NFS: Ensure we call nfs_sb_deactive() after releasing the directory inode
[linux-2.6.git] / fs / nfs / unlink.c
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         struct super_block *sb = data->dir->i_sb;
99
100         nfs_dec_sillycount(data->dir);
101         nfs_free_unlinkdata(data);
102         nfs_sb_deactive(NFS_SB(sb));
103 }
104
105 static const struct rpc_call_ops nfs_unlink_ops = {
106         .rpc_call_done = nfs_async_unlink_done,
107         .rpc_release = nfs_async_unlink_release,
108 };
109
110 static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
111 {
112         struct rpc_message msg = {
113                 .rpc_argp = &data->args,
114                 .rpc_resp = &data->res,
115                 .rpc_cred = data->cred,
116         };
117         struct rpc_task_setup task_setup_data = {
118                 .rpc_message = &msg,
119                 .callback_ops = &nfs_unlink_ops,
120                 .callback_data = data,
121                 .flags = RPC_TASK_ASYNC,
122         };
123         struct rpc_task *task;
124         struct dentry *alias;
125
126         alias = d_lookup(parent, &data->args.name);
127         if (alias != NULL) {
128                 int ret = 0;
129
130                 /*
131                  * Hey, we raced with lookup... See if we need to transfer
132                  * the sillyrename information to the aliased dentry.
133                  */
134                 nfs_free_dname(data);
135                 spin_lock(&alias->d_lock);
136                 if (alias->d_inode != NULL &&
137                     !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
138                         alias->d_fsdata = data;
139                         alias->d_flags |= DCACHE_NFSFS_RENAMED;
140                         ret = 1;
141                 }
142                 spin_unlock(&alias->d_lock);
143                 nfs_dec_sillycount(dir);
144                 dput(alias);
145                 return ret;
146         }
147         data->dir = igrab(dir);
148         if (!data->dir) {
149                 nfs_dec_sillycount(dir);
150                 return 0;
151         }
152         nfs_sb_active(NFS_SERVER(dir));
153         data->args.fh = NFS_FH(dir);
154         nfs_fattr_init(&data->res.dir_attr);
155
156         NFS_PROTO(dir)->unlink_setup(&msg, dir);
157
158         task_setup_data.rpc_client = NFS_CLIENT(dir);
159         task = rpc_run_task(&task_setup_data);
160         if (!IS_ERR(task))
161                 rpc_put_task(task);
162         return 1;
163 }
164
165 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
166 {
167         struct dentry *parent;
168         struct inode *dir;
169         int ret = 0;
170
171
172         parent = dget_parent(dentry);
173         if (parent == NULL)
174                 goto out_free;
175         dir = parent->d_inode;
176         if (nfs_copy_dname(dentry, data) != 0)
177                 goto out_dput;
178         /* Non-exclusive lock protects against concurrent lookup() calls */
179         spin_lock(&dir->i_lock);
180         if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
181                 /* Deferred delete */
182                 hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
183                 spin_unlock(&dir->i_lock);
184                 ret = 1;
185                 goto out_dput;
186         }
187         spin_unlock(&dir->i_lock);
188         ret = nfs_do_call_unlink(parent, dir, data);
189 out_dput:
190         dput(parent);
191 out_free:
192         return ret;
193 }
194
195 void nfs_block_sillyrename(struct dentry *dentry)
196 {
197         struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
198
199         wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
200 }
201
202 void nfs_unblock_sillyrename(struct dentry *dentry)
203 {
204         struct inode *dir = dentry->d_inode;
205         struct nfs_inode *nfsi = NFS_I(dir);
206         struct nfs_unlinkdata *data;
207
208         atomic_inc(&nfsi->silly_count);
209         spin_lock(&dir->i_lock);
210         while (!hlist_empty(&nfsi->silly_list)) {
211                 if (!atomic_inc_not_zero(&nfsi->silly_count))
212                         break;
213                 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
214                 hlist_del(&data->list);
215                 spin_unlock(&dir->i_lock);
216                 if (nfs_do_call_unlink(dentry, dir, data) == 0)
217                         nfs_free_unlinkdata(data);
218                 spin_lock(&dir->i_lock);
219         }
220         spin_unlock(&dir->i_lock);
221 }
222
223 /**
224  * nfs_async_unlink - asynchronous unlinking of a file
225  * @dir: parent directory of dentry
226  * @dentry: dentry to unlink
227  */
228 int
229 nfs_async_unlink(struct inode *dir, struct dentry *dentry)
230 {
231         struct nfs_unlinkdata *data;
232         int status = -ENOMEM;
233
234         data = kzalloc(sizeof(*data), GFP_KERNEL);
235         if (data == NULL)
236                 goto out;
237
238         data->cred = rpc_lookup_cred();
239         if (IS_ERR(data->cred)) {
240                 status = PTR_ERR(data->cred);
241                 goto out_free;
242         }
243
244         status = -EBUSY;
245         spin_lock(&dentry->d_lock);
246         if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
247                 goto out_unlock;
248         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
249         dentry->d_fsdata = data;
250         spin_unlock(&dentry->d_lock);
251         return 0;
252 out_unlock:
253         spin_unlock(&dentry->d_lock);
254         put_rpccred(data->cred);
255 out_free:
256         kfree(data);
257 out:
258         return status;
259 }
260
261 /**
262  * nfs_complete_unlink - Initialize completion of the sillydelete
263  * @dentry: dentry to delete
264  * @inode: inode
265  *
266  * Since we're most likely to be called by dentry_iput(), we
267  * only use the dentry to find the sillydelete. We then copy the name
268  * into the qstr.
269  */
270 void
271 nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
272 {
273         struct nfs_unlinkdata   *data = NULL;
274
275         spin_lock(&dentry->d_lock);
276         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
277                 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
278                 data = dentry->d_fsdata;
279         }
280         spin_unlock(&dentry->d_lock);
281
282         if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
283                 nfs_free_unlinkdata(data);
284 }