[PATCH] NFS: Add support for NFSv3 ACLs

 This adds acl support fo nfs clients via the NFSACL protocol extension, by
 implementing the getxattr, listxattr, setxattr, and removexattr iops for the
 system.posix_acl_access and system.posix_acl_default attributes.  This patch
 implements a dumb version that uses no caching (and thus adds some overhead).
 (Another patch in this patchset adds caching as well.)

 Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
 Acked-by: Olaf Kirch <okir@suse.de>
 Signed-off-by: Andrew Morton <akpm@osdl.org>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 303 insertions, 0 deletions

diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
new file mode 100644
index 000000000000..393ba79fc14f
--- /dev/null
+++ b/fs/nfs/nfs3acl.c
@@ -0,0 +1,303 @@
+#include <linux/fs.h>
+#include <linux/nfs.h>
+#include <linux/nfs3.h>
+#include <linux/nfs_fs.h>
+#include <linux/xattr_acl.h>
+#include <linux/nfsacl.h>
+
+#define NFSDBG_FACILITY NFSDBG_PROC
+
+ssize_t nfs3_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+        struct inode *inode = dentry->d_inode;
+        struct posix_acl *acl;
+        int pos=0, len=0;
+
+#       define output(s) do {                                           \
+                        if (pos + sizeof(s) <= size) {                  \
+                                memcpy(buffer + pos, s, sizeof(s));     \
+                                pos += sizeof(s);                       \
+                        }                                               \
+                        len += sizeof(s);                               \
+                } while(0)
+
+        acl = nfs3_proc_getacl(inode, ACL_TYPE_ACCESS);
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        if (acl) {
+                output("system.posix_acl_access");
+                posix_acl_release(acl);
+        }
+
+        if (S_ISDIR(inode->i_mode)) {
+                acl = nfs3_proc_getacl(inode, ACL_TYPE_DEFAULT);
+                if (IS_ERR(acl))
+                        return PTR_ERR(acl);
+                if (acl) {
+                        output("system.posix_acl_default");
+                        posix_acl_release(acl);
+                }
+        }
+
+#       undef output
+
+        if (!buffer || len <= size)
+                return len;
+        return -ERANGE;
+}
+
+ssize_t nfs3_getxattr(struct dentry *dentry, const char *name,
+                void *buffer, size_t size)
+{
+        struct inode *inode = dentry->d_inode;
+        struct posix_acl *acl;
+        int type, error = 0;
+
+        if (strcmp(name, XATTR_NAME_ACL_ACCESS) == 0)
+                type = ACL_TYPE_ACCESS;
+        else if (strcmp(name, XATTR_NAME_ACL_DEFAULT) == 0)
+                type = ACL_TYPE_DEFAULT;
+        else
+                return -EOPNOTSUPP;
+
+        acl = nfs3_proc_getacl(inode, type);
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        else if (acl) {
+                if (type == ACL_TYPE_ACCESS && acl->a_count == 0)
+                        error = -ENODATA;
+                else
+                        error = posix_acl_to_xattr(acl, buffer, size);
+                posix_acl_release(acl);
+        } else
+                error = -ENODATA;
+
+        return error;
+}
+
+int nfs3_setxattr(struct dentry *dentry, const char *name,
+             const void *value, size_t size, int flags)
+{
+        struct inode *inode = dentry->d_inode;
+        struct posix_acl *acl;
+        int type, error;
+
+        if (strcmp(name, XATTR_NAME_ACL_ACCESS) == 0)
+                type = ACL_TYPE_ACCESS;
+        else if (strcmp(name, XATTR_NAME_ACL_DEFAULT) == 0)
+                type = ACL_TYPE_DEFAULT;
+        else
+                return -EOPNOTSUPP;
+
+        acl = posix_acl_from_xattr(value, size);
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        error = nfs3_proc_setacl(inode, type, acl);
+        posix_acl_release(acl);
+
+        return error;
+}
+
+int nfs3_removexattr(struct dentry *dentry, const char *name)
+{
+        struct inode *inode = dentry->d_inode;
+        int type;
+
+        if (strcmp(name, XATTR_NAME_ACL_ACCESS) == 0)
+                type = ACL_TYPE_ACCESS;
+        else if (strcmp(name, XATTR_NAME_ACL_DEFAULT) == 0)
+                type = ACL_TYPE_DEFAULT;
+        else
+                return -EOPNOTSUPP;
+
+        return nfs3_proc_setacl(inode, type, NULL);
+}
+
+struct posix_acl *nfs3_proc_getacl(struct inode *inode, int type)
+{
+        struct nfs_server *server = NFS_SERVER(inode);
+        struct nfs_fattr fattr;
+        struct page *pages[NFSACL_MAXPAGES] = { };
+        struct nfs3_getaclargs args = {
+                .fh = NFS_FH(inode),
+                /* The xdr layer may allocate pages here. */
+                .pages = pages,
+        };
+        struct nfs3_getaclres res = {
+                .fattr =        &fattr,
+        };
+        struct posix_acl *acl = NULL;
+        int status, count;
+
+        if (!nfs_server_capable(inode, NFS_CAP_ACLS))
+                return ERR_PTR(-EOPNOTSUPP);
+
+        switch (type) {
+                case ACL_TYPE_ACCESS:
+                        args.mask = NFS_ACLCNT|NFS_ACL;
+                        break;
+
+                case ACL_TYPE_DEFAULT:
+                        if (!S_ISDIR(inode->i_mode))
+                                return NULL;
+                        args.mask = NFS_DFACLCNT|NFS_DFACL;
+                        break;
+
+                default:
+                        return ERR_PTR(-EINVAL);
+        }
+
+        dprintk("NFS call getacl\n");
+        status = rpc_call(server->client_acl, ACLPROC3_GETACL,
+                          &args, &res, 0);
+        dprintk("NFS reply getacl: %d\n", status);
+
+        /* pages may have been allocated at the xdr layer. */
+        for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
+                __free_page(args.pages[count]);
+
+        switch (status) {
+                case 0:
+                        status = nfs_refresh_inode(inode, &fattr);
+                        break;
+                case -EPFNOSUPPORT:
+                case -EPROTONOSUPPORT:
+                        dprintk("NFS_V3_ACL extension not supported; disabling\n");
+                        server->caps &= ~NFS_CAP_ACLS;
+                case -ENOTSUPP:
+                        status = -EOPNOTSUPP;
+                default:
+                        goto getout;
+        }
+        if ((args.mask & res.mask) != args.mask) {
+                status = -EIO;
+                goto getout;
+        }
+
+        if (res.acl_access != NULL) {
+                if (posix_acl_equiv_mode(res.acl_access, NULL) == 0) {
+                        posix_acl_release(res.acl_access);
+                        res.acl_access = NULL;
+                }
+        }
+
+        switch(type) {
+                case ACL_TYPE_ACCESS:
+                        acl = res.acl_access;
+                        res.acl_access = NULL;
+                        break;
+
+                case ACL_TYPE_DEFAULT:
+                        acl = res.acl_default;
+                        res.acl_default = NULL;
+        }
+
+getout:
+        posix_acl_release(res.acl_access);
+        posix_acl_release(res.acl_default);
+
+        if (status != 0) {
+                posix_acl_release(acl);
+                acl = ERR_PTR(status);
+        }
+        return acl;
+}
+
+static int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
+                  struct posix_acl *dfacl)
+{
+        struct nfs_server *server = NFS_SERVER(inode);
+        struct nfs_fattr fattr;
+        struct page *pages[NFSACL_MAXPAGES] = { };
+        struct nfs3_setaclargs args = {
+                .inode = inode,
+                .mask = NFS_ACL,
+                .acl_access = acl,
+                .pages = pages,
+        };
+        int status, count;
+
+        status = -EOPNOTSUPP;
+        if (!nfs_server_capable(inode, NFS_CAP_ACLS))
+                goto out;
+
+        /* We are doing this here, because XDR marshalling can only
+           return -ENOMEM. */
+        status = -ENOSPC;
+        if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
+                goto out;
+        if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
+                goto out;
+        if (S_ISDIR(inode->i_mode)) {
+                args.mask |= NFS_DFACL;
+                args.acl_default = dfacl;
+        }
+
+        dprintk("NFS call setacl\n");
+        nfs_begin_data_update(inode);
+        status = rpc_call(server->client_acl, ACLPROC3_SETACL,
+                          &args, &fattr, 0);
+        NFS_FLAGS(inode) |= NFS_INO_INVALID_ACCESS;
+        nfs_end_data_update(inode);
+        dprintk("NFS reply setacl: %d\n", status);
+
+        /* pages may have been allocated at the xdr layer. */
+        for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
+                __free_page(args.pages[count]);
+
+        switch (status) {
+                case 0:
+                        status = nfs_refresh_inode(inode, &fattr);
+                        break;
+                case -EPFNOSUPPORT:
+                case -EPROTONOSUPPORT:
+                        dprintk("NFS_V3_ACL SETACL RPC not supported"
+                                        "(will not retry)\n");
+                        server->caps &= ~NFS_CAP_ACLS;
+                case -ENOTSUPP:
+                        status = -EOPNOTSUPP;
+        }
+out:
+        return status;
+}
+
+int nfs3_proc_setacl(struct inode *inode, int type, struct posix_acl *acl)
+{
+        struct posix_acl *alloc = NULL, *dfacl = NULL;
+        int status;
+
+        if (S_ISDIR(inode->i_mode)) {
+                switch(type) {
+                        case ACL_TYPE_ACCESS:
+                                alloc = dfacl = nfs3_proc_getacl(inode,
+                                                ACL_TYPE_DEFAULT);
+                                if (IS_ERR(alloc))
+                                        goto fail;
+                                break;
+
+                        case ACL_TYPE_DEFAULT:
+                                dfacl = acl;
+                                alloc = acl = nfs3_proc_getacl(inode,
+                                                ACL_TYPE_ACCESS);
+                                if (IS_ERR(alloc))
+                                        goto fail;
+                                break;
+
+                        default:
+                                return -EINVAL;
+                }
+        } else if (type != ACL_TYPE_ACCESS)
+                        return -EINVAL;
+
+        if (acl == NULL) {
+                alloc = acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
+                if (IS_ERR(alloc))
+                        goto fail;
+        }
+        status = nfs3_proc_setacls(inode, acl, dfacl);
+        posix_acl_release(alloc);
+        return status;
+
+fail:
+        return PTR_ERR(alloc);
+}