3 files changed, 77 insertions, 22 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 400b187595bb..67284edb84d7 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -86,7 +86,7 @@ xfs_rw_ilock_demote(
  *      valid before the operation, it will be read from disk before
  *      being partially zeroed.
  */
-STATIC int
+int
 xfs_iozero(
         struct xfs_inode        *ip,    /* inode                        */
         loff_t                  pos,    /* offset in file               */
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 26880793feca..d95f565a390e 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -2095,6 +2095,73 @@ xfs_free_file_space(
         return error;
 }
 
+
+STATIC int
+xfs_zero_file_space(
+        struct xfs_inode        *ip,
+        xfs_off_t               offset,
+        xfs_off_t               len,
+        int                     attr_flags)
+{
+        struct xfs_mount        *mp = ip->i_mount;
+        uint                    granularity;
+        xfs_off_t               start_boundary;
+        xfs_off_t               end_boundary;
+        int                     error;
+
+        granularity = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
+
+        /*
+         * Round the range of extents we are going to convert inwards.  If the
+         * offset is aligned, then it doesn't get changed so we zero from the
+         * start of the block offset points to.
+         */
+        start_boundary = round_up(offset, granularity);
+        end_boundary = round_down(offset + len, granularity);
+
+        ASSERT(start_boundary >= offset);
+        ASSERT(end_boundary <= offset + len);
+
+        if (!(attr_flags & XFS_ATTR_NOLOCK))
+                xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+        if (start_boundary < end_boundary - 1) {
+                /* punch out the page cache over the conversion range */
+                truncate_pagecache_range(VFS_I(ip), start_boundary,
+                                         end_boundary - 1);
+                /* convert the blocks */
+                error = xfs_alloc_file_space(ip, start_boundary,
+                                        end_boundary - start_boundary - 1,
+                                        XFS_BMAPI_PREALLOC | XFS_BMAPI_CONVERT,
+                                        attr_flags);
+                if (error)
+                        goto out_unlock;
+
+                /* We've handled the interior of the range, now for the edges */
+                if (start_boundary != offset)
+                        error = xfs_iozero(ip, offset, start_boundary - offset);
+                if (error)
+                        goto out_unlock;
+
+                if (end_boundary != offset + len)
+                        error = xfs_iozero(ip, end_boundary,
+                                           offset + len - end_boundary);
+
+        } else {
+                /*
+                 * It's either a sub-granularity range or the range spanned lies
+                 * partially across two adjacent blocks.
+                 */
+                error = xfs_iozero(ip, offset, len);
+        }
+
+out_unlock:
+        if (!(attr_flags & XFS_ATTR_NOLOCK))
+                xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+        return error;
+
+}
+
 /*
  * xfs_change_file_space()
  *      This routine allocates or frees disk space for the given file.
@@ -2120,10 +2187,8 @@ xfs_change_file_space(
         xfs_fsize_t     fsize;
         int             setprealloc;
         xfs_off_t       startoffset;
-        xfs_off_t       end;
         xfs_trans_t     *tp;
         struct iattr    iattr;
-        int             prealloc_type;
 
         if (!S_ISREG(ip->i_d.di_mode))
                 return XFS_ERROR(EINVAL);
@@ -2172,31 +2237,20 @@ xfs_change_file_space(
         startoffset = bf->l_start;
         fsize = XFS_ISIZE(ip);
 
-        /*
-         * XFS_IOC_RESVSP and XFS_IOC_UNRESVSP will reserve or unreserve
-         * file space.
-         * These calls do NOT zero the data space allocated to the file,
-         * nor do they change the file size.
-         *
-         * XFS_IOC_ALLOCSP and XFS_IOC_FREESP will allocate and free file
-         * space.
-         * These calls cause the new file data to be zeroed and the file
-         * size to be changed.
-         */
         setprealloc = clrprealloc = 0;
-        prealloc_type = XFS_BMAPI_PREALLOC;
-
         switch (cmd) {
         case XFS_IOC_ZERO_RANGE:
-                prealloc_type |= XFS_BMAPI_CONVERT;
-                end = round_down(startoffset + bf->l_len, PAGE_SIZE) - 1;
-                if (startoffset <= end)
-                        truncate_pagecache_range(VFS_I(ip), startoffset, end);
-                /* FALLTHRU */
+                error = xfs_zero_file_space(ip, startoffset, bf->l_len,
+                                                attr_flags);
+                if (error)
+                        return error;
+                setprealloc = 1;
+                break;
+
         case XFS_IOC_RESVSP:
         case XFS_IOC_RESVSP64:
                 error = xfs_alloc_file_space(ip, startoffset, bf->l_len,
-                                                prealloc_type, attr_flags);
+                                                XFS_BMAPI_PREALLOC, attr_flags);
                 if (error)
                         return error;
                 setprealloc = 1;
diff --git a/fs/xfs/xfs_vnodeops.h b/fs/xfs/xfs_vnodeops.h
index 91a03fa3814f..5163022d9808 100644
--- a/fs/xfs/xfs_vnodeops.h
+++ b/fs/xfs/xfs_vnodeops.h
@@ -49,6 +49,7 @@ int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
 int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
                 int flags, struct attrlist_cursor_kern *cursor);
 
+int xfs_iozero(struct xfs_inode *, loff_t, size_t);
 int xfs_zero_eof(struct xfs_inode *, xfs_off_t, xfs_fsize_t);
 int xfs_free_eofblocks(struct xfs_mount *, struct xfs_inode *, bool);