NFSv3/v4: be more efficient when doing ACCESS RPC calls. Always ask

   for the full set of permissions.

Signed-off-by: Trond Myklebust <trond.myklebust@fys.uio.no>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index f061e70cdc7dd59a18dc9e054321a57ab1d66cfd..ba5171f147c560ce5c6e089be732184c2b3eb19d 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1498,10 +1498,56 @@ out:
        return error;
 }
 
-int
-nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
+static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res)
+{
+       struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
+
+       if (cache->cred != cred
+                       || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
+                       || (NFS_FLAGS(inode) & NFS_INO_INVALID_ATTR))
+               return -ENOENT;
+       memcpy(res, cache, sizeof(*res));
+       return 0;
+}
+
+static void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set)
+{
+       struct nfs_access_entry *cache = &NFS_I(inode)->cache_access;
+
+       if (cache->cred != set->cred) {
+               if (cache->cred)
+                       put_rpccred(cache->cred);
+               cache->cred = get_rpccred(set->cred);
+       }
+       cache->jiffies = set->jiffies;
+       cache->mask = set->mask;
+}
+
+static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
+{
+       struct nfs_access_entry cache;
+       int status;
+
+       status = nfs_access_get_cached(inode, cred, &cache);
+       if (status == 0)
+               goto out;
+
+       /* Be clever: ask server to check for all possible rights */
+       cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
+       cache.cred = cred;
+       cache.jiffies = jiffies;
+       status = NFS_PROTO(inode)->access(inode, &cache);
+       if (status != 0)
+               return status;
+       nfs_access_add_cache(inode, &cache);
+out:
+       if ((cache.mask & mask) == mask)
+               return 0;
+       return -EACCES;
+}
+
+int nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 {
-       struct nfs_access_cache *cache = &NFS_I(inode)->cache_access;
        struct rpc_cred *cred;
        int mode = inode->i_mode;
        int res;
@@ -1542,24 +1588,7 @@ nfs_permission(struct inode *inode, int mask, struct nameidata *nd)
                goto out_notsup;
 
        cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
-       if (cache->cred == cred
-           && time_before(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))
-           && !(NFS_FLAGS(inode) & NFS_INO_INVALID_ATTR)) {
-               if (!(res = cache->err)) {
-                       /* Is the mask a subset of an accepted mask? */
-                       if ((cache->mask & mask) == mask)
-                               goto out;
-               } else {
-                       /* ...or is it a superset of a rejected mask? */
-                       if ((cache->mask & mask) == cache->mask)
-                               goto out;
-               }
-       }
-
-       res = NFS_PROTO(inode)->access(inode, cred, mask);
-       if (!res || res == -EACCES)
-               goto add_cache;
-out:
+       res = nfs_do_access(inode, cred, mask);
        put_rpccred(cred);
        unlock_kernel();
        return res;
@@ -1568,15 +1597,6 @@ out_notsup:
        res = vfs_permission(inode, mask);
        unlock_kernel();
        return res;
-add_cache:
-       cache->jiffies = jiffies;
-       if (cache->cred)
-               put_rpccred(cache->cred);
-       cache->cred = cred;
-       cache->mask = mask;
-       cache->err = res;
-       unlock_kernel();
-       return res;
 }
 
 /*

diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index a759f5a5f8334cbba0ce97e4a5c20ffcf2a419c5..67c0793ef14391ee9056d5f0ee579b81ff20b714 100644 (file)
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -164,8 +164,7 @@ nfs3_proc_lookup(struct inode *dir, struct qstr *name,
        return status;
 }
 
-static int
-nfs3_proc_access(struct inode *inode, struct rpc_cred *cred, int mode)
+static int nfs3_proc_access(struct inode *inode, struct nfs_access_entry *entry)
 {
        struct nfs_fattr        fattr;
        struct nfs3_accessargs  arg = {
@@ -178,9 +177,10 @@ nfs3_proc_access(struct inode *inode, struct rpc_cred *cred, int mode)
                .rpc_proc       = &nfs3_procedures[NFS3PROC_ACCESS],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
-               .rpc_cred       = cred
+               .rpc_cred       = entry->cred
        };
-       int     status;
+       int mode = entry->mask;
+       int status;
 
        dprintk("NFS call  access\n");
        fattr.valid = 0;
@@ -200,10 +200,16 @@ nfs3_proc_access(struct inode *inode, struct rpc_cred *cred, int mode)
        }
        status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
        nfs_refresh_inode(inode, &fattr);
-       dprintk("NFS reply access\n");
-
-       if (status == 0 && (arg.access & res.access) != arg.access)
-               status = -EACCES;
+       if (status == 0) {
+               entry->mask = 0;
+               if (res.access & NFS3_ACCESS_READ)
+                       entry->mask |= MAY_READ;
+               if (res.access & (NFS3_ACCESS_MODIFY | NFS3_ACCESS_EXTEND | NFS3_ACCESS_DELETE))
+                       entry->mask |= MAY_WRITE;
+               if (res.access & (NFS3_ACCESS_LOOKUP|NFS3_ACCESS_EXECUTE))
+                       entry->mask |= MAY_EXEC;
+       }
+       dprintk("NFS reply access, status = %d\n", status);
        return status;
 }
 

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 2eb124475a23a5123419c15c45971614ab5e441d..1fab10970a2816d82d007ec6445aa688d1b9c4c9 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -734,9 +734,8 @@ static int nfs4_proc_lookup(struct inode *dir, struct qstr *name,
        return nfs4_map_errors(status);
 }
 
-static int nfs4_proc_access(struct inode *inode, struct rpc_cred *cred, int mode)
+static int nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
 {
-       int                     status;
        struct nfs4_accessargs args = {
                .fh = NFS_FH(inode),
        };
@@ -745,8 +744,10 @@ static int nfs4_proc_access(struct inode *inode, struct rpc_cred *cred, int mode
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_ACCESS],
                .rpc_argp = &args,
                .rpc_resp = &res,
-               .rpc_cred = cred,
+               .rpc_cred = entry->cred,
        };
+       int mode = entry->mask;
+       int status;
 
        /*
         * Determine which access bits we want to ask for...
@@ -758,8 +759,7 @@ static int nfs4_proc_access(struct inode *inode, struct rpc_cred *cred, int mode
                        args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE;
                if (mode & MAY_EXEC)
                        args.access |= NFS4_ACCESS_LOOKUP;
-       }
-       else {
+       } else {
                if (mode & MAY_WRITE)
                        args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND;
                if (mode & MAY_EXEC)
@@ -767,11 +767,13 @@ static int nfs4_proc_access(struct inode *inode, struct rpc_cred *cred, int mode
        }
        status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
        if (!status) {
-               if (args.access != res.supported) {
-                       printk(KERN_NOTICE "NFS: server didn't support all access bits!\n");
-                       status = -ENOTSUPP;
-               } else if ((args.access & res.access) != args.access)
-                       status = -EACCES;
+               entry->mask = 0;
+               if (res.access & NFS4_ACCESS_READ)
+                       entry->mask |= MAY_READ;
+               if (res.access & (NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE))
+                       entry->mask |= MAY_WRITE;
+               if (res.access & (NFS4_ACCESS_LOOKUP|NFS4_ACCESS_EXECUTE))
+                       entry->mask |= MAY_EXEC;
        }
        return nfs4_map_errors(status);
 }

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 0fd3f817831eafeff81c07b6b2e182c2b7d612b7..e50205d31df3f0295cbf09587dd3f91fcb365302 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -75,13 +75,12 @@
 #ifdef __KERNEL__
 
 /*
- * NFSv3 Access mode cache
+ * NFSv3/v4 Access mode cache entry
  */
-struct nfs_access_cache {
+struct nfs_access_entry {
        unsigned long           jiffies;
        struct rpc_cred *       cred;
        int                     mask;
-       int                     err;
 };
 
 /*
@@ -137,7 +136,7 @@ struct nfs_inode {
         */
        atomic_t                data_updates;
 
-       struct nfs_access_cache cache_access;
+       struct nfs_access_entry cache_access;
 
        /*
         * This is the cookie verifier used for NFSv3 readdir

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index f47e3c27af27f64fede2dd7cdcd2a09dc3fd04b1..2c7f4617e650e3740a82b9731a15ab589681560d 100644 (file)
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -657,6 +657,8 @@ struct nfs_write_data {
        void (*complete) (struct nfs_write_data *, int);
 };
 
+struct nfs_access_entry;
+
 /*
  * RPC procedure vector for NFSv2/NFSv3 demuxing
  */
@@ -672,7 +674,7 @@ struct nfs_rpc_ops {
                            struct iattr *);
        int     (*lookup)  (struct inode *, struct qstr *,
                            struct nfs_fh *, struct nfs_fattr *);
-       int     (*access)  (struct inode *, struct rpc_cred *, int);
+       int     (*access)  (struct inode *, struct nfs_access_entry *);
        int     (*readlink)(struct inode *, struct page *);
        int     (*read)    (struct nfs_read_data *, struct file *);
        int     (*write)   (struct nfs_write_data *, struct file *);