NFS: Reduce the stack usage in NFSv3 create operations

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

1 files changed, 142 insertions, 129 deletions

diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index c3523ad03ed1..cf7d4e5927d6 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -248,6 +248,53 @@ static int nfs3_proc_readlink(struct inode *inode, struct page *page,
         return status;
 }
 
+struct nfs3_createdata {
+        struct rpc_message msg;
+        union {
+                struct nfs3_createargs create;
+                struct nfs3_mkdirargs mkdir;
+                struct nfs3_symlinkargs symlink;
+                struct nfs3_mknodargs mknod;
+        } arg;
+        struct nfs3_diropres res;
+        struct nfs_fh fh;
+        struct nfs_fattr fattr;
+        struct nfs_fattr dir_attr;
+};
+
+static struct nfs3_createdata *nfs3_alloc_createdata(void)
+{
+        struct nfs3_createdata *data;
+
+        data = kzalloc(sizeof(*data), GFP_KERNEL);
+        if (data != NULL) {
+                data->msg.rpc_argp = &data->arg;
+                data->msg.rpc_resp = &data->res;
+                data->res.fh = &data->fh;
+                data->res.fattr = &data->fattr;
+                data->res.dir_attr = &data->dir_attr;
+                nfs_fattr_init(data->res.fattr);
+                nfs_fattr_init(data->res.dir_attr);
+        }
+        return data;
+}
+
+static int nfs3_do_create(struct inode *dir, struct dentry *dentry, struct nfs3_createdata *data)
+{
+        int status;
+
+        status = rpc_call_sync(NFS_CLIENT(dir), &data->msg, 0);
+        nfs_post_op_update_inode(dir, data->res.dir_attr);
+        if (status == 0)
+                status = nfs_instantiate(dentry, data->res.fh, data->res.fattr);
+        return status;
+}
+
+static void nfs3_free_createdata(struct nfs3_createdata *data)
+{
+        kfree(data);
+}
+
 /*
  * Create a regular file.
  * For now, we don't implement O_EXCL.
@@ -256,70 +303,60 @@ static int
 nfs3_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                  int flags, struct nameidata *nd)
 {
-        struct nfs_fh           fhandle;
-        struct nfs_fattr        fattr;
-        struct nfs_fattr        dir_attr;
-        struct nfs3_createargs  arg = {
-                .fh             = NFS_FH(dir),
-                .name           = dentry->d_name.name,
-                .len            = dentry->d_name.len,
-                .sattr          = sattr,
-        };
-        struct nfs3_diropres    res = {
-                .dir_attr       = &dir_attr,
-                .fh             = &fhandle,
-                .fattr          = &fattr
-        };
-        struct rpc_message msg = {
-                .rpc_proc       = &nfs3_procedures[NFS3PROC_CREATE],
-                .rpc_argp       = &arg,
-                .rpc_resp       = &res,
-        };
+        struct nfs3_createdata *data;
         mode_t mode = sattr->ia_mode;
-        int status;
+        int status = -ENOMEM;
 
         dprintk("NFS call  create %s\n", dentry->d_name.name);
-        arg.createmode = NFS3_CREATE_UNCHECKED;
+
+        data = nfs3_alloc_createdata();
+        if (data == NULL)
+                goto out;
+
+        data->msg.rpc_proc = &nfs3_procedures[NFS3PROC_CREATE];
+        data->arg.create.fh = NFS_FH(dir);
+        data->arg.create.name = dentry->d_name.name;
+        data->arg.create.len = dentry->d_name.len;
+        data->arg.create.sattr = sattr;
+
+        data->arg.create.createmode = NFS3_CREATE_UNCHECKED;
         if (flags & O_EXCL) {
-                arg.createmode  = NFS3_CREATE_EXCLUSIVE;
-                arg.verifier[0] = jiffies;
-                arg.verifier[1] = current->pid;
+                data->arg.create.createmode  = NFS3_CREATE_EXCLUSIVE;
+                data->arg.create.verifier[0] = jiffies;
+                data->arg.create.verifier[1] = current->pid;
         }
 
         sattr->ia_mode &= ~current->fs->umask;
 
-again:
-        nfs_fattr_init(&dir_attr);
-        nfs_fattr_init(&fattr);
-        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
-        nfs_refresh_inode(dir, &dir_attr);
+        for (;;) {
+                status = nfs3_do_create(dir, dentry, data);
 
-        /* If the server doesn't support the exclusive creation semantics,
-         * try again with simple 'guarded' mode. */
-        if (status == -ENOTSUPP) {
-                switch (arg.createmode) {
+                if (status != -ENOTSUPP)
+                        break;
+                /* If the server doesn't support the exclusive creation
+                 * semantics, try again with simple 'guarded' mode. */
+                switch (data->arg.create.createmode) {
                         case NFS3_CREATE_EXCLUSIVE:
-                                arg.createmode = NFS3_CREATE_GUARDED;
+                                data->arg.create.createmode = NFS3_CREATE_GUARDED;
                                 break;
 
                         case NFS3_CREATE_GUARDED:
-                                arg.createmode = NFS3_CREATE_UNCHECKED;
+                                data->arg.create.createmode = NFS3_CREATE_UNCHECKED;
                                 break;
 
                         case NFS3_CREATE_UNCHECKED:
                                 goto out;
                 }
-                goto again;
+                nfs_fattr_init(data->res.dir_attr);
+                nfs_fattr_init(data->res.fattr);
         }
 
-        if (status == 0)
-                status = nfs_instantiate(dentry, &fhandle, &fattr);
         if (status != 0)
                 goto out;
 
         /* When we created the file with exclusive semantics, make
          * sure we set the attributes afterwards. */
-        if (arg.createmode == NFS3_CREATE_EXCLUSIVE) {
+        if (data->arg.create.createmode == NFS3_CREATE_EXCLUSIVE) {
                 dprintk("NFS call  setattr (post-create)\n");
 
                 if (!(sattr->ia_valid & ATTR_ATIME_SET))
@@ -330,14 +367,15 @@ again:
                 /* Note: we could use a guarded setattr here, but I'm
                  * not sure this buys us anything (and I'd have
                  * to revamp the NFSv3 XDR code) */
-                status = nfs3_proc_setattr(dentry, &fattr, sattr);
-                nfs_post_op_update_inode(dentry->d_inode, &fattr);
+                status = nfs3_proc_setattr(dentry, data->res.fattr, sattr);
+                nfs_post_op_update_inode(dentry->d_inode, data->res.fattr);
                 dprintk("NFS reply setattr (post-create): %d\n", status);
+                if (status != 0)
+                        goto out;
         }
-        if (status != 0)
-                goto out;
         status = nfs3_proc_set_default_acl(dir, dentry->d_inode, mode);
 out:
+        nfs3_free_createdata(data);
         dprintk("NFS reply create: %d\n", status);
         return status;
 }
@@ -452,40 +490,28 @@ static int
 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;
-        struct nfs3_symlinkargs arg = {
-                .fromfh         = NFS_FH(dir),
-                .fromname       = dentry->d_name.name,
-                .fromlen        = dentry->d_name.len,
-                .pages          = &page,
-                .pathlen        = len,
-                .sattr          = sattr
-        };
-        struct nfs3_diropres    res = {
-                .dir_attr       = &dir_attr,
-                .fh             = &fhandle,
-                .fattr          = &fattr
-        };
-        struct rpc_message msg = {
-                .rpc_proc       = &nfs3_procedures[NFS3PROC_SYMLINK],
-                .rpc_argp       = &arg,
-                .rpc_resp       = &res,
-        };
-        int                     status;
+        struct nfs3_createdata *data;
+        int status = -ENOMEM;
 
         if (len > NFS3_MAXPATHLEN)
                 return -ENAMETOOLONG;
 
         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);
-        nfs_post_op_update_inode(dir, &dir_attr);
-        if (status != 0)
+        data = nfs3_alloc_createdata();
+        if (data == NULL)
                 goto out;
-        status = nfs_instantiate(dentry, &fhandle, &fattr);
+        data->msg.rpc_proc = &nfs3_procedures[NFS3PROC_SYMLINK];
+        data->arg.symlink.fromfh = NFS_FH(dir);
+        data->arg.symlink.fromname = dentry->d_name.name;
+        data->arg.symlink.fromlen = dentry->d_name.len;
+        data->arg.symlink.pages = &page;
+        data->arg.symlink.pathlen = len;
+        data->arg.symlink.sattr = sattr;
+
+        status = nfs3_do_create(dir, dentry, data);
+
+        nfs3_free_createdata(data);
 out:
         dprintk("NFS reply symlink: %d\n", status);
         return status;
@@ -494,42 +520,31 @@ out:
 static int
 nfs3_proc_mkdir(struct inode *dir, struct dentry *dentry, struct iattr *sattr)
 {
-        struct nfs_fh fhandle;
-        struct nfs_fattr fattr, dir_attr;
-        struct nfs3_mkdirargs   arg = {
-                .fh             = NFS_FH(dir),
-                .name           = dentry->d_name.name,
-                .len            = dentry->d_name.len,
-                .sattr          = sattr
-        };
-        struct nfs3_diropres    res = {
-                .dir_attr       = &dir_attr,
-                .fh             = &fhandle,
-                .fattr          = &fattr
-        };
-        struct rpc_message msg = {
-                .rpc_proc       = &nfs3_procedures[NFS3PROC_MKDIR],
-                .rpc_argp       = &arg,
-                .rpc_resp       = &res,
-        };
+        struct nfs3_createdata *data;
         int mode = sattr->ia_mode;
-        int status;
+        int status = -ENOMEM;
 
         dprintk("NFS call  mkdir %s\n", dentry->d_name.name);
 
         sattr->ia_mode &= ~current->fs->umask;
 
-        nfs_fattr_init(&dir_attr);
-        nfs_fattr_init(&fattr);
-        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
-        nfs_post_op_update_inode(dir, &dir_attr);
-        if (status != 0)
+        data = nfs3_alloc_createdata();
+        if (data == NULL)
                 goto out;
-        status = nfs_instantiate(dentry, &fhandle, &fattr);
+
+        data->msg.rpc_proc = &nfs3_procedures[NFS3PROC_MKDIR];
+        data->arg.mkdir.fh = NFS_FH(dir);
+        data->arg.mkdir.name = dentry->d_name.name;
+        data->arg.mkdir.len = dentry->d_name.len;
+        data->arg.mkdir.sattr = sattr;
+
+        status = nfs3_do_create(dir, dentry, data);
         if (status != 0)
                 goto out;
+
         status = nfs3_proc_set_default_acl(dir, dentry->d_inode, mode);
 out:
+        nfs3_free_createdata(data);
         dprintk("NFS reply mkdir: %d\n", status);
         return status;
 }
@@ -615,52 +630,50 @@ static int
 nfs3_proc_mknod(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                 dev_t rdev)
 {
-        struct nfs_fh fh;
-        struct nfs_fattr fattr, dir_attr;
-        struct nfs3_mknodargs   arg = {
-                .fh             = NFS_FH(dir),
-                .name           = dentry->d_name.name,
-                .len            = dentry->d_name.len,
-                .sattr          = sattr,
-                .rdev           = rdev
-        };
-        struct nfs3_diropres    res = {
-                .dir_attr       = &dir_attr,
-                .fh             = &fh,
-                .fattr          = &fattr
-        };
-        struct rpc_message msg = {
-                .rpc_proc       = &nfs3_procedures[NFS3PROC_MKNOD],
-                .rpc_argp       = &arg,
-                .rpc_resp       = &res,
-        };
+        struct nfs3_createdata *data;
         mode_t mode = sattr->ia_mode;
-        int status;
-
-        switch (sattr->ia_mode & S_IFMT) {
-        case S_IFBLK:   arg.type = NF3BLK;  break;
-        case S_IFCHR:   arg.type = NF3CHR;  break;
-        case S_IFIFO:   arg.type = NF3FIFO; break;
-        case S_IFSOCK:  arg.type = NF3SOCK; break;
-        default:        return -EINVAL;
-        }
+        int status = -ENOMEM;
 
         dprintk("NFS call  mknod %s %u:%u\n", dentry->d_name.name,
                         MAJOR(rdev), MINOR(rdev));
 
         sattr->ia_mode &= ~current->fs->umask;
 
-        nfs_fattr_init(&dir_attr);
-        nfs_fattr_init(&fattr);
-        status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
-        nfs_post_op_update_inode(dir, &dir_attr);
-        if (status != 0)
+        data = nfs3_alloc_createdata();
+        if (data == NULL)
                 goto out;
-        status = nfs_instantiate(dentry, &fh, &fattr);
+
+        data->msg.rpc_proc = &nfs3_procedures[NFS3PROC_MKNOD];
+        data->arg.mknod.fh = NFS_FH(dir);
+        data->arg.mknod.name = dentry->d_name.name;
+        data->arg.mknod.len = dentry->d_name.len;
+        data->arg.mknod.sattr = sattr;
+        data->arg.mknod.rdev = rdev;
+
+        switch (sattr->ia_mode & S_IFMT) {
+        case S_IFBLK:
+                data->arg.mknod.type = NF3BLK;
+                break;
+        case S_IFCHR:
+                data->arg.mknod.type = NF3CHR;
+                break;
+        case S_IFIFO:
+                data->arg.mknod.type = NF3FIFO;
+                break;
+        case S_IFSOCK:
+                data->arg.mknod.type = NF3SOCK;
+                break;
+        default:
+                status = -EINVAL;
+                goto out;
+        }
+
+        status = nfs3_do_create(dir, dentry, data);
         if (status != 0)
                 goto out;
         status = nfs3_proc_set_default_acl(dir, dentry->d_inode, mode);
 out:
+        nfs3_free_createdata(data);
         dprintk("NFS reply mknod: %d\n", status);
         return status;
 }