| Message ID | 20220415123614.54024-21-jefflexu@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fscache,erofs: fscache-based on-demand read semantics | expand |
On Fri, Apr 15, 2022 at 08:36:13PM +0800, Jeffle Xu wrote: > Implement fscache-based data readahead. Also registers an individual > bdi for each erofs instance to enable readahead. > > Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> > --- > fs/erofs/fscache.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++ > fs/erofs/super.c | 4 +++ > 2 files changed, 90 insertions(+) > > diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c > index 08849c15500f..eaa50692ddba 100644 > --- a/fs/erofs/fscache.c > +++ b/fs/erofs/fscache.c > @@ -163,12 +163,98 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) > return ret; > } > > +static void erofs_fscache_unlock_folios(struct readahead_control *rac, > + size_t len) > +{ > + while (len) { > + struct folio *folio = readahead_folio(rac); > + > + len -= folio_size(folio); > + folio_mark_uptodate(folio); > + folio_unlock(folio); > + } > +} > + > +static void erofs_fscache_readahead(struct readahead_control *rac) > +{ > + struct inode *inode = rac->mapping->host; > + struct super_block *sb = inode->i_sb; > + size_t len, count, done = 0; > + erofs_off_t pos; > + loff_t start, offset; > + int ret; > + > + if (!readahead_count(rac)) > + return; > + > + start = readahead_pos(rac); > + len = readahead_length(rac); > + > + do { > + struct erofs_map_blocks map; > + struct erofs_map_dev mdev; > + > + pos = start + done; > + map.m_la = pos; > + > + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); > + if (ret) > + return; > + > + offset = start + done; > + count = min_t(size_t, map.m_llen - (pos - map.m_la), > + len - done); > + > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > + struct iov_iter iter; > + > + iov_iter_xarray(&iter, READ, &rac->mapping->i_pages, > + offset, count); > + iov_iter_zero(count, &iter); > + > + erofs_fscache_unlock_folios(rac, count); > + ret = count; > + continue; > + } > + > + if (map.m_flags & EROFS_MAP_META) { > + struct folio *folio = readahead_folio(rac); > + > + ret = erofs_fscache_readpage_inline(folio, &map); > + if (!ret) { > + folio_mark_uptodate(folio); > + ret = folio_size(folio); > + } > + > + folio_unlock(folio); > + continue; > + } > + > + mdev = (struct erofs_map_dev) { > + .m_deviceid = map.m_deviceid, > + .m_pa = map.m_pa, > + }; > + ret = erofs_map_dev(sb, &mdev); > + if (ret) > + return; > + > + ret = erofs_fscache_read_folios(mdev.m_fscache->cookie, > + rac->mapping, offset, count, > + mdev.m_pa + (pos - map.m_la)); > + if (!ret) { > + erofs_fscache_unlock_folios(rac, count); > + ret = count; > + } I think this really needs a comment why we don't need to unlock folios for the error cases. Thanks, Gao Xiang > + } while (ret > 0 && ((done += ret) < len)); > +} > +
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 08849c15500f..eaa50692ddba 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -163,12 +163,98 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) return ret; } +static void erofs_fscache_unlock_folios(struct readahead_control *rac, + size_t len) +{ + while (len) { + struct folio *folio = readahead_folio(rac); + + len -= folio_size(folio); + folio_mark_uptodate(folio); + folio_unlock(folio); + } +} + +static void erofs_fscache_readahead(struct readahead_control *rac) +{ + struct inode *inode = rac->mapping->host; + struct super_block *sb = inode->i_sb; + size_t len, count, done = 0; + erofs_off_t pos; + loff_t start, offset; + int ret; + + if (!readahead_count(rac)) + return; + + start = readahead_pos(rac); + len = readahead_length(rac); + + do { + struct erofs_map_blocks map; + struct erofs_map_dev mdev; + + pos = start + done; + map.m_la = pos; + + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); + if (ret) + return; + + offset = start + done; + count = min_t(size_t, map.m_llen - (pos - map.m_la), + len - done); + + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + struct iov_iter iter; + + iov_iter_xarray(&iter, READ, &rac->mapping->i_pages, + offset, count); + iov_iter_zero(count, &iter); + + erofs_fscache_unlock_folios(rac, count); + ret = count; + continue; + } + + if (map.m_flags & EROFS_MAP_META) { + struct folio *folio = readahead_folio(rac); + + ret = erofs_fscache_readpage_inline(folio, &map); + if (!ret) { + folio_mark_uptodate(folio); + ret = folio_size(folio); + } + + folio_unlock(folio); + continue; + } + + mdev = (struct erofs_map_dev) { + .m_deviceid = map.m_deviceid, + .m_pa = map.m_pa, + }; + ret = erofs_map_dev(sb, &mdev); + if (ret) + return; + + ret = erofs_fscache_read_folios(mdev.m_fscache->cookie, + rac->mapping, offset, count, + mdev.m_pa + (pos - map.m_la)); + if (!ret) { + erofs_fscache_unlock_folios(rac, count); + ret = count; + } + } while (ret > 0 && ((done += ret) < len)); +} + static const struct address_space_operations erofs_fscache_meta_aops = { .readpage = erofs_fscache_meta_readpage, }; const struct address_space_operations erofs_fscache_access_aops = { .readpage = erofs_fscache_readpage, + .readahead = erofs_fscache_readahead, }; /* diff --git a/fs/erofs/super.c b/fs/erofs/super.c index c6755bcae4a6..f68ba929100d 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -619,6 +619,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) sbi->opt.fsid, true); if (err) return err; + + err = super_setup_bdi(sb); + if (err) + return err; } else { if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) { erofs_err(sb, "failed to set erofs blksize");
Implement fscache-based data readahead. Also registers an individual bdi for each erofs instance to enable readahead. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- fs/erofs/fscache.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++ fs/erofs/super.c | 4 +++ 2 files changed, 90 insertions(+)