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path: root/fs/cifs/inode.c
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Diffstat (limited to 'fs/cifs/inode.c')
-rw-r--r--fs/cifs/inode.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index dd4167762a8..97ccc513730 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1377,8 +1377,17 @@ static int cifs_vmtruncate(struct inode *inode, loff_t offset)
}
i_size_write(inode, offset);
spin_unlock(&inode->i_lock);
+ /*
+ * unmap_mapping_range is called twice, first simply for efficiency
+ * so that truncate_inode_pages does fewer single-page unmaps. However
+ * after this first call, and before truncate_inode_pages finishes,
+ * it is possible for private pages to be COWed, which remain after
+ * truncate_inode_pages finishes, hence the second unmap_mapping_range
+ * call must be made for correctness.
+ */
unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
truncate_inode_pages(mapping, offset);
+ unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
goto out_truncate;
do_expand: