From ce748eaa65f2e9392ba82726503c8d994ffd6393 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Wed, 29 Jul 2015 11:53:31 +1000 Subject: xfs: create new metadata UUID field and incompat flag This adds a new superblock field, sb_meta_uuid. If set, along with a new incompat flag, the code will use that field on a V5 filesystem to compare to metadata UUIDs, which allows us to change the user- visible UUID at will. Userspace handles the setting and clearing of the incompat flag as appropriate, as the UUID gets changed; i.e. setting the user-visible UUID back to the original UUID (as stored in the new field) will remove the incompatible feature flag. If the incompat flag is not set, this copies the user-visible UUID into into the meta_uuid slot in memory when the superblock is read from disk; the meta_uuid field is not written back to disk in this case. The remainder of this patch simply switches verifiers, initializers, etc to use the new sb_meta_uuid field. Signed-off-by: Eric Sandeen Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_alloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/xfs/libxfs/xfs_alloc.c') diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index f9e9ffe6fb46..b7fc17ce8233 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -464,7 +464,7 @@ xfs_agfl_verify( struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp); int i; - if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_uuid)) + if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid)) return false; if (be32_to_cpu(agfl->agfl_magicnum) != XFS_AGFL_MAGIC) return false; @@ -2260,7 +2260,7 @@ xfs_agf_verify( struct xfs_agf *agf = XFS_BUF_TO_AGF(bp); if (xfs_sb_version_hascrc(&mp->m_sb) && - !uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_uuid)) + !uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid)) return false; if (!(agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) && -- cgit v1.2.3