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 struct nfs_unlinkdata { 18 struct hlist_node list; 19 struct nfs_removeargs args; 20 struct nfs_removeres res; 21 struct inode *dir; 22 struct rpc_cred *cred; 23 }; 24 25 /** 26 * nfs_free_unlinkdata - release data from a sillydelete operation. 27 * @data: pointer to unlink structure. 28 */ 29 static void 30 nfs_free_unlinkdata(struct nfs_unlinkdata *data) 31 { 32 iput(data->dir); 33 put_rpccred(data->cred); 34 kfree(data->args.name.name); 35 kfree(data); 36 } 37 38 #define NAME_ALLOC_LEN(len) ((len+16) & ~15) 39 /** 40 * nfs_copy_dname - copy dentry name to data structure 41 * @dentry: pointer to dentry 42 * @data: nfs_unlinkdata 43 */ 44 static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data) 45 { 46 char *str; 47 int len = dentry->d_name.len; 48 49 str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL); 50 if (!str) 51 return -ENOMEM; 52 data->args.name.len = len; 53 data->args.name.name = str; 54 return 0; 55 } 56 57 static void nfs_free_dname(struct nfs_unlinkdata *data) 58 { 59 kfree(data->args.name.name); 60 data->args.name.name = NULL; 61 data->args.name.len = 0; 62 } 63 64 static void nfs_dec_sillycount(struct inode *dir) 65 { 66 struct nfs_inode *nfsi = NFS_I(dir); 67 if (atomic_dec_return(&nfsi->silly_count) == 1) 68 wake_up(&nfsi->waitqueue); 69 } 70 71 /** 72 * nfs_async_unlink_init - Initialize the RPC info 73 * task: rpc_task of the sillydelete 74 */ 75 static void nfs_async_unlink_init(struct rpc_task *task, void *calldata) 76 { 77 struct nfs_unlinkdata *data = calldata; 78 struct inode *dir = data->dir; 79 struct rpc_message msg = { 80 .rpc_argp = &data->args, 81 .rpc_resp = &data->res, 82 .rpc_cred = data->cred, 83 }; 84 85 NFS_PROTO(dir)->unlink_setup(&msg, dir); 86 rpc_call_setup(task, &msg, 0); 87 } 88 89 /** 90 * nfs_async_unlink_done - Sillydelete post-processing 91 * @task: rpc_task of the sillydelete 92 * 93 * Do the directory attribute update. 94 */ 95 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata) 96 { 97 struct nfs_unlinkdata *data = calldata; 98 struct inode *dir = data->dir; 99 100 if (!NFS_PROTO(dir)->unlink_done(task, dir)) 101 rpc_restart_call(task); 102 } 103 104 /** 105 * nfs_async_unlink_release - Release the sillydelete data. 106 * @task: rpc_task of the sillydelete 107 * 108 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the 109 * rpc_task would be freed too. 110 */ 111 static void nfs_async_unlink_release(void *calldata) 112 { 113 struct nfs_unlinkdata *data = calldata; 114 115 nfs_dec_sillycount(data->dir); 116 nfs_free_unlinkdata(data); 117 } 118 119 static const struct rpc_call_ops nfs_unlink_ops = { 120 .rpc_call_prepare = nfs_async_unlink_init, 121 .rpc_call_done = nfs_async_unlink_done, 122 .rpc_release = nfs_async_unlink_release, 123 }; 124 125 static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data) 126 { 127 struct rpc_task *task; 128 struct dentry *alias; 129 130 alias = d_lookup(parent, &data->args.name); 131 if (alias != NULL) { 132 int ret = 0; 133 /* 134 * Hey, we raced with lookup... See if we need to transfer 135 * the sillyrename information to the aliased dentry. 136 */ 137 nfs_free_dname(data); 138 spin_lock(&alias->d_lock); 139 if (!(alias->d_flags & DCACHE_NFSFS_RENAMED)) { 140 alias->d_fsdata = data; 141 alias->d_flags |= DCACHE_NFSFS_RENAMED; 142 ret = 1; 143 } 144 spin_unlock(&alias->d_lock); 145 nfs_dec_sillycount(dir); 146 dput(alias); 147 return ret; 148 } 149 data->dir = igrab(dir); 150 if (!data->dir) { 151 nfs_dec_sillycount(dir); 152 return 0; 153 } 154 data->args.fh = NFS_FH(dir); 155 nfs_fattr_init(&data->res.dir_attr); 156 157 task = rpc_run_task(NFS_CLIENT(dir), RPC_TASK_ASYNC, &nfs_unlink_ops, data); 158 if (!IS_ERR(task)) 159 rpc_put_task(task); 160 return 1; 161 } 162 163 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data) 164 { 165 struct dentry *parent; 166 struct inode *dir; 167 int ret = 0; 168 169 170 parent = dget_parent(dentry); 171 if (parent == NULL) 172 goto out_free; 173 dir = parent->d_inode; 174 if (nfs_copy_dname(dentry, data) != 0) 175 goto out_dput; 176 /* Non-exclusive lock protects against concurrent lookup() calls */ 177 spin_lock(&dir->i_lock); 178 if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) { 179 /* Deferred delete */ 180 hlist_add_head(&data->list, &NFS_I(dir)->silly_list); 181 spin_unlock(&dir->i_lock); 182 ret = 1; 183 goto out_dput; 184 } 185 spin_unlock(&dir->i_lock); 186 ret = nfs_do_call_unlink(parent, dir, data); 187 out_dput: 188 dput(parent); 189 out_free: 190 return ret; 191 } 192 193 void nfs_block_sillyrename(struct dentry *dentry) 194 { 195 struct nfs_inode *nfsi = NFS_I(dentry->d_inode); 196 197 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1); 198 } 199 200 void nfs_unblock_sillyrename(struct dentry *dentry) 201 { 202 struct inode *dir = dentry->d_inode; 203 struct nfs_inode *nfsi = NFS_I(dir); 204 struct nfs_unlinkdata *data; 205 206 atomic_inc(&nfsi->silly_count); 207 spin_lock(&dir->i_lock); 208 while (!hlist_empty(&nfsi->silly_list)) { 209 if (!atomic_inc_not_zero(&nfsi->silly_count)) 210 break; 211 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list); 212 hlist_del(&data->list); 213 spin_unlock(&dir->i_lock); 214 if (nfs_do_call_unlink(dentry, dir, data) == 0) 215 nfs_free_unlinkdata(data); 216 spin_lock(&dir->i_lock); 217 } 218 spin_unlock(&dir->i_lock); 219 } 220 221 /** 222 * nfs_async_unlink - asynchronous unlinking of a file 223 * @dir: parent directory of dentry 224 * @dentry: dentry to unlink 225 */ 226 int 227 nfs_async_unlink(struct inode *dir, struct dentry *dentry) 228 { 229 struct nfs_unlinkdata *data; 230 int status = -ENOMEM; 231 232 data = kzalloc(sizeof(*data), GFP_KERNEL); 233 if (data == NULL) 234 goto out; 235 236 data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0); 237 if (IS_ERR(data->cred)) { 238 status = PTR_ERR(data->cred); 239 goto out_free; 240 } 241 242 status = -EBUSY; 243 spin_lock(&dentry->d_lock); 244 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 245 goto out_unlock; 246 dentry->d_flags |= DCACHE_NFSFS_RENAMED; 247 dentry->d_fsdata = data; 248 spin_unlock(&dentry->d_lock); 249 return 0; 250 out_unlock: 251 spin_unlock(&dentry->d_lock); 252 put_rpccred(data->cred); 253 out_free: 254 kfree(data); 255 out: 256 return status; 257 } 258 259 /** 260 * nfs_complete_unlink - Initialize completion of the sillydelete 261 * @dentry: dentry to delete 262 * @inode: inode 263 * 264 * Since we're most likely to be called by dentry_iput(), we 265 * only use the dentry to find the sillydelete. We then copy the name 266 * into the qstr. 267 */ 268 void 269 nfs_complete_unlink(struct dentry *dentry, struct inode *inode) 270 { 271 struct nfs_unlinkdata *data = NULL; 272 273 spin_lock(&dentry->d_lock); 274 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 275 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED; 276 data = dentry->d_fsdata; 277 } 278 spin_unlock(&dentry->d_lock); 279 280 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))) 281 nfs_free_unlinkdata(data); 282 } 283