ceph: use fscache as a local presisent cache

Adding support for fscache to the Ceph filesystem. This would bring it to on
par with some of the other network filesystems in Linux (like NFS, AFS, etc...)

In order to mount the filesystem with fscache the 'fsc' mount option must be
passed.

Signed-off-by: Milosz Tanski <milosz@adfin.com>
Signed-off-by: Sage Weil <sage@inktank.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 5a26bc1..7b451eb 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -10,6 +10,7 @@
 
 #include "super.h"
 #include "mds_client.h"
+#include "cache.h"
 #include <linux/ceph/decode.h>
 #include <linux/ceph/messenger.h>
 
@@ -479,8 +480,9 @@ static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
 	 * i_rdcache_gen.
 	 */
 	if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
-	    (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
+	    (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) {
 		ci->i_rdcache_gen++;
+	}
 
 	/*
 	 * if we are newly issued FILE_SHARED, mark dir not complete; we
@@ -2395,6 +2397,7 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
 	int writeback = 0;
 	int queue_invalidate = 0;
 	int deleted_inode = 0;
+	int queue_revalidate = 0;
 
 	dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
 	     inode, cap, mds, seq, ceph_cap_string(newcaps));
@@ -2417,6 +2420,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
 				ci->i_rdcache_revoking = ci->i_rdcache_gen;
 			}
 		}
+
+		ceph_fscache_invalidate(inode);
 	}
 
 	/* side effects now are allowed */
@@ -2458,6 +2463,11 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
 		}
 	}
 
+	/* Do we need to revalidate our fscache cookie. Don't bother on the
+	 * first cache cap as we already validate at cookie creation time. */
+	if ((issued & CEPH_CAP_FILE_CACHE) && ci->i_rdcache_gen > 1)
+		queue_revalidate = 1;
+
 	/* size/ctime/mtime/atime? */
 	ceph_fill_file_size(inode, issued,
 			    le32_to_cpu(grant->truncate_seq),
@@ -2542,6 +2552,7 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
 	BUG_ON(cap->issued & ~cap->implemented);
 
 	spin_unlock(&ci->i_ceph_lock);
+
 	if (writeback)
 		/*
 		 * queue inode for writeback: we can't actually call
@@ -2553,6 +2564,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
 		ceph_queue_invalidate(inode);
 	if (deleted_inode)
 		invalidate_aliases(inode);
+	if (queue_revalidate)
+		ceph_queue_revalidate(inode);
 	if (wake)
 		wake_up_all(&ci->i_cap_wq);
 
@@ -2709,8 +2722,10 @@ static void handle_cap_trunc(struct inode *inode,
 					  truncate_seq, truncate_size, size);
 	spin_unlock(&ci->i_ceph_lock);
 
-	if (queue_trunc)
+	if (queue_trunc) {
 		ceph_queue_vmtruncate(inode);
+		ceph_fscache_invalidate(inode);
+	}
 }
 
 /*