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 struct super_block *sb = data->dir->i_sb; 99 100 nfs_dec_sillycount(data->dir); 101 nfs_free_unlinkdata(data); 102 nfs_sb_deactive(NFS_SB(sb)); 103 } 104 105 static const struct rpc_call_ops nfs_unlink_ops = { 106 .rpc_call_done = nfs_async_unlink_done, 107 .rpc_release = nfs_async_unlink_release, 108 }; 109 110 static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data) 111 { 112 struct rpc_message msg = { 113 .rpc_argp = &data->args, 114 .rpc_resp = &data->res, 115 .rpc_cred = data->cred, 116 }; 117 struct rpc_task_setup task_setup_data = { 118 .rpc_message = &msg, 119 .callback_ops = &nfs_unlink_ops, 120 .callback_data = data, 121 .flags = RPC_TASK_ASYNC, 122 }; 123 struct rpc_task *task; 124 struct dentry *alias; 125 126 alias = d_lookup(parent, &data->args.name); 127 if (alias != NULL) { 128 int ret = 0; 129 130 /* 131 * Hey, we raced with lookup... See if we need to transfer 132 * the sillyrename information to the aliased dentry. 133 */ 134 nfs_free_dname(data); 135 spin_lock(&alias->d_lock); 136 if (alias->d_inode != NULL && 137 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) { 138 alias->d_fsdata = data; 139 alias->d_flags |= DCACHE_NFSFS_RENAMED; 140 ret = 1; 141 } 142 spin_unlock(&alias->d_lock); 143 nfs_dec_sillycount(dir); 144 dput(alias); 145 return ret; 146 } 147 data->dir = igrab(dir); 148 if (!data->dir) { 149 nfs_dec_sillycount(dir); 150 return 0; 151 } 152 nfs_sb_active(NFS_SERVER(dir)); 153 data->args.fh = NFS_FH(dir); 154 nfs_fattr_init(&data->res.dir_attr); 155 156 NFS_PROTO(dir)->unlink_setup(&msg, dir); 157 158 task_setup_data.rpc_client = NFS_CLIENT(dir); 159 task = rpc_run_task(&task_setup_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 = rpc_lookup_cred(); 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