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
  15
  16 struct nfs_unlinkdata {
  17         struct nfs_removeargs args;
  18         struct nfs_removeres res;
  19         struct inode *dir;
  20         struct rpc_cred *cred;
  21 };
  22
  23 /**
  24  * nfs_free_unlinkdata - release data from a sillydelete operation.
  25  * @data: pointer to unlink structure.
  26  */
  27 static void
  28 nfs_free_unlinkdata(struct nfs_unlinkdata *data)
  29 {
  30         iput(data->dir);
  31         put_rpccred(data->cred);
  32         kfree(data->args.name.name);
  33         kfree(data);
  34 }
  35
  36 #define NAME_ALLOC_LEN(len)     ((len+16) & ~15)
  37 /**
  38  * nfs_copy_dname - copy dentry name to data structure
  39  * @dentry: pointer to dentry
  40  * @data: nfs_unlinkdata
  41  */
  42 static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
  43 {
  44         char            *str;
  45         int             len = dentry->d_name.len;
  46
  47         str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
  48         if (!str)
  49                 return -ENOMEM;
  50         data->args.name.len = len;
  51         data->args.name.name = str;
  52         return 0;
  53 }
  54
  55 /**
  56  * nfs_async_unlink_init - Initialize the RPC info
  57  * task: rpc_task of the sillydelete
  58  */
  59 static void nfs_async_unlink_init(struct rpc_task *task, void *calldata)
  60 {
  61         struct nfs_unlinkdata *data = calldata;
  62         struct inode *dir = data->dir;
  63         struct rpc_message msg = {
  64                 .rpc_argp = &data->args,
  65                 .rpc_resp = &data->res,
  66                 .rpc_cred = data->cred,
  67         };
  68
  69         NFS_PROTO(dir)->unlink_setup(&msg, dir);
  70         rpc_call_setup(task, &msg, 0);
  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         nfs_free_unlinkdata(data);
  99 }
 100
 101 static const struct rpc_call_ops nfs_unlink_ops = {
 102         .rpc_call_prepare = nfs_async_unlink_init,
 103         .rpc_call_done = nfs_async_unlink_done,
 104         .rpc_release = nfs_async_unlink_release,
 105 };
 106
 107 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
 108 {
 109         struct rpc_task *task;
 110         struct dentry *parent;
 111         struct inode *dir;
 112
 113         if (nfs_copy_dname(dentry, data) < 0)
 114                 goto out_free;
 115
 116         parent = dget_parent(dentry);
 117         if (parent == NULL)
 118                 goto out_free;
 119         dir = igrab(parent->d_inode);
 120         dput(parent);
 121         if (dir == NULL)
 122                 goto out_free;
 123
 124         data->dir = dir;
 125         data->args.fh = NFS_FH(dir);
 126         nfs_fattr_init(&data->res.dir_attr);
 127
 128         task = rpc_run_task(NFS_CLIENT(dir), RPC_TASK_ASYNC, &nfs_unlink_ops, data);
 129         if (!IS_ERR(task))
 130                 rpc_put_task(task);
 131         return 1;
 132 out_free:
 133         return 0;
 134 }
 135
 136 /**
 137  * nfs_async_unlink - asynchronous unlinking of a file
 138  * @dir: parent directory of dentry
 139  * @dentry: dentry to unlink
 140  */
 141 int
 142 nfs_async_unlink(struct inode *dir, struct dentry *dentry)
 143 {
 144         struct nfs_unlinkdata *data;
 145         int status = -ENOMEM;
 146
 147         data = kzalloc(sizeof(*data), GFP_KERNEL);
 148         if (data == NULL)
 149                 goto out;
 150
 151         data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
 152         if (IS_ERR(data->cred)) {
 153                 status = PTR_ERR(data->cred);
 154                 goto out_free;
 155         }
 156
 157         status = -EBUSY;
 158         spin_lock(&dentry->d_lock);
 159         if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
 160                 goto out_unlock;
 161         dentry->d_flags |= DCACHE_NFSFS_RENAMED;
 162         dentry->d_fsdata = data;
 163         spin_unlock(&dentry->d_lock);
 164         return 0;
 165 out_unlock:
 166         spin_unlock(&dentry->d_lock);
 167         put_rpccred(data->cred);
 168 out_free:
 169         kfree(data);
 170 out:
 171         return status;
 172 }
 173
 174 /**
 175  * nfs_complete_unlink - Initialize completion of the sillydelete
 176  * @dentry: dentry to delete
 177  * @inode: inode
 178  *
 179  * Since we're most likely to be called by dentry_iput(), we
 180  * only use the dentry to find the sillydelete. We then copy the name
 181  * into the qstr.
 182  */
 183 void
 184 nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
 185 {
 186         struct nfs_unlinkdata   *data = NULL;
 187
 188         spin_lock(&dentry->d_lock);
 189         if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
 190                 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
 191                 data = dentry->d_fsdata;
 192         }
 193         spin_unlock(&dentry->d_lock);
 194
 195         if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
 196                 nfs_free_unlinkdata(data);
 197 }