Implement fscache-based data readahead. Also registers an individual
bdi for each erofs instance to enable readahead.
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
---
fs/erofs/fscache.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++
fs/erofs/super.c | 4 ++
2 files changed, 98 insertions(+)
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index d32cb5840c6d..620d44210809 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -148,12 +148,106 @@ static int erofs_fscache_readpage(struct file *file, struct page *page)
return ret;
}
+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 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;
+
+ /*
+ * 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.
+ */
+ offset = start + done;
+ count = min_t(size_t, map.m_llen - (pos - map.m_la), len - done);
+
+ /* Read-ahead Hole */
+ 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;
+ }
+
+ /* 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 */
+ 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 8c7181cd37e6..a5e4de60a0d8 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -621,6 +621,10 @@ 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;
}
err = erofs_read_superblock(sb);
--
2.27.0
