1 /*
2 * linux/fs/nfs/unlink.c
3 *
4 * nfs sillydelete handling
5 *
6 * NOTE: we rely on holding the BKL for list manipulation protection.
7 */
8
9 #include <linux/slab.h>
10 #include <linux/string.h>
11 #include <linux/dcache.h>
12 #include <linux/sunrpc/sched.h>
13 #include <linux/sunrpc/clnt.h>
14 #include <linux/nfs_fs.h>
15
16
17 struct nfs_unlinkdata {
18 struct nfs_unlinkdata *next;
19 struct dentry *dir, *dentry;
20 struct qstr name;
21 struct rpc_task task;
22 struct rpc_cred *cred;
23 unsigned int count;
24 };
25
26 static struct nfs_unlinkdata *nfs_deletes;
27 static RPC_WAITQ(nfs_delete_queue, "nfs_delete_queue");
28
29 /**
30 * nfs_detach_unlinkdata - Remove asynchronous unlink from global list
31 * @data: pointer to descriptor
32 */
33 static inline void
34 nfs_detach_unlinkdata(struct nfs_unlinkdata *data)
35 {
36 struct nfs_unlinkdata **q;
37
38 for (q = &nfs_deletes; *q != NULL; q = &((*q)->next)) {
39 if (*q == data) {
40 *q = data->next;
41 break;
42 }
43 }
44 }
45
46 /**
47 * nfs_put_unlinkdata - release data from a sillydelete operation.
48 * @data: pointer to unlink structure.
49 */
50 static void
51 nfs_put_unlinkdata(struct nfs_unlinkdata *data)
52 {
53 if (--data->count == 0) {
54 nfs_detach_unlinkdata(data);
55 if (data->name.name != NULL)
56 kfree(data->name.name);
57 kfree(data);
58 }
59 }
60
61 #define NAME_ALLOC_LEN(len) ((len+16) & ~15)
62 /**
63 * nfs_copy_dname - copy dentry name to data structure
64 * @dentry: pointer to dentry
65 * @data: nfs_unlinkdata
66 */
67 static inline void
68 nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
69 {
70 char *str;
71 int len = dentry->d_name.len;
72
73 str = kmalloc(NAME_ALLOC_LEN(len), GFP_KERNEL);
74 if (!str)
75 return;
76 memcpy(str, dentry->d_name.name, len);
77 if (!data->name.len) {
78 data->name.len = len;
79 data->name.name = str;
80 } else
81 kfree(str);
82 }
83
84 /**
85 * nfs_async_unlink_init - Initialize the RPC info
86 * @task: rpc_task of the sillydelete
87 *
88 * We delay initializing RPC info until after the call to dentry_iput()
89 * in order to minimize races against rename().
90 */
91 static void
92 nfs_async_unlink_init(struct rpc_task *task)
93 {
94 struct nfs_unlinkdata *data = (struct nfs_unlinkdata *)task->tk_calldata;
95 struct dentry *dir = data->dir;
96 struct rpc_message msg = {
97 .rpc_cred = data->cred,
98 };
99 int status = -ENOENT;
100
101 if (!data->name.len)
102 goto out_err;
103
104 status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);
105 if (status < 0)
106 goto out_err;
107 nfs_begin_data_update(dir->d_inode);
108 rpc_call_setup(task, &msg, 0);
109 return;
110 out_err:
111 rpc_exit(task, status);
112 }
113
114 /**
115 * nfs_async_unlink_done - Sillydelete post-processing
116 * @task: rpc_task of the sillydelete
117 *
118 * Do the directory attribute update.
119 */
120 static void
121 nfs_async_unlink_done(struct rpc_task *task)
122 {
123 struct nfs_unlinkdata *data = (struct nfs_unlinkdata *)task->tk_calldata;
124 struct dentry *dir = data->dir;
125 struct inode *dir_i;
126
127 if (!dir)
128 return;
129 dir_i = dir->d_inode;
130 nfs_end_data_update(dir_i);
131 if (NFS_PROTO(dir_i)->unlink_done(dir, task))
132 return;
133 put_rpccred(data->cred);
134 data->cred = NULL;
135 dput(dir);
136 }
137
138 /**
139 * nfs_async_unlink_release - Release the sillydelete data.
140 * @task: rpc_task of the sillydelete
141 *
142 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
143 * rpc_task would be freed too.
144 */
145 static void
146 nfs_async_unlink_release(struct rpc_task *task)
147 {
148 struct nfs_unlinkdata *data = (struct nfs_unlinkdata *)task->tk_calldata;
149 nfs_put_unlinkdata(data);
150 }
151
152 /**
153 * nfs_async_unlink - asynchronous unlinking of a file
154 * @dentry: dentry to unlink
155 */
156 int
157 nfs_async_unlink(struct dentry *dentry)
158 {
159 struct dentry *dir = dentry->d_parent;
160 struct nfs_unlinkdata *data;
161 struct rpc_task *task;
162 struct rpc_clnt *clnt = NFS_CLIENT(dir->d_inode);
163 int status = -ENOMEM;
164
165 data = kmalloc(sizeof(*data), GFP_KERNEL);
166 if (!data)
167 goto out;
168 memset(data, 0, sizeof(*data));
169
170 data->dir = dget(dir);
171 data->dentry = dentry;
172
173 data->next = nfs_deletes;
174 nfs_deletes = data;
175 data->count = 1;
176
177 task = &data->task;
178 rpc_init_task(task, clnt, nfs_async_unlink_done , RPC_TASK_ASYNC);
179 task->tk_calldata = data;
180 task->tk_action = nfs_async_unlink_init;
181 task->tk_release = nfs_async_unlink_release;
182
183 spin_lock(&dentry->d_lock);
184 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
185 spin_unlock(&dentry->d_lock);
186 data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);
187
188 rpc_sleep_on(&nfs_delete_queue, task, NULL, NULL);
189 status = 0;
190 out:
191 return status;
192 }
193
194 /**
195 * nfs_complete_unlink - Initialize completion of the sillydelete
196 * @dentry: dentry to delete
197 *
198 * Since we're most likely to be called by dentry_iput(), we
199 * only use the dentry to find the sillydelete. We then copy the name
200 * into the qstr.
201 */
202 void
203 nfs_complete_unlink(struct dentry *dentry)
204 {
205 struct nfs_unlinkdata *data;
206
207 for(data = nfs_deletes; data != NULL; data = data->next) {
208 if (dentry == data->dentry)
209 break;
210 }
211 if (!data)
212 return;
213 data->count++;
214 nfs_copy_dname(dentry, data);
215 spin_lock(&dentry->d_lock);
216 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
217 spin_unlock(&dentry->d_lock);
218 rpc_wake_up_task(&data->task);
219 nfs_put_unlinkdata(data);
220 }
221
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