| Message ID | 20200217112706.20085-1-yi.zhang@huawei.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | jbd2: improve comments about freeing data buffers whose page mapping is NULL | expand |
On Mon 17-02-20 19:27:06, zhangyi (F) wrote: > 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. > > Fixes: c96dceeabf76 ("jbd2: do not clear the BH_Mapped flag when forgetting a metadata buffer") > Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> > Suggested-by: Jan Kara <jack@suse.cz> Thanks! You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/jbd2/commit.c | 7 ++++--- > 1 file 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 @@ void jbd2_journal_commit_transaction(journal_t *journal) > * 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)) { > -- > 2.17.2 >
On Mon, Feb 17, 2020 at 07:27:06PM +0800, zhangyi (F) wrote: > 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. > > Fixes: c96dceeabf76 ("jbd2: do not clear the BH_Mapped flag when forgetting a metadata buffer") > Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> > Suggested-by: Jan Kara <jack@suse.cz> Thanks, applied. - Ted
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 @@ void jbd2_journal_commit_transaction(journal_t *journal) * 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)) {
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. Fixes: c96dceeabf76 ("jbd2: do not clear the BH_Mapped flag when forgetting a metadata buffer") Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> Suggested-by: Jan Kara <jack@suse.cz> --- fs/jbd2/commit.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)