[PATCH 4/6] ceph: convert readpage to fscache read helper

Jeff Layton
2021-01-26T14:09:45Z

Have the ceph KConfig select NETFS_SUPPORT. Add a new netfs ops
structure and the operations for it. Convert ceph_readpage to use
the new netfs_readpage helper.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/Kconfig | 1 +
fs/ceph/addr.c | 149 ++++++++++++++++++++++++++++++++++++++++++++----
fs/ceph/cache.h | 36 ++++++++++++
3 files changed, 176 insertions(+), 10 deletions(-)

diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
index 471e40156065..94df854147d3 100644
--- a/fs/ceph/Kconfig
+++ b/fs/ceph/Kconfig
@@ -6,6 +6,7 @@ config CEPH_FS
select LIBCRC32C
select CRYPTO_AES
select CRYPTO
+ select NETFS_SUPPORT
default n
help
Choose Y or M here to include support for mounting the
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index fbfa49db06fd..9ae6c0fddb80 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -12,6 +12,7 @@
#include <linux/signal.h>
#include <linux/iversion.h>
#include <linux/ktime.h>
+#include <linux/netfs.h>

#include "super.h"
#include "mds_client.h"
@@ -183,6 +184,144 @@ static int ceph_releasepage(struct page *page, gfp_t gfp_flags)
return !PagePrivate(page);
}

+static bool ceph_netfs_clamp_length(struct netfs_read_subrequest *subreq)
+{
+ struct inode *inode = subreq->rreq->mapping->host;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ u64 objno, objoff;
+ u32 xlen;
+
+ /* Truncate the extent at the end of the current object */
+ ceph_calc_file_object_mapping(&ci->i_layout, subreq->start, subreq->len,
+ &objno, &objoff, &xlen);
+ subreq->len = xlen;
+ return true;
+}
+
+static void finish_netfs_read(struct ceph_osd_request *req)
+{
+ struct ceph_fs_client *fsc = ceph_inode_to_client(req->r_inode);
+ struct ceph_osd_data *osd_data = osd_req_op_extent_osd_data(req, 0);
+ struct netfs_read_subrequest *subreq = req->r_priv;
+ int num_pages;
+ int err = req->r_result;
+
+ ceph_update_read_latency(&fsc->mdsc->metric, req->r_start_latency,
+ req->r_end_latency, err);
+
+ dout("%s: result %d subreq->len=%zu i_size=%lld\n", __func__, req->r_result,
+ subreq->len, i_size_read(req->r_inode));
+
+ /* no object means success but no data */
+ if (err == -ENOENT)
+ err = 0;
+ else if (err == -EBLOCKLISTED)
+ fsc->blocklisted = true;
+
+ if (err >= 0 && err < subreq->len)
+ __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+
+ netfs_subreq_terminated(subreq, err);
+
+ num_pages = calc_pages_for(osd_data->alignment, osd_data->length);
+ ceph_put_page_vector(osd_data->pages, num_pages, false);
+ iput(req->r_inode);
+}
+
+static void ceph_netfs_issue_op(struct netfs_read_subrequest *subreq)
+{
+ struct netfs_read_request *rreq = subreq->rreq;
+ struct inode *inode = rreq->mapping->host;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+ struct ceph_osd_request *req = NULL;
+ struct ceph_vino vino = ceph_vino(inode);
+ struct iov_iter iter;
+ struct page **pages;
+ size_t page_off;
+ int err = 0;
+ u64 len = subreq->len;
+
+ req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, vino, subreq->start, &len,
+ 0, 1, CEPH_OSD_OP_READ,
+ CEPH_OSD_FLAG_READ | fsc->client->osdc.client->options->read_from_replica,
+ NULL, ci->i_truncate_seq, ci->i_truncate_size, false);
+ if (IS_ERR(req)) {
+ err = PTR_ERR(req);
+ goto out;
+ }
+
+ dout("%s: pos=%llu orig_len=%zu len=%llu\n", __func__, subreq->start, subreq->len, len);
+ iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start, len);
+ err = iov_iter_get_pages_alloc(&iter, &pages, len, &page_off);
+ if (err < 0) {
+ dout("%s: iov_ter_get_pages_alloc returned %d\n", __func__, err);
+ goto out;
+ }
+
+ /* should always give us a page-aligned read */
+ WARN_ON_ONCE(page_off);
+ len = err;
+
+ osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
+ req->r_callback = finish_netfs_read;
+ req->r_priv = subreq;
+ req->r_inode = inode;
+ ihold(inode);
+
+ err = ceph_osdc_start_request(req->r_osdc, req, false);
+ if (err)
+ iput(inode);
+out:
+ if (req)
+ ceph_osdc_put_request(req);
+ if (err)
+ netfs_subreq_terminated(subreq, err);
+ dout("%s: result %d\n", __func__, err);
+}
+
+static void ceph_init_rreq(struct netfs_read_request *rreq, struct file *file)
+{
+}
+
+const struct netfs_read_request_ops ceph_readpage_netfs_ops = {
+ .init_rreq = ceph_init_rreq,
+ .is_cache_enabled = ceph_is_cache_enabled,
+ .begin_cache_operation = ceph_begin_cache_operation,
+ .issue_op = ceph_netfs_issue_op,
+ .clamp_length = ceph_netfs_clamp_length,
+};
+
+/* read a single page, without unlocking it. */
+static int ceph_readpage(struct file *file, struct page *page)
+{
+ struct inode *inode = file_inode(file);
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_vino vino = ceph_vino(inode);
+ u64 off = page_offset(page);
+ u64 len = PAGE_SIZE;
+
+ if (ci->i_inline_version != CEPH_INLINE_NONE) {
+ /*
+ * Uptodate inline data should have been added
+ * into page cache while getting Fcr caps.
+ */
+ if (off == 0) {
+ unlock_page(page);
+ return -EINVAL;
+ }
+ zero_user_segment(page, 0, PAGE_SIZE);
+ SetPageUptodate(page);
+ unlock_page(page);
+ return 0;
+ }
+
+ dout("readpage ino %llx.%llx file %p off %llu len %llu page %p index %lu\n",
+ vino.ino, vino.snap, file, off, len, page, page->index);
+
+ return netfs_readpage(file, page, &ceph_readpage_netfs_ops, NULL);
+}
+
/* read a single page, without unlocking it. */
static int ceph_do_readpage(struct file *filp, struct page *page)
{
@@ -253,16 +392,6 @@ static int ceph_do_readpage(struct file *filp, struct page *page)
return err < 0 ? err : 0;
}

-static int ceph_readpage(struct file *filp, struct page *page)
-{
- int r = ceph_do_readpage(filp, page);
- if (r != -EINPROGRESS)
- unlock_page(page);
- else
- r = 0;
- return r;
-}
-
/*
* Finish an async read(ahead) op.
*/
diff --git a/fs/ceph/cache.h b/fs/ceph/cache.h
index 10c21317b62f..1409d6149281 100644
--- a/fs/ceph/cache.h
+++ b/fs/ceph/cache.h
@@ -9,6 +9,8 @@
#ifndef _CEPH_CACHE_H
#define _CEPH_CACHE_H

+#include <linux/netfs.h>
+
#ifdef CONFIG_CEPH_FSCACHE

extern struct fscache_netfs ceph_cache_netfs;
@@ -35,11 +37,31 @@ static inline void ceph_fscache_inode_init(struct ceph_inode_info *ci)
ci->fscache = NULL;
}

+static inline struct fscache_cookie *ceph_fscache_cookie(struct ceph_inode_info *ci)
+{
+ return ci->fscache;
+}
+
static inline void ceph_fscache_invalidate(struct inode *inode)
{
fscache_invalidate(ceph_inode(inode)->fscache);
}

+static inline bool ceph_is_cache_enabled(struct inode *inode)
+{
+ struct fscache_cookie *cookie = ceph_fscache_cookie(ceph_inode(inode));
+
+ if (!cookie)
+ return false;
+ return fscache_cookie_enabled(cookie);
+}
+
+static inline int ceph_begin_cache_operation(struct netfs_read_request *rreq)
+{
+ struct fscache_cookie *cookie = ceph_fscache_cookie(ceph_inode(rreq->inode));
+
+ return fscache_begin_read_operation(rreq, cookie);
+}
#else

static inline int ceph_fscache_register(void)
@@ -65,6 +87,11 @@ static inline void ceph_fscache_inode_init(struct ceph_inode_info *ci)
{
}

+static inline struct fscache_cookie *ceph_fscache_cookie(struct ceph_inode_info *ci)
+{
+ return NULL;
+}
+
static inline void ceph_fscache_register_inode_cookie(struct inode *inode)
{
}
@@ -82,6 +109,15 @@ static inline void ceph_fscache_invalidate(struct inode *inode)
{
}

+static inline bool ceph_is_cache_enabled(struct inode *inode)
+{
+ return false;
+}
+
+static inline int ceph_begin_cache_operation(struct netfs_read_request *rreq)
+{
+ return -ENOBUFS;
+}
#endif

#endif /* _CEPH_CACHE_H */
--
2.29.2