[PATCH 1/3] xfs: pass inode instead of file to xfs_reflink_dirty_range

[Christoph Hellwig <hch@xxxxxx>]

We don't actually need a file for write_begin/end, those can be passed
as NULL for disk based file systems.  This is important as we won't
even have a file pointer during a truncate operation, which gives a
guaranteed NULL pointer dererference with the current code.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/xfs/xfs_reflink.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index da4a715..4a3f0ee 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1316,7 +1316,7 @@ out_error:
  */
 STATIC int
 xfs_reflink_dirty_range(
-       struct file             *filp,
+       struct inode            *inode,
        xfs_off_t               pos,
        xfs_off_t               len)
 {
@@ -1330,14 +1330,14 @@ xfs_reflink_dirty_range(
        unsigned long           bytes;  /* Bytes to write to page */
        void                    *fsdata;
 
-       mapping = filp->f_mapping;
+       mapping = inode->i_mapping;
        a_ops = mapping->a_ops;
        flags = AOP_FLAG_UNINTERRUPTIBLE;
        do {
 
                offset = (pos & (PAGE_CACHE_SIZE - 1));
                bytes = min_t(unsigned long, len, PAGE_CACHE_SIZE) - offset;
-               rpage = xfs_get_page(file_inode(filp), pos);
+               rpage = xfs_get_page(inode, pos);
                if (IS_ERR(rpage)) {
                        error = PTR_ERR(rpage);
                        break;
@@ -1346,24 +1346,24 @@ xfs_reflink_dirty_range(
                        break;
                }
 
-               error = a_ops->write_begin(filp, mapping, pos, bytes, flags,
+               error = a_ops->write_begin(NULL, mapping, pos, bytes, flags,
                                           &page, &fsdata);
                page_cache_release(rpage);
                if (error < 0)
                        break;
 
-               trace_xfs_reflink_unshare_page(file_inode(filp), page,
+               trace_xfs_reflink_unshare_page(inode, page,
                                pos, bytes);
 
                if (!PageUptodate(page)) {
-                       pr_err("%s: STALE? ino=%lu pos=%llu\n",
-                               __func__, filp->f_inode->i_ino, pos);
+                       pr_err("%s: STALE? ino=%llu pos=%llu\n",
+                               __func__, XFS_I(inode)->i_ino, pos);
                        WARN_ON(1);
                }
                if (mapping_writably_mapped(mapping))
                        flush_dcache_page(page);
 
-               error = a_ops->write_end(filp, mapping, pos, bytes, bytes,
+               error = a_ops->write_end(NULL, mapping, pos, bytes, bytes,
                                         page, fsdata);
                if (error < 0)
                        break;
@@ -1454,7 +1454,7 @@ xfs_reflink_dirty_extents(
                        flen = XFS_FSB_TO_B(mp, rlen);
                        if (fpos + flen > isize)
                                flen = isize - fpos;
-                       error = xfs_reflink_dirty_range(filp, fpos, flen);
+                       error = xfs_reflink_dirty_range(VFS_I(ip), fpos, flen);
                        xfs_ilock(ip, XFS_ILOCK_EXCL);
                        if (error)
                                goto out;
-- 
1.9.1