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Message-Id: <20220118131216.85338-16-jefflexu@linux.alibaba.com>
Date: Tue, 18 Jan 2022 21:12:11 +0800
From: Jeffle Xu <jefflexu@...ux.alibaba.com>
To: dhowells@...hat.com, linux-cachefs@...hat.com, xiang@...nel.org,
chao@...nel.org, linux-erofs@...ts.ozlabs.org
Cc: linux-fsdevel@...r.kernel.org, joseph.qi@...ux.alibaba.com,
bo.liu@...ux.alibaba.com, tao.peng@...ux.alibaba.com,
gerry@...ux.alibaba.com, eguan@...ux.alibaba.com,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 15/20] erofs: implement fscache-based data read for non-inline layout
This patch implements the data plane of reading data from bootstrap blob
file over fscache for non-inline layout.
Be noted that compressed layout is not supported yet.
Signed-off-by: Jeffle Xu <jefflexu@...ux.alibaba.com>
---
fs/erofs/fscache.c | 111 ++++++++++++++++++++++++++++++++++++++++++++
fs/erofs/inode.c | 6 ++-
fs/erofs/internal.h | 1 +
3 files changed, 117 insertions(+), 1 deletion(-)
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 5a25ae523e5e..588c33ab6a90 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -4,6 +4,17 @@
*/
#include "internal.h"
+struct erofs_fscache_map {
+ struct erofs_fscache_context *m_ctx;
+ erofs_off_t m_pa, m_la, o_la;
+ u64 m_llen;
+};
+
+struct erofs_fscache_priv {
+ struct fscache_cookie *cookie;
+ loff_t offset;
+};
+
static struct fscache_volume *volume;
static int erofs_blob_begin_cache_operation(struct netfs_read_request *rreq)
@@ -22,6 +33,33 @@ static const struct netfs_read_request_ops erofs_blob_req_ops = {
.cleanup = erofs_noop_cleanup,
};
+static int erofs_begin_cache_operation(struct netfs_read_request *rreq)
+{
+ struct erofs_fscache_priv *priv = rreq->netfs_priv;
+
+ rreq->p_start = priv->offset;
+ return fscache_begin_read_operation(&rreq->cache_resources,
+ priv->cookie);
+}
+
+static bool erofs_clamp_length(struct netfs_read_subrequest *subreq)
+{
+ /*
+ * For non-inline layout, rreq->i_size is actually the size of upper
+ * file in erofs rather than that of blob file. Thus when cache miss,
+ * subreq->len can be restricted to the upper file size, while we hope
+ * blob file can be filled in a EROFS_BLKSIZ granule.
+ */
+ subreq->len = round_up(subreq->len, EROFS_BLKSIZ);
+ return true;
+}
+
+static const struct netfs_read_request_ops erofs_req_ops = {
+ .begin_cache_operation = erofs_begin_cache_operation,
+ .cleanup = erofs_noop_cleanup,
+ .clamp_length = erofs_clamp_length,
+};
+
static int erofs_fscache_blob_readpage(struct file *data, struct page *page)
{
struct folio *folio = page_folio(page);
@@ -42,6 +80,79 @@ struct page *erofs_fscache_read_cache_page(struct erofs_fscache_context *ctx,
return read_mapping_page(ctx->inode->i_mapping, index, ctx);
}
+static int erofs_fscache_readpage_noinline(struct page *page,
+ struct erofs_fscache_map *fsmap)
+{
+ struct folio *folio = page_folio(page);
+ struct erofs_fscache_priv priv;
+
+ /*
+ * 1) For FLAT_PLAIN layout, the output map.m_la shall be equal to o_la,
+ * and the output map.m_pa is exactly the physical address of o_la.
+ * 2) For CHUNK_BASED layout, the output map.m_la is rounded down to the
+ * nearest chunk boundary, and the output map.m_pa is actually the
+ * physical address of this chunk boundary. So we need to recalculate
+ * the actual physical address of o_la.
+ */
+ priv.offset = fsmap->m_pa + fsmap->o_la - fsmap->m_la;
+ priv.cookie = fsmap->m_ctx->cookie;
+
+ return netfs_readpage(NULL, folio, &erofs_req_ops, &priv);
+}
+
+static int erofs_fscache_readpage(struct file *file, struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_map_blocks map;
+ struct erofs_fscache_map fsmap;
+ int ret;
+
+ if (erofs_inode_is_data_compressed(vi->datalayout)) {
+ erofs_info(sb, "compressed layout not supported yet");
+ ret = -EOPNOTSUPP;
+ goto err_out;
+ }
+
+ map.m_la = fsmap.o_la = page_offset(page);
+
+ ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
+ if (ret)
+ goto err_out;
+
+ if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+ zero_user(page, 0, PAGE_SIZE);
+ SetPageUptodate(page);
+ unlock_page(page);
+ return 0;
+ }
+
+ fsmap.m_ctx = sbi->bootstrap;
+ fsmap.m_la = map.m_la;
+ fsmap.m_pa = map.m_pa;
+ fsmap.m_llen = map.m_llen;
+
+ switch (vi->datalayout) {
+ case EROFS_INODE_FLAT_PLAIN:
+ case EROFS_INODE_CHUNK_BASED:
+ return erofs_fscache_readpage_noinline(page, &fsmap);
+ default:
+ DBG_BUGON(1);
+ ret = -EOPNOTSUPP;
+ }
+
+err_out:
+ SetPageError(page);
+ unlock_page(page);
+ return ret;
+}
+
+const struct address_space_operations erofs_fscache_access_aops = {
+ .readpage = erofs_fscache_readpage,
+};
+
static int erofs_fscache_init_cookie(struct erofs_fscache_context *ctx,
char *path)
{
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index ff62f84f47d3..2f450cb3a7b9 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -296,7 +296,11 @@ static int erofs_fill_inode(struct inode *inode, int isdir)
err = z_erofs_fill_inode(inode);
goto out_unlock;
}
- inode->i_mapping->a_ops = &erofs_raw_access_aops;
+
+ if (erofs_bdev_mode(inode->i_sb))
+ inode->i_mapping->a_ops = &erofs_raw_access_aops;
+ else
+ inode->i_mapping->a_ops = &erofs_fscache_access_aops;
out_unlock:
erofs_put_metabuf(&buf);
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index fca706cfaf72..548f928b0ded 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -393,6 +393,7 @@ struct page *erofs_grab_cache_page_nowait(struct address_space *mapping,
extern const struct super_operations erofs_sops;
extern const struct address_space_operations erofs_raw_access_aops;
+extern const struct address_space_operations erofs_fscache_access_aops;
extern const struct address_space_operations z_erofs_aops;
/*
--
2.27.0
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