ceph: perform lazy reads when file mode and caps permit

If the file mode is marked as "lazy," perform cached/buffered reads when
the caps permit it.  Adjust the rdcache_gen and invalidation logic
accordingly so that we manage our cache based on the FILE_CACHE -or-
FILE_LAZYIO cap bits.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 10 insertions, 6 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 1a70a3ebf013..b28915d5f404 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -482,8 +482,8 @@ static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
          * Each time we receive FILE_CACHE anew, we increment
          * i_rdcache_gen.
          */
-        if ((issued & CEPH_CAP_FILE_CACHE) &&
-            (had & CEPH_CAP_FILE_CACHE) == 0)
+        if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
+            (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
                 ci->i_rdcache_gen++;
 
         /*
@@ -1509,11 +1509,13 @@ retry_locked:
             ci->i_wrbuffer_ref == 0 &&               /* no dirty pages... */
             ci->i_rdcache_gen &&                     /* may have cached pages */
             (file_wanted == 0 ||                     /* no open files */
-             (revoking & CEPH_CAP_FILE_CACHE)) &&     /*  or revoking cache */
+             (revoking & (CEPH_CAP_FILE_CACHE|
+                          CEPH_CAP_FILE_LAZYIO))) && /*  or revoking cache */
             !tried_invalidate) {
                 dout("check_caps trying to invalidate on %p\n", inode);
                 if (try_nonblocking_invalidate(inode) < 0) {
-                        if (revoking & CEPH_CAP_FILE_CACHE) {
+                        if (revoking & (CEPH_CAP_FILE_CACHE|
+                                        CEPH_CAP_FILE_LAZYIO)) {
                                 dout("check_caps queuing invalidate\n");
                                 queue_invalidate = 1;
                                 ci->i_rdcache_revoking = ci->i_rdcache_gen;
@@ -2276,7 +2278,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
          * try to invalidate (once).  (If there are dirty buffers, we
          * will invalidate _after_ writeback.)
          */
-        if (((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
+        if (((cap->issued & ~newcaps) & (CEPH_CAP_FILE_CACHE|
+                                         CEPH_CAP_FILE_LAZYIO)) &&
             !ci->i_wrbuffer_ref) {
                 if (try_nonblocking_invalidate(inode) == 0) {
                         revoked_rdcache = 1;
@@ -2374,7 +2377,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
                         writeback = 1; /* will delay ack */
                 else if (dirty & ~newcaps)
                         check_caps = 1;  /* initiate writeback in check_caps */
-                else if (((used & ~newcaps) & CEPH_CAP_FILE_CACHE) == 0 ||
+                else if (((used & ~newcaps) & (CEPH_CAP_FILE_CACHE|
+                                               CEPH_CAP_FILE_LAZYIO)) == 0 ||
                            revoked_rdcache)
                         check_caps = 2;     /* send revoke ack in check_caps */
                 cap->issued = newcaps;