From 02f75405a75eadfb072609f6bf839e027de6a29a Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Mon, 27 May 2013 16:38:24 +1000 Subject: [PATCH] xfs: disable swap extents ioctl on CRC enabled filesystems Currently, swapping extents from one inode to another is a simple act of switching data and attribute forks from one inode to another. This, unfortunately in no longer so simple with CRC enabled filesystems as there is owner information embedded into the BMBT blocks that are swapped between inodes. Hence swapping the forks between inodes results in the inodes having mapping blocks that point to the wrong owner and hence are considered corrupt. To fix this we need an extent tree block or record based swap algorithm so that the BMBT block owner information can be updated atomically in the swap transaction. This is a significant piece of new work, so for the moment simply don't allow swap extent operations to succeed on CRC enabled filesystems. Signed-off-by: Dave Chinner Reviewed-by: Ben Myers Reviewed-by: Brian Foster Signed-off-by: Ben Myers --- fs/xfs/xfs_dfrag.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c index f852b082a084..c407e1ccff43 100644 --- a/fs/xfs/xfs_dfrag.c +++ b/fs/xfs/xfs_dfrag.c @@ -219,6 +219,14 @@ xfs_swap_extents( int taforkblks = 0; __uint64_t tmp; + /* + * We have no way of updating owner information in the BMBT blocks for + * each inode on CRC enabled filesystems, so to avoid corrupting the + * this metadata we simply don't allow extent swaps to occur. + */ + if (xfs_sb_version_hascrc(&mp->m_sb)) + return XFS_ERROR(EINVAL); + tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL); if (!tempifp) { error = XFS_ERROR(ENOMEM); -- 2.20.1