From ad747e3b299671e1a53db74963cc6c5f6cdb9f6d Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Wed, 6 Apr 2016 07:06:20 +1000 Subject: [PATCH] xfs: Don't wrap growfs AGFL indexes Commit 96f859d ("libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correct") allowed the freelist to use the empty slot at the end of the freelist on 64 bit systems that was not being used due to sizeof() rounding up the structure size. This has caused versions of xfs_repair prior to 4.5.0 (which also has the fix) to report this as a corruption once the filesystem has been grown. Older kernels can also have problems (seen from a whacky container/vm management environment) mounting filesystems grown on a system with a newer kernel than the vm/container it is deployed on. To avoid this problem, change the initial free list indexes not to wrap across the end of the AGFL, hence avoiding the initialisation of agf_fllast to the last index in the AGFL. cc: # 4.4-4.5 Signed-off-by: Dave Chinner Reviewed-by: Carlos Maiolino Signed-off-by: Dave Chinner --- fs/xfs/xfs_fsops.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index ee3aaa0a5317..ca0d3eb44925 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -243,8 +243,8 @@ xfs_growfs_data_private( agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp)); agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1); agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1); - agf->agf_flfirst = 0; - agf->agf_fllast = cpu_to_be32(XFS_AGFL_SIZE(mp) - 1); + agf->agf_flfirst = cpu_to_be32(1); + agf->agf_fllast = 0; agf->agf_flcount = 0; tmpsize = agsize - XFS_PREALLOC_BLOCKS(mp); agf->agf_freeblks = cpu_to_be32(tmpsize);