| Message ID | 20220325122223.102958-22-jefflexu@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fscache,erofs: fscache-based on-demand read semantics | expand |
On Fri, Mar 25, 2022 at 08:22:22PM +0800, Jeffle Xu wrote: > Implements 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 | 114 +++++++++++++++++++++++++++++++++++++++++++++ > fs/erofs/super.c | 4 ++ > 2 files changed, 118 insertions(+) > > diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c > index cbb39657615e..589d1e7c2b1b 100644 > --- a/fs/erofs/fscache.c > +++ b/fs/erofs/fscache.c > @@ -191,12 +191,126 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) > return ret; > } > > +static inline size_t erofs_fscache_calc_len(struct erofs_map_blocks *map, > + size_t len, size_t done) > +{ > + /* > + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the > + * nearest chunk boundary, and the output m_llen actually starts from > + * the start of the containing chunk. > + * 2) For other cases, the output m_la is equal to o_la. > + */ > + size_t length = map->m_llen - (map->o_la - map->m_la); > + > + return min_t(size_t, length, len - done); This helper can be folded too. > +} > + > +static inline 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 erofs_inode *vi = EROFS_I(inode); > + struct super_block *sb = inode->i_sb; > + size_t len, done = 0; > + loff_t start; > + int ret; > + > + if (erofs_inode_is_data_compressed(vi->datalayout)) { > + erofs_info(sb, "compressed layout not supported yet"); > + return; > + } Redundant check. > + > + if (!readahead_count(rac)) > + return; > + > + start = readahead_pos(rac); > + len = readahead_length(rac); > + > + do { > + struct erofs_map_blocks map; > + > + map.m_la = map.o_la = start + done; > + > + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); > + if (ret) > + return; > + > + /* Read-ahead Hole > + * Two cases will hit this: > + * 1) EOF. Imposibble in readahead routine; > + * 2) hole. Only CHUNK_BASED layout supports hole. > + */ /* * */ and typo `Imposibble'. Also I think this comment may not be useful though. > + if (!(map.m_flags & EROFS_MAP_MAPPED)) { > + struct iov_iter iter; > + loff_t offset = start + done; > + size_t count = erofs_fscache_calc_len(&map, len, done); > + > + 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; > + } > + > + ret = erofs_fscache_get_map(&map, sb); > + if (ret) > + return; > + > + /* Read-ahead Inline */ > + 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; > + } > + > + /* Read-ahead No-inline */ > + if (vi->datalayout == EROFS_INODE_FLAT_PLAIN || > + vi->datalayout == EROFS_INODE_FLAT_INLINE || > + vi->datalayout == EROFS_INODE_CHUNK_BASED) { > + struct fscache_cookie *cookie = map.m_fscache->cookie; > + loff_t offset = start + done; > + size_t count = erofs_fscache_calc_len(&map, len, done); You could promote `offset' and `count' to the outer block. So another `offset' and `count' in !EROFS_MAP_MAPPED can be dropped then. Thanks, Gao Xiang
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index cbb39657615e..589d1e7c2b1b 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -191,12 +191,126 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) return ret; } +static inline size_t erofs_fscache_calc_len(struct erofs_map_blocks *map, + size_t len, size_t done) +{ + /* + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the + * nearest chunk boundary, and the output m_llen actually starts from + * the start of the containing chunk. + * 2) For other cases, the output m_la is equal to o_la. + */ + size_t length = map->m_llen - (map->o_la - map->m_la); + + return min_t(size_t, length, len - done); +} + +static inline 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 erofs_inode *vi = EROFS_I(inode); + struct super_block *sb = inode->i_sb; + size_t len, done = 0; + loff_t start; + int ret; + + if (erofs_inode_is_data_compressed(vi->datalayout)) { + erofs_info(sb, "compressed layout not supported yet"); + return; + } + + if (!readahead_count(rac)) + return; + + start = readahead_pos(rac); + len = readahead_length(rac); + + do { + struct erofs_map_blocks map; + + map.m_la = map.o_la = start + done; + + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); + if (ret) + return; + + /* Read-ahead Hole + * Two cases will hit this: + * 1) EOF. Imposibble in readahead routine; + * 2) hole. Only CHUNK_BASED layout supports hole. + */ + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + struct iov_iter iter; + loff_t offset = start + done; + size_t count = erofs_fscache_calc_len(&map, len, done); + + 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; + } + + ret = erofs_fscache_get_map(&map, sb); + if (ret) + return; + + /* Read-ahead Inline */ + 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; + } + + /* Read-ahead No-inline */ + if (vi->datalayout == EROFS_INODE_FLAT_PLAIN || + vi->datalayout == EROFS_INODE_FLAT_INLINE || + vi->datalayout == EROFS_INODE_CHUNK_BASED) { + struct fscache_cookie *cookie = map.m_fscache->cookie; + loff_t offset = start + done; + size_t count = erofs_fscache_calc_len(&map, len, done); + loff_t pstart = map.m_pa + (map.o_la - map.m_la); + + ret = erofs_fscache_read_folios(cookie, rac->mapping, + offset, count, pstart); + if (!ret) { + erofs_fscache_unlock_folios(rac, count); + ret = count; + } + } else { + DBG_BUGON(1); + return; + } + } while (ret > 0 && ((done += ret) < len)); +} + static const struct address_space_operations erofs_fscache_blob_aops = { .readpage = erofs_fscache_readpage_blob, }; 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 9a6f35e0c22b..8ac400581784 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) return PTR_ERR(bootstrap); sbi->bootstrap = bootstrap; + + err = super_setup_bdi(sb); + if (err) + return err; } err = erofs_read_superblock(sb);
Implements 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 | 114 +++++++++++++++++++++++++++++++++++++++++++++ fs/erofs/super.c | 4 ++ 2 files changed, 118 insertions(+)