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| author | zhangyi (F) <yi.zhang@huawei.com> | 2020-02-17 14:27:06 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2020-03-06 04:25:05 +0300 |
| commit | 780f66e59231fcf882f36c63f287252ee47cc75a (patch) | |
| tree | 893f357631fc8f070e9f9b84f43c87a772aa236c /fs | |
| parent | 6cfb061fe9e901dd0b6cfa3ed50bc39c81523532 (diff) | |
| download | linux-780f66e59231fcf882f36c63f287252ee47cc75a.tar.xz | |
jbd2: improve comments about freeing data buffers whose page mapping is NULL
Improve comments in jbd2_journal_commit_transaction() to describe why
we don't need to clear the buffer_mapped bit for freeing file mapping
buffers whose page mapping is NULL.
Link: https://lore.kernel.org/r/20200217112706.20085-1-yi.zhang@huawei.com
Fixes: c96dceeabf76 ("jbd2: do not clear the BH_Mapped flag when forgetting a metadata buffer")
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/jbd2/commit.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 27373f5792a4..e855d8260433 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -997,9 +997,10 @@ restart_loop: * journalled data) we need to unmap buffer and clear * more bits. We also need to be careful about the check * because the data page mapping can get cleared under - * out hands, which alse need not to clear more bits - * because the page and buffers will be freed and can - * never be reused once we are done with them. + * our hands. Note that if mapping == NULL, we don't + * need to make buffer unmapped because the page is + * already detached from the mapping and buffers cannot + * get reused. */ mapping = READ_ONCE(bh->b_page->mapping); if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) { |