[PATCH v4 03/39] netfs, fscache: Remove ->begin_cache_operation

David Howells
2023-12-13T15:24:15Z

Remove ->begin_cache_operation() in favour of just calling fscache directly.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Christian Brauner <christian@brauner.io>
cc: linux-fsdevel@vger.kernel.org
cc: linux-cachefs@redhat.com
---
Documentation/filesystems/netfs_library.rst | 23 +++-----------
fs/9p/vfs_addr.c | 16 ----------
fs/afs/file.c | 13 --------
fs/ceph/addr.c | 1 -
fs/ceph/cache.h | 12 --------
fs/netfs/buffered_read.c | 33 +++++++++++----------
fs/nfs/fscache.c | 7 -----
include/linux/fscache.h | 3 --
include/linux/netfs.h | 4 +--
9 files changed, 23 insertions(+), 89 deletions(-)

diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst
index 48b95d04f72d..4cc657d743f7 100644
--- a/Documentation/filesystems/netfs_library.rst
+++ b/Documentation/filesystems/netfs_library.rst
@@ -295,7 +295,6 @@ through which it can issue requests and negotiate::
struct netfs_request_ops {
void (*init_request)(struct netfs_io_request *rreq, struct file *file);
void (*free_request)(struct netfs_io_request *rreq);
- int (*begin_cache_operation)(struct netfs_io_request *rreq);
void (*expand_readahead)(struct netfs_io_request *rreq);
bool (*clamp_length)(struct netfs_io_subrequest *subreq);
void (*issue_read)(struct netfs_io_subrequest *subreq);
@@ -317,20 +316,6 @@ The operations are as follows:
[Optional] This is called as the request is being deallocated so that the
filesystem can clean up any state it has attached there.

- * ``begin_cache_operation()``
-
- [Optional] This is called to ask the network filesystem to call into the
- cache (if present) to initialise the caching state for this read. The netfs
- library module cannot access the cache directly, so the cache should call
- something like fscache_begin_read_operation() to do this.
-
- The cache gets to store its state in ->cache_resources and must set a table
- of operations of its own there (though of a different type).
-
- This should return 0 on success and an error code otherwise. If an error is
- reported, the operation may proceed anyway, just without local caching (only
- out of memory and interruption errors cause failure here).
-
* ``expand_readahead()``

[Optional] This is called to allow the filesystem to expand the size of a
@@ -460,14 +445,14 @@ When implementing a local cache to be used by the read helpers, two things are
required: some way for the network filesystem to initialise the caching for a
read request and a table of operations for the helpers to call.

-The network filesystem's ->begin_cache_operation() method is called to set up a
-cache and this must call into the cache to do the work. If using fscache, for
-example, the cache would call::
+To begin a cache operation on an fscache object, the following function is
+called::

int fscache_begin_read_operation(struct netfs_io_request *rreq,
struct fscache_cookie *cookie);

-passing in the request pointer and the cookie corresponding to the file.
+passing in the request pointer and the cookie corresponding to the file. This
+fills in the cache resources mentioned below.

The netfs_io_request object contains a place for the cache to hang its
state::
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 8a635999a7d6..39db7c01e30a 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -82,25 +82,9 @@ static void v9fs_free_request(struct netfs_io_request *rreq)
p9_fid_put(fid);
}

-/**
- * v9fs_begin_cache_operation - Begin a cache operation for a read
- * @rreq: The read request
- */
-static int v9fs_begin_cache_operation(struct netfs_io_request *rreq)
-{
-#ifdef CONFIG_9P_FSCACHE
- struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode));
-
- return fscache_begin_read_operation(&rreq->cache_resources, cookie);
-#else
- return -ENOBUFS;
-#endif
-}
-
const struct netfs_request_ops v9fs_req_ops = {
.init_request = v9fs_init_request,
.free_request = v9fs_free_request,
- .begin_cache_operation = v9fs_begin_cache_operation,
.issue_read = v9fs_issue_read,
};

diff --git a/fs/afs/file.c b/fs/afs/file.c
index 30914e0d9cb2..0326ae21fbea 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -363,18 +363,6 @@ static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
return 0;
}

-static int afs_begin_cache_operation(struct netfs_io_request *rreq)
-{
-#ifdef CONFIG_AFS_FSCACHE
- struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
-
- return fscache_begin_read_operation(&rreq->cache_resources,
- afs_vnode_cache(vnode));
-#else
- return -ENOBUFS;
-#endif
-}
-
static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
struct folio **foliop, void **_fsdata)
{
@@ -391,7 +379,6 @@ static void afs_free_request(struct netfs_io_request *rreq)
const struct netfs_request_ops afs_req_ops = {
.init_request = afs_init_request,
.free_request = afs_free_request,
- .begin_cache_operation = afs_begin_cache_operation,
.check_write_begin = afs_check_write_begin,
.issue_read = afs_issue_read,
};
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 13af429ab030..654f408a0aca 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -509,7 +509,6 @@ static void ceph_netfs_free_request(struct netfs_io_request *rreq)
const struct netfs_request_ops ceph_netfs_ops = {
.init_request = ceph_init_request,
.free_request = ceph_netfs_free_request,
- .begin_cache_operation = ceph_begin_cache_operation,
.issue_read = ceph_netfs_issue_read,
.expand_readahead = ceph_netfs_expand_readahead,
.clamp_length = ceph_netfs_clamp_length,
diff --git a/fs/ceph/cache.h b/fs/ceph/cache.h
index dc502daac49a..b804f1094764 100644
--- a/fs/ceph/cache.h
+++ b/fs/ceph/cache.h
@@ -57,13 +57,6 @@ static inline int ceph_fscache_dirty_folio(struct address_space *mapping,
return fscache_dirty_folio(mapping, folio, ceph_fscache_cookie(ci));
}

-static inline int ceph_begin_cache_operation(struct netfs_io_request *rreq)
-{
- struct fscache_cookie *cookie = ceph_fscache_cookie(ceph_inode(rreq->inode));
-
- return fscache_begin_read_operation(&rreq->cache_resources, cookie);
-}
-
static inline bool ceph_is_cache_enabled(struct inode *inode)
{
return fscache_cookie_enabled(ceph_fscache_cookie(ceph_inode(inode)));
@@ -135,11 +128,6 @@ static inline bool ceph_is_cache_enabled(struct inode *inode)
return false;
}

-static inline int ceph_begin_cache_operation(struct netfs_io_request *rreq)
-{
- return -ENOBUFS;
-}
-
static inline void ceph_fscache_note_page_release(struct inode *inode)
{
}
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 2cd3ccf4c439..d39d0ffe75d2 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -147,6 +147,15 @@ static void netfs_rreq_expand(struct netfs_io_request *rreq,
}
}

+/*
+ * Begin an operation, and fetch the stored zero point value from the cookie if
+ * available.
+ */
+static int netfs_begin_cache_read(struct netfs_io_request *rreq, struct netfs_inode *ctx)
+{
+ return fscache_begin_read_operation(&rreq->cache_resources, netfs_i_cookie(ctx));
+}
+
/**
* netfs_readahead - Helper to manage a read request
* @ractl: The description of the readahead request
@@ -180,11 +189,9 @@ void netfs_readahead(struct readahead_control *ractl)
if (IS_ERR(rreq))
return;

- if (ctx->ops->begin_cache_operation) {
- ret = ctx->ops->begin_cache_operation(rreq);
- if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
- goto cleanup_free;
- }
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto cleanup_free;

netfs_stat(&netfs_n_rh_readahead);
trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl),
@@ -238,11 +245,9 @@ int netfs_read_folio(struct file *file, struct folio *folio)
goto alloc_error;
}

- if (ctx->ops->begin_cache_operation) {
- ret = ctx->ops->begin_cache_operation(rreq);
- if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
- goto discard;
- }
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto discard;

netfs_stat(&netfs_n_rh_readpage);
trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);
@@ -390,11 +395,9 @@ int netfs_write_begin(struct netfs_inode *ctx,
rreq->no_unlock_folio = folio_index(folio);
__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);

- if (ctx->ops->begin_cache_operation) {
- ret = ctx->ops->begin_cache_operation(rreq);
- if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
- goto error_put;
- }
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto error_put;

netfs_stat(&netfs_n_rh_write_begin);
trace_netfs_read(rreq, pos, len, netfs_read_trace_write_begin);
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index b05717fe0d4e..2d1bfee225c3 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -274,12 +274,6 @@ static void nfs_netfs_free_request(struct netfs_io_request *rreq)
put_nfs_open_context(rreq->netfs_priv);
}

-static inline int nfs_netfs_begin_cache_operation(struct netfs_io_request *rreq)
-{
- return fscache_begin_read_operation(&rreq->cache_resources,
- netfs_i_cookie(netfs_inode(rreq->inode)));
-}
-
static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest *sreq)
{
struct nfs_netfs_io_data *netfs;
@@ -387,7 +381,6 @@ void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
const struct netfs_request_ops nfs_netfs_ops = {
.init_request = nfs_netfs_init_request,
.free_request = nfs_netfs_free_request,
- .begin_cache_operation = nfs_netfs_begin_cache_operation,
.issue_read = nfs_netfs_issue_read,
.clamp_length = nfs_netfs_clamp_length
};
diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index 8e312c8323a8..9ed6696aee7a 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -437,9 +437,6 @@ const struct netfs_cache_ops *fscache_operation_valid(const struct netfs_cache_r
* indicates the cache resources to which the operation state should be
* attached; @cookie indicates the cache object that will be accessed.
*
- * This is intended to be called from the ->begin_cache_operation() netfs lib
- * operation as implemented by the network filesystem.
- *
* @cres->inval_counter is set from @cookie->inval_counter for comparison at
* the end of the operation. This allows invalidation during the operation to
* be detected by the caller.
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index b11a84f6c32b..d294ff8f9ae4 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -208,7 +208,6 @@ struct netfs_io_request {
struct netfs_request_ops {
int (*init_request)(struct netfs_io_request *rreq, struct file *file);
void (*free_request)(struct netfs_io_request *rreq);
- int (*begin_cache_operation)(struct netfs_io_request *rreq);

void (*expand_readahead)(struct netfs_io_request *rreq);
bool (*clamp_length)(struct netfs_io_subrequest *subreq);
@@ -229,8 +228,7 @@ enum netfs_read_from_hole {
};

/*
- * Table of operations for access to a cache. This is obtained by
- * rreq->ops->begin_cache_operation().
+ * Table of operations for access to a cache.
*/
struct netfs_cache_ops {
/* End an operation */