Messages in this thread | | | Date | Tue, 11 Sep 2012 07:14:34 +0200 | From | Goffredo Baroncelli <> | Subject | Re: [PATCH] btrfs: fix disk-io.c/btrfs_read_dev_super with BTRFS_SUPER_MIRROR_MAX to control the loops |
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Hi,
On 09/10/2012 08:38 AM, Wang Sheng-Hui wrote: > To check the duplicated super blocks, use BTRFS_SUPER_MIRROR_MAX > as the loops limit. > > Signed-off-by: Wang Sheng-Hui<shhuiw@gmail.com> > --- > fs/btrfs/disk-io.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 22e98e0..a431144 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -2723,7 +2723,7 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev) > * So, we need to add a special mount option to scan for > * later supers, using BTRFS_SUPER_MIRROR_MAX instead > */ > - for (i = 0; i< 1; i++) { > + for (i = 0; i< BTRFS_SUPER_MIRROR_MAX; i++) { > bytenr = btrfs_sb_offset(i); > if (bytenr + 4096>= i_size_read(bdev->bd_inode)) > break;
Pay attention that when a device is removed from a filesystem by the command "btrfs device delete", *only* the 1st superblock btrfs signature is zeroed [1]. This means that the other (backup) superblocks will be considered valid with your change.
[1] See the function btrfs_rm_device() in volume.c
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