1 /*
2 * linux/fs/nfs/unlink.c
3 *
4 * nfs sillydelete handling
5 *
6 */
7
8 #include <linux/slab.h>
9 #include <linux/string.h>
10 #include <linux/dcache.h>
11 #include <linux/sunrpc/sched.h>
12 #include <linux/sunrpc/clnt.h>
13 #include <linux/nfs_fs.h>
14 #include <linux/sched.h>
15 #include <linux/wait.h>
16
17 #include "internal.h"
18
19 struct nfs_unlinkdata {
20 struct hlist_node list;
21 struct nfs_removeargs args;
22 struct nfs_removeres res;
23 struct inode *dir;
24 struct rpc_cred *cred;
25 };
26
27 /**
28 * nfs_free_unlinkdata - release data from a sillydelete operation.
29 * @data: pointer to unlink structure.
30 */
31 static void
32 nfs_free_unlinkdata(struct nfs_unlinkdata *data)
33 {
34 iput(data->dir);
35 put_rpccred(data->cred);
36 kfree(data->args.name.name);
37 kfree(data);
38 }
39
40 #define NAME_ALLOC_LEN(len) ((len+16) & ~15)
41 /**
42 * nfs_copy_dname - copy dentry name to data structure
43 * @dentry: pointer to dentry
44 * @data: nfs_unlinkdata
45 */
46 static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
47 {
48 char *str;
49 int len = dentry->d_name.len;
50
51 str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
52 if (!str)
53 return -ENOMEM;
54 data->args.name.len = len;
55 data->args.name.name = str;
56 return 0;
57 }
58
59 static void nfs_free_dname(struct nfs_unlinkdata *data)
60 {
61 kfree(data->args.name.name);
62 data->args.name.name = NULL;
63 data->args.name.len = 0;
64 }
65
66 static void nfs_dec_sillycount(struct inode *dir)
67 {
68 struct nfs_inode *nfsi = NFS_I(dir);
69 if (atomic_dec_return(&nfsi->silly_count) == 1)
70 wake_up(&nfsi->waitqueue);
71 }
72
73 /**
74 * nfs_async_unlink_done - Sillydelete post-processing
75 * @task: rpc_task of the sillydelete
76 *
77 * Do the directory attribute update.
78 */
79 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
80 {
81 struct nfs_unlinkdata *data = calldata;
82 struct inode *dir = data->dir;
83
84 if (!NFS_PROTO(dir)->unlink_done(task, dir))
85 rpc_restart_call(task);
86 }
87
88 /**
89 * nfs_async_unlink_release - Release the sillydelete data.
90 * @task: rpc_task of the sillydelete
91 *
92 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
93 * rpc_task would be freed too.
94 */
95 static void nfs_async_unlink_release(void *calldata)
96 {
97 struct nfs_unlinkdata *data = calldata;
98
99 nfs_dec_sillycount(data->dir);
100 nfs_sb_deactive(NFS_SERVER(data->dir));
101 nfs_free_unlinkdata(data);
102 }
103
104 static const struct rpc_call_ops nfs_unlink_ops = {
105 .rpc_call_done = nfs_async_unlink_done,
106 .rpc_release = nfs_async_unlink_release,
107 };
108
109 static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
110 {
111 struct rpc_message msg = {
112 .rpc_argp = &data->args,
113 .rpc_resp = &data->res,
114 .rpc_cred = data->cred,
115 };
116 struct rpc_task_setup task_setup_data = {
117 .rpc_message = &msg,
118 .callback_ops = &nfs_unlink_ops,
119 .callback_data = data,
120 .flags = RPC_TASK_ASYNC,
121 };
122 struct rpc_task *task;
123 struct dentry *alias;
124
125 alias = d_lookup(parent, &data->args.name);
126 if (alias != NULL) {
127 int ret = 0;
128
129 /*
130 * Hey, we raced with lookup... See if we need to transfer
131 * the sillyrename information to the aliased dentry.
132 */
133 nfs_free_dname(data);
134 spin_lock(&alias->d_lock);
135 if (alias->d_inode != NULL &&
136 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
137 alias->d_fsdata = data;
138 alias->d_flags |= DCACHE_NFSFS_RENAMED;
139 ret = 1;
140 }
141 spin_unlock(&alias->d_lock);
142 nfs_dec_sillycount(dir);
143 dput(alias);
144 return ret;
145 }
146 data->dir = igrab(dir);
147 if (!data->dir) {
148 nfs_dec_sillycount(dir);
149 return 0;
150 }
151 nfs_sb_active(NFS_SERVER(dir));
152 data->args.fh = NFS_FH(dir);
153 nfs_fattr_init(&data->res.dir_attr);
154
155 NFS_PROTO(dir)->unlink_setup(&msg, dir);
156
157 task_setup_data.rpc_client = NFS_CLIENT(dir);
158 task = rpc_run_task(&task_setup_data);
159 if (!IS_ERR(task))
160 rpc_put_task(task);
161 return 1;
162 }
163
164 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
165 {
166 struct dentry *parent;
167 struct inode *dir;
168 int ret = 0;
169
170
171 parent = dget_parent(dentry);
172 if (parent == NULL)
173 goto out_free;
174 dir = parent->d_inode;
175 if (nfs_copy_dname(dentry, data) != 0)
176 goto out_dput;
177 /* Non-exclusive lock protects against concurrent lookup() calls */
178 spin_lock(&dir->i_lock);
179 if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
180 /* Deferred delete */
181 hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
182 spin_unlock(&dir->i_lock);
183 ret = 1;
184 goto out_dput;
185 }
186 spin_unlock(&dir->i_lock);
187 ret = nfs_do_call_unlink(parent, dir, data);
188 out_dput:
189 dput(parent);
190 out_free:
191 return ret;
192 }
193
194 void nfs_block_sillyrename(struct dentry *dentry)
195 {
196 struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
197
198 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
199 }
200
201 void nfs_unblock_sillyrename(struct dentry *dentry)
202 {
203 struct inode *dir = dentry->d_inode;
204 struct nfs_inode *nfsi = NFS_I(dir);
205 struct nfs_unlinkdata *data;
206
207 atomic_inc(&nfsi->silly_count);
208 spin_lock(&dir->i_lock);
209 while (!hlist_empty(&nfsi->silly_list)) {
210 if (!atomic_inc_not_zero(&nfsi->silly_count))
211 break;
212 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
213 hlist_del(&data->list);
214 spin_unlock(&dir->i_lock);
215 if (nfs_do_call_unlink(dentry, dir, data) == 0)
216 nfs_free_unlinkdata(data);
217 spin_lock(&dir->i_lock);
218 }
219 spin_unlock(&dir->i_lock);
220 }
221
222 /**
223 * nfs_async_unlink - asynchronous unlinking of a file
224 * @dir: parent directory of dentry
225 * @dentry: dentry to unlink
226 */
227 int
228 nfs_async_unlink(struct inode *dir, struct dentry *dentry)
229 {
230 struct nfs_unlinkdata *data;
231 int status = -ENOMEM;
232
233 data = kzalloc(sizeof(*data), GFP_KERNEL);
234 if (data == NULL)
235 goto out;
236
237 data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
238 if (IS_ERR(data->cred)) {
239 status = PTR_ERR(data->cred);
240 goto out_free;
241 }
242
243 status = -EBUSY;
244 spin_lock(&dentry->d_lock);
245 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
246 goto out_unlock;
247 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
248 dentry->d_fsdata = data;
249 spin_unlock(&dentry->d_lock);
250 return 0;
251 out_unlock:
252 spin_unlock(&dentry->d_lock);
253 put_rpccred(data->cred);
254 out_free:
255 kfree(data);
256 out:
257 return status;
258 }
259
260 /**
261 * nfs_complete_unlink - Initialize completion of the sillydelete
262 * @dentry: dentry to delete
263 * @inode: inode
264 *
265 * Since we're most likely to be called by dentry_iput(), we
266 * only use the dentry to find the sillydelete. We then copy the name
267 * into the qstr.
268 */
269 void
270 nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
271 {
272 struct nfs_unlinkdata *data = NULL;
273
274 spin_lock(&dentry->d_lock);
275 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
276 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
277 data = dentry->d_fsdata;
278 }
279 spin_unlock(&dentry->d_lock);
280
281 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
282 nfs_free_unlinkdata(data);
283 }
284
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