| Message ID | 1411404065-767-1-git-send-email-fdmanana@suse.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Mon, Sep 22, 2014 at 05:41:04PM +0100, Filipe Manana wrote: > If submit_extent_page() fails in write_one_eb(), we end up with the current > page not marked dirty anymore, unlocked and marked for writeback. But we never > end up calling end_page_writeback() against the page, which will make calls to > filemap_fdatawait_range (e.g. at transaction commit time) hang forever waiting > for the writeback bit to be cleared from the page. > > Signed-off-by: Filipe Manana <fdmanana@suse.com> > --- > fs/btrfs/extent_io.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index 3af4966..91f866c 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -3668,6 +3668,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, > if (ret) { > set_bit(EXTENT_BUFFER_IOERR, &eb->bflags); > SetPageError(p); > + end_page_writeback(p); This is not always true, and it depends on the place where we get error in submit_extent_page(), whether it has built and submitted a bio, if it's true, case can be different as bio_endio will be called, and calling end_page_writeback() again will end up with panic. thanks, -liubo > if (atomic_sub_and_test(num_pages - i, &eb->io_pages)) > end_extent_buffer_writeback(eb); > ret = -EIO; > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 23, 2014 at 11:14 AM, Liu Bo <bo.li.liu@oracle.com> wrote: > On Mon, Sep 22, 2014 at 05:41:04PM +0100, Filipe Manana wrote: >> If submit_extent_page() fails in write_one_eb(), we end up with the current >> page not marked dirty anymore, unlocked and marked for writeback. But we never >> end up calling end_page_writeback() against the page, which will make calls to >> filemap_fdatawait_range (e.g. at transaction commit time) hang forever waiting >> for the writeback bit to be cleared from the page. >> >> Signed-off-by: Filipe Manana <fdmanana@suse.com> >> --- >> fs/btrfs/extent_io.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c >> index 3af4966..91f866c 100644 >> --- a/fs/btrfs/extent_io.c >> +++ b/fs/btrfs/extent_io.c >> @@ -3668,6 +3668,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, >> if (ret) { >> set_bit(EXTENT_BUFFER_IOERR, &eb->bflags); >> SetPageError(p); >> + end_page_writeback(p); > > This is not always true, and it depends on the place where we get error in > submit_extent_page(), whether it has built and submitted a bio, if it's true, > case can be different as bio_endio will be called, and calling end_page_writeback() > again will end up with panic. No, it's always true when the caller is write_one_eb(). If submit_extent_page() returns an error, we're sure that the page wasn't added to a bio, because bio_ret is always not NULL (but *bio_ret can be). Also, if we call submit_one_bio() in submit_extent_page() (first if statement) , we know that the bio doesn't contain the page. thanks > > thanks, > -liubo > >> if (atomic_sub_and_test(num_pages - i, &eb->io_pages)) >> end_extent_buffer_writeback(eb); >> ret = -EIO; >> -- >> 1.9.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 23, 2014 at 02:03:07PM +0100, Filipe David Manana wrote: > On Tue, Sep 23, 2014 at 11:14 AM, Liu Bo <bo.li.liu@oracle.com> wrote: > > On Mon, Sep 22, 2014 at 05:41:04PM +0100, Filipe Manana wrote: > >> If submit_extent_page() fails in write_one_eb(), we end up with the current > >> page not marked dirty anymore, unlocked and marked for writeback. But we never > >> end up calling end_page_writeback() against the page, which will make calls to > >> filemap_fdatawait_range (e.g. at transaction commit time) hang forever waiting > >> for the writeback bit to be cleared from the page. > >> > >> Signed-off-by: Filipe Manana <fdmanana@suse.com> > >> --- > >> fs/btrfs/extent_io.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > >> index 3af4966..91f866c 100644 > >> --- a/fs/btrfs/extent_io.c > >> +++ b/fs/btrfs/extent_io.c > >> @@ -3668,6 +3668,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, > >> if (ret) { > >> set_bit(EXTENT_BUFFER_IOERR, &eb->bflags); > >> SetPageError(p); > >> + end_page_writeback(p); > > > > This is not always true, and it depends on the place where we get error in > > submit_extent_page(), whether it has built and submitted a bio, if it's true, > > case can be different as bio_endio will be called, and calling end_page_writeback() > > again will end up with panic. > > No, it's always true when the caller is write_one_eb(). If > submit_extent_page() returns an error, we're sure that the page wasn't > added to a bio, because bio_ret is always not NULL (but *bio_ret can > be). Also, if we call submit_one_bio() in submit_extent_page() (first > if statement) , we know that the bio doesn't contain the page. I see, you're right. Reviewed-by: Liu Bo <bo.li.liu@oracle.com> thanks, -liubo > > thanks > > > > > thanks, > > -liubo > > > >> if (atomic_sub_and_test(num_pages - i, &eb->io_pages)) > >> end_extent_buffer_writeback(eb); > >> ret = -EIO; > >> -- > >> 1.9.1 > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > Filipe David Manana, > > "Reasonable men adapt themselves to the world. > Unreasonable men adapt the world to themselves. > That's why all progress depends on unreasonable men." -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 3af4966..91f866c 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3668,6 +3668,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, if (ret) { set_bit(EXTENT_BUFFER_IOERR, &eb->bflags); SetPageError(p); + end_page_writeback(p); if (atomic_sub_and_test(num_pages - i, &eb->io_pages)) end_extent_buffer_writeback(eb); ret = -EIO;
If submit_extent_page() fails in write_one_eb(), we end up with the current page not marked dirty anymore, unlocked and marked for writeback. But we never end up calling end_page_writeback() against the page, which will make calls to filemap_fdatawait_range (e.g. at transaction commit time) hang forever waiting for the writeback bit to be cleared from the page. Signed-off-by: Filipe Manana <fdmanana@suse.com> --- fs/btrfs/extent_io.c | 1 + 1 file changed, 1 insertion(+)