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 } 284