Merge tag 'driver-core-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git...

[cascardo/linux.git] / fs / xfs / xfs_iomap.c

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index d907eb9..436e109 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -566,6 +566,17 @@ xfs_file_iomap_begin_delay(
        xfs_bmap_search_extents(ip, offset_fsb, XFS_DATA_FORK, &eof, &idx,
                        &got, &prev);
        if (!eof && got.br_startoff <= offset_fsb) {
+               if (xfs_is_reflink_inode(ip)) {
+                       bool            shared;
+
+                       end_fsb = min(XFS_B_TO_FSB(mp, offset + count),
+                                       maxbytes_fsb);
+                       xfs_trim_extent(&got, offset_fsb, end_fsb - offset_fsb);
+                       error = xfs_reflink_reserve_cow(ip, &got, &shared);
+                       if (error)
+                               goto out_unlock;
+               }
+
                trace_xfs_iomap_found(ip, offset, count, 0, &got);
                goto done;
        }
@@ -961,19 +972,13 @@ 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;
+       bool                    shared = false, trimmed = false;
        unsigned                lockmode;
 
        if (XFS_FORCED_SHUTDOWN(mp))
                return -EIO;
 
-       if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
-               error = xfs_reflink_reserve_cow_range(ip, offset, length);
-               if (error < 0)
-                       return error;
-       }
-
        if ((flags & IOMAP_WRITE) && !IS_DAX(inode) &&
                   !xfs_get_extsz_hint(ip)) {
                /* Reserve delalloc blocks for regular writeback. */
@@ -981,7 +986,16 @@ xfs_file_iomap_begin(
                                iomap);
        }
 
-       lockmode = xfs_ilock_data_map_shared(ip);
+       /*
+        * COW writes will allocate delalloc space, so we need to make sure
+        * to take the lock exclusively here.
+        */
+       if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+               lockmode = XFS_ILOCK_EXCL;
+               xfs_ilock(ip, XFS_ILOCK_EXCL);
+       } else {
+               lockmode = xfs_ilock_data_map_shared(ip);
+       }
 
        ASSERT(offset <= mp->m_super->s_maxbytes);
        if ((xfs_fsize_t)offset + length > mp->m_super->s_maxbytes)
@@ -991,16 +1005,24 @@ xfs_file_iomap_begin(
 
        error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
                               &nimaps, 0);
-       if (error) {
-               xfs_iunlock(ip, lockmode);
-               return error;
+       if (error)
+               goto out_unlock;
+
+       if (flags & IOMAP_REPORT) {
+               /* Trim the mapping to the nearest shared extent boundary. */
+               error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
+                               &trimmed);
+               if (error)
+                       goto out_unlock;
        }
 
-       /* 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;
+       if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+               error = xfs_reflink_reserve_cow(ip, &imap, &shared);
+               if (error)
+                       goto out_unlock;
+
+               end_fsb = imap.br_startoff + imap.br_blockcount;
+               length = XFS_FSB_TO_B(mp, end_fsb) - offset;
        }
 
        if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) {
@@ -1039,6 +1061,9 @@ xfs_file_iomap_begin(
        if (shared)
                iomap->flags |= IOMAP_F_SHARED;
        return 0;
+out_unlock:
+       xfs_iunlock(ip, lockmode);
+       return error;
 }
 
 static int