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author | Ryan Ding <ryan.ding@oracle.com> | 2016-03-25 21:21:06 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-25 23:37:42 (GMT) |
commit | 4506cfb6f8cad594ac73e0df2b2961ca10dbd25e (patch) | |
tree | 2dff95967b493d1629ad384ec593895564c64c03 /fs/ocfs2/file.h | |
parent | 2de6a3c73180ef4071b45185756be51a6c767924 (diff) | |
download | linux-4506cfb6f8cad594ac73e0df2b2961ca10dbd25e.tar.xz |
ocfs2: record UNWRITTEN extents when populate write desc
To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock.
There is still one issue in the direct write procedure.
phase 1: alloc extent with UNWRITTEN flag
phase 2: submit direct data to disk, add zero page to page cache
phase 3: clear UNWRITTEN flag when data has been written to disk
When there are 2 direct write A(0~3KB),B(4~7KB) writing to the same
cluster 0~7KB (cluster size 8KB). Write request A arrive phase 2 first,
it will zero the region (4~7KB). Before request A enter to phase 3,
request B arrive phase 2, it will zero region (0~3KB). This is just like
request B steps request A.
To resolve this issue, we should let request B knows this cluster is already
under zero, to prevent it from steps the previous write request.
This patch will add function ocfs2_unwritten_check() to do this job. It
will record all clusters that are under direct write(it will be recorded
in the 'ip_unwritten_list' member of inode info), and prevent the later
direct write writing to the same cluster to do the zero work again.
Signed-off-by: Ryan Ding <ryan.ding@oracle.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2/file.h')
0 files changed, 0 insertions, 0 deletions