Btrfs: SB read failure should return EIO for __bread failure

This will return EIO when __bread() fails to read SB,
instead of EINVAL.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7673473..357d9f9 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2653,8 +2653,8 @@ int open_ctree(struct super_block *sb,
         * Read super block and check the signature bytes only
         */
        bh = btrfs_read_dev_super(fs_devices->latest_bdev);
-       if (!bh) {
-               err = -EINVAL;
+       if (IS_ERR(bh)) {
+               err = PTR_ERR(bh);
                goto fail_alloc;
        }
 
@@ -3196,6 +3196,7 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
        int i;
        u64 transid = 0;
        u64 bytenr;
+       int ret = -EINVAL;
 
        /* we would like to check all the supers, but that would make
         * a btrfs mount succeed after a mkfs from a different FS.
@@ -3209,13 +3210,20 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
                        break;
                bh = __bread(bdev, bytenr / 4096,
                                        BTRFS_SUPER_INFO_SIZE);
-               if (!bh)
+               /*
+                * If we fail to read from the underlying devices, as of now
+                * the best option we have is to mark it EIO.
+                */
+               if (!bh) {
+                       ret = -EIO;
                        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;
                }
 
@@ -3227,6 +3235,10 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
                        brelse(bh);
                }
        }
+
+       if (!latest)
+               return ERR_PTR(ret);
+
        return latest;
 }
 

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 6438792..e8a6182 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -211,8 +211,8 @@ btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
        }
        invalidate_bdev(*bdev);
        *bh = btrfs_read_dev_super(*bdev);
-       if (!*bh) {
-               ret = -EINVAL;
+       if (IS_ERR(*bh)) {
+               ret = PTR_ERR(*bh);
                blkdev_put(*bdev, flags);
                goto error;
        }
@@ -6746,8 +6746,8 @@ int btrfs_scratch_superblock(struct btrfs_device *device)
        struct btrfs_super_block *disk_super;
 
        bh = btrfs_read_dev_super(device->bdev);
-       if (!bh)
-               return -EINVAL;
+       if (IS_ERR(bh))
+               return PTR_ERR(bh);
        disk_super = (struct btrfs_super_block *)bh->b_data;
 
        memset(&disk_super->magic, 0, sizeof(disk_super->magic));