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