From db1327b16c2b24e28d1e5899bced89db9ae6538e Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 3 Oct 2016 09:11:36 -0700 Subject: xfs: report shared extent mappings to userspace correctly Report shared extents through the iomap interface so that FIEMAP flags shared blocks accurately. Have xfs_vm_bmap return zero for reflinked files because the bmap-based swap code requires static block mappings, which is incompatible with copy on write. NOTE: Existing userspace bmap users such as lilo will have the same problem with reflink files. Signed-off-by: Christoph Hellwig Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_iomap.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_iomap.c') diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index ad6939df9680..765849ed9b70 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -961,6 +961,7 @@ xfs_file_iomap_begin( struct xfs_mount *mp = ip->i_mount; struct xfs_bmbt_irec imap; xfs_fileoff_t offset_fsb, end_fsb; + bool shared, trimmed; int nimaps = 1, error = 0; unsigned lockmode; @@ -989,7 +990,14 @@ xfs_file_iomap_begin( end_fsb = XFS_B_TO_FSB(mp, offset + length); error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap, - &nimaps, XFS_BMAPI_ENTIRE); + &nimaps, 0); + if (error) { + xfs_iunlock(ip, lockmode); + return error; + } + + /* Trim the mapping to the nearest shared extent boundary. */ + error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed); if (error) { xfs_iunlock(ip, lockmode); return error; @@ -1028,6 +1036,8 @@ xfs_file_iomap_begin( } xfs_bmbt_to_iomap(ip, iomap, &imap); + if (shared) + iomap->flags |= IOMAP_F_SHARED; return 0; } -- cgit v1.2.3