ceph: enable/disable dentry complete flags via mount option

Enable/disable use of the dentry dir 'complete' flag via a mount option.
This lets the admin control whether ceph uses the dcache to satisfy
negative lookups or readdir when it has the entire directory contents in
its cache.

This is purely a performance optimization; correctness is guaranteed
whether it is enabled or not.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>

diff --git a/Documentation/filesystems/ceph.txt b/Documentation/filesystems/ceph.txt
index 763d8ebbbebdeb59129742daa5f5b7a105ac8fbb..d6030aa3337605e7550397a303820952c8666bc8 100644 (file)
--- a/Documentation/filesystems/ceph.txt
+++ b/Documentation/filesystems/ceph.txt
@@ -119,12 +119,20 @@ Mount Options
        must rely on TCP's error correction to detect data corruption
        in the data payload.
 
-  noasyncreaddir
-       Disable client's use its local cache to satisfy readdir
-       requests.  (This does not change correctness; the client uses
-       cached metadata only when a lease or capability ensures it is
-       valid.)
+  dcache
+        Use the dcache contents to perform negative lookups and
+        readdir when the client has the entire directory contents in
+        its cache.  (This does not change correctness; the client uses
+        cached metadata only when a lease or capability ensures it is
+        valid.)
+
+  nodcache
+        Do not use the dcache as above.  This avoids a significant amount of
+        complex code, sacrificing performance without affecting correctness,
+        and is useful for tracking down bugs.
 
+  noasyncreaddir
+       Do not use the dcache as above for readdir.
 
 More Information
 ================

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 974ef1e4d268b46f6e3d7eebd9468c03e71bc627..5259abfb5dd947a69feb169f2f2c9f358eb9756a 100644 (file)
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1094,17 +1094,36 @@ static int ceph_snapdir_d_revalidate(struct dentry *dentry,
  */
 void ceph_dir_set_complete(struct inode *inode)
 {
-       /* not yet implemented */
+       struct dentry *dentry = d_find_any_alias(inode);
+       
+       if (dentry && ceph_dentry(dentry) &&
+           ceph_test_mount_opt(ceph_sb_to_client(dentry->d_sb), DCACHE)) {
+               dout(" marking %p (%p) complete\n", inode, dentry);
+               set_bit(CEPH_D_COMPLETE, &ceph_dentry(dentry)->flags);
+       }
+       dput(dentry);
 }
 
 void ceph_dir_clear_complete(struct inode *inode)
 {
-       /* not yet implemented */
+       struct dentry *dentry = d_find_any_alias(inode);
+
+       if (dentry && ceph_dentry(dentry)) {
+               dout(" marking %p (%p) complete\n", inode, dentry);
+               set_bit(CEPH_D_COMPLETE, &ceph_dentry(dentry)->flags);
+       }
+       dput(dentry);
 }
 
 bool ceph_dir_test_complete(struct inode *inode)
 {
-       /* not yet implemented */
+       struct dentry *dentry = d_find_any_alias(inode);
+
+       if (dentry && ceph_dentry(dentry)) {
+               dout(" marking %p (%p) NOT complete\n", inode, dentry);
+               clear_bit(CEPH_D_COMPLETE, &ceph_dentry(dentry)->flags);
+       }
+       dput(dentry);
        return false;
 }
 

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index ec74313e901f2e3c2f40d8ad3351b16aebfc86bc..9c62fe02ce05f259d7b9e90f7c021f97ddb00048 100644 (file)
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -131,6 +131,8 @@ enum {
        Opt_rbytes,
        Opt_norbytes,
        Opt_noasyncreaddir,
+       Opt_dcache,
+       Opt_nodcache,
        Opt_ino32,
 };
 
@@ -152,6 +154,8 @@ static match_table_t fsopt_tokens = {
        {Opt_rbytes, "rbytes"},
        {Opt_norbytes, "norbytes"},
        {Opt_noasyncreaddir, "noasyncreaddir"},
+       {Opt_dcache, "dcache"},
+       {Opt_nodcache, "nodcache"},
        {Opt_ino32, "ino32"},
        {-1, NULL}
 };
@@ -231,6 +235,12 @@ static int parse_fsopt_token(char *c, void *private)
        case Opt_noasyncreaddir:
                fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;
                break;
+       case Opt_dcache:
+               fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;
+               break;
+       case Opt_nodcache:
+               fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;
+               break;
        case Opt_ino32:
                fsopt->flags |= CEPH_MOUNT_OPT_INO32;
                break;
@@ -377,6 +387,10 @@ static int ceph_show_options(struct seq_file *m, struct vfsmount *mnt)
                seq_puts(m, ",norbytes");
        if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)
                seq_puts(m, ",noasyncreaddir");
+       if (fsopt->flags & CEPH_MOUNT_OPT_DCACHE)
+               seq_puts(m, ",dcache");
+       else
+               seq_puts(m, ",nodcache");
 
        if (fsopt->wsize)
                seq_printf(m, ",wsize=%d", fsopt->wsize);

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index edcbf3774a56460d377b31a9d51ea543a114a839..140f99f978c4052c70676f683334c51c4da1947a 100644 (file)
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -28,6 +28,7 @@
 #define CEPH_MOUNT_OPT_RBYTES          (1<<5) /* dir st_bytes = rbytes */
 #define CEPH_MOUNT_OPT_NOASYNCREADDIR  (1<<7) /* no dcache readdir */
 #define CEPH_MOUNT_OPT_INO32           (1<<8) /* 32 bit inos */
+#define CEPH_MOUNT_OPT_DCACHE          (1<<9) /* use dcache for readdir etc */
 
 #define CEPH_MOUNT_OPT_DEFAULT    (CEPH_MOUNT_OPT_RBYTES)