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_ialloc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs/xfs/libxfs/xfs_ialloc.c') diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c index 66efc702452a..ce63e0431f3e 100644 --- a/fs/xfs/libxfs/xfs_ialloc.c +++ b/fs/xfs/libxfs/xfs_ialloc.c @@ -338,7 +338,8 @@ xfs_ialloc_inode_init( if (version == 3) { free->di_ino = cpu_to_be64(ino); ino++; - uuid_copy(&free->di_uuid, &mp->m_sb.sb_uuid); + uuid_copy(&free->di_uuid, + &mp->m_sb.sb_meta_uuid); xfs_dinode_calc_crc(mp, free); } else if (tp) { /* just log the inode core */ @@ -2500,7 +2501,7 @@ xfs_agi_verify( struct xfs_agi *agi = XFS_BUF_TO_AGI(bp); if (xfs_sb_version_hascrc(&mp->m_sb) && - !uuid_equal(&agi->agi_uuid, &mp->m_sb.sb_uuid)) + !uuid_equal(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid)) return false; /* * Validate the magic number of the agi block. -- cgit v1.2.3