NFS: Use cached page as buffer for NFS symlink requests

Now that we have a copy of the symlink path in the page cache, we can pass
a struct page down to the XDR routines instead of a string buffer.

Test plan:
Connectathon, all NFS versions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

8 files changed, 59 insertions, 42 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b483e5d206cb..51328ae640dd 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1464,10 +1464,6 @@ static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *sym
         char *kaddr;
         struct iattr attr;
         unsigned int pathlen = strlen(symname);
-        struct qstr qsymname = {
-                .name   = symname,
-                .len    = pathlen,
-        };
         int error;
 
         dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s)\n", dir->i_sb->s_id,
@@ -1493,10 +1489,8 @@ static int nfs_symlink(struct inode *dir, struct dentry *dentry, const char *sym
                 memset(kaddr + pathlen, 0, PAGE_SIZE - pathlen);
         kunmap_atomic(kaddr, KM_USER0);
 
-        /* XXX: eventually this will pass in {page, pathlen},
-         *      instead of qsymname; need XDR changes for that */
         nfs_begin_data_update(dir);
-        error = NFS_PROTO(dir)->symlink(dir, dentry, &qsymname, &attr);
+        error = NFS_PROTO(dir)->symlink(dir, dentry, page, pathlen, &attr);
         nfs_end_data_update(dir);
         if (error != 0) {
                 dfprintk(VFS, "NFS: symlink(%s/%ld, %s, %s) error %d\n",
diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index 67391eef6b93..b49501fc0a79 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -51,7 +51,7 @@
 #define NFS_createargs_sz       (NFS_diropargs_sz+NFS_sattr_sz)
 #define NFS_renameargs_sz       (NFS_diropargs_sz+NFS_diropargs_sz)
 #define NFS_linkargs_sz         (NFS_fhandle_sz+NFS_diropargs_sz)
-#define NFS_symlinkargs_sz      (NFS_diropargs_sz+NFS_path_sz+NFS_sattr_sz)
+#define NFS_symlinkargs_sz      (NFS_diropargs_sz+1+NFS_sattr_sz)
 #define NFS_readdirargs_sz      (NFS_fhandle_sz+2)
 
 #define NFS_attrstat_sz         (1+NFS_fattr_sz)
@@ -351,11 +351,26 @@ nfs_xdr_linkargs(struct rpc_rqst *req, u32 *p, struct nfs_linkargs *args)
 static int
 nfs_xdr_symlinkargs(struct rpc_rqst *req, u32 *p, struct nfs_symlinkargs *args)
 {
+        struct xdr_buf *sndbuf = &req->rq_snd_buf;
+        size_t pad;
+
         p = xdr_encode_fhandle(p, args->fromfh);
         p = xdr_encode_array(p, args->fromname, args->fromlen);
-        p = xdr_encode_array(p, args->topath, args->tolen);
+        *p++ = htonl(args->pathlen);
+        sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
+
+        xdr_encode_pages(sndbuf, args->pages, 0, args->pathlen);
+
+        /*
+         * xdr_encode_pages may have added a few bytes to ensure the
+         * pathname ends on a 4-byte boundary.  Start encoding the
+         * attributes after the pad bytes.
+         */
+        pad = sndbuf->tail->iov_len;
+        if (pad > 0)
+                p++;
         p = xdr_encode_sattr(p, args->sattr);
-        req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
+        sndbuf->len += xdr_adjust_iovec(sndbuf->tail, p) - pad;
         return 0;
 }
 
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index d85ac427c326..f8688eaa0001 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -544,8 +544,8 @@ nfs3_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
 }
 
 static int
-nfs3_proc_symlink(struct inode *dir, struct dentry *dentry, struct qstr *path,
-                  struct iattr *sattr)
+nfs3_proc_symlink(struct inode *dir, struct dentry *dentry, struct page *page,
+                  unsigned int len, struct iattr *sattr)
 {
         struct nfs_fh fhandle;
         struct nfs_fattr fattr, dir_attr;
@@ -553,8 +553,8 @@ nfs3_proc_symlink(struct inode *dir, struct dentry *dentry, struct qstr *path,
                 .fromfh         = NFS_FH(dir),
                 .fromname       = dentry->d_name.name,
                 .fromlen        = dentry->d_name.len,
-                .topath         = path->name,
-                .tolen          = path->len,
+                .pages          = &page,
+                .pathlen        = len,
                 .sattr          = sattr
         };
         struct nfs3_diropres    res = {
@@ -569,11 +569,11 @@ nfs3_proc_symlink(struct inode *dir, struct dentry *dentry, struct qstr *path,
         };
         int                     status;
 
-        if (path->len > NFS3_MAXPATHLEN)
+        if (len > NFS3_MAXPATHLEN)
                 return -ENAMETOOLONG;
 
-        dprintk("NFS call  symlink %s -> %s\n", dentry->d_name.name,
-                        path->name);
+        dprintk("NFS call  symlink %s\n", dentry->d_name.name);
+
         nfs_fattr_init(&dir_attr);
         nfs_fattr_init(&fattr);
         status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 0250269e9753..16556fa4effb 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -56,7 +56,7 @@
 #define NFS3_writeargs_sz       (NFS3_fh_sz+5)
 #define NFS3_createargs_sz      (NFS3_diropargs_sz+NFS3_sattr_sz)
 #define NFS3_mkdirargs_sz       (NFS3_diropargs_sz+NFS3_sattr_sz)
-#define NFS3_symlinkargs_sz     (NFS3_diropargs_sz+NFS3_path_sz+NFS3_sattr_sz)
+#define NFS3_symlinkargs_sz     (NFS3_diropargs_sz+1+NFS3_sattr_sz)
 #define NFS3_mknodargs_sz       (NFS3_diropargs_sz+2+NFS3_sattr_sz)
 #define NFS3_renameargs_sz      (NFS3_diropargs_sz+NFS3_diropargs_sz)
 #define NFS3_linkargs_sz                (NFS3_fh_sz+NFS3_diropargs_sz)
@@ -398,8 +398,11 @@ nfs3_xdr_symlinkargs(struct rpc_rqst *req, u32 *p, struct nfs3_symlinkargs *args
         p = xdr_encode_fhandle(p, args->fromfh);
         p = xdr_encode_array(p, args->fromname, args->fromlen);
         p = xdr_encode_sattr(p, args->sattr);
-        p = xdr_encode_array(p, args->topath, args->tolen);
+        *p++ = htonl(args->pathlen);
         req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
+
+        /* Copy the page */
+        xdr_encode_pages(&req->rq_snd_buf, args->pages, 0, args->pathlen);
         return 0;
 }
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 2d18eac6bee5..7f60beb40df3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2085,7 +2085,7 @@ static int nfs4_proc_link(struct inode *inode, struct inode *dir, struct qstr *n
 }
 
 static int _nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
-                struct qstr *path, struct iattr *sattr)
+                struct page *page, unsigned int len, struct iattr *sattr)
 {
         struct nfs_server *server = NFS_SERVER(dir);
         struct nfs_fh fhandle;
@@ -2111,10 +2111,11 @@ static int _nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
         };
         int                     status;
 
-        if (path->len > NFS4_MAXPATHLEN)
+        if (len > NFS4_MAXPATHLEN)
                 return -ENAMETOOLONG;
 
-        arg.u.symlink = path;
+        arg.u.symlink.pages = &page;
+        arg.u.symlink.len = len;
         nfs_fattr_init(&fattr);
         nfs_fattr_init(&dir_fattr);
         
@@ -2128,13 +2129,14 @@ static int _nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
 }
 
 static int nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
-                struct qstr *path, struct iattr *sattr)
+                struct page *page, unsigned int len, struct iattr *sattr)
 {
         struct nfs4_exception exception = { };
         int err;
         do {
                 err = nfs4_handle_exception(NFS_SERVER(dir),
-                                _nfs4_proc_symlink(dir, dentry, path, sattr),
+                                _nfs4_proc_symlink(dir, dentry, page,
+                                                        len, sattr),
                                 &exception);
         } while (exception.retry);
         return err;
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 99926067eca4..3dd413f52da1 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -128,7 +128,7 @@ static int nfs4_stat_to_errno(int);
 #define decode_link_maxsz       (op_decode_hdr_maxsz + 5)
 #define encode_symlink_maxsz    (op_encode_hdr_maxsz + \
                                 1 + nfs4_name_maxsz + \
-                                nfs4_path_maxsz + \
+                                1 + \
                                 nfs4_fattr_maxsz)
 #define decode_symlink_maxsz    (op_decode_hdr_maxsz + 8)
 #define encode_create_maxsz     (op_encode_hdr_maxsz + \
@@ -673,9 +673,9 @@ static int encode_create(struct xdr_stream *xdr, const struct nfs4_create_arg *c
 
         switch (create->ftype) {
         case NF4LNK:
-                RESERVE_SPACE(4 + create->u.symlink->len);
-                WRITE32(create->u.symlink->len);
-                WRITEMEM(create->u.symlink->name, create->u.symlink->len);
+                RESERVE_SPACE(4);
+                WRITE32(create->u.symlink.len);
+                xdr_write_pages(xdr, create->u.symlink.pages, 0, create->u.symlink.len);
                 break;
 
         case NF4BLK: case NF4CHR:
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 0b507bf0f330..630e50647bbb 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -425,8 +425,8 @@ nfs_proc_link(struct inode *inode, struct inode *dir, struct qstr *name)
 }
 
 static int
-nfs_proc_symlink(struct inode *dir, struct dentry *dentry, struct qstr *path,
-                 struct iattr *sattr)
+nfs_proc_symlink(struct inode *dir, struct dentry *dentry, struct page *page,
+                 unsigned int len, struct iattr *sattr)
 {
         struct nfs_fh fhandle;
         struct nfs_fattr fattr;
@@ -434,8 +434,8 @@ nfs_proc_symlink(struct inode *dir, struct dentry *dentry, struct qstr *path,
                 .fromfh         = NFS_FH(dir),
                 .fromname       = dentry->d_name.name,
                 .fromlen        = dentry->d_name.len,
-                .topath         = path->name,
-                .tolen          = path->len,
+                .pages          = &page,
+                .pathlen        = len,
                 .sattr          = sattr
         };
         struct rpc_message msg = {
@@ -444,11 +444,11 @@ nfs_proc_symlink(struct inode *dir, struct dentry *dentry, struct qstr *path,
         };
         int                     status;
 
-        if (path->len > NFS2_MAXPATHLEN)
+        if (len > NFS2_MAXPATHLEN)
                 return -ENAMETOOLONG;
 
-        dprintk("NFS call  symlink %s -> %s\n", dentry->d_name.name,
-                        path->name);
+        dprintk("NFS call  symlink %s\n", dentry->d_name.name);
+
         status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
         nfs_mark_for_revalidate(dir);
 
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index ddf5d75e97a2..dc5397d9d23c 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -358,8 +358,8 @@ struct nfs_symlinkargs {
         struct nfs_fh *         fromfh;
         const char *            fromname;
         unsigned int            fromlen;
-        const char *            topath;
-        unsigned int            tolen;
+        struct page **          pages;
+        unsigned int            pathlen;
         struct iattr *          sattr;
 };
 
@@ -434,8 +434,8 @@ struct nfs3_symlinkargs {
         struct nfs_fh *         fromfh;
         const char *            fromname;
         unsigned int            fromlen;
-        const char *            topath;
-        unsigned int            tolen;
+        struct page **          pages;
+        unsigned int            pathlen;
         struct iattr *          sattr;
 };
 
@@ -533,7 +533,10 @@ struct nfs4_accessres {
 struct nfs4_create_arg {
         u32                             ftype;
         union {
-                struct qstr *           symlink;    /* NF4LNK */
+                struct {
+                        struct page **  pages;
+                        unsigned int    len;
+                } symlink;   /* NF4LNK */
                 struct {
                         u32             specdata1;
                         u32             specdata2;
@@ -793,8 +796,8 @@ struct nfs_rpc_ops {
         int     (*rename)  (struct inode *, struct qstr *,
                             struct inode *, struct qstr *);
         int     (*link)    (struct inode *, struct inode *, struct qstr *);
-        int     (*symlink) (struct inode *, struct dentry *, struct qstr *,
-                            struct iattr *);
+        int     (*symlink) (struct inode *, struct dentry *, struct page *,
+                            unsigned int, struct iattr *);
         int     (*mkdir)   (struct inode *, struct dentry *, struct iattr *);
         int     (*rmdir)   (struct inode *, struct qstr *);
         int     (*readdir) (struct dentry *, struct rpc_cred *,