Merge tag 'gfs2-4.16.rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 fix from Bob Peterson:
 "Fix regressions in the gfs2 iomap for block_map implementation we
  recently discovered in commit 3974320ca6"

* tag 'gfs2-4.16.rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fixes to "Implement iomap for block_map"

1 files changed, 23 insertions, 20 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 86863792f36a..86d6a4435c87 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -716,7 +716,7 @@ int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
         __be64 *ptr;
         sector_t lblock;
         sector_t lend;
-        int ret;
+        int ret = 0;
         int eob;
         unsigned int len;
         struct buffer_head *bh;
@@ -728,12 +728,14 @@ int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
                 goto out;
         }
 
-        if ((flags & IOMAP_REPORT) && gfs2_is_stuffed(ip)) {
-                gfs2_stuffed_iomap(inode, iomap);
-                if (pos >= iomap->length)
-                        return -ENOENT;
-                ret = 0;
-                goto out;
+        if (gfs2_is_stuffed(ip)) {
+                if (flags & IOMAP_REPORT) {
+                        gfs2_stuffed_iomap(inode, iomap);
+                        if (pos >= iomap->length)
+                                ret = -ENOENT;
+                        goto out;
+                }
+                BUG_ON(!(flags & IOMAP_WRITE));
         }
 
         lblock = pos >> inode->i_blkbits;
@@ -744,7 +746,7 @@ int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
         iomap->type = IOMAP_HOLE;
         iomap->length = (u64)(lend - lblock) << inode->i_blkbits;
         iomap->flags = IOMAP_F_MERGED;
-        bmap_lock(ip, 0);
+        bmap_lock(ip, flags & IOMAP_WRITE);
 
         /*
          * Directory data blocks have a struct gfs2_meta_header header, so the
@@ -787,27 +789,28 @@ int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
                 iomap->flags |= IOMAP_F_BOUNDARY;
         iomap->length = (u64)len << inode->i_blkbits;
 
-        ret = 0;
-
 out_release:
         release_metapath(&mp);
-        bmap_unlock(ip, 0);
+        bmap_unlock(ip, flags & IOMAP_WRITE);
 out:
         trace_gfs2_iomap_end(ip, iomap, ret);
         return ret;
 
 do_alloc:
-        if (!(flags & IOMAP_WRITE)) {
-                if (pos >= i_size_read(inode)) {
+        if (flags & IOMAP_WRITE) {
+                ret = gfs2_iomap_alloc(inode, iomap, flags, &mp);
+        } else if (flags & IOMAP_REPORT) {
+                loff_t size = i_size_read(inode);
+                if (pos >= size)
                         ret = -ENOENT;
-                        goto out_release;
-                }
-                ret = 0;
-                iomap->length = hole_size(inode, lblock, &mp);
-                goto out_release;
+                else if (height <= ip->i_height)
+                        iomap->length = hole_size(inode, lblock, &mp);
+                else
+                        iomap->length = size - pos;
+        } else {
+                if (height <= ip->i_height)
+                        iomap->length = hole_size(inode, lblock, &mp);
         }
-
-        ret = gfs2_iomap_alloc(inode, iomap, flags, &mp);
         goto out_release;
 }