fs/nfs/nfs3acl.c

   1 #include <linux/fs.h>
   2 #include <linux/gfp.h>
   3 #include <linux/nfs.h>
   4 #include <linux/nfs3.h>
   5 #include <linux/nfs_fs.h>
   6 #include <linux/posix_acl_xattr.h>
   7 #include <linux/nfsacl.h>
   8
   9 #include "internal.h"
  10 #include "nfs3_fs.h"
  11
  12 #define NFSDBG_FACILITY NFSDBG_PROC
  13
  14 /*
  15  * nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for
  16  * caching get_acl results in a race-free way.  See fs/posix_acl.c:get_acl()
  17  * for explanations.
  18  */
  19 static void nfs3_prepare_get_acl(struct posix_acl **p)
  20 {
  21         struct posix_acl *sentinel = uncached_acl_sentinel(current);
  22
  23         if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) {
  24                 /* Not the first reader or sentinel already in place. */
  25         }
  26 }
  27
  28 static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl)
  29 {
  30         struct posix_acl *sentinel = uncached_acl_sentinel(current);
  31
  32         /* Only cache the ACL if our sentinel is still in place. */
  33         posix_acl_dup(acl);
  34         if (cmpxchg(p, sentinel, acl) != sentinel)
  35                 posix_acl_release(acl);
  36 }
  37
  38 static void nfs3_abort_get_acl(struct posix_acl **p)
  39 {
  40         struct posix_acl *sentinel = uncached_acl_sentinel(current);
  41
  42         /* Remove our sentinel upon failure. */
  43         cmpxchg(p, sentinel, ACL_NOT_CACHED);
  44 }
  45
  46 struct posix_acl *nfs3_get_acl(struct inode *inode, int type)
  47 {
  48         struct nfs_server *server = NFS_SERVER(inode);
  49         struct page *pages[NFSACL_MAXPAGES] = { };
  50         struct nfs3_getaclargs args = {
  51                 .fh = NFS_FH(inode),
  52                 /* The xdr layer may allocate pages here. */
  53                 .pages = pages,
  54         };
  55         struct nfs3_getaclres res = {
  56                 NULL,
  57         };
  58         struct rpc_message msg = {
  59                 .rpc_argp       = &args,
  60                 .rpc_resp       = &res,
  61         };
  62         int status, count;
  63
  64         if (!nfs_server_capable(inode, NFS_CAP_ACLS))
  65                 return ERR_PTR(-EOPNOTSUPP);
  66
  67         status = nfs_revalidate_inode(server, inode);
  68         if (status < 0)
  69                 return ERR_PTR(status);
  70
  71         /*
  72          * Only get the access acl when explicitly requested: We don't
  73          * need it for access decisions, and only some applications use
  74          * it. Applications which request the access acl first are not
  75          * penalized from this optimization.
  76          */
  77         if (type == ACL_TYPE_ACCESS)
  78                 args.mask |= NFS_ACLCNT|NFS_ACL;
  79         if (S_ISDIR(inode->i_mode))
  80                 args.mask |= NFS_DFACLCNT|NFS_DFACL;
  81         if (args.mask == 0)
  82                 return NULL;
  83
  84         dprintk("NFS call getacl\n");
  85         msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL];
  86         res.fattr = nfs_alloc_fattr();
  87         if (res.fattr == NULL)
  88                 return ERR_PTR(-ENOMEM);
  89
  90         if (args.mask & NFS_ACL)
  91                 nfs3_prepare_get_acl(&inode->i_acl);
  92         if (args.mask & NFS_DFACL)
  93                 nfs3_prepare_get_acl(&inode->i_default_acl);
  94
  95         status = rpc_call_sync(server->client_acl, &msg, 0);
  96         dprintk("NFS reply getacl: %d\n", status);
  97
  98         /* pages may have been allocated at the xdr layer. */
  99         for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
 100                 __free_page(args.pages[count]);
 101
 102         switch (status) {
 103                 case 0:
 104                         status = nfs_refresh_inode(inode, res.fattr);
 105                         break;
 106                 case -EPFNOSUPPORT:
 107                 case -EPROTONOSUPPORT:
 108                         dprintk("NFS_V3_ACL extension not supported; disabling\n");
 109                         server->caps &= ~NFS_CAP_ACLS;
 110                 case -ENOTSUPP:
 111                         status = -EOPNOTSUPP;
 112                 default:
 113                         goto getout;
 114         }
 115         if ((args.mask & res.mask) != args.mask) {
 116                 status = -EIO;
 117                 goto getout;
 118         }
 119
 120         if (res.acl_access != NULL) {
 121                 if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) ||
 122                     res.acl_access->a_count == 0) {
 123                         posix_acl_release(res.acl_access);
 124                         res.acl_access = NULL;
 125                 }
 126         }
 127
 128         if (res.mask & NFS_ACL)
 129                 nfs3_complete_get_acl(&inode->i_acl, res.acl_access);
 130         else
 131                 forget_cached_acl(inode, ACL_TYPE_ACCESS);
 132
 133         if (res.mask & NFS_DFACL)
 134                 nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default);
 135         else
 136                 forget_cached_acl(inode, ACL_TYPE_DEFAULT);
 137
 138         nfs_free_fattr(res.fattr);
 139         if (type == ACL_TYPE_ACCESS) {
 140                 posix_acl_release(res.acl_default);
 141                 return res.acl_access;
 142         } else {
 143                 posix_acl_release(res.acl_access);
 144                 return res.acl_default;
 145         }
 146
 147 getout:
 148         nfs3_abort_get_acl(&inode->i_acl);
 149         nfs3_abort_get_acl(&inode->i_default_acl);
 150         posix_acl_release(res.acl_access);
 151         posix_acl_release(res.acl_default);
 152         nfs_free_fattr(res.fattr);
 153         return ERR_PTR(status);
 154 }
 155
 156 static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
 157                 struct posix_acl *dfacl)
 158 {
 159         struct nfs_server *server = NFS_SERVER(inode);
 160         struct nfs_fattr *fattr;
 161         struct page *pages[NFSACL_MAXPAGES];
 162         struct nfs3_setaclargs args = {
 163                 .inode = inode,
 164                 .mask = NFS_ACL,
 165                 .acl_access = acl,
 166                 .pages = pages,
 167         };
 168         struct rpc_message msg = {
 169                 .rpc_argp       = &args,
 170                 .rpc_resp       = &fattr,
 171         };
 172         int status = 0;
 173
 174         if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL))
 175                 goto out;
 176
 177         status = -EOPNOTSUPP;
 178         if (!nfs_server_capable(inode, NFS_CAP_ACLS))
 179                 goto out;
 180
 181         /* We are doing this here because XDR marshalling does not
 182          * return any results, it BUGs. */
 183         status = -ENOSPC;
 184         if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
 185                 goto out;
 186         if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
 187                 goto out;
 188         if (S_ISDIR(inode->i_mode)) {
 189                 args.mask |= NFS_DFACL;
 190                 args.acl_default = dfacl;
 191                 args.len = nfsacl_size(acl, dfacl);
 192         } else
 193                 args.len = nfsacl_size(acl, NULL);
 194
 195         if (args.len > NFS_ACL_INLINE_BUFSIZE) {
 196                 unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT);
 197
 198                 status = -ENOMEM;
 199                 do {
 200                         args.pages[args.npages] = alloc_page(GFP_KERNEL);
 201                         if (args.pages[args.npages] == NULL)
 202                                 goto out_freepages;
 203                         args.npages++;
 204                 } while (args.npages < npages);
 205         }
 206
 207         dprintk("NFS call setacl\n");
 208         status = -ENOMEM;
 209         fattr = nfs_alloc_fattr();
 210         if (fattr == NULL)
 211                 goto out_freepages;
 212
 213         msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL];
 214         msg.rpc_resp = fattr;
 215         status = rpc_call_sync(server->client_acl, &msg, 0);
 216         nfs_access_zap_cache(inode);
 217         nfs_zap_acl_cache(inode);
 218         dprintk("NFS reply setacl: %d\n", status);
 219
 220         switch (status) {
 221                 case 0:
 222                         status = nfs_refresh_inode(inode, fattr);
 223                         set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
 224                         set_cached_acl(inode, ACL_TYPE_DEFAULT, dfacl);
 225                         break;
 226                 case -EPFNOSUPPORT:
 227                 case -EPROTONOSUPPORT:
 228                         dprintk("NFS_V3_ACL SETACL RPC not supported"
 229                                         "(will not retry)\n");
 230                         server->caps &= ~NFS_CAP_ACLS;
 231                 case -ENOTSUPP:
 232                         status = -EOPNOTSUPP;
 233         }
 234         nfs_free_fattr(fattr);
 235 out_freepages:
 236         while (args.npages != 0) {
 237                 args.npages--;
 238                 __free_page(args.pages[args.npages]);
 239         }
 240 out:
 241         return status;
 242 }
 243
 244 int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
 245                 struct posix_acl *dfacl)
 246 {
 247         int ret;
 248         ret = __nfs3_proc_setacls(inode, acl, dfacl);
 249         return (ret == -EOPNOTSUPP) ? 0 : ret;
 250
 251 }
 252
 253 int nfs3_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 254 {
 255         struct posix_acl *alloc = NULL, *dfacl = NULL;
 256         int status;
 257
 258         if (S_ISDIR(inode->i_mode)) {
 259                 switch(type) {
 260                 case ACL_TYPE_ACCESS:
 261                         alloc = dfacl = get_acl(inode, ACL_TYPE_DEFAULT);
 262                         if (IS_ERR(alloc))
 263                                 goto fail;
 264                         break;
 265
 266                 case ACL_TYPE_DEFAULT:
 267                         dfacl = acl;
 268                         alloc = acl = get_acl(inode, ACL_TYPE_ACCESS);
 269                         if (IS_ERR(alloc))
 270                                 goto fail;
 271                         break;
 272                 }
 273         }
 274
 275         if (acl == NULL) {
 276                 alloc = acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
 277                 if (IS_ERR(alloc))
 278                         goto fail;
 279         }
 280         status = __nfs3_proc_setacls(inode, acl, dfacl);
 281         posix_acl_release(alloc);
 282         return status;
 283
 284 fail:
 285         return PTR_ERR(alloc);
 286 }
 287
 288 const struct xattr_handler *nfs3_xattr_handlers[] = {
 289         &posix_acl_access_xattr_handler,
 290         &posix_acl_default_xattr_handler,
 291         NULL,
 292 };
 293
 294 static int
 295 nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data,
 296                 size_t size, ssize_t *result)
 297 {
 298         struct posix_acl *acl;
 299         char *p = data + *result;
 300
 301         acl = get_acl(inode, type);
 302         if (IS_ERR_OR_NULL(acl))
 303                 return 0;
 304
 305         posix_acl_release(acl);
 306
 307         *result += strlen(name);
 308         *result += 1;
 309         if (!size)
 310                 return 0;
 311         if (*result > size)
 312                 return -ERANGE;
 313
 314         strcpy(p, name);
 315         return 0;
 316 }
 317
 318 ssize_t
 319 nfs3_listxattr(struct dentry *dentry, char *data, size_t size)
 320 {
 321         struct inode *inode = d_inode(dentry);
 322         ssize_t result = 0;
 323         int error;
 324
 325         error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS,
 326                         XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result);
 327         if (error)
 328                 return error;
 329
 330         error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT,
 331                         XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result);
 332         if (error)
 333                 return error;
 334         return result;
 335 }