Christoph Hellwig | e38f981 | 2007-10-21 16:42:19 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) Neil Brown 2002 |
| 3 | * Copyright (C) Christoph Hellwig 2007 |
| 4 | * |
| 5 | * This file contains the code mapping from inodes to NFS file handles, |
| 6 | * and for mapping back from file handles to dentries. |
| 7 | * |
| 8 | * For details on why we do all the strange and hairy things in here |
J. Bruce Fields | dc7a081 | 2009-10-27 14:41:35 -0400 | [diff] [blame] | 9 | * take a look at Documentation/filesystems/nfs/Exporting. |
Christoph Hellwig | e38f981 | 2007-10-21 16:42:19 -0700 | [diff] [blame] | 10 | */ |
Christoph Hellwig | a569425 | 2007-07-17 04:04:28 -0700 | [diff] [blame] | 11 | #include <linux/exportfs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/fs.h> |
| 13 | #include <linux/file.h> |
| 14 | #include <linux/module.h> |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 15 | #include <linux/mount.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include <linux/namei.h> |
David Howells | 745ca24 | 2008-11-14 10:39:22 +1100 | [diff] [blame] | 17 | #include <linux/sched.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #define dprintk(fmt, args...) do{}while(0) |
| 20 | |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 21 | |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 22 | static int get_name(const struct path *path, char *name, struct dentry *child); |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 23 | |
| 24 | |
Christoph Hellwig | e38f981 | 2007-10-21 16:42:19 -0700 | [diff] [blame] | 25 | static int exportfs_get_name(struct vfsmount *mnt, struct dentry *dir, |
| 26 | char *name, struct dentry *child) |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 27 | { |
Christoph Hellwig | 3965516 | 2007-10-21 16:42:17 -0700 | [diff] [blame] | 28 | const struct export_operations *nop = dir->d_sb->s_export_op; |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 29 | struct path path = {.mnt = mnt, .dentry = dir}; |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 30 | |
| 31 | if (nop->get_name) |
| 32 | return nop->get_name(dir, name, child); |
| 33 | else |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 34 | return get_name(&path, name, child); |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 35 | } |
| 36 | |
Christoph Hellwig | fb66a19 | 2007-07-17 04:04:32 -0700 | [diff] [blame] | 37 | /* |
| 38 | * Check if the dentry or any of it's aliases is acceptable. |
| 39 | */ |
Christoph Hellwig | e2f9901 | 2006-01-18 17:43:52 -0800 | [diff] [blame] | 40 | static struct dentry * |
| 41 | find_acceptable_alias(struct dentry *result, |
| 42 | int (*acceptable)(void *context, struct dentry *dentry), |
| 43 | void *context) |
| 44 | { |
| 45 | struct dentry *dentry, *toput = NULL; |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 46 | struct inode *inode; |
Christoph Hellwig | e2f9901 | 2006-01-18 17:43:52 -0800 | [diff] [blame] | 47 | |
Christoph Hellwig | fb66a19 | 2007-07-17 04:04:32 -0700 | [diff] [blame] | 48 | if (acceptable(context, result)) |
| 49 | return result; |
| 50 | |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 51 | inode = result->d_inode; |
| 52 | spin_lock(&inode->i_lock); |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 53 | hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) { |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 54 | dget(dentry); |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 55 | spin_unlock(&inode->i_lock); |
Christoph Hellwig | e2f9901 | 2006-01-18 17:43:52 -0800 | [diff] [blame] | 56 | if (toput) |
| 57 | dput(toput); |
| 58 | if (dentry != result && acceptable(context, dentry)) { |
| 59 | dput(result); |
| 60 | return dentry; |
| 61 | } |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 62 | spin_lock(&inode->i_lock); |
Christoph Hellwig | e2f9901 | 2006-01-18 17:43:52 -0800 | [diff] [blame] | 63 | toput = dentry; |
| 64 | } |
Nick Piggin | 873feea | 2011-01-07 17:50:06 +1100 | [diff] [blame] | 65 | spin_unlock(&inode->i_lock); |
Christoph Hellwig | e2f9901 | 2006-01-18 17:43:52 -0800 | [diff] [blame] | 66 | |
| 67 | if (toput) |
| 68 | dput(toput); |
| 69 | return NULL; |
| 70 | } |
| 71 | |
J. Bruce Fields | a056cc8 | 2013-10-16 21:09:30 -0400 | [diff] [blame] | 72 | static bool dentry_connected(struct dentry *dentry) |
| 73 | { |
| 74 | dget(dentry); |
| 75 | while (dentry->d_flags & DCACHE_DISCONNECTED) { |
| 76 | struct dentry *parent = dget_parent(dentry); |
| 77 | |
| 78 | dput(dentry); |
| 79 | if (IS_ROOT(dentry)) { |
| 80 | dput(parent); |
| 81 | return false; |
| 82 | } |
| 83 | dentry = parent; |
| 84 | } |
| 85 | dput(dentry); |
| 86 | return true; |
| 87 | } |
| 88 | |
J. Bruce Fields | 0dbc018 | 2013-09-09 16:15:13 -0400 | [diff] [blame] | 89 | static void clear_disconnected(struct dentry *dentry) |
| 90 | { |
| 91 | dget(dentry); |
| 92 | while (dentry->d_flags & DCACHE_DISCONNECTED) { |
| 93 | struct dentry *parent = dget_parent(dentry); |
| 94 | |
| 95 | WARN_ON_ONCE(IS_ROOT(dentry)); |
| 96 | |
| 97 | spin_lock(&dentry->d_lock); |
| 98 | dentry->d_flags &= ~DCACHE_DISCONNECTED; |
| 99 | spin_unlock(&dentry->d_lock); |
| 100 | |
| 101 | dput(dentry); |
| 102 | dentry = parent; |
| 103 | } |
| 104 | dput(dentry); |
| 105 | } |
| 106 | |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 107 | /* |
J. Bruce Fields | bbf7a8a | 2013-10-17 11:13:00 -0400 | [diff] [blame] | 108 | * Reconnect a directory dentry with its parent. |
| 109 | * |
| 110 | * This can return a dentry, or NULL, or an error. |
| 111 | * |
| 112 | * In the first case the returned dentry is the parent of the given |
| 113 | * dentry, and may itself need to be reconnected to its parent. |
| 114 | * |
| 115 | * In the NULL case, a concurrent VFS operation has either renamed or |
| 116 | * removed this directory. The concurrent operation has reconnected our |
| 117 | * dentry, so we no longer need to. |
| 118 | */ |
| 119 | static struct dentry *reconnect_one(struct vfsmount *mnt, |
| 120 | struct dentry *dentry, char *nbuf) |
| 121 | { |
| 122 | struct dentry *parent; |
| 123 | struct dentry *tmp; |
| 124 | int err; |
| 125 | |
| 126 | parent = ERR_PTR(-EACCES); |
| 127 | mutex_lock(&dentry->d_inode->i_mutex); |
| 128 | if (mnt->mnt_sb->s_export_op->get_parent) |
| 129 | parent = mnt->mnt_sb->s_export_op->get_parent(dentry); |
| 130 | mutex_unlock(&dentry->d_inode->i_mutex); |
| 131 | |
| 132 | if (IS_ERR(parent)) { |
| 133 | dprintk("%s: get_parent of %ld failed, err %d\n", |
| 134 | __func__, dentry->d_inode->i_ino, PTR_ERR(parent)); |
| 135 | return parent; |
| 136 | } |
| 137 | |
| 138 | dprintk("%s: find name of %lu in %lu\n", __func__, |
| 139 | dentry->d_inode->i_ino, parent->d_inode->i_ino); |
| 140 | err = exportfs_get_name(mnt, parent, nbuf, dentry); |
| 141 | if (err == -ENOENT) |
| 142 | goto out_reconnected; |
| 143 | if (err) |
| 144 | goto out_err; |
| 145 | dprintk("%s: found name: %s\n", __func__, nbuf); |
| 146 | mutex_lock(&parent->d_inode->i_mutex); |
| 147 | tmp = lookup_one_len(nbuf, parent, strlen(nbuf)); |
| 148 | mutex_unlock(&parent->d_inode->i_mutex); |
| 149 | if (IS_ERR(tmp)) { |
| 150 | dprintk("%s: lookup failed: %d\n", __func__, PTR_ERR(tmp)); |
| 151 | goto out_err; |
| 152 | } |
| 153 | if (tmp != dentry) { |
| 154 | dput(tmp); |
| 155 | goto out_reconnected; |
| 156 | } |
| 157 | dput(tmp); |
| 158 | if (IS_ROOT(dentry)) { |
| 159 | err = -ESTALE; |
| 160 | goto out_err; |
| 161 | } |
| 162 | return parent; |
| 163 | |
| 164 | out_err: |
| 165 | dput(parent); |
| 166 | return ERR_PTR(err); |
| 167 | out_reconnected: |
| 168 | dput(parent); |
| 169 | /* |
| 170 | * Someone must have renamed our entry into another parent, in |
| 171 | * which case it has been reconnected by the rename. |
| 172 | * |
| 173 | * Or someone removed it entirely, in which case filehandle |
| 174 | * lookup will succeed but the directory is now IS_DEAD and |
| 175 | * subsequent operations on it will fail. |
| 176 | * |
| 177 | * Alternatively, maybe there was no race at all, and the |
| 178 | * filesystem is just corrupt and gave us a parent that doesn't |
| 179 | * actually contain any entry pointing to this inode. So, |
| 180 | * double check that this worked and return -ESTALE if not: |
| 181 | */ |
| 182 | if (!dentry_connected(dentry)) |
| 183 | return ERR_PTR(-ESTALE); |
| 184 | return NULL; |
| 185 | } |
| 186 | |
| 187 | /* |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 188 | * Make sure target_dir is fully connected to the dentry tree. |
| 189 | * |
J. Bruce Fields | 78cee9a | 2013-10-22 20:59:19 -0400 | [diff] [blame] | 190 | * On successful return, DCACHE_DISCONNECTED will be cleared on |
| 191 | * target_dir, and target_dir->d_parent->...->d_parent will reach the |
| 192 | * root of the filesystem. |
| 193 | * |
| 194 | * Whenever DCACHE_DISCONNECTED is unset, target_dir is fully connected. |
| 195 | * But the converse is not true: target_dir may have DCACHE_DISCONNECTED |
| 196 | * set but already be connected. In that case we'll verify the |
| 197 | * connection to root and then clear the flag. |
| 198 | * |
| 199 | * Note that target_dir could be removed by a concurrent operation. In |
| 200 | * that case reconnect_path may still succeed with target_dir fully |
| 201 | * connected, but further operations using the filehandle will fail when |
| 202 | * necessary (due to S_DEAD being set on the directory). |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 203 | */ |
| 204 | static int |
Al Viro | f3f8e175 | 2008-08-11 12:39:47 -0400 | [diff] [blame] | 205 | reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf) |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 206 | { |
J. Bruce Fields | f27c929 | 2013-10-17 21:34:21 -0400 | [diff] [blame] | 207 | struct dentry *dentry, *parent; |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 208 | |
J. Bruce Fields | f27c929 | 2013-10-17 21:34:21 -0400 | [diff] [blame] | 209 | dentry = dget(target_dir); |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 210 | |
J. Bruce Fields | f27c929 | 2013-10-17 21:34:21 -0400 | [diff] [blame] | 211 | while (dentry->d_flags & DCACHE_DISCONNECTED) { |
J. Bruce Fields | efbf201 | 2013-10-17 21:42:35 -0400 | [diff] [blame] | 212 | BUG_ON(dentry == mnt->mnt_sb->s_root); |
Christoph Hellwig | 854ff5c | 2013-10-16 15:48:53 -0400 | [diff] [blame] | 213 | |
J. Bruce Fields | f27c929 | 2013-10-17 21:34:21 -0400 | [diff] [blame] | 214 | if (IS_ROOT(dentry)) |
| 215 | parent = reconnect_one(mnt, dentry, nbuf); |
| 216 | else |
| 217 | parent = dget_parent(dentry); |
| 218 | |
| 219 | if (!parent) |
J. Bruce Fields | 0dbc018 | 2013-09-09 16:15:13 -0400 | [diff] [blame] | 220 | break; |
J. Bruce Fields | efbf201 | 2013-10-17 21:42:35 -0400 | [diff] [blame] | 221 | dput(dentry); |
J. Bruce Fields | f27c929 | 2013-10-17 21:34:21 -0400 | [diff] [blame] | 222 | if (IS_ERR(parent)) |
| 223 | return PTR_ERR(parent); |
| 224 | dentry = parent; |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 225 | } |
J. Bruce Fields | f27c929 | 2013-10-17 21:34:21 -0400 | [diff] [blame] | 226 | dput(dentry); |
J. Bruce Fields | a056cc8 | 2013-10-16 21:09:30 -0400 | [diff] [blame] | 227 | clear_disconnected(target_dir); |
| 228 | return 0; |
Christoph Hellwig | 019ab80 | 2007-07-17 04:04:33 -0700 | [diff] [blame] | 229 | } |
| 230 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | struct getdents_callback { |
Al Viro | 5c0ba4e | 2013-05-15 13:52:59 -0400 | [diff] [blame] | 232 | struct dir_context ctx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | char *name; /* name that was found. It already points to a |
| 234 | buffer NAME_MAX+1 is size */ |
J. Bruce Fields | 950ee95 | 2013-09-10 11:41:12 -0400 | [diff] [blame] | 235 | u64 ino; /* the inum we are looking for */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | int found; /* inode matched? */ |
| 237 | int sequence; /* sequence counter */ |
| 238 | }; |
| 239 | |
| 240 | /* |
| 241 | * A rather strange filldir function to capture |
| 242 | * the name matching the specified inode number. |
| 243 | */ |
| 244 | static int filldir_one(void * __buf, const char * name, int len, |
David Howells | afefdbb | 2006-10-03 01:13:46 -0700 | [diff] [blame] | 245 | loff_t pos, u64 ino, unsigned int d_type) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | { |
| 247 | struct getdents_callback *buf = __buf; |
| 248 | int result = 0; |
| 249 | |
| 250 | buf->sequence++; |
Al Viro | dfc59e2c | 2013-09-06 16:55:36 -0400 | [diff] [blame] | 251 | if (buf->ino == ino && len <= NAME_MAX) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | memcpy(buf->name, name, len); |
| 253 | buf->name[len] = '\0'; |
| 254 | buf->found = 1; |
| 255 | result = -1; |
| 256 | } |
| 257 | return result; |
| 258 | } |
| 259 | |
| 260 | /** |
| 261 | * get_name - default export_operations->get_name function |
Fabian Frederick | 00f0179 | 2014-06-04 16:11:15 -0700 | [diff] [blame] | 262 | * @path: the directory in which to find a name |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | * @name: a pointer to a %NAME_MAX+1 char buffer to store the name |
| 264 | * @child: the dentry for the child directory. |
| 265 | * |
| 266 | * calls readdir on the parent until it finds an entry with |
| 267 | * the same inode number as the child, and returns that. |
| 268 | */ |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 269 | static int get_name(const struct path *path, char *name, struct dentry *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | { |
David Howells | 745ca24 | 2008-11-14 10:39:22 +1100 | [diff] [blame] | 271 | const struct cred *cred = current_cred(); |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 272 | struct inode *dir = path->dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | int error; |
| 274 | struct file *file; |
J. Bruce Fields | 950ee95 | 2013-09-10 11:41:12 -0400 | [diff] [blame] | 275 | struct kstat stat; |
| 276 | struct path child_path = { |
| 277 | .mnt = path->mnt, |
| 278 | .dentry = child, |
| 279 | }; |
Al Viro | ac6614b | 2013-05-22 22:22:04 -0400 | [diff] [blame] | 280 | struct getdents_callback buffer = { |
| 281 | .ctx.actor = filldir_one, |
| 282 | .name = name, |
Al Viro | ac6614b | 2013-05-22 22:22:04 -0400 | [diff] [blame] | 283 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | |
| 285 | error = -ENOTDIR; |
| 286 | if (!dir || !S_ISDIR(dir->i_mode)) |
| 287 | goto out; |
| 288 | error = -EINVAL; |
| 289 | if (!dir->i_fop) |
| 290 | goto out; |
| 291 | /* |
J. Bruce Fields | 950ee95 | 2013-09-10 11:41:12 -0400 | [diff] [blame] | 292 | * inode->i_ino is unsigned long, kstat->ino is u64, so the |
| 293 | * former would be insufficient on 32-bit hosts when the |
| 294 | * filesystem supports 64-bit inode numbers. So we need to |
| 295 | * actually call ->getattr, not just read i_ino: |
| 296 | */ |
| 297 | error = vfs_getattr_nosec(&child_path, &stat); |
| 298 | if (error) |
| 299 | return error; |
| 300 | buffer.ino = stat.ino; |
| 301 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | * Open the directory ... |
| 303 | */ |
Al Viro | 765927b | 2012-06-26 21:58:53 +0400 | [diff] [blame] | 304 | file = dentry_open(path, O_RDONLY, cred); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | error = PTR_ERR(file); |
| 306 | if (IS_ERR(file)) |
| 307 | goto out; |
| 308 | |
| 309 | error = -EINVAL; |
Al Viro | 2233f31 | 2013-05-22 21:44:23 -0400 | [diff] [blame] | 310 | if (!file->f_op->iterate) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | goto out_close; |
| 312 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | buffer.sequence = 0; |
| 314 | while (1) { |
| 315 | int old_seq = buffer.sequence; |
| 316 | |
Al Viro | 5c0ba4e | 2013-05-15 13:52:59 -0400 | [diff] [blame] | 317 | error = iterate_dir(file, &buffer.ctx); |
Al Viro | 53c9c5c | 2008-08-24 07:29:52 -0400 | [diff] [blame] | 318 | if (buffer.found) { |
| 319 | error = 0; |
| 320 | break; |
| 321 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | |
| 323 | if (error < 0) |
| 324 | break; |
| 325 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 326 | error = -ENOENT; |
| 327 | if (old_seq == buffer.sequence) |
| 328 | break; |
| 329 | } |
| 330 | |
| 331 | out_close: |
| 332 | fput(file); |
| 333 | out: |
| 334 | return error; |
| 335 | } |
| 336 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | /** |
| 338 | * export_encode_fh - default export_operations->encode_fh function |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 339 | * @inode: the object to encode |
Fabian Frederick | 00f0179 | 2014-06-04 16:11:15 -0700 | [diff] [blame] | 340 | * @fid: where to store the file handle fragment |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | * @max_len: maximum length to store there |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 342 | * @parent: parent directory inode, if wanted |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | * |
| 344 | * This default encode_fh function assumes that the 32 inode number |
| 345 | * is suitable for locating an inode, and that the generation number |
| 346 | * can be used to check that it is still valid. It places them in the |
| 347 | * filehandle fragment where export_decode_fh expects to find them. |
| 348 | */ |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 349 | static int export_encode_fh(struct inode *inode, struct fid *fid, |
| 350 | int *max_len, struct inode *parent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | int len = *max_len; |
Christoph Hellwig | 6e91ea2 | 2007-10-21 16:42:03 -0700 | [diff] [blame] | 353 | int type = FILEID_INO32_GEN; |
Aneesh Kumar K.V | 5fe0c23 | 2011-01-29 18:43:25 +0530 | [diff] [blame] | 354 | |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 355 | if (parent && (len < 4)) { |
Aneesh Kumar K.V | 5fe0c23 | 2011-01-29 18:43:25 +0530 | [diff] [blame] | 356 | *max_len = 4; |
Namjae Jeon | 216b6cb | 2012-08-29 10:10:10 -0400 | [diff] [blame] | 357 | return FILEID_INVALID; |
Aneesh Kumar K.V | 5fe0c23 | 2011-01-29 18:43:25 +0530 | [diff] [blame] | 358 | } else if (len < 2) { |
| 359 | *max_len = 2; |
Namjae Jeon | 216b6cb | 2012-08-29 10:10:10 -0400 | [diff] [blame] | 360 | return FILEID_INVALID; |
Aneesh Kumar K.V | 5fe0c23 | 2011-01-29 18:43:25 +0530 | [diff] [blame] | 361 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | |
| 363 | len = 2; |
Christoph Hellwig | 6e91ea2 | 2007-10-21 16:42:03 -0700 | [diff] [blame] | 364 | fid->i32.ino = inode->i_ino; |
| 365 | fid->i32.gen = inode->i_generation; |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 366 | if (parent) { |
Christoph Hellwig | 6e91ea2 | 2007-10-21 16:42:03 -0700 | [diff] [blame] | 367 | fid->i32.parent_ino = parent->i_ino; |
| 368 | fid->i32.parent_gen = parent->i_generation; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | len = 4; |
Christoph Hellwig | 6e91ea2 | 2007-10-21 16:42:03 -0700 | [diff] [blame] | 370 | type = FILEID_INO32_GEN_PARENT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | } |
| 372 | *max_len = len; |
| 373 | return type; |
| 374 | } |
| 375 | |
Cyrill Gorcunov | 711c7bf | 2012-12-17 16:05:08 -0800 | [diff] [blame] | 376 | int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, |
| 377 | int *max_len, struct inode *parent) |
| 378 | { |
| 379 | const struct export_operations *nop = inode->i_sb->s_export_op; |
| 380 | |
| 381 | if (nop && nop->encode_fh) |
| 382 | return nop->encode_fh(inode, fid->raw, max_len, parent); |
| 383 | |
| 384 | return export_encode_fh(inode, fid, max_len, parent); |
| 385 | } |
| 386 | EXPORT_SYMBOL_GPL(exportfs_encode_inode_fh); |
| 387 | |
Christoph Hellwig | 6e91ea2 | 2007-10-21 16:42:03 -0700 | [diff] [blame] | 388 | int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len, |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 389 | int connectable) |
| 390 | { |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 391 | int error; |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 392 | struct dentry *p = NULL; |
| 393 | struct inode *inode = dentry->d_inode, *parent = NULL; |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 394 | |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 395 | if (connectable && !S_ISDIR(inode->i_mode)) { |
| 396 | p = dget_parent(dentry); |
| 397 | /* |
| 398 | * note that while p might've ceased to be our parent already, |
| 399 | * it's still pinned by and still positive. |
| 400 | */ |
| 401 | parent = p->d_inode; |
| 402 | } |
Cyrill Gorcunov | 711c7bf | 2012-12-17 16:05:08 -0800 | [diff] [blame] | 403 | |
| 404 | error = exportfs_encode_inode_fh(inode, fid, max_len, parent); |
Al Viro | b0b0382 | 2012-04-02 14:34:06 -0400 | [diff] [blame] | 405 | dput(p); |
Christoph Hellwig | 10f11c3 | 2007-07-17 04:04:31 -0700 | [diff] [blame] | 406 | |
| 407 | return error; |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 408 | } |
| 409 | EXPORT_SYMBOL_GPL(exportfs_encode_fh); |
| 410 | |
Christoph Hellwig | 6e91ea2 | 2007-10-21 16:42:03 -0700 | [diff] [blame] | 411 | struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, |
| 412 | int fh_len, int fileid_type, |
| 413 | int (*acceptable)(void *, struct dentry *), void *context) |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 414 | { |
Christoph Hellwig | 3965516 | 2007-10-21 16:42:17 -0700 | [diff] [blame] | 415 | const struct export_operations *nop = mnt->mnt_sb->s_export_op; |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 416 | struct dentry *result, *alias; |
Al Viro | f3f8e175 | 2008-08-11 12:39:47 -0400 | [diff] [blame] | 417 | char nbuf[NAME_MAX+1]; |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 418 | int err; |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 419 | |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 420 | /* |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 421 | * Try to get any dentry for the given file handle from the filesystem. |
| 422 | */ |
Aneesh Kumar K.V | becfd1f | 2011-01-29 18:43:26 +0530 | [diff] [blame] | 423 | if (!nop || !nop->fh_to_dentry) |
| 424 | return ERR_PTR(-ESTALE); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 425 | result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type); |
J. Bruce Fields | a4f4d6d | 2008-12-08 18:24:18 -0500 | [diff] [blame] | 426 | if (!result) |
| 427 | result = ERR_PTR(-ESTALE); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 428 | if (IS_ERR(result)) |
| 429 | return result; |
| 430 | |
| 431 | if (S_ISDIR(result->d_inode->i_mode)) { |
| 432 | /* |
| 433 | * This request is for a directory. |
| 434 | * |
| 435 | * On the positive side there is only one dentry for each |
| 436 | * directory inode. On the negative side this implies that we |
| 437 | * to ensure our dentry is connected all the way up to the |
| 438 | * filesystem root. |
| 439 | */ |
| 440 | if (result->d_flags & DCACHE_DISCONNECTED) { |
Al Viro | f3f8e175 | 2008-08-11 12:39:47 -0400 | [diff] [blame] | 441 | err = reconnect_path(mnt, result, nbuf); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 442 | if (err) |
| 443 | goto err_result; |
| 444 | } |
| 445 | |
| 446 | if (!acceptable(context, result)) { |
| 447 | err = -EACCES; |
| 448 | goto err_result; |
| 449 | } |
| 450 | |
| 451 | return result; |
| 452 | } else { |
| 453 | /* |
| 454 | * It's not a directory. Life is a little more complicated. |
| 455 | */ |
| 456 | struct dentry *target_dir, *nresult; |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 457 | |
| 458 | /* |
| 459 | * See if either the dentry we just got from the filesystem |
| 460 | * or any alias for it is acceptable. This is always true |
| 461 | * if this filesystem is exported without the subtreecheck |
| 462 | * option. If the filesystem is exported with the subtree |
| 463 | * check option there's a fair chance we need to look at |
| 464 | * the parent directory in the file handle and make sure |
| 465 | * it's connected to the filesystem root. |
| 466 | */ |
| 467 | alias = find_acceptable_alias(result, acceptable, context); |
| 468 | if (alias) |
| 469 | return alias; |
| 470 | |
| 471 | /* |
| 472 | * Try to extract a dentry for the parent directory from the |
| 473 | * file handle. If this fails we'll have to give up. |
| 474 | */ |
| 475 | err = -ESTALE; |
| 476 | if (!nop->fh_to_parent) |
| 477 | goto err_result; |
| 478 | |
| 479 | target_dir = nop->fh_to_parent(mnt->mnt_sb, fid, |
| 480 | fh_len, fileid_type); |
J. Bruce Fields | a4f4d6d | 2008-12-08 18:24:18 -0500 | [diff] [blame] | 481 | if (!target_dir) |
| 482 | goto err_result; |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 483 | err = PTR_ERR(target_dir); |
| 484 | if (IS_ERR(target_dir)) |
| 485 | goto err_result; |
| 486 | |
| 487 | /* |
| 488 | * And as usual we need to make sure the parent directory is |
| 489 | * connected to the filesystem root. The VFS really doesn't |
| 490 | * like disconnected directories.. |
| 491 | */ |
Al Viro | f3f8e175 | 2008-08-11 12:39:47 -0400 | [diff] [blame] | 492 | err = reconnect_path(mnt, target_dir, nbuf); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 493 | if (err) { |
| 494 | dput(target_dir); |
| 495 | goto err_result; |
| 496 | } |
| 497 | |
| 498 | /* |
| 499 | * Now that we've got both a well-connected parent and a |
| 500 | * dentry for the inode we're after, make sure that our |
| 501 | * inode is actually connected to the parent. |
| 502 | */ |
Christoph Hellwig | e38f981 | 2007-10-21 16:42:19 -0700 | [diff] [blame] | 503 | err = exportfs_get_name(mnt, target_dir, nbuf, result); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 504 | if (!err) { |
| 505 | mutex_lock(&target_dir->d_inode->i_mutex); |
| 506 | nresult = lookup_one_len(nbuf, target_dir, |
| 507 | strlen(nbuf)); |
| 508 | mutex_unlock(&target_dir->d_inode->i_mutex); |
| 509 | if (!IS_ERR(nresult)) { |
| 510 | if (nresult->d_inode) { |
| 511 | dput(result); |
| 512 | result = nresult; |
| 513 | } else |
| 514 | dput(nresult); |
| 515 | } |
| 516 | } |
| 517 | |
| 518 | /* |
| 519 | * At this point we are done with the parent, but it's pinned |
| 520 | * by the child dentry anyway. |
| 521 | */ |
| 522 | dput(target_dir); |
| 523 | |
| 524 | /* |
| 525 | * And finally make sure the dentry is actually acceptable |
| 526 | * to NFSD. |
| 527 | */ |
| 528 | alias = find_acceptable_alias(result, acceptable, context); |
| 529 | if (!alias) { |
| 530 | err = -EACCES; |
| 531 | goto err_result; |
| 532 | } |
| 533 | |
| 534 | return alias; |
| 535 | } |
| 536 | |
| 537 | err_result: |
| 538 | dput(result); |
| 539 | return ERR_PTR(err); |
Christoph Hellwig | d37065c | 2007-07-17 04:04:30 -0700 | [diff] [blame] | 540 | } |
| 541 | EXPORT_SYMBOL_GPL(exportfs_decode_fh); |
| 542 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | MODULE_LICENSE("GPL"); |