summaryrefslogtreecommitdiffstats
path: root/fs/afs/dir_silly.c
blob: dae9a57d7ec0c11b105ffa7fc26c3da40d9a7158 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS silly rename handling
 *
 * Copyright (C) 2019 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * - Derived from NFS's sillyrename.
 */

#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/fsnotify.h>
#include "internal.h"

static void afs_silly_rename_success(struct afs_operation *op)
{
	_enter("op=%08x", op->debug_id);

	afs_check_dir_conflict(op, &op->file[0]);
	afs_vnode_commit_status(op, &op->file[0]);
}

static void afs_silly_rename_edit_dir(struct afs_operation *op)
{
	struct afs_vnode_param *dvp = &op->file[0];
	struct afs_vnode *dvnode = dvp->vnode;
	struct afs_vnode *vnode = AFS_FS_I(d_inode(op->dentry));
	struct dentry *old = op->dentry;
	struct dentry *new = op->dentry_2;

	spin_lock(&old->d_lock);
	old->d_flags |= DCACHE_NFSFS_RENAMED;
	spin_unlock(&old->d_lock);
	if (dvnode->silly_key != op->key) {
		key_put(dvnode->silly_key);
		dvnode->silly_key = key_get(op->key);
	}

	down_write(&dvnode->validate_lock);
	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
	    dvnode->status.data_version == dvp->dv_before + dvp->dv_delta) {
		afs_edit_dir_remove(dvnode, &old->d_name,
				    afs_edit_dir_for_silly_0);
		afs_edit_dir_add(dvnode, &new->d_name,
				 &vnode->fid, afs_edit_dir_for_silly_1);
	}
	up_write(&dvnode->validate_lock);
}

static const struct afs_operation_ops afs_silly_rename_operation = {
	.issue_afs_rpc	= afs_fs_rename,
	.issue_yfs_rpc	= yfs_fs_rename,
	.success	= afs_silly_rename_success,
	.edit_dir	= afs_silly_rename_edit_dir,
};

/*
 * Actually perform the silly rename step.
 */
static int afs_do_silly_rename(struct afs_vnode *dvnode, struct afs_vnode *vnode,
			       struct dentry *old, struct dentry *new,
			       struct key *key)
{
	struct afs_operation *op;

	_enter("%pd,%pd", old, new);

	op = afs_alloc_operation(key, dvnode->volume);
	if (IS_ERR(op))
		return PTR_ERR(op);

	afs_op_set_vnode(op, 0, dvnode);
	afs_op_set_vnode(op, 1, dvnode);
	op->file[0].dv_delta = 1;
	op->file[1].dv_delta = 1;
	op->file[0].modification = true;
	op->file[1].modification = true;
	op->file[0].update_ctime = true;
	op->file[1].update_ctime = true;

	op->dentry		= old;
	op->dentry_2		= new;
	op->ops			= &afs_silly_rename_operation;

	trace_afs_silly_rename(vnode, false);
	return afs_do_sync_operation(op);
}

/**
 * afs_sillyrename - Perform a silly-rename of a dentry
 *
 * AFS is stateless and the server doesn't know when the client is holding a
 * file open.  To prevent application problems when a file is unlinked while
 * it's still open, the client performs a "silly-rename".  That is, it renames
 * the file to a hidden file in the same directory, and only performs the
 * unlink once the last reference to it is put.
 *
 * The final cleanup is done during dentry_iput.
 */
int afs_sillyrename(struct afs_vnode *dvnode, struct afs_vnode *vnode,
		    struct dentry *dentry, struct key *key)
{
	static unsigned int sillycounter;
	struct dentry *sdentry = NULL;
	unsigned char silly[16];
	int ret = -EBUSY;

	_enter("");

	/* We don't allow a dentry to be silly-renamed twice. */
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
		return -EBUSY;

	sdentry = NULL;
	do {
		int slen;

		dput(sdentry);
		sillycounter++;

		/* Create a silly name.  Note that the ".__afs" prefix is
		 * understood by the salvager and must not be changed.
		 */
		slen = scnprintf(silly, sizeof(silly), ".__afs%04X", sillycounter);
		sdentry = lookup_one_len(silly, dentry->d_parent, slen);

		/* N.B. Better to return EBUSY here ... it could be dangerous
		 * to delete the file while it's in use.
		 */
		if (IS_ERR(sdentry))
			goto out;
	} while (!d_is_negative(sdentry));

	ihold(&vnode->vfs_inode);

	ret = afs_do_silly_rename(dvnode, vnode, dentry, sdentry, key);
	switch (ret) {
	case 0:
		/* The rename succeeded. */
		set_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags);
		d_move(dentry, sdentry);
		break;
	case -ERESTARTSYS:
		/* The result of the rename is unknown. Play it safe by forcing
		 * a new lookup.
		 */
		d_drop(dentry);
		d_drop(sdentry);
	}

	iput(&vnode->vfs_inode);
	dput(sdentry);
out:
	_leave(" = %d", ret);
	return ret;
}

static void afs_silly_unlink_success(struct afs_operation *op)
{
	_enter("op=%08x", op->debug_id);
	afs_check_dir_conflict(op, &op->file[0]);
	afs_vnode_commit_status(op, &op->file[0]);
	afs_vnode_commit_status(op, &op->file[1]);
	afs_update_dentry_version(op, &op->file[0], op->dentry);
}

static void afs_silly_unlink_edit_dir(struct afs_operation *op)
{
	struct afs_vnode_param *dvp = &op->file[0];
	struct afs_vnode *dvnode = dvp->vnode;

	_enter("op=%08x", op->debug_id);
	down_write(&dvnode->validate_lock);
	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) &&
	    dvnode->status.data_version == dvp->dv_before + dvp->dv_delta)
		afs_edit_dir_remove(dvnode, &op->dentry->d_name,
				    afs_edit_dir_for_unlink);
	up_write(&dvnode->validate_lock);
}

static const struct afs_operation_ops afs_silly_unlink_operation = {
	.issue_afs_rpc	= afs_fs_remove_file,
	.issue_yfs_rpc	= yfs_fs_remove_file,
	.success	= afs_silly_unlink_success,
	.aborted	= afs_check_for_remote_deletion,
	.edit_dir	= afs_silly_unlink_edit_dir,
};

/*
 * Tell the server to remove a sillyrename file.
 */
static int afs_do_silly_unlink(struct afs_vnode *dvnode, struct afs_vnode *vnode,
			       struct dentry *dentry, struct key *key)
{
	struct afs_operation *op;

	_enter("");

	op = afs_alloc_operation(NULL, dvnode->volume);
	if (IS_ERR(op))
		return PTR_ERR(op);

	afs_op_set_vnode(op, 0, dvnode);
	afs_op_set_vnode(op, 1, vnode);
	op->file[0].dv_delta = 1;
	op->file[0].modification = true;
	op->file[0].update_ctime = true;
	op->file[1].op_unlinked = true;
	op->file[1].update_ctime = true;

	op->dentry	= dentry;
	op->ops		= &afs_silly_unlink_operation;

	trace_afs_silly_rename(vnode, true);
	afs_begin_vnode_operation(op);
	afs_wait_for_operation(op);

	/* If there was a conflict with a third party, check the status of the
	 * unlinked vnode.
	 */
	if (op->error == 0 && (op->flags & AFS_OPERATION_DIR_CONFLICT)) {
		op->file[1].update_ctime = false;
		op->fetch_status.which = 1;
		op->ops = &afs_fetch_status_operation;
		afs_begin_vnode_operation(op);
		afs_wait_for_operation(op);
	}

	return afs_put_operation(op);
}

/*
 * Remove sillyrename file on iput.
 */
int afs_silly_iput(struct dentry *dentry, struct inode *inode)
{
	struct afs_vnode *dvnode = AFS_FS_I(d_inode(dentry->d_parent));
	struct afs_vnode *vnode = AFS_FS_I(inode);
	struct dentry *alias;
	int ret;

	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);

	_enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode);

	down_read(&dvnode->rmdir_lock);

	alias = d_alloc_parallel(dentry->d_parent, &dentry->d_name, &wq);
	if (IS_ERR(alias)) {
		up_read(&dvnode->rmdir_lock);
		return 0;
	}

	if (!d_in_lookup(alias)) {
		/* We raced with lookup...  See if we need to transfer the
		 * sillyrename information to the aliased dentry.
		 */
		ret = 0;
		spin_lock(&alias->d_lock);
		if (d_really_is_positive(alias) &&
		    !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
			alias->d_flags |= DCACHE_NFSFS_RENAMED;
			ret = 1;
		}
		spin_unlock(&alias->d_lock);
		up_read(&dvnode->rmdir_lock);
		dput(alias);
		return ret;
	}

	/* Stop lock-release from complaining. */
	spin_lock(&vnode->lock);
	vnode->lock_state = AFS_VNODE_LOCK_DELETED;
	trace_afs_flock_ev(vnode, NULL, afs_flock_silly_delete, 0);
	spin_unlock(&vnode->lock);

	afs_do_silly_unlink(dvnode, vnode, dentry, dvnode->silly_key);
	up_read(&dvnode->rmdir_lock);
	d_lookup_done(alias);
	dput(alias);
	return 1;
}