| Message ID | 20231218153553.807799-4-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/17] writeback: fix done_index when hitting the wbc->nr_to_write | expand |
On Mon 18-12-23 16:35:39, Christoph Hellwig wrote: > Rework we deal with the cleanup after the writepage call. First handle ^^ the way > the magic AOP_WRITEPAGE_ACTIVATE separately from real error returns to > get it out of the way of the actual error handling. Then merge the > code to set ret for integrity vs non-integrity writeback. For > non-integrity writeback the loop is terminated on the first error, so > ret will never be non-zero. Then use a single block to check for > non-integrity writewack to consolidate the cases where it returns for > either an error or running off the end of nr_to_write. > > Signed-off-by: Christoph Hellwig <hch@lst.de> Otherwise looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > mm/page-writeback.c | 62 +++++++++++++++++++++------------------------ > 1 file changed, 29 insertions(+), 33 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 8e312d73475646..7ed6c2bc8dd51c 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -2474,43 +2474,39 @@ int write_cache_pages(struct address_space *mapping, > error = writepage(folio, wbc, data); > nr = folio_nr_pages(folio); > wbc->nr_to_write -= nr; > - if (unlikely(error)) { > - /* > - * Handle errors according to the type of > - * writeback. There's no need to continue for > - * background writeback. Just push done_index > - * past this page so media errors won't choke > - * writeout for the entire file. For integrity > - * writeback, we must process the entire dirty > - * set regardless of errors because the fs may > - * still have state to clear for each page. In > - * that case we continue processing and return > - * the first error. > - */ > - if (error == AOP_WRITEPAGE_ACTIVATE) { > - folio_unlock(folio); > - error = 0; > - } else if (wbc->sync_mode != WB_SYNC_ALL) { > - ret = error; > - done_index = folio->index + nr; > - done = 1; > - break; > - } > - if (!ret) > - ret = error; > + > + /* > + * Handle the legacy AOP_WRITEPAGE_ACTIVATE magic return > + * value. Eventually all instances should just unlock > + * the folio themselves and return 0; > + */ > + if (error == AOP_WRITEPAGE_ACTIVATE) { > + folio_unlock(folio); > + error = 0; > } > > /* > - * We stop writing back only if we are not doing > - * integrity sync. In case of integrity sync we have to > - * keep going until we have written all the pages > - * we tagged for writeback prior to entering this loop. > + * For integrity sync we have to keep going until we > + * have written all the folios we tagged for writeback > + * prior to entering this loop, even if we run past > + * wbc->nr_to_write or encounter errors. This is > + * because the file system may still have state to clear > + * for each folio. We'll eventually return the first > + * error encountered. > + * > + * For background writeback just push done_index past > + * this folio so that we can just restart where we left > + * off and media errors won't choke writeout for the > + * entire file. > */ > - done_index = folio->index + nr; > - if (wbc->nr_to_write <= 0 && > - wbc->sync_mode == WB_SYNC_NONE) { > - done = 1; > - break; > + if (error && !ret) > + ret = error; > + if (wbc->sync_mode == WB_SYNC_NONE) { > + if (ret || wbc->nr_to_write <= 0) { > + done_index = folio->index + nr; > + done = 1; > + break; > + } > } > } > folio_batch_release(&fbatch); > -- > 2.39.2 >
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 8e312d73475646..7ed6c2bc8dd51c 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2474,43 +2474,39 @@ int write_cache_pages(struct address_space *mapping, error = writepage(folio, wbc, data); nr = folio_nr_pages(folio); wbc->nr_to_write -= nr; - if (unlikely(error)) { - /* - * Handle errors according to the type of - * writeback. There's no need to continue for - * background writeback. Just push done_index - * past this page so media errors won't choke - * writeout for the entire file. For integrity - * writeback, we must process the entire dirty - * set regardless of errors because the fs may - * still have state to clear for each page. In - * that case we continue processing and return - * the first error. - */ - if (error == AOP_WRITEPAGE_ACTIVATE) { - folio_unlock(folio); - error = 0; - } else if (wbc->sync_mode != WB_SYNC_ALL) { - ret = error; - done_index = folio->index + nr; - done = 1; - break; - } - if (!ret) - ret = error; + + /* + * Handle the legacy AOP_WRITEPAGE_ACTIVATE magic return + * value. Eventually all instances should just unlock + * the folio themselves and return 0; + */ + if (error == AOP_WRITEPAGE_ACTIVATE) { + folio_unlock(folio); + error = 0; } /* - * We stop writing back only if we are not doing - * integrity sync. In case of integrity sync we have to - * keep going until we have written all the pages - * we tagged for writeback prior to entering this loop. + * For integrity sync we have to keep going until we + * have written all the folios we tagged for writeback + * prior to entering this loop, even if we run past + * wbc->nr_to_write or encounter errors. This is + * because the file system may still have state to clear + * for each folio. We'll eventually return the first + * error encountered. + * + * For background writeback just push done_index past + * this folio so that we can just restart where we left + * off and media errors won't choke writeout for the + * entire file. */ - done_index = folio->index + nr; - if (wbc->nr_to_write <= 0 && - wbc->sync_mode == WB_SYNC_NONE) { - done = 1; - break; + if (error && !ret) + ret = error; + if (wbc->sync_mode == WB_SYNC_NONE) { + if (ret || wbc->nr_to_write <= 0) { + done_index = folio->index + nr; + done = 1; + break; + } } } folio_batch_release(&fbatch);
Rework we deal with the cleanup after the writepage call. First handle the magic AOP_WRITEPAGE_ACTIVATE separately from real error returns to get it out of the way of the actual error handling. Then merge the code to set ret for integrity vs non-integrity writeback. For non-integrity writeback the loop is terminated on the first error, so ret will never be non-zero. Then use a single block to check for non-integrity writewack to consolidate the cases where it returns for either an error or running off the end of nr_to_write. Signed-off-by: Christoph Hellwig <hch@lst.de> --- mm/page-writeback.c | 62 +++++++++++++++++++++------------------------ 1 file changed, 29 insertions(+), 33 deletions(-)