xfs: introduce xfs_aligned_fsb_count

Factor a helper to calculate the extent-size aligned block out of the
iomap code, so that it can be reused by the upcoming reflink dio code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 52d9d1f..06bfc82 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -162,7 +162,7 @@ xfs_iomap_write_direct(
        xfs_fileoff_t   last_fsb;
        xfs_filblks_t   count_fsb, resaligned;
        xfs_fsblock_t   firstfsb;
-       xfs_extlen_t    extsz, temp;
+       xfs_extlen_t    extsz;
        int             nimaps;
        int             quota_flag;
        int             rt;
@@ -203,14 +203,7 @@ xfs_iomap_write_direct(
        }
        count_fsb = last_fsb - offset_fsb;
        ASSERT(count_fsb > 0);
-
-       resaligned = count_fsb;
-       if (unlikely(extsz)) {
-               if ((temp = do_mod(offset_fsb, extsz)))
-                       resaligned += temp;
-               if ((temp = do_mod(resaligned, extsz)))
-                       resaligned += extsz - temp;
-       }
+       resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb, extsz);
 
        if (unlikely(rt)) {
                resrtextents = qblocks = resaligned;

diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 705224b..00db3ec 100644 (file)
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -33,6 +33,26 @@ void xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
                struct xfs_bmbt_irec *);
 xfs_extlen_t xfs_eof_alignment(struct xfs_inode *ip, xfs_extlen_t extsize);
 
+static inline xfs_filblks_t
+xfs_aligned_fsb_count(
+       xfs_fileoff_t           offset_fsb,
+       xfs_filblks_t           count_fsb,
+       xfs_extlen_t            extsz)
+{
+       if (extsz) {
+               xfs_extlen_t    align;
+
+               align = do_mod(offset_fsb, extsz);
+               if (align)
+                       count_fsb += align;
+               align = do_mod(count_fsb, extsz);
+               if (align)
+                       count_fsb += extsz - align;
+       }
+
+       return count_fsb;
+}
+
 extern const struct iomap_ops xfs_iomap_ops;
 extern const struct iomap_ops xfs_xattr_iomap_ops;