vfs_super.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *
  4 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
  5 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/module.h>
 10#include <linux/errno.h>
 11#include <linux/fs.h>
 12#include <linux/file.h>
 13#include <linux/stat.h>
 14#include <linux/string.h>
 15#include <linux/pagemap.h>
 16#include <linux/mount.h>
 17#include <linux/sched.h>
 18#include <linux/slab.h>
 19#include <linux/statfs.h>
 20#include <linux/magic.h>
 21#include <linux/fscache.h>
 22#include <linux/fs_context.h>
 23#include <net/9p/9p.h>
 24#include <net/9p/client.h>
 25
 26#include "v9fs.h"
 27#include "v9fs_vfs.h"
 28#include "fid.h"
 29#include "xattr.h"
 30#include "acl.h"
 31
 32static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
 33
 34static int v9fs_fill_super(struct super_block *sb)
 35{
 36	int ret;
 37	struct v9fs_session_info *v9ses = v9ses = sb->s_fs_info;
 38
 39	sb->s_maxbytes = MAX_LFS_FILESIZE;
 40	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
 41	sb->s_blocksize = 1 << sb->s_blocksize_bits;
 42	sb->s_magic = V9FS_MAGIC;
 43	if (v9fs_proto_dotl(v9ses)) {
 44		sb->s_op = &v9fs_super_ops_dotl;
 45		if (!(v9ses->flags & V9FS_NO_XATTR))
 46			sb->s_xattr = v9fs_xattr_handlers;
 47	} else {
 48		sb->s_op = &v9fs_super_ops;
 49		sb->s_time_max = U32_MAX;
 50	}
 51
 52	sb->s_time_min = 0;
 53
 54	ret = super_setup_bdi(sb);
 55	if (ret)
 56		return ret;
 57
 58	if (!v9ses->cache) {
 59		sb->s_bdi->ra_pages = 0;
 60		sb->s_bdi->io_pages = 0;
 61	} else {
 62		sb->s_bdi->ra_pages = v9ses->maxdata >> PAGE_SHIFT;
 63		sb->s_bdi->io_pages = v9ses->maxdata >> PAGE_SHIFT;
 64	}
 65
 66	sb->s_flags |= SB_ACTIVE;
 67
 68#ifdef CONFIG_9P_FS_POSIX_ACL
 69	if ((v9ses->flags & V9FS_ACL_MASK) == V9FS_POSIX_ACL)
 70		sb->s_flags |= SB_POSIXACL;
 71#endif
 72
 73	return 0;
 74}
 75
 76/**
 77 * v9fs_get_tree - create the mountable root and superblock
 78 * @fc: the filesystem context
 79 *
 80 */
 81
 82static int v9fs_get_tree(struct fs_context *fc)
 83{
 84	struct super_block *sb = NULL;
 85	struct inode *inode = NULL;
 86	struct dentry *root = NULL;
 87	struct v9fs_session_info *v9ses = NULL;
 88	struct p9_fid *fid;
 89	int retval = 0;
 90
 91	p9_debug(P9_DEBUG_VFS, "\n");
 92
 93	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
 94	if (!v9ses)
 95		return -ENOMEM;
 96
 97	fid = v9fs_session_init(v9ses, fc);
 98	if (IS_ERR(fid)) {
 99		retval = PTR_ERR(fid);
100		goto free_session;
101	}
102
103	fc->s_fs_info = v9ses;
104	sb = sget_fc(fc, NULL, set_anon_super_fc);
105	if (IS_ERR(sb)) {
106		retval = PTR_ERR(sb);
107		goto clunk_fid;
108	}
109	retval = v9fs_fill_super(sb);
110	if (retval)
111		goto release_sb;
112
113	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
114		set_default_d_op(sb, &v9fs_cached_dentry_operations);
115	} else {
116		set_default_d_op(sb, &v9fs_dentry_operations);
117		sb->s_d_flags |= DCACHE_DONTCACHE;
118	}
119
120	inode = v9fs_get_new_inode_from_fid(v9ses, fid, sb);
121	if (IS_ERR(inode)) {
122		retval = PTR_ERR(inode);
123		goto release_sb;
124	}
125
126	root = d_make_root(inode);
127	if (!root) {
128		retval = -ENOMEM;
129		goto release_sb;
130	}
131	sb->s_root = root;
132	retval = v9fs_get_acl(inode, fid);
133	if (retval)
134		goto release_sb;
135	v9fs_fid_add(root, &fid);
136
137	p9_debug(P9_DEBUG_VFS, " simple set mount, return 0\n");
138	fc->root = dget(sb->s_root);
139	return 0;
140
141clunk_fid:
142	p9_fid_put(fid);
143	v9fs_session_close(v9ses);
144free_session:
145	kfree(v9ses);
146	return retval;
147
148release_sb:
149	/*
150	 * we will do the session_close and root dentry release
151	 * in the below call. But we need to clunk fid, because we haven't
152	 * attached the fid to dentry so it won't get clunked
153	 * automatically.
154	 */
155	p9_fid_put(fid);
156	deactivate_locked_super(sb);
157	return retval;
158}
159
160/**
161 * v9fs_kill_super - Kill Superblock
162 * @s: superblock
163 *
164 */
165
166static void v9fs_kill_super(struct super_block *s)
167{
168	struct v9fs_session_info *v9ses = s->s_fs_info;
169
170	p9_debug(P9_DEBUG_VFS, " %p\n", s);
171
172	kill_anon_super(s);
173
174	v9fs_session_cancel(v9ses);
175	v9fs_session_close(v9ses);
176	kfree(v9ses);
177	s->s_fs_info = NULL;
178	p9_debug(P9_DEBUG_VFS, "exiting kill_super\n");
179}
180
181static void
182v9fs_umount_begin(struct super_block *sb)
183{
184	struct v9fs_session_info *v9ses;
185
186	v9ses = sb->s_fs_info;
187	v9fs_session_begin_cancel(v9ses);
188}
189
190static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
191{
192	struct v9fs_session_info *v9ses;
193	struct p9_fid *fid;
194	struct p9_rstatfs rs;
195	int res;
196
197	fid = v9fs_fid_lookup(dentry);
198	if (IS_ERR(fid)) {
199		res = PTR_ERR(fid);
200		goto done;
201	}
202
203	v9ses = v9fs_dentry2v9ses(dentry);
204	if (v9fs_proto_dotl(v9ses)) {
205		res = p9_client_statfs(fid, &rs);
206		if (res == 0) {
207			buf->f_type = rs.type;
208			buf->f_bsize = rs.bsize;
209			buf->f_blocks = rs.blocks;
210			buf->f_bfree = rs.bfree;
211			buf->f_bavail = rs.bavail;
212			buf->f_files = rs.files;
213			buf->f_ffree = rs.ffree;
214			buf->f_fsid = u64_to_fsid(rs.fsid);
215			buf->f_namelen = rs.namelen;
216		}
217		if (res != -ENOSYS)
218			goto done;
219	}
220	res = simple_statfs(dentry, buf);
221done:
222	p9_fid_put(fid);
223	return res;
224}
225
226static int v9fs_drop_inode(struct inode *inode)
227{
228	struct v9fs_session_info *v9ses;
229
230	v9ses = v9fs_inode2v9ses(inode);
231	if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
232		return inode_generic_drop(inode);
233	/*
234	 * in case of non cached mode always drop the
235	 * inode because we want the inode attribute
236	 * to always match that on the server.
237	 */
238	return 1;
239}
240
241static int v9fs_write_inode(struct inode *inode,
242			    struct writeback_control *wbc)
243{
244	/*
245	 * send an fsync request to server irrespective of
246	 * wbc->sync_mode.
247	 */
248	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
249	return netfs_unpin_writeback(inode, wbc);
250}
251
252static int v9fs_write_inode_dotl(struct inode *inode,
253				 struct writeback_control *wbc)
254{
255
256	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
257
258	return netfs_unpin_writeback(inode, wbc);
259}
260
261static const struct super_operations v9fs_super_ops = {
262	.alloc_inode = v9fs_alloc_inode,
263	.free_inode = v9fs_free_inode,
264	.statfs = simple_statfs,
265	.drop_inode = v9fs_drop_inode,
266	.evict_inode = v9fs_evict_inode,
267	.show_options = v9fs_show_options,
268	.umount_begin = v9fs_umount_begin,
269	.write_inode = v9fs_write_inode,
270};
271
272static const struct super_operations v9fs_super_ops_dotl = {
273	.alloc_inode = v9fs_alloc_inode,
274	.free_inode = v9fs_free_inode,
275	.statfs = v9fs_statfs,
276	.drop_inode = v9fs_drop_inode,
277	.evict_inode = v9fs_evict_inode,
278	.show_options = v9fs_show_options,
279	.umount_begin = v9fs_umount_begin,
280	.write_inode = v9fs_write_inode_dotl,
281};
282
283static void v9fs_free_fc(struct fs_context *fc)
284{
285	struct v9fs_context *ctx = fc->fs_private;
286
287	if (!ctx)
288		return;
289
290	/* These should be NULL by now but guard against leaks */
291	kfree(ctx->session_opts.uname);
292	kfree(ctx->session_opts.aname);
293#ifdef CONFIG_9P_FSCACHE
294	kfree(ctx->session_opts.cachetag);
295#endif
296	if (ctx->client_opts.trans_mod)
297		v9fs_put_trans(ctx->client_opts.trans_mod);
298	kfree(ctx);
299}
300
301static const struct fs_context_operations v9fs_context_ops = {
302	.parse_param	= v9fs_parse_param,
303	.get_tree	= v9fs_get_tree,
304	.free		= v9fs_free_fc,
305};
306
307static int v9fs_init_fs_context(struct fs_context *fc)
308{
309	struct v9fs_context	*ctx;
310
311	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
312	if (!ctx)
313		return -ENOMEM;
314
315	/* initialize core options */
316	ctx->session_opts.afid = ~0;
317	ctx->session_opts.cache = CACHE_NONE;
318	ctx->session_opts.session_lock_timeout = P9_LOCK_TIMEOUT;
319	ctx->session_opts.uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
320	if (!ctx->session_opts.uname)
321		goto error;
322
323	ctx->session_opts.aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
324	if (!ctx->session_opts.aname)
325		goto error;
326
327	ctx->session_opts.uid = INVALID_UID;
328	ctx->session_opts.dfltuid = V9FS_DEFUID;
329	ctx->session_opts.dfltgid = V9FS_DEFGID;
330
331	/* initialize client options */
332	ctx->client_opts.proto_version = p9_proto_2000L;
333	ctx->client_opts.msize = DEFAULT_MSIZE;
334
335	/* initialize fd transport options */
336	ctx->fd_opts.port = P9_FD_PORT;
337	ctx->fd_opts.rfd = ~0;
338	ctx->fd_opts.wfd = ~0;
339	ctx->fd_opts.privport = false;
340
341	/* initialize rdma transport options */
342	ctx->rdma_opts.port = P9_RDMA_PORT;
343	ctx->rdma_opts.sq_depth = P9_RDMA_SQ_DEPTH;
344	ctx->rdma_opts.rq_depth = P9_RDMA_RQ_DEPTH;
345	ctx->rdma_opts.timeout = P9_RDMA_TIMEOUT;
346	ctx->rdma_opts.privport = false;
347
348	fc->ops = &v9fs_context_ops;
349	fc->fs_private = ctx;
350
351	return 0;
352error:
353	fc->need_free = 1;
354	return -ENOMEM;
355}
356
357struct file_system_type v9fs_fs_type = {
358	.name = "9p",
359	.kill_sb = v9fs_kill_super,
360	.owner = THIS_MODULE,
361	.fs_flags = FS_RENAME_DOES_D_MOVE,
362	.init_fs_context = v9fs_init_fs_context,
363	.parameters = v9fs_param_spec,
364};
365MODULE_ALIAS_FS("9p");