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