1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2008 Christoph Hellwig.
4 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_da_format.h"
12 #include "xfs_trans_resv.h"
13 #include "xfs_mount.h"
14 #include "xfs_inode.h"
15 #include "xfs_da_btree.h"
19 #include "xfs_xattr.h"
21 #include <linux/posix_acl_xattr.h>
24 * Get permission to use log-assisted atomic exchange of file extents.
26 * Callers must not be running any transactions or hold any inode locks, and
27 * they must release the permission by calling xlog_drop_incompat_feat
31 xfs_attr_grab_log_assist(
37 * Protect ourselves from an idle log clearing the logged xattrs log
38 * incompat feature bit.
40 xlog_use_incompat_feat(mp->m_log);
43 * If log-assisted xattrs are already enabled, the caller can use the
44 * log assisted swap functions with the log-incompat reference we got.
46 if (xfs_sb_version_haslogxattrs(&mp->m_sb))
50 * Check if the filesystem featureset is new enough to set this log
51 * incompat feature bit. Strictly speaking, the minimum requirement is
52 * a V5 filesystem for the superblock field, but we'll require rmap
53 * or reflink to avoid having to deal with really old kernels.
55 if (!xfs_has_reflink(mp) && !xfs_has_rmapbt(mp)) {
60 /* Enable log-assisted xattrs. */
61 error = xfs_add_incompat_log_feature(mp,
62 XFS_SB_FEAT_INCOMPAT_LOG_XATTRS);
66 xfs_warn_mount(mp, XFS_OPSTATE_WARNED_LARP,
67 "EXPERIMENTAL logged extended attributes feature in use. Use at your own risk!");
71 xlog_drop_incompat_feat(mp->m_log);
76 xfs_attr_rele_log_assist(
79 xlog_drop_incompat_feat(mp->m_log);
83 xfs_attr_want_log_assist(
87 /* Logged xattrs require a V5 super for log_incompat */
88 return xfs_has_crc(mp) && xfs_globals.larp;
95 * Set or remove an xattr, having grabbed the appropriate logging resources
96 * prior to calling libxfs.
100 struct xfs_da_args *args)
102 struct xfs_mount *mp = args->dp->i_mount;
103 bool use_logging = false;
106 ASSERT(!(args->op_flags & XFS_DA_OP_LOGGED));
108 if (xfs_attr_want_log_assist(mp)) {
109 error = xfs_attr_grab_log_assist(mp);
113 args->op_flags |= XFS_DA_OP_LOGGED;
117 error = xfs_attr_set(args);
120 xfs_attr_rele_log_assist(mp);
126 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
127 struct inode *inode, const char *name, void *value, size_t size)
129 struct xfs_da_args args = {
131 .attr_filter = handler->flags,
133 .namelen = strlen(name),
139 if (xfs_ifork_zapped(XFS_I(inode), XFS_ATTR_FORK))
142 error = xfs_attr_get(&args);
145 return args.valuelen;
149 xfs_xattr_set(const struct xattr_handler *handler,
150 struct mnt_idmap *idmap, struct dentry *unused,
151 struct inode *inode, const char *name, const void *value,
152 size_t size, int flags)
154 struct xfs_da_args args = {
156 .attr_filter = handler->flags,
159 .namelen = strlen(name),
160 .value = (void *)value,
165 error = xfs_attr_change(&args);
166 if (!error && (handler->flags & XFS_ATTR_ROOT))
167 xfs_forget_acl(inode, name);
171 static const struct xattr_handler xfs_xattr_user_handler = {
172 .prefix = XATTR_USER_PREFIX,
173 .flags = 0, /* no flags implies user namespace */
174 .get = xfs_xattr_get,
175 .set = xfs_xattr_set,
178 static const struct xattr_handler xfs_xattr_trusted_handler = {
179 .prefix = XATTR_TRUSTED_PREFIX,
180 .flags = XFS_ATTR_ROOT,
181 .get = xfs_xattr_get,
182 .set = xfs_xattr_set,
185 static const struct xattr_handler xfs_xattr_security_handler = {
186 .prefix = XATTR_SECURITY_PREFIX,
187 .flags = XFS_ATTR_SECURE,
188 .get = xfs_xattr_get,
189 .set = xfs_xattr_set,
192 const struct xattr_handler * const xfs_xattr_handlers[] = {
193 &xfs_xattr_user_handler,
194 &xfs_xattr_trusted_handler,
195 &xfs_xattr_security_handler,
200 __xfs_xattr_put_listent(
201 struct xfs_attr_list_context *context,
210 if (context->count < 0 || context->seen_enough)
213 if (!context->buffer)
216 arraytop = context->count + prefix_len + namelen + 1;
217 if (arraytop > context->firstu) {
218 context->count = -1; /* insufficient space */
219 context->seen_enough = 1;
222 offset = context->buffer + context->count;
223 memcpy(offset, prefix, prefix_len);
224 offset += prefix_len;
225 strncpy(offset, (char *)name, namelen); /* real name */
230 context->count += prefix_len + namelen + 1;
235 xfs_xattr_put_listent(
236 struct xfs_attr_list_context *context,
245 ASSERT(context->count >= 0);
247 if (flags & XFS_ATTR_ROOT) {
248 #ifdef CONFIG_XFS_POSIX_ACL
249 if (namelen == SGI_ACL_FILE_SIZE &&
250 strncmp(name, SGI_ACL_FILE,
251 SGI_ACL_FILE_SIZE) == 0) {
252 __xfs_xattr_put_listent(
253 context, XATTR_SYSTEM_PREFIX,
254 XATTR_SYSTEM_PREFIX_LEN,
255 XATTR_POSIX_ACL_ACCESS,
256 strlen(XATTR_POSIX_ACL_ACCESS));
257 } else if (namelen == SGI_ACL_DEFAULT_SIZE &&
258 strncmp(name, SGI_ACL_DEFAULT,
259 SGI_ACL_DEFAULT_SIZE) == 0) {
260 __xfs_xattr_put_listent(
261 context, XATTR_SYSTEM_PREFIX,
262 XATTR_SYSTEM_PREFIX_LEN,
263 XATTR_POSIX_ACL_DEFAULT,
264 strlen(XATTR_POSIX_ACL_DEFAULT));
269 * Only show root namespace entries if we are actually allowed to
272 if (!capable(CAP_SYS_ADMIN))
275 prefix = XATTR_TRUSTED_PREFIX;
276 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
277 } else if (flags & XFS_ATTR_SECURE) {
278 prefix = XATTR_SECURITY_PREFIX;
279 prefix_len = XATTR_SECURITY_PREFIX_LEN;
281 prefix = XATTR_USER_PREFIX;
282 prefix_len = XATTR_USER_PREFIX_LEN;
285 __xfs_xattr_put_listent(context, prefix, prefix_len, name,
292 struct dentry *dentry,
296 struct xfs_attr_list_context context;
297 struct inode *inode = d_inode(dentry);
300 if (xfs_ifork_zapped(XFS_I(inode), XFS_ATTR_FORK))
304 * First read the regular on-disk attributes.
306 memset(&context, 0, sizeof(context));
307 context.dp = XFS_I(inode);
309 context.buffer = size ? data : NULL;
310 context.bufsize = size;
311 context.firstu = context.bufsize;
312 context.put_listent = xfs_xattr_put_listent;
314 error = xfs_attr_list(&context);
317 if (context.count < 0)
320 return context.count;