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