ext4: introduce lseek SEEK_DATA/SEEK_HOLE support
This patch makes ext4 really support SEEK_DATA/SEEK_HOLE flags. Block-mapped
and extent-mapped files are fully implemented together because ext4_map_blocks
hides this differences.
After applying this patch, it will cause a failure in xfstest #285 when the file
is block-mapped due to block-mapped file isn't support fallocate(2).
I had tried to use ext4_ext_walk_space() to retrieve the offset for a
extent-mapped file. But finally I decide to keep using ext4_map_blocks() to
support SEEK_DATA/SEEK_HOLE because ext4_map_blocks() can hide the difference
between block-mapped file and extent-mapped file. Moreover, in next step,
extent status tree will track all extent status, and we can get all mappings
from this tree. So I think that using ext4_map_blocks() is a better choice.
CC: Hugh Dickins <hughd@google.com>
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
1 file changed