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   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 #include "nfs4_fs.h"
  19
  20 struct nfs_unlinkdata {
  21         struct hlist_node list;
  22         struct nfs_removeargs args;
  23         struct nfs_removeres res;
  24         struct inode *dir;
  25         struct rpc_cred *cred;
  26 };
  27
  28 /**
  29  * nfs_free_unlinkdata - release data from a sillydelete operation.
  30  * @data: pointer to unlink structure.
  31  */
  32 static void
  33 nfs_free_unlinkdata(struct nfs_unlinkdata *data)
  34 {
  35         iput(data->dir);
  36         put_rpccred(data->cred);
  37         kfree(data->args.name.name);
  38         kfree(data);
  39 }
  40
  41 #define NAME_ALLOC_LEN(len)     ((len+16) & ~15)
  42 /**
  43  * nfs_copy_dname - copy dentry name to data structure
  44  * @dentry: pointer to dentry
  45  * @data: nfs_unlinkdata
  46  */
  47 static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
  48 {
  49         char            *str;
  50         int             len = dentry->d_name.len;
  51
  52         str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
  53         if (!str)
  54                 return -ENOMEM;
  55         data->args.name.len = len;
  56         data->args.name.name = str;
  57         return 0;
  58 }
  59
  60 static void nfs_free_dname(struct nfs_unlinkdata *data)
  61 {
  62         kfree(data->args.name.name);
  63         data->args.name.name = NULL;
  64         data->args.name.len = 0;
  65 }
  66
  67 static void nfs_dec_sillycount(struct inode *dir)
  68 {
  69         struct nfs_inode *nfsi = NFS_I(dir);
  70         if (atomic_dec_return(&nfsi->silly_count) == 1)
  71                 wake_up(&nfsi->waitqueue);
  72 }
  73
  74 /**
  75  * nfs_async_unlink_done - Sillydelete post-processing
  76  * @task: rpc_task of the sillydelete
  77  *
  78  * Do the directory attribute update.
  79  */
  80 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
  81 {
  82         struct nfs_unlinkdata *data = calldata;
  83         struct inode *dir = data->dir;
  84         struct nfs_removeres *res = task->tk_msg.rpc_resp;
  85
  86         if (!NFS_PROTO(dir)->unlink_done(task, dir))
  87                 nfs4_restart_rpc(task, NFS_SERVER(dir)->nfs_client,
  88                                  &res->seq_res);
  89 }
  90
  91 /**
  92  * nfs_async_unlink_release - Release the sillydelete data.
  93  * @task: rpc_task of the sillydelete
  94  *
  95  * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
  96  * rpc_task would be freed too.
  97  */
  98 static void nfs_async_unlink_release(void *calldata)
  99 {
 100         struct nfs_unlinkdata   *data = calldata;
 101         struct super_block *sb = data->dir->i_sb;
 102
 103         nfs_dec_sillycount(data->dir);
 104         nfs_free_unlinkdata(data);
 105         nfs_sb_deactive(sb);
 106 }
 107
 108 #if defined(CONFIG_NFS_V4_1)
 109 void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
 110 {
 111         struct nfs_unlinkdata *data = calldata;
 112         struct nfs_server *server = NFS_SERVER(data->dir);
 113
 114         if (nfs4_setup_sequence(server->nfs_client, &data->args.seq_args,
 115                                 &data->res.seq_res, 1, task))
 116                 return;
 117         rpc_call_start(task);
 118 }
 119 #endif /* CONFIG_NFS_V4_1 */
 120
 121 static const struct rpc_call_ops nfs_unlink_ops = {
 122         .rpc_call_done = nfs_async_unlink_done,
 123         .rpc_release = nfs_async_unlink_release,
 124 #if defined(CONFIG_NFS_V4_1)
 125         .rpc_call_prepare = nfs_unlink_prepare,
 126 #endif /* CONFIG_NFS_V4_1 */
 127 };
 128
 129 static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
 130 {
 131         struct rpc_message msg = {
 132                 .rpc_argp = &data->args,
 133                 .rpc_resp = &data->res,
 134                 .rpc_cred = data->cred,
 135         };
 136         struct rpc_task_setup task_setup_data = {
 137                 .rpc_message = &msg,
 138                 .callback_ops = &nfs_unlink_ops,
 139                 .callback_data = data,
 140                 .workqueue = nfsiod_workqueue,
 141                 .flags = RPC_TASK_ASYNC,
 142         };
 143         struct rpc_task *task;
 144         struct dentry *alias;
 145
 146         alias = d_lookup(parent, &data->args.name);
 147         if (alias != NULL) {
 148                 int ret = 0;
 149
 150                 /*
 151                  * Hey, we raced with lookup... See if we need to transfer
 152                  * the sillyrename information to the aliased dentry.
 153                  */
 154                 nfs_free_dname(data);
 155                 spin_lock(&alias->d_lock);
 156                 if (alias->d_inode != NULL &&
 157                     !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
 158                         alias->d_fsdata = data;
 159                         alias->d_flags |= DCACHE_NFSFS_RENAMED;
 160                         ret = 1;
 161                 }
 162                 spin_unlock(&alias->d_lock);
 163                 nfs_dec_sillycount(dir);
 164                 dput(alias);
 165                 return ret;
 166         }
 167         data->dir = igrab(dir);
 168         if (!data->dir) {
 169                 nfs_dec_sillycount(dir);
 170                 return 0;
 171         }
 172         nfs_sb_active(dir->i_sb);
 173         data->args.fh = NFS_FH(dir);
 174         nfs_fattr_init(&data->res.dir_attr);
 175
 176         NFS_PROTO(dir)->unlink_setup(&msg, dir);
 177
 178         task_setup_data.rpc_client = NFS_CLIENT(dir);
 179         task = rpc_run_task(&task_setup_data);
 180         if (!IS_ERR(task))
 181                 rpc_put_task(task);
 182         return 1;
 183 }
 184
 185 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
 186 {
 187         struct dentry *parent;
 188         struct inode *dir;
 189         int ret = 0;
 190
 191
 192         parent = dget_parent(dentry);
 193         if (parent == NULL)
 194                 goto out_free;
 195         dir = parent->d_inode;
 196         if (nfs_copy_dname(dentry, data) != 0)
 197                 goto out_dput;
 198         /* Non-exclusive lock protects against concurrent lookup() calls */
 199         spin_lock(&dir->i_lock);
 200         if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
 201                 /* Deferred delete */
 202                 hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
 203                 spin_unlock(&dir->i_lock);
 204                 ret = 1;
 205                 goto out_dput;
 206         }
 207         spin_unlock(&dir->i_lock);
 208         ret = nfs_do_call_unlink(parent, dir, data);
 209 out_dput:
 210         dput(parent);
 211 out_free:
 212         return ret;
 213 }
 214
 215 void nfs_block_sillyrename(struct dentry *dentry)
 216 {
 217         struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
 218
 219         wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
 220 }
 221
 222 void nfs_unblock_sillyrename(struct dentry *dentry)
 223 {
 224         struct inode *dir = dentry->d_inode;
 225         struct nfs_inode *nfsi = NFS_I(dir);
 226         struct nfs_unlinkdata *data;
 227
 228         atomic_inc(&nfsi->silly_count);
 229         spin_lock(&dir->i_lock);
 230         while (!hlist_empty(&nfsi->silly_list)) {
 231                 if (!atomic_inc_not_zero(&nfsi->silly_count))
 232                         break;
 233                 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
 234                 hlist_del(&data->list);
 235                 spin_unlock(&dir->i_lock);
 236                 if (nfs_do_call_unlink(dentry, dir, data) == 0)
 237                         nfs_free_unlinkdata(data);
 238                 spin_lock(&dir->i_lock);
 239         }
 240         spin_unlock(&dir->i_lock);
 241 }
 242
 243 /**
 244  * nfs_async_unlink - asynchronous unlinking of a file
 245  * @dir: parent directory of dentry
 246  * @dentry: dentry to unlink
 247  */
 248 int
 249 nfs_async_unlink(struct inode *dir, struct dentry *dentry)
 250 {
 251         struct nfs_unlinkdata *data;
 252         int status = -ENOMEM;
 253
 254         data = kzalloc(sizeof(*data), GFP_KERNEL);
 255         if (data == NULL)
 256                 goto out;
 257
 258         data->cred = rpc_lookup_cred();
 259         if (IS_ERR(data->cred)) {
 260                 status = PTR_ERR(data->cred);
 261                 goto out_free;
 262         }
 263         data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
 264
 265         status = -EBUSY;
 266         spin_lock(&dentry->d_lock);
 267         if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
 268                 goto out_unlock;
 269         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
 270         dentry->d_fsdata = data;
 271         spin_unlock(&dentry->d_lock);
 272         return 0;
 273 out_unlock:
 274         spin_unlock(&dentry->d_lock);
 275         put_rpccred(data->cred);
 276 out_free:
 277         kfree(data);
 278 out:
 279         return status;
 280 }
 281
 282 /**
 283  * nfs_complete_unlink - Initialize completion of the sillydelete
 284  * @dentry: dentry to delete
 285  * @inode: inode
 286  *
 287  * Since we're most likely to be called by dentry_iput(), we
 288  * only use the dentry to find the sillydelete. We then copy the name
 289  * into the qstr.
 290  */
 291 void
 292 nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
 293 {
 294         struct nfs_unlinkdata   *data = NULL;
 295
 296         spin_lock(&dentry->d_lock);
 297         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
 298                 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
 299                 data = dentry->d_fsdata;
 300         }
 301         spin_unlock(&dentry->d_lock);
 302
 303         if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
 304                 nfs_free_unlinkdata(data);
 305 }