xfs: fix fallocate functions when rtextsize is larger than 1

In commit fe341eb151ec, I forgot that xfs_free_file_space isn't strictly
a "remove mapped blocks" function.  It is actually a function to zero
file space by punching out the middle and writing zeroes to the
unaligned ends of the specified range.  Therefore, putting a rtextsize
alignment check in that function is wrong because that breaks unaligned
ZERO_RANGE on the realtime volume.

Furthermore, xfs_file_fallocate already has alignment checks for the
functions require the file range to be aligned to the size of a
fundamental allocation unit (which is 1 FSB on the data volume and 1 rt
extent on the realtime volume).  Create a new helper to check fallocate
arguments against the realtiem allocation unit size, fix the fallocate
frontend to use it, fix free_file_space to delete the correct range, and
remove a now redundant check from insert_file_space.

NOTE: The realtime extent size is not required to be a power of two!

Fixes: fe341eb151ec ("xfs: ensure that fpunch, fcollapse, and finsert operations are aligned to rt extent size")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>

1 files changed, 5 insertions, 13 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index f2a8a0e75e1f..7371a7f7c652 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -947,11 +947,11 @@ xfs_free_file_space(
 	endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
 
 	/* We can only free complete realtime extents. */
-	if (XFS_IS_REALTIME_INODE(ip)) {
-		xfs_extlen_t	extsz = xfs_get_extsz_hint(ip);
-
-		if ((startoffset_fsb | endoffset_fsb) & (extsz - 1))
-			return -EINVAL;
+	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
+		startoffset_fsb = roundup_64(startoffset_fsb,
+					     mp->m_sb.sb_rextsize);
+		endoffset_fsb = rounddown_64(endoffset_fsb,
+					     mp->m_sb.sb_rextsize);
 	}
 
 	/*
@@ -1147,14 +1147,6 @@ xfs_insert_file_space(
 
 	trace_xfs_insert_file_space(ip);
 
-	/* We can only insert complete realtime extents. */
-	if (XFS_IS_REALTIME_INODE(ip)) {
-		xfs_extlen_t	extsz = xfs_get_extsz_hint(ip);
-
-		if ((stop_fsb | shift_fsb) & (extsz - 1))
-			return -EINVAL;
-	}
-
 	error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
 	if (error)
 		return error;