+ logical = start - em->start;
+ logical = em->block_start + logical;
+ failrec->logical = logical;
+ free_extent_map(em);
+ set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
+ EXTENT_DIRTY, GFP_NOFS);
+ set_state_private(failure_tree, start, (u64)failrec);
+ } else {
+ failrec = (struct io_failure_record *)private;
+ }
+ num_copies = btrfs_num_copies(
+ &BTRFS_I(inode)->root->fs_info->mapping_tree,
+ failrec->logical, failrec->len);
+ failrec->last_mirror++;
+ if (!state) {
+ spin_lock_irq(&BTRFS_I(inode)->io_tree.lock);
+ state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
+ failrec->start,
+ EXTENT_LOCKED);
+ if (state && state->start != failrec->start)
+ state = NULL;
+ spin_unlock_irq(&BTRFS_I(inode)->io_tree.lock);
+ }
+ if (!state || failrec->last_mirror > num_copies) {
+ set_state_private(failure_tree, failrec->start, 0);
+ clear_extent_bits(failure_tree, failrec->start,
+ failrec->start + failrec->len - 1,
+ EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
+ kfree(failrec);
+ return -EIO;
+ }
+ bio = bio_alloc(GFP_NOFS, 1);
+ bio->bi_private = state;
+ bio->bi_end_io = failed_bio->bi_end_io;
+ bio->bi_sector = failrec->logical >> 9;
+ bio->bi_bdev = failed_bio->bi_bdev;
+ bio_add_page(bio, page, failrec->len, start - page_offset(page));
+ btrfs_submit_bio_hook(inode, READ, bio, failrec->last_mirror);
+ return 0;
+}
+
int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
struct extent_state *state)
{
@@ -419,6 +499,29 @@
}
kunmap_atomic(kaddr, KM_IRQ0);
local_irq_restore(flags);
+
+ /* if the io failure tree for this inode is non-empty,
+ * check to see if we've recovered from a failed IO
+ */
+ private = 0;
+ if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
+ (u64)-1, 1, EXTENT_DIRTY)) {
+ u64 private_failure;
+ struct io_failure_record *failure;
+ ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
+ start, &private_failure);
+ if (ret == 0) {
+ failure = (struct io_failure_record *)private_failure;
+ set_state_private(&BTRFS_I(inode)->io_failure_tree,
+ failure->start, 0);
+ clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
+ failure->start,
+ failure->start + failure->len - 1,
+ EXTENT_DIRTY | EXTENT_LOCKED,
+ GFP_NOFS);
+ kfree(failure);
+ }
+ }
return 0;
zeroit:
@@ -429,7 +532,7 @@
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_IRQ0);
local_irq_restore(flags);
- return 0;
+ return -EIO;
}
void btrfs_read_locked_inode(struct inode *inode)
@@ -1271,6 +1374,8 @@
extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
extent_io_tree_init(&BTRFS_I(inode)->io_tree,
inode->i_mapping, GFP_NOFS);
+ extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
+ inode->i_mapping, GFP_NOFS);
return 0;
}
@@ -1578,6 +1683,8 @@
extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
extent_io_tree_init(&BTRFS_I(inode)->io_tree,
inode->i_mapping, GFP_NOFS);
+ extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
+ inode->i_mapping, GFP_NOFS);
BTRFS_I(inode)->delalloc_bytes = 0;
BTRFS_I(inode)->root = root;
@@ -1803,6 +1910,8 @@
extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
extent_io_tree_init(&BTRFS_I(inode)->io_tree,
inode->i_mapping, GFP_NOFS);
+ extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
+ inode->i_mapping, GFP_NOFS);
BTRFS_I(inode)->delalloc_bytes = 0;
BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
}
@@ -2972,6 +3081,8 @@
extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
extent_io_tree_init(&BTRFS_I(inode)->io_tree,
inode->i_mapping, GFP_NOFS);
+ extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
+ inode->i_mapping, GFP_NOFS);
BTRFS_I(inode)->delalloc_bytes = 0;
BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
}
@@ -3070,6 +3181,7 @@
.merge_bio_hook = btrfs_merge_bio_hook,
.readpage_io_hook = btrfs_readpage_io_hook,
.readpage_end_io_hook = btrfs_readpage_end_io_hook,
+ .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
.set_bit_hook = btrfs_set_bit_hook,
.clear_bit_hook = btrfs_clear_bit_hook,
};