xfs: fix fallocate functions when rtextsize is larger than 1rt-fixes-5.10_2020-10-10

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 return the
desired 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.

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>

4 files changed, 22 insertions, 19 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index f2a8a0e75e1f..52cddcfee8a1 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -947,11 +947,10 @@ 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 > 0) {
+		startoffset_fsb = round_up(startoffset_fsb,
+					   mp->m_sb.sb_rextsize);
+		endoffset_fsb = round_down(endoffset_fsb, mp->m_sb.sb_rextsize);
 	}
 
 	/*
@@ -1147,14 +1146,6 @@ 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;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 3d1b95124744..e9b4b1dada75 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -803,6 +803,8 @@ xfs_file_fallocate(
 	enum xfs_prealloc_flags	flags = 0;
 	uint			iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
 	loff_t			new_size = 0;
+	unsigned int		blksize = xfs_inode_alloc_blocksize(ip);
+	unsigned int		blkmask = blksize - 1;
 	bool			do_file_insert = false;
 
 	if (!S_ISREG(inode->i_mode))
@@ -850,9 +852,7 @@ xfs_file_fallocate(
 		if (error)
 			goto out_unlock;
 	} else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
-		unsigned int blksize_mask = i_blocksize(inode) - 1;
-
-		if (offset & blksize_mask || len & blksize_mask) {
+		if ((offset | len) & blkmask) {
 			error = -EINVAL;
 			goto out_unlock;
 		}
@@ -872,10 +872,9 @@ xfs_file_fallocate(
 		if (error)
 			goto out_unlock;
 	} else if (mode & FALLOC_FL_INSERT_RANGE) {
-		unsigned int	blksize_mask = i_blocksize(inode) - 1;
 		loff_t		isize = i_size_read(inode);
 
-		if (offset & blksize_mask || len & blksize_mask) {
+		if ((offset | len) & blkmask) {
 			error = -EINVAL;
 			goto out_unlock;
 		}
@@ -917,7 +916,6 @@ xfs_file_fallocate(
 			 *   2.) If prealloc returns ENOSPC, the file range is
 			 *       still zero-valued by virtue of the hole punch.
 			 */
-			unsigned int blksize = i_blocksize(inode);
 
 			trace_xfs_zero_file_space(ip);
 
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 2bfbcf28b1bd..20bb5fae0d00 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3813,3 +3813,16 @@ xfs_iunlock2_io_mmap(
 	if (!same_inode)
 		inode_unlock(VFS_I(ip1));
 }
+
+/* Returns the size of fundamental allocation unit for a file, in bytes. */
+unsigned int
+xfs_inode_alloc_blocksize(
+	struct xfs_inode	*ip)
+{
+	unsigned int		blocks = 1;
+
+	if (XFS_IS_REALTIME_INODE(ip))
+		blocks = ip->i_mount->m_sb.sb_rextsize;
+
+	return XFS_FSB_TO_B(ip->i_mount, blocks);
+}
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 751a3d1d7d84..270b35d9dcb0 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -475,5 +475,6 @@ void xfs_end_io(struct work_struct *work);
 
 int xfs_ilock2_io_mmap(struct xfs_inode *ip1, struct xfs_inode *ip2);
 void xfs_iunlock2_io_mmap(struct xfs_inode *ip1, struct xfs_inode *ip2);
+unsigned int xfs_inode_alloc_blocksize(struct xfs_inode *ip);
 
 #endif	/* __XFS_INODE_H__ */