This uses a chunk of code from btrfs_read_dev_super() and creates
a function called btrfs_read_dev_one_super() so that next patch
can use it for scratch superblock.
Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
fs/btrfs/disk-io.c | 54 ++++++++++++++++++++++++++++++++++--------------------
fs/btrfs/disk-io.h | 2 ++
2 files changed, 36 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f47c643..3681e1e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3085,6 +3085,37 @@ static void btrfs_end_buffer_write_sync(struct
buffer_head *bh, int uptodate)
put_bh(bh);
}
+int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num,
+ struct buffer_head **bh)
+{
+ struct buffer_head *bufhead;
+ struct btrfs_super_block *super;
+ u64 bytenr;
+
+ bytenr = btrfs_sb_offset(copy_num);
+ if (bytenr + BTRFS_SUPER_INFO_SIZE >= i_size_read(bdev->bd_inode))
+ return -EINVAL;
+
+ bufhead = __bread(bdev, bytenr / 4096, BTRFS_SUPER_INFO_SIZE);
+ /*
+ * If we fail to read from the underlaying drivers, as of now
+ * the best option we have is to mark it EIO.
+ */
+ if (!bufhead)
+ return -EIO;
+
+ super = (struct btrfs_super_block *)bufhead->b_data;
+ if (btrfs_super_bytenr(super) != bytenr ||
+ btrfs_super_magic(super) != BTRFS_MAGIC) {
+ brelse(bufhead);
+ return -EINVAL;
+ }
+
+ *bh = bufhead;
+ return 0;
+}
+
+
struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
{
struct buffer_head *bh;
@@ -3092,7 +3123,6 @@ struct buffer_head *btrfs_read_dev_super(struct
block_device *bdev)
struct btrfs_super_block *super;
int i;
u64 transid = 0;
- u64 bytenr;
int ret = -EINVAL;
/* we would like to check all the supers, but that would make
@@ -3101,28 +3131,12 @@ struct buffer_head *btrfs_read_dev_super(struct
block_device *bdev)
* later supers, using BTRFS_SUPER_MIRROR_MAX instead
*/
for (i = 0; i < 1; i++) {
- bytenr = btrfs_sb_offset(i);
- if (bytenr + BTRFS_SUPER_INFO_SIZE >=
- i_size_read(bdev->bd_inode))
- break;
- bh = __bread(bdev, bytenr / 4096,
- BTRFS_SUPER_INFO_SIZE);
- /*
- * If we fail to read from the underlaying drivers, as of now
- * the best option we have is to mark it EIO.
- */
- if (!bh) {
- ret = -EIO;
+
+ ret = btrfs_read_dev_one_super(bdev, i, &bh);
+ if (ret)
continue;
- }
super = (struct btrfs_super_block *)bh->b_data;
- if (btrfs_super_bytenr(super) != bytenr ||
- btrfs_super_magic(super) != BTRFS_MAGIC) {
- brelse(bh);
- ret = -EINVAL;
- continue;
- }
if (!latest || btrfs_super_generation(super) > transid) {
brelse(latest);
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 27d44c0..36bd1fc 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -60,6 +60,8 @@ void close_ctree(struct btrfs_root *root);
int write_ctree_super(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int max_mirrors);
struct buffer_head *btrfs_read_dev_super(struct block_device *bdev);
+int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num,
+ struct buffer_head **bh);
int btrfs_commit_super(struct btrfs_root *root);
struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
u64 bytenr);
--
2.0.0.153.g79dcccc
--
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