347 lines
8.1 KiB
C
347 lines
8.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/fs.h>
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#include <linux/gfp.h>
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#include <linux/nfs.h>
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#include <linux/nfs3.h>
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#include <linux/nfs_fs.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/nfsacl.h>
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#include "internal.h"
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#include "nfs3_fs.h"
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#define NFSDBG_FACILITY NFSDBG_PROC
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/*
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* nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for
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* caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl()
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* for explanations.
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*/
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static void nfs3_prepare_get_acl(struct posix_acl **p)
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{
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struct posix_acl *sentinel = uncached_acl_sentinel(current);
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if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) {
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/* Not the first reader or sentinel already in place. */
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}
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}
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static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl)
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{
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struct posix_acl *sentinel = uncached_acl_sentinel(current);
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/* Only cache the ACL if our sentinel is still in place. */
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posix_acl_dup(acl);
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if (cmpxchg(p, sentinel, acl) != sentinel)
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posix_acl_release(acl);
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}
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static void nfs3_abort_get_acl(struct posix_acl **p)
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{
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struct posix_acl *sentinel = uncached_acl_sentinel(current);
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/* Remove our sentinel upon failure. */
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cmpxchg(p, sentinel, ACL_NOT_CACHED);
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}
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struct posix_acl *nfs3_get_acl(struct inode *inode, int type)
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{
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struct nfs_server *server = NFS_SERVER(inode);
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struct page *pages[NFSACL_MAXPAGES] = { };
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struct nfs3_getaclargs args = {
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.fh = NFS_FH(inode),
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/* The xdr layer may allocate pages here. */
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.pages = pages,
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};
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struct nfs3_getaclres res = {
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NULL,
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};
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struct rpc_message msg = {
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.rpc_argp = &args,
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.rpc_resp = &res,
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};
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int status, count;
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if (!nfs_server_capable(inode, NFS_CAP_ACLS))
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return ERR_PTR(-EOPNOTSUPP);
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status = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE);
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if (status < 0)
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return ERR_PTR(status);
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/*
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* Only get the access acl when explicitly requested: We don't
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* need it for access decisions, and only some applications use
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* it. Applications which request the access acl first are not
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* penalized from this optimization.
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*/
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if (type == ACL_TYPE_ACCESS)
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args.mask |= NFS_ACLCNT|NFS_ACL;
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if (S_ISDIR(inode->i_mode))
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args.mask |= NFS_DFACLCNT|NFS_DFACL;
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if (args.mask == 0)
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return NULL;
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dprintk("NFS call getacl\n");
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msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL];
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res.fattr = nfs_alloc_fattr();
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if (res.fattr == NULL)
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return ERR_PTR(-ENOMEM);
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if (args.mask & NFS_ACL)
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nfs3_prepare_get_acl(&inode->i_acl);
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if (args.mask & NFS_DFACL)
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nfs3_prepare_get_acl(&inode->i_default_acl);
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status = rpc_call_sync(server->client_acl, &msg, 0);
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dprintk("NFS reply getacl: %d\n", status);
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/* pages may have been allocated at the xdr layer. */
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for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
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__free_page(args.pages[count]);
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switch (status) {
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case 0:
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status = nfs_refresh_inode(inode, res.fattr);
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break;
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case -EPFNOSUPPORT:
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case -EPROTONOSUPPORT:
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dprintk("NFS_V3_ACL extension not supported; disabling\n");
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server->caps &= ~NFS_CAP_ACLS;
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fallthrough;
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case -ENOTSUPP:
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status = -EOPNOTSUPP;
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goto getout;
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default:
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goto getout;
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}
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if ((args.mask & res.mask) != args.mask) {
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status = -EIO;
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goto getout;
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}
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if (res.acl_access != NULL) {
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if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) ||
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res.acl_access->a_count == 0) {
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posix_acl_release(res.acl_access);
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res.acl_access = NULL;
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}
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}
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if (res.mask & NFS_ACL)
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nfs3_complete_get_acl(&inode->i_acl, res.acl_access);
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else
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forget_cached_acl(inode, ACL_TYPE_ACCESS);
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if (res.mask & NFS_DFACL)
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nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default);
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else
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forget_cached_acl(inode, ACL_TYPE_DEFAULT);
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nfs_free_fattr(res.fattr);
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if (type == ACL_TYPE_ACCESS) {
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posix_acl_release(res.acl_default);
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return res.acl_access;
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} else {
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posix_acl_release(res.acl_access);
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return res.acl_default;
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}
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getout:
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nfs3_abort_get_acl(&inode->i_acl);
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nfs3_abort_get_acl(&inode->i_default_acl);
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posix_acl_release(res.acl_access);
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posix_acl_release(res.acl_default);
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nfs_free_fattr(res.fattr);
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return ERR_PTR(status);
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}
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static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
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struct posix_acl *dfacl)
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{
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struct nfs_server *server = NFS_SERVER(inode);
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struct nfs_fattr *fattr;
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struct page *pages[NFSACL_MAXPAGES];
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struct nfs3_setaclargs args = {
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.inode = inode,
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.mask = NFS_ACL,
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.acl_access = acl,
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.pages = pages,
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};
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struct rpc_message msg = {
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.rpc_argp = &args,
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.rpc_resp = &fattr,
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};
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int status = 0;
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if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL))
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goto out;
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status = -EOPNOTSUPP;
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if (!nfs_server_capable(inode, NFS_CAP_ACLS))
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goto out;
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/* We are doing this here because XDR marshalling does not
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* return any results, it BUGs. */
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status = -ENOSPC;
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if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
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goto out;
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if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
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goto out;
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if (S_ISDIR(inode->i_mode)) {
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args.mask |= NFS_DFACL;
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args.acl_default = dfacl;
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args.len = nfsacl_size(acl, dfacl);
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} else
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args.len = nfsacl_size(acl, NULL);
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if (args.len > NFS_ACL_INLINE_BUFSIZE) {
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unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT);
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status = -ENOMEM;
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do {
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args.pages[args.npages] = alloc_page(GFP_KERNEL);
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if (args.pages[args.npages] == NULL)
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goto out_freepages;
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args.npages++;
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} while (args.npages < npages);
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}
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dprintk("NFS call setacl\n");
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status = -ENOMEM;
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fattr = nfs_alloc_fattr();
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if (fattr == NULL)
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goto out_freepages;
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msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL];
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msg.rpc_resp = fattr;
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status = rpc_call_sync(server->client_acl, &msg, 0);
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nfs_access_zap_cache(inode);
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nfs_zap_acl_cache(inode);
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dprintk("NFS reply setacl: %d\n", status);
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switch (status) {
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case 0:
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status = nfs_refresh_inode(inode, fattr);
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break;
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case -EPFNOSUPPORT:
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case -EPROTONOSUPPORT:
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dprintk("NFS_V3_ACL SETACL RPC not supported"
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"(will not retry)\n");
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server->caps &= ~NFS_CAP_ACLS;
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fallthrough;
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case -ENOTSUPP:
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status = -EOPNOTSUPP;
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}
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nfs_free_fattr(fattr);
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out_freepages:
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while (args.npages != 0) {
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args.npages--;
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__free_page(args.pages[args.npages]);
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}
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out:
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return status;
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}
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int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
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struct posix_acl *dfacl)
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{
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int ret;
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ret = __nfs3_proc_setacls(inode, acl, dfacl);
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return (ret == -EOPNOTSUPP) ? 0 : ret;
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}
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int nfs3_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
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struct posix_acl *acl, int type)
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{
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struct posix_acl *orig = acl, *dfacl = NULL, *alloc;
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int status;
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if (S_ISDIR(inode->i_mode)) {
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switch(type) {
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case ACL_TYPE_ACCESS:
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alloc = get_acl(inode, ACL_TYPE_DEFAULT);
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if (IS_ERR(alloc))
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goto fail;
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dfacl = alloc;
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break;
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case ACL_TYPE_DEFAULT:
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alloc = get_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(alloc))
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goto fail;
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dfacl = acl;
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acl = alloc;
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break;
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}
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}
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if (acl == NULL) {
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alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
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if (IS_ERR(alloc))
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goto fail;
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acl = alloc;
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}
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status = __nfs3_proc_setacls(inode, acl, dfacl);
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out:
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if (acl != orig)
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posix_acl_release(acl);
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if (dfacl != orig)
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posix_acl_release(dfacl);
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return status;
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fail:
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status = PTR_ERR(alloc);
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goto out;
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}
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const struct xattr_handler *nfs3_xattr_handlers[] = {
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&posix_acl_access_xattr_handler,
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&posix_acl_default_xattr_handler,
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NULL,
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};
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static int
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nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data,
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size_t size, ssize_t *result)
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{
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struct posix_acl *acl;
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char *p = data + *result;
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acl = get_acl(inode, type);
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if (IS_ERR_OR_NULL(acl))
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return 0;
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posix_acl_release(acl);
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*result += strlen(name);
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*result += 1;
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if (!size)
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return 0;
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if (*result > size)
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return -ERANGE;
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strcpy(p, name);
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return 0;
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}
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ssize_t
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nfs3_listxattr(struct dentry *dentry, char *data, size_t size)
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{
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struct inode *inode = d_inode(dentry);
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ssize_t result = 0;
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int error;
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error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS,
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XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result);
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if (error)
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return error;
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error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT,
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XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result);
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if (error)
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return error;
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return result;
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}
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