When working as the local cache, the @file parameter of
netfs_alloc_read_request() represents the backed file inside netfs. It
is for two use: 1) we can derive the corresponding inode from file,
2) works as the argument for ops->init_rreq().

In the new introduced demand-read mode, netfs_readpage() will be called
by the upper fs to read from backing files. However in this new mode,
the backed file may not be opened, and thus the @file argument is NULL
in this case.

For netfs_readpage(), @file parameter represents the backed file inside
netfs, while @folio parameter represents one page cache inside the
address space of this backed file. We can still derive the inode from
the @folio parameter, even when @file parameter is NULL.

Thus refactor netfs_alloc_read_request() somewhat for this change.

Signed-off-by: Jeffle Xu <jeffl...@linux.alibaba.com>
---
 fs/netfs/read_helper.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 8c58cff420ba..ca84918b6b5d 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -39,7 +39,7 @@ static void netfs_put_subrequest(struct netfs_read_subrequest 
*subreq,
 
 static struct netfs_read_request *netfs_alloc_read_request(
        const struct netfs_read_request_ops *ops, void *netfs_priv,
-       struct file *file)
+       struct inode *inode, struct file *file)
 {
        static atomic_t debug_ids;
        struct netfs_read_request *rreq;
@@ -48,7 +48,7 @@ static struct netfs_read_request *netfs_alloc_read_request(
        if (rreq) {
                rreq->netfs_ops = ops;
                rreq->netfs_priv = netfs_priv;
-               rreq->inode     = file_inode(file);
+               rreq->inode     = inode;
                rreq->i_size    = i_size_read(rreq->inode);
                rreq->debug_id  = atomic_inc_return(&debug_ids);
                INIT_LIST_HEAD(&rreq->subrequests);
@@ -870,6 +870,7 @@ void netfs_readahead(struct readahead_control *ractl,
                     void *netfs_priv)
 {
        struct netfs_read_request *rreq;
+       struct inode *inode = file_inode(ractl->file);
        unsigned int debug_index = 0;
        int ret;
 
@@ -878,7 +879,7 @@ void netfs_readahead(struct readahead_control *ractl,
        if (readahead_count(ractl) == 0)
                goto cleanup;
 
-       rreq = netfs_alloc_read_request(ops, netfs_priv, ractl->file);
+       rreq = netfs_alloc_read_request(ops, netfs_priv, inode, ractl->file);
        if (!rreq)
                goto cleanup;
        rreq->mapping   = ractl->mapping;
@@ -948,12 +949,13 @@ int netfs_readpage(struct file *file,
                   void *netfs_priv)
 {
        struct netfs_read_request *rreq;
+       struct inode *inode = folio_file_mapping(folio)->host;
        unsigned int debug_index = 0;
        int ret;
 
        _enter("%lx", folio_index(folio));
 
-       rreq = netfs_alloc_read_request(ops, netfs_priv, file);
+       rreq = netfs_alloc_read_request(ops, netfs_priv, inode, file);
        if (!rreq) {
                if (netfs_priv)
                        ops->cleanup(folio_file_mapping(folio), netfs_priv);
@@ -1122,7 +1124,7 @@ int netfs_write_begin(struct file *file, struct 
address_space *mapping,
        }
 
        ret = -ENOMEM;
-       rreq = netfs_alloc_read_request(ops, netfs_priv, file);
+       rreq = netfs_alloc_read_request(ops, netfs_priv, inode, file);
        if (!rreq)
                goto error;
        rreq->mapping           = folio_file_mapping(folio);
-- 
2.27.0

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