Commit cdee7843 authored Mar 10, 2013 by Zheng Liu Committed by Theodore Ts'o Mar 10, 2013

ext4: fix wrong m_len value after unwritten extent conversion



The ext4_ext_handle_uninitialized_extents() function was assuming the
return value of ext4_ext_map_blocks() is equal to map->m_len.  This
incorrect assumption was harmless until we started use status tree as
a extent cache because we need to update status tree according to
'm_len' value.

Meanwhile this commit marks EXT4_MAP_MAPPED flag after unwritten extent
conversion.  It shouldn't cause a bug because we update status tree
according to checking EXT4_MAP_UNWRITTEN flag.  But it should be fixed.

After applied this commit, the following error message from self-testing
infrastructure disappears.

    ...
    kernel: ES len assertation failed for inode: 230 retval 1 !=
    map->m_len 3 in ext4_map_blocks (allocation)
    ...

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>

parent 921f266b

fs/ext4/extents.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -3650,6 +3650,10 @@ ext4_ext_handle_uninitialized_extents(handle_t handle, struct inode inode,
		path, map->m_len);
		} else
		err = ret;
		map->m_flags \|= EXT4_MAP_MAPPED;
		if (allocated > map->m_len)
		allocated = map->m_len;
		map->m_len = allocated;
		goto out2;
		}
		/* buffered IO case */

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