NFSv4.1: Enable open-by-filehandle

Sometimes, we actually _want_ to do open-by-filehandle, for instance
when recovering opens after a network partition, or when called
from nfs4_file_open.
Enable that functionality using a new capability NFS_CAP_ATOMIC_OPEN_V1,
and which is only enabled for NFSv4.1 servers that support it.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index f23f455..e093e73 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1486,6 +1486,8 @@ static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags)
                goto no_open;
        if (d_mountpoint(dentry))
                goto no_open;
+       if (NFS_SB(dentry->d_sb)->caps & NFS_CAP_ATOMIC_OPEN_V1)
+               goto no_open;
 
        inode = dentry->d_inode;
        parent = dget_parent(dentry);

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 7bbb06f..732b76f 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -767,6 +767,35 @@ struct nfs4_opendata {
        int cancelled;
 };
 
+static bool nfs4_clear_cap_atomic_open_v1(struct nfs_server *server,
+               int err, struct nfs4_exception *exception)
+{
+       if (err != -EINVAL)
+               return false;
+       if (!(server->caps & NFS_CAP_ATOMIC_OPEN_V1))
+               return false;
+       server->caps &= ~NFS_CAP_ATOMIC_OPEN_V1;
+       exception->retry = 1;
+       return true;
+}
+
+static enum open_claim_type4
+nfs4_map_atomic_open_claim(struct nfs_server *server,
+               enum open_claim_type4 claim)
+{
+       if (server->caps & NFS_CAP_ATOMIC_OPEN_V1)
+               return claim;
+       switch (claim) {
+       default:
+               return claim;
+       case NFS4_OPEN_CLAIM_FH:
+               return NFS4_OPEN_CLAIM_NULL;
+       case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
+               return NFS4_OPEN_CLAIM_DELEGATE_CUR;
+       case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
+               return NFS4_OPEN_CLAIM_DELEGATE_PREV;
+       }
+}
 
 static void nfs4_init_opendata_res(struct nfs4_opendata *p)
 {
@@ -818,8 +847,8 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
        p->o_arg.server = server;
        p->o_arg.bitmask = server->attr_bitmask;
        p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
-       p->o_arg.claim = claim;
-       switch (claim) {
+       p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
+       switch (p->o_arg.claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
@@ -1326,6 +1355,8 @@ static int nfs4_do_open_reclaim(struct nfs_open_context *ctx, struct nfs4_state
        int err;
        do {
                err = _nfs4_do_open_reclaim(ctx, state);
+               if (nfs4_clear_cap_atomic_open_v1(server, err, &exception))
+                       continue;
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
@@ -1741,7 +1772,7 @@ static int _nfs4_open_expired(struct nfs_open_context *ctx, struct nfs4_state *s
        int ret;
 
        opendata = nfs4_open_recoverdata_alloc(ctx, state,
-                       NFS4_OPEN_CLAIM_NULL);
+                       NFS4_OPEN_CLAIM_FH);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        ret = nfs4_open_recover(opendata, state);
@@ -1759,6 +1790,8 @@ static int nfs4_do_open_expired(struct nfs_open_context *ctx, struct nfs4_state
 
        do {
                err = _nfs4_open_expired(ctx, state);
+               if (nfs4_clear_cap_atomic_open_v1(server, err, &exception))
+                       continue;
                switch (err) {
                default:
                        goto out;
@@ -1926,6 +1959,7 @@ static int _nfs4_do_open(struct inode *dir,
        struct nfs4_state     *state = NULL;
        struct nfs_server       *server = NFS_SERVER(dir);
        struct nfs4_opendata *opendata;
+       enum open_claim_type4 claim = NFS4_OPEN_CLAIM_NULL;
        int status;
 
        /* Protect against reboot recovery conflicts */
@@ -1941,9 +1975,10 @@ static int _nfs4_do_open(struct inode *dir,
        if (dentry->d_inode != NULL)
                nfs4_return_incompatible_delegation(dentry->d_inode, fmode);
        status = -ENOMEM;
+       if (dentry->d_inode)
+               claim = NFS4_OPEN_CLAIM_FH;
        opendata = nfs4_opendata_alloc(dentry, sp, fmode, flags, sattr,
-                       NFS4_OPEN_CLAIM_NULL,
-                       GFP_KERNEL);
+                       claim, GFP_KERNEL);
        if (opendata == NULL)
                goto err_put_state_owner;
 
@@ -2001,6 +2036,7 @@ static struct nfs4_state *nfs4_do_open(struct inode *dir,
                                        struct rpc_cred *cred,
                                        struct nfs4_threshold **ctx_th)
 {
+       struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_exception exception = { };
        struct nfs4_state *res;
        int status;
@@ -2044,7 +2080,9 @@ static struct nfs4_state *nfs4_do_open(struct inode *dir,
                        exception.retry = 1;
                        continue;
                }
-               res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),
+               if (nfs4_clear_cap_atomic_open_v1(server, status, &exception))
+                       continue;
+               res = ERR_PTR(nfs4_handle_exception(server,
                                        status, &exception));
        } while (exception.retry);
        return res;
@@ -6858,7 +6896,8 @@ static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
                | NFS_CAP_ATOMIC_OPEN
                | NFS_CAP_CHANGE_ATTR
                | NFS_CAP_POSIX_LOCK
-               | NFS_CAP_STATEID_NFSV41,
+               | NFS_CAP_STATEID_NFSV41
+               | NFS_CAP_ATOMIC_OPEN_V1,
        .call_sync = nfs4_call_sync_sequence,
        .match_stateid = nfs41_match_stateid,
        .find_root_sec = nfs41_find_root_sec,

diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 74c9e52..d8fdfdc 100644 (file)
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -198,5 +198,6 @@ struct nfs_server {
 #define NFS_CAP_POSIX_LOCK     (1U << 14)
 #define NFS_CAP_UIDGID_NOMAP   (1U << 15)
 #define NFS_CAP_STATEID_NFSV41 (1U << 16)
+#define NFS_CAP_ATOMIC_OPEN_V1 (1U << 17)
 
 #endif