fs/nfs/unlink.c

   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/malloc.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 struct rpc_wait_queue    nfs_delete_queue = RPC_INIT_WAITQ("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         int                     status = -ENOENT;
  98
  99         if (!data->name.len)
 100                 goto out_err;
 101
 102         memset(&msg, 0, sizeof(msg));
 103         msg.rpc_cred = data->cred;
 104         status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);
 105         if (status < 0)
 106                 goto out_err;
 107         rpc_call_setup(task, &msg, 0);
 108         return;
 109  out_err:
 110         rpc_exit(task, status);
 111 }
 112
 113 /**
 114  * nfs_async_unlink_done - Sillydelete post-processing
 115  * @task: rpc_task of the sillydelete
 116  *
 117  * Do the directory attribute update.
 118  */
 119 static void
 120 nfs_async_unlink_done(struct rpc_task *task)
 121 {
 122         struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;
 123         struct dentry           *dir = data->dir;
 124         struct inode            *dir_i;
 125
 126         if (!dir)
 127                 return;
 128         dir_i = dir->d_inode;
 129         nfs_zap_caches(dir_i);
 130         NFS_PROTO(dir_i)->unlink_done(dir, &task->tk_msg);
 131         rpcauth_releasecred(task->tk_auth, data->cred);
 132         data->cred = NULL;
 133         dput(dir);
 134 }
 135
 136 /**
 137  * nfs_async_unlink_release - Release the sillydelete data.
 138  * @task: rpc_task of the sillydelete
 139  *
 140  * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
 141  * rpc_task would be freed too.
 142  */
 143 static void
 144 nfs_async_unlink_release(struct rpc_task *task)
 145 {
 146         struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;
 147         nfs_put_unlinkdata(data);
 148 }
 149
 150 /**
 151  * nfs_async_unlink - asynchronous unlinking of a file
 152  * @dir: directory in which the file resides.
 153  * @name: name of the file to unlink.
 154  */
 155 int
 156 nfs_async_unlink(struct dentry *dentry)
 157 {
 158         struct dentry   *dir = dentry->d_parent;
 159         struct nfs_unlinkdata   *data;
 160         struct rpc_task *task;
 161         struct rpc_clnt *clnt = NFS_CLIENT(dir->d_inode);
 162         int             status = -ENOMEM;
 163
 164         data = kmalloc(sizeof(*data), GFP_KERNEL);
 165         if (!data)
 166                 goto out;
 167         memset(data, 0, sizeof(*data));
 168
 169         data->dir = dget(dir);
 170         data->dentry = dentry;
 171
 172         data->next = nfs_deletes;
 173         nfs_deletes = data;
 174         data->count = 1;
 175
 176         task = &data->task;
 177         rpc_init_task(task, clnt, nfs_async_unlink_done , RPC_TASK_ASYNC);
 178         task->tk_calldata = data;
 179         task->tk_action = nfs_async_unlink_init;
 180         task->tk_release = nfs_async_unlink_release;
 181
 182         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
 183         data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);
 184
 185         rpc_sleep_on(&nfs_delete_queue, task, NULL, NULL);
 186         status = 0;
 187  out:
 188         return status;
 189 }
 190
 191 /**
 192  * nfs_complete_remove - Initialize completion of the sillydelete
 193  * @dentry: dentry to delete
 194  *
 195  * Since we're most likely to be called by dentry_iput(), we
 196  * only use the dentry to find the sillydelete. We then copy the name
 197  * into the qstr.
 198  */
 199 void
 200 nfs_complete_unlink(struct dentry *dentry)
 201 {
 202         struct nfs_unlinkdata   *data;
 203
 204         for(data = nfs_deletes; data != NULL; data = data->next) {
 205                 if (dentry == data->dentry)
 206                         break;
 207         }
 208         if (!data)
 209                 return;
 210         data->count++;
 211         nfs_copy_dname(dentry, data);
 212         dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
 213         if (data->task.tk_rpcwait == &nfs_delete_queue)
 214                 rpc_wake_up_task(&data->task);
 215         nfs_put_unlinkdata(data);
 216 }