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 /* 135 * Hey, we raced with lookup... See if we need to transfer 136 * the sillyrename information to the aliased dentry. 137 */ 138 nfs_free_dname(data); 139 spin_lock(&alias->d_lock); 140 if (alias->d_inode != NULL && 141 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) { 142 alias->d_fsdata = data; 143 alias->d_flags |= DCACHE_NFSFS_RENAMED; 144 ret = 1; 145 } 146 spin_unlock(&alias->d_lock); 147 nfs_dec_sillycount(dir); 148 dput(alias); 149 return ret; 150 } 151 data->dir = igrab(dir); 152 if (!data->dir) { 153 nfs_dec_sillycount(dir); 154 return 0; 155 } 156 data->args.fh = NFS_FH(dir); 157 nfs_fattr_init(&data->res.dir_attr); 158 159 task = rpc_run_task(NFS_CLIENT(dir), RPC_TASK_ASYNC, &nfs_unlink_ops, data); 160 if (!IS_ERR(task)) 161 rpc_put_task(task); 162 return 1; 163 } 164 165 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data) 166 { 167 struct dentry *parent; 168 struct inode *dir; 169 int ret = 0; 170 171 172 parent = dget_parent(dentry); 173 if (parent == NULL) 174 goto out_free; 175 dir = parent->d_inode; 176 if (nfs_copy_dname(dentry, data) != 0) 177 goto out_dput; 178 /* Non-exclusive lock protects against concurrent lookup() calls */ 179 spin_lock(&dir->i_lock); 180 if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) { 181 /* Deferred delete */ 182 hlist_add_head(&data->list, &NFS_I(dir)->silly_list); 183 spin_unlock(&dir->i_lock); 184 ret = 1; 185 goto out_dput; 186 } 187 spin_unlock(&dir->i_lock); 188 ret = nfs_do_call_unlink(parent, dir, data); 189 out_dput: 190 dput(parent); 191 out_free: 192 return ret; 193 } 194 195 void nfs_block_sillyrename(struct dentry *dentry) 196 { 197 struct nfs_inode *nfsi = NFS_I(dentry->d_inode); 198 199 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1); 200 } 201 202 void nfs_unblock_sillyrename(struct dentry *dentry) 203 { 204 struct inode *dir = dentry->d_inode; 205 struct nfs_inode *nfsi = NFS_I(dir); 206 struct nfs_unlinkdata *data; 207 208 atomic_inc(&nfsi->silly_count); 209 spin_lock(&dir->i_lock); 210 while (!hlist_empty(&nfsi->silly_list)) { 211 if (!atomic_inc_not_zero(&nfsi->silly_count)) 212 break; 213 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list); 214 hlist_del(&data->list); 215 spin_unlock(&dir->i_lock); 216 if (nfs_do_call_unlink(dentry, dir, data) == 0) 217 nfs_free_unlinkdata(data); 218 spin_lock(&dir->i_lock); 219 } 220 spin_unlock(&dir->i_lock); 221 } 222 223 /** 224 * nfs_async_unlink - asynchronous unlinking of a file 225 * @dir: parent directory of dentry 226 * @dentry: dentry to unlink 227 */ 228 int 229 nfs_async_unlink(struct inode *dir, struct dentry *dentry) 230 { 231 struct nfs_unlinkdata *data; 232 int status = -ENOMEM; 233 234 data = kzalloc(sizeof(*data), GFP_KERNEL); 235 if (data == NULL) 236 goto out; 237 238 data->cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0); 239 if (IS_ERR(data->cred)) { 240 status = PTR_ERR(data->cred); 241 goto out_free; 242 } 243 244 status = -EBUSY; 245 spin_lock(&dentry->d_lock); 246 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 247 goto out_unlock; 248 dentry->d_flags |= DCACHE_NFSFS_RENAMED; 249 dentry->d_fsdata = data; 250 spin_unlock(&dentry->d_lock); 251 return 0; 252 out_unlock: 253 spin_unlock(&dentry->d_lock); 254 put_rpccred(data->cred); 255 out_free: 256 kfree(data); 257 out: 258 return status; 259 } 260 261 /** 262 * nfs_complete_unlink - Initialize completion of the sillydelete 263 * @dentry: dentry to delete 264 * @inode: inode 265 * 266 * Since we're most likely to be called by dentry_iput(), we 267 * only use the dentry to find the sillydelete. We then copy the name 268 * into the qstr. 269 */ 270 void 271 nfs_complete_unlink(struct dentry *dentry, struct inode *inode) 272 { 273 struct nfs_unlinkdata *data = NULL; 274 275 spin_lock(&dentry->d_lock); 276 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 277 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED; 278 data = dentry->d_fsdata; 279 } 280 spin_unlock(&dentry->d_lock); 281 282 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))) 283 nfs_free_unlinkdata(data); 284 } 285