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(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 .workqueue = nfsiod_workqueue, 122 .flags = RPC_TASK_ASYNC, 123 }; 124 struct rpc_task *task; 125 struct dentry *alias; 126 127 alias = d_lookup(parent, &data->args.name); 128 if (alias != NULL) { 129 int ret = 0; 130 131 /* 132 * Hey, we raced with lookup... See if we need to transfer 133 * the sillyrename information to the aliased dentry. 134 */ 135 nfs_free_dname(data); 136 spin_lock(&alias->d_lock); 137 if (alias->d_inode != NULL && 138 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) { 139 alias->d_fsdata = data; 140 alias->d_flags |= DCACHE_NFSFS_RENAMED; 141 ret = 1; 142 } 143 spin_unlock(&alias->d_lock); 144 nfs_dec_sillycount(dir); 145 dput(alias); 146 return ret; 147 } 148 data->dir = igrab(dir); 149 if (!data->dir) { 150 nfs_dec_sillycount(dir); 151 return 0; 152 } 153 nfs_sb_active(dir->i_sb); 154 data->args.fh = NFS_FH(dir); 155 nfs_fattr_init(&data->res.dir_attr); 156 157 NFS_PROTO(dir)->unlink_setup(&msg, dir); 158 159 task_setup_data.rpc_client = NFS_CLIENT(dir); 160 task = rpc_run_task(&task_setup_data); 161 if (!IS_ERR(task)) 162 rpc_put_task(task); 163 return 1; 164 } 165 166 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data) 167 { 168 struct dentry *parent; 169 struct inode *dir; 170 int ret = 0; 171 172 173 parent = dget_parent(dentry); 174 if (parent == NULL) 175 goto out_free; 176 dir = parent->d_inode; 177 if (nfs_copy_dname(dentry, data) != 0) 178 goto out_dput; 179 /* Non-exclusive lock protects against concurrent lookup() calls */ 180 spin_lock(&dir->i_lock); 181 if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) { 182 /* Deferred delete */ 183 hlist_add_head(&data->list, &NFS_I(dir)->silly_list); 184 spin_unlock(&dir->i_lock); 185 ret = 1; 186 goto out_dput; 187 } 188 spin_unlock(&dir->i_lock); 189 ret = nfs_do_call_unlink(parent, dir, data); 190 out_dput: 191 dput(parent); 192 out_free: 193 return ret; 194 } 195 196 void nfs_block_sillyrename(struct dentry *dentry) 197 { 198 struct nfs_inode *nfsi = NFS_I(dentry->d_inode); 199 200 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1); 201 } 202 203 void nfs_unblock_sillyrename(struct dentry *dentry) 204 { 205 struct inode *dir = dentry->d_inode; 206 struct nfs_inode *nfsi = NFS_I(dir); 207 struct nfs_unlinkdata *data; 208 209 atomic_inc(&nfsi->silly_count); 210 spin_lock(&dir->i_lock); 211 while (!hlist_empty(&nfsi->silly_list)) { 212 if (!atomic_inc_not_zero(&nfsi->silly_count)) 213 break; 214 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list); 215 hlist_del(&data->list); 216 spin_unlock(&dir->i_lock); 217 if (nfs_do_call_unlink(dentry, dir, data) == 0) 218 nfs_free_unlinkdata(data); 219 spin_lock(&dir->i_lock); 220 } 221 spin_unlock(&dir->i_lock); 222 } 223 224 /** 225 * nfs_async_unlink - asynchronous unlinking of a file 226 * @dir: parent directory of dentry 227 * @dentry: dentry to unlink 228 */ 229 int 230 nfs_async_unlink(struct inode *dir, struct dentry *dentry) 231 { 232 struct nfs_unlinkdata *data; 233 int status = -ENOMEM; 234 235 data = kzalloc(sizeof(*data), GFP_KERNEL); 236 if (data == NULL) 237 goto out; 238 239 data->cred = rpc_lookup_cred(); 240 if (IS_ERR(data->cred)) { 241 status = PTR_ERR(data->cred); 242 goto out_free; 243 } 244 245 status = -EBUSY; 246 spin_lock(&dentry->d_lock); 247 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) 248 goto out_unlock; 249 dentry->d_flags |= DCACHE_NFSFS_RENAMED; 250 dentry->d_fsdata = data; 251 spin_unlock(&dentry->d_lock); 252 return 0; 253 out_unlock: 254 spin_unlock(&dentry->d_lock); 255 put_rpccred(data->cred); 256 out_free: 257 kfree(data); 258 out: 259 return status; 260 } 261 262 /** 263 * nfs_complete_unlink - Initialize completion of the sillydelete 264 * @dentry: dentry to delete 265 * @inode: inode 266 * 267 * Since we're most likely to be called by dentry_iput(), we 268 * only use the dentry to find the sillydelete. We then copy the name 269 * into the qstr. 270 */ 271 void 272 nfs_complete_unlink(struct dentry *dentry, struct inode *inode) 273 { 274 struct nfs_unlinkdata *data = NULL; 275 276 spin_lock(&dentry->d_lock); 277 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) { 278 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED; 279 data = dentry->d_fsdata; 280 } 281 spin_unlock(&dentry->d_lock); 282 283 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))) 284 nfs_free_unlinkdata(data); 285 } 286