ceph: Make ceph_init_request() check caps on readahead

Move the caps check from ceph_readahead() to ceph_init_request(),
conditional on the origin being NETFS_READAHEAD so that in a future patch,
ceph can point its ->readahead() vector directly at netfs_readahead().

Changes
=======
ver #4)
 - Move the check for NETFS_READAHEAD up in ceph_init_request()[2].

ver #3)
 - Split from the patch to add a netfs inode context[1].
 - Need to store the caps got in rreq->netfs_priv for later freeing.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: ceph-devel@vger.kernel.org
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/8af0d47f17d89c06bbf602496dd845f2b0bf25b3.camel@kernel.org/
Link: https://lore.kernel.org/r/dd054c962818716e718bd9b446ee5322ca097675.camel@redhat.com/
Link: https://lore.kernel.org/r/164692907694.2099075.10081819855690054094.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/2533821.1647006574@warthog.procyon.org.uk/

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 9189257..4aeccaf 100644 (file)
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -354,6 +354,45 @@ out:
        dout("%s: result %d\n", __func__, err);
 }
 
+static int ceph_init_request(struct netfs_io_request *rreq, struct file *file)
+{
+       struct inode *inode = rreq->inode;
+       int got = 0, want = CEPH_CAP_FILE_CACHE;
+       int ret = 0;
+
+       if (rreq->origin != NETFS_READAHEAD)
+               return 0;
+
+       if (file) {
+               struct ceph_rw_context *rw_ctx;
+               struct ceph_file_info *fi = file->private_data;
+
+               rw_ctx = ceph_find_rw_context(fi);
+               if (rw_ctx)
+                       return 0;
+       }
+
+       /*
+        * readahead callers do not necessarily hold Fcb caps
+        * (e.g. fadvise, madvise).
+        */
+       ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want, true, &got);
+       if (ret < 0) {
+               dout("start_read %p, error getting cap\n", inode);
+               return ret;
+       }
+
+       if (!(got & want)) {
+               dout("start_read %p, no cache cap\n", inode);
+               return -EACCES;
+       }
+       if (ret == 0)
+               return -EACCES;
+
+       rreq->netfs_priv = (void *)(uintptr_t)got;
+       return 0;
+}
+
 static void ceph_readahead_cleanup(struct address_space *mapping, void *priv)
 {
        struct inode *inode = mapping->host;
@@ -365,7 +404,7 @@ static void ceph_readahead_cleanup(struct address_space *mapping, void *priv)
 }
 
 static const struct netfs_request_ops ceph_netfs_read_ops = {
-       .is_cache_enabled       = ceph_is_cache_enabled,
+       .init_request           = ceph_init_request,
        .begin_cache_operation  = ceph_begin_cache_operation,
        .issue_read             = ceph_netfs_issue_read,
        .expand_readahead       = ceph_netfs_expand_readahead,
@@ -393,33 +432,7 @@ static int ceph_readpage(struct file *file, struct page *subpage)
 
 static void ceph_readahead(struct readahead_control *ractl)
 {
-       struct inode *inode = file_inode(ractl->file);
-       struct ceph_file_info *fi = ractl->file->private_data;
-       struct ceph_rw_context *rw_ctx;
-       int got = 0;
-       int ret = 0;
-
-       if (ceph_inode(inode)->i_inline_version != CEPH_INLINE_NONE)
-               return;
-
-       rw_ctx = ceph_find_rw_context(fi);
-       if (!rw_ctx) {
-               /*
-                * readahead callers do not necessarily hold Fcb caps
-                * (e.g. fadvise, madvise).
-                */
-               int want = CEPH_CAP_FILE_CACHE;
-
-               ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want, true, &got);
-               if (ret < 0)
-                       dout("start_read %p, error getting cap\n", inode);
-               else if (!(got & want))
-                       dout("start_read %p, no cache cap\n", inode);
-
-               if (ret <= 0)
-                       return;
-       }
-       netfs_readahead(ractl, &ceph_netfs_read_ops, (void *)(uintptr_t)got);
+       netfs_readahead(ractl, &ceph_netfs_read_ops, NULL);
 }
 
 #ifdef CONFIG_CEPH_FSCACHE