Yehuda Sadeh | 3d14c5d | 2010-04-06 15:14:15 -0700 | [diff] [blame] | 1 | #include <linux/ceph/ceph_debug.h> |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 2 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 3 | #include <linux/sort.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 4 | #include <linux/slab.h> |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 5 | |
| 6 | #include "super.h" |
Yehuda Sadeh | 3d14c5d | 2010-04-06 15:14:15 -0700 | [diff] [blame] | 7 | #include "mds_client.h" |
| 8 | |
| 9 | #include <linux/ceph/decode.h> |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 10 | |
| 11 | /* |
| 12 | * Snapshots in ceph are driven in large part by cooperation from the |
| 13 | * client. In contrast to local file systems or file servers that |
| 14 | * implement snapshots at a single point in the system, ceph's |
| 15 | * distributed access to storage requires clients to help decide |
| 16 | * whether a write logically occurs before or after a recently created |
| 17 | * snapshot. |
| 18 | * |
| 19 | * This provides a perfect instantanous client-wide snapshot. Between |
| 20 | * clients, however, snapshots may appear to be applied at slightly |
| 21 | * different points in time, depending on delays in delivering the |
| 22 | * snapshot notification. |
| 23 | * |
| 24 | * Snapshots are _not_ file system-wide. Instead, each snapshot |
| 25 | * applies to the subdirectory nested beneath some directory. This |
| 26 | * effectively divides the hierarchy into multiple "realms," where all |
| 27 | * of the files contained by each realm share the same set of |
| 28 | * snapshots. An individual realm's snap set contains snapshots |
| 29 | * explicitly created on that realm, as well as any snaps in its |
| 30 | * parent's snap set _after_ the point at which the parent became it's |
| 31 | * parent (due to, say, a rename). Similarly, snaps from prior parents |
| 32 | * during the time intervals during which they were the parent are included. |
| 33 | * |
| 34 | * The client is spared most of this detail, fortunately... it must only |
| 35 | * maintains a hierarchy of realms reflecting the current parent/child |
| 36 | * realm relationship, and for each realm has an explicit list of snaps |
| 37 | * inherited from prior parents. |
| 38 | * |
| 39 | * A snap_realm struct is maintained for realms containing every inode |
| 40 | * with an open cap in the system. (The needed snap realm information is |
| 41 | * provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq' |
| 42 | * version number is used to ensure that as realm parameters change (new |
| 43 | * snapshot, new parent, etc.) the client's realm hierarchy is updated. |
| 44 | * |
| 45 | * The realm hierarchy drives the generation of a 'snap context' for each |
| 46 | * realm, which simply lists the resulting set of snaps for the realm. This |
| 47 | * is attached to any writes sent to OSDs. |
| 48 | */ |
| 49 | /* |
| 50 | * Unfortunately error handling is a bit mixed here. If we get a snap |
| 51 | * update, but don't have enough memory to update our realm hierarchy, |
| 52 | * it's not clear what we can do about it (besides complaining to the |
| 53 | * console). |
| 54 | */ |
| 55 | |
| 56 | |
| 57 | /* |
| 58 | * increase ref count for the realm |
| 59 | * |
| 60 | * caller must hold snap_rwsem for write. |
| 61 | */ |
| 62 | void ceph_get_snap_realm(struct ceph_mds_client *mdsc, |
| 63 | struct ceph_snap_realm *realm) |
| 64 | { |
| 65 | dout("get_realm %p %d -> %d\n", realm, |
| 66 | atomic_read(&realm->nref), atomic_read(&realm->nref)+1); |
| 67 | /* |
| 68 | * since we _only_ increment realm refs or empty the empty |
| 69 | * list with snap_rwsem held, adjusting the empty list here is |
| 70 | * safe. we do need to protect against concurrent empty list |
| 71 | * additions, however. |
| 72 | */ |
| 73 | if (atomic_read(&realm->nref) == 0) { |
| 74 | spin_lock(&mdsc->snap_empty_lock); |
| 75 | list_del_init(&realm->empty_item); |
| 76 | spin_unlock(&mdsc->snap_empty_lock); |
| 77 | } |
| 78 | |
| 79 | atomic_inc(&realm->nref); |
| 80 | } |
| 81 | |
Sage Weil | a105f00 | 2010-02-15 14:37:55 -0800 | [diff] [blame] | 82 | static void __insert_snap_realm(struct rb_root *root, |
| 83 | struct ceph_snap_realm *new) |
| 84 | { |
| 85 | struct rb_node **p = &root->rb_node; |
| 86 | struct rb_node *parent = NULL; |
| 87 | struct ceph_snap_realm *r = NULL; |
| 88 | |
| 89 | while (*p) { |
| 90 | parent = *p; |
| 91 | r = rb_entry(parent, struct ceph_snap_realm, node); |
| 92 | if (new->ino < r->ino) |
| 93 | p = &(*p)->rb_left; |
| 94 | else if (new->ino > r->ino) |
| 95 | p = &(*p)->rb_right; |
| 96 | else |
| 97 | BUG(); |
| 98 | } |
| 99 | |
| 100 | rb_link_node(&new->node, parent, p); |
| 101 | rb_insert_color(&new->node, root); |
| 102 | } |
| 103 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 104 | /* |
| 105 | * create and get the realm rooted at @ino and bump its ref count. |
| 106 | * |
| 107 | * caller must hold snap_rwsem for write. |
| 108 | */ |
| 109 | static struct ceph_snap_realm *ceph_create_snap_realm( |
| 110 | struct ceph_mds_client *mdsc, |
| 111 | u64 ino) |
| 112 | { |
| 113 | struct ceph_snap_realm *realm; |
| 114 | |
| 115 | realm = kzalloc(sizeof(*realm), GFP_NOFS); |
| 116 | if (!realm) |
| 117 | return ERR_PTR(-ENOMEM); |
| 118 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 119 | atomic_set(&realm->nref, 0); /* tree does not take a ref */ |
| 120 | realm->ino = ino; |
| 121 | INIT_LIST_HEAD(&realm->children); |
| 122 | INIT_LIST_HEAD(&realm->child_item); |
| 123 | INIT_LIST_HEAD(&realm->empty_item); |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 124 | INIT_LIST_HEAD(&realm->dirty_item); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 125 | INIT_LIST_HEAD(&realm->inodes_with_caps); |
| 126 | spin_lock_init(&realm->inodes_with_caps_lock); |
Sage Weil | a105f00 | 2010-02-15 14:37:55 -0800 | [diff] [blame] | 127 | __insert_snap_realm(&mdsc->snap_realms, realm); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 128 | dout("create_snap_realm %llx %p\n", realm->ino, realm); |
| 129 | return realm; |
| 130 | } |
| 131 | |
| 132 | /* |
Sage Weil | a105f00 | 2010-02-15 14:37:55 -0800 | [diff] [blame] | 133 | * lookup the realm rooted at @ino. |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 134 | * |
| 135 | * caller must hold snap_rwsem for write. |
| 136 | */ |
| 137 | struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc, |
| 138 | u64 ino) |
| 139 | { |
Sage Weil | a105f00 | 2010-02-15 14:37:55 -0800 | [diff] [blame] | 140 | struct rb_node *n = mdsc->snap_realms.rb_node; |
| 141 | struct ceph_snap_realm *r; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 142 | |
Sage Weil | a105f00 | 2010-02-15 14:37:55 -0800 | [diff] [blame] | 143 | while (n) { |
| 144 | r = rb_entry(n, struct ceph_snap_realm, node); |
| 145 | if (ino < r->ino) |
| 146 | n = n->rb_left; |
| 147 | else if (ino > r->ino) |
| 148 | n = n->rb_right; |
| 149 | else { |
| 150 | dout("lookup_snap_realm %llx %p\n", r->ino, r); |
| 151 | return r; |
| 152 | } |
| 153 | } |
| 154 | return NULL; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 155 | } |
| 156 | |
| 157 | static void __put_snap_realm(struct ceph_mds_client *mdsc, |
| 158 | struct ceph_snap_realm *realm); |
| 159 | |
| 160 | /* |
| 161 | * called with snap_rwsem (write) |
| 162 | */ |
| 163 | static void __destroy_snap_realm(struct ceph_mds_client *mdsc, |
| 164 | struct ceph_snap_realm *realm) |
| 165 | { |
| 166 | dout("__destroy_snap_realm %p %llx\n", realm, realm->ino); |
| 167 | |
Sage Weil | a105f00 | 2010-02-15 14:37:55 -0800 | [diff] [blame] | 168 | rb_erase(&realm->node, &mdsc->snap_realms); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 169 | |
| 170 | if (realm->parent) { |
| 171 | list_del_init(&realm->child_item); |
| 172 | __put_snap_realm(mdsc, realm->parent); |
| 173 | } |
| 174 | |
| 175 | kfree(realm->prior_parent_snaps); |
| 176 | kfree(realm->snaps); |
| 177 | ceph_put_snap_context(realm->cached_context); |
| 178 | kfree(realm); |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * caller holds snap_rwsem (write) |
| 183 | */ |
| 184 | static void __put_snap_realm(struct ceph_mds_client *mdsc, |
| 185 | struct ceph_snap_realm *realm) |
| 186 | { |
| 187 | dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm, |
| 188 | atomic_read(&realm->nref), atomic_read(&realm->nref)-1); |
| 189 | if (atomic_dec_and_test(&realm->nref)) |
| 190 | __destroy_snap_realm(mdsc, realm); |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * caller needn't hold any locks |
| 195 | */ |
| 196 | void ceph_put_snap_realm(struct ceph_mds_client *mdsc, |
| 197 | struct ceph_snap_realm *realm) |
| 198 | { |
| 199 | dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm, |
| 200 | atomic_read(&realm->nref), atomic_read(&realm->nref)-1); |
| 201 | if (!atomic_dec_and_test(&realm->nref)) |
| 202 | return; |
| 203 | |
| 204 | if (down_write_trylock(&mdsc->snap_rwsem)) { |
| 205 | __destroy_snap_realm(mdsc, realm); |
| 206 | up_write(&mdsc->snap_rwsem); |
| 207 | } else { |
| 208 | spin_lock(&mdsc->snap_empty_lock); |
Henry C Chang | a26a185 | 2011-05-11 10:29:53 +0000 | [diff] [blame] | 209 | list_add(&realm->empty_item, &mdsc->snap_empty); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 210 | spin_unlock(&mdsc->snap_empty_lock); |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * Clean up any realms whose ref counts have dropped to zero. Note |
| 216 | * that this does not include realms who were created but not yet |
| 217 | * used. |
| 218 | * |
| 219 | * Called under snap_rwsem (write) |
| 220 | */ |
| 221 | static void __cleanup_empty_realms(struct ceph_mds_client *mdsc) |
| 222 | { |
| 223 | struct ceph_snap_realm *realm; |
| 224 | |
| 225 | spin_lock(&mdsc->snap_empty_lock); |
| 226 | while (!list_empty(&mdsc->snap_empty)) { |
| 227 | realm = list_first_entry(&mdsc->snap_empty, |
| 228 | struct ceph_snap_realm, empty_item); |
| 229 | list_del(&realm->empty_item); |
| 230 | spin_unlock(&mdsc->snap_empty_lock); |
| 231 | __destroy_snap_realm(mdsc, realm); |
| 232 | spin_lock(&mdsc->snap_empty_lock); |
| 233 | } |
| 234 | spin_unlock(&mdsc->snap_empty_lock); |
| 235 | } |
| 236 | |
| 237 | void ceph_cleanup_empty_realms(struct ceph_mds_client *mdsc) |
| 238 | { |
| 239 | down_write(&mdsc->snap_rwsem); |
| 240 | __cleanup_empty_realms(mdsc); |
| 241 | up_write(&mdsc->snap_rwsem); |
| 242 | } |
| 243 | |
| 244 | /* |
| 245 | * adjust the parent realm of a given @realm. adjust child list, and parent |
| 246 | * pointers, and ref counts appropriately. |
| 247 | * |
| 248 | * return true if parent was changed, 0 if unchanged, <0 on error. |
| 249 | * |
| 250 | * caller must hold snap_rwsem for write. |
| 251 | */ |
| 252 | static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc, |
| 253 | struct ceph_snap_realm *realm, |
| 254 | u64 parentino) |
| 255 | { |
| 256 | struct ceph_snap_realm *parent; |
| 257 | |
| 258 | if (realm->parent_ino == parentino) |
| 259 | return 0; |
| 260 | |
| 261 | parent = ceph_lookup_snap_realm(mdsc, parentino); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 262 | if (!parent) { |
| 263 | parent = ceph_create_snap_realm(mdsc, parentino); |
| 264 | if (IS_ERR(parent)) |
| 265 | return PTR_ERR(parent); |
| 266 | } |
| 267 | dout("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n", |
| 268 | realm->ino, realm, realm->parent_ino, realm->parent, |
| 269 | parentino, parent); |
| 270 | if (realm->parent) { |
| 271 | list_del_init(&realm->child_item); |
| 272 | ceph_put_snap_realm(mdsc, realm->parent); |
| 273 | } |
| 274 | realm->parent_ino = parentino; |
| 275 | realm->parent = parent; |
| 276 | ceph_get_snap_realm(mdsc, parent); |
| 277 | list_add(&realm->child_item, &parent->children); |
| 278 | return 1; |
| 279 | } |
| 280 | |
| 281 | |
| 282 | static int cmpu64_rev(const void *a, const void *b) |
| 283 | { |
| 284 | if (*(u64 *)a < *(u64 *)b) |
| 285 | return 1; |
| 286 | if (*(u64 *)a > *(u64 *)b) |
| 287 | return -1; |
| 288 | return 0; |
| 289 | } |
| 290 | |
Yan, Zheng | 97c85a8 | 2014-11-06 15:09:41 +0800 | [diff] [blame] | 291 | |
| 292 | static struct ceph_snap_context *empty_snapc; |
| 293 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 294 | /* |
| 295 | * build the snap context for a given realm. |
| 296 | */ |
| 297 | static int build_snap_context(struct ceph_snap_realm *realm) |
| 298 | { |
| 299 | struct ceph_snap_realm *parent = realm->parent; |
| 300 | struct ceph_snap_context *snapc; |
| 301 | int err = 0; |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 302 | u32 num = realm->num_prior_parent_snaps + realm->num_snaps; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 303 | |
| 304 | /* |
| 305 | * build parent context, if it hasn't been built. |
| 306 | * conservatively estimate that all parent snaps might be |
| 307 | * included by us. |
| 308 | */ |
| 309 | if (parent) { |
| 310 | if (!parent->cached_context) { |
| 311 | err = build_snap_context(parent); |
| 312 | if (err) |
| 313 | goto fail; |
| 314 | } |
| 315 | num += parent->cached_context->num_snaps; |
| 316 | } |
| 317 | |
| 318 | /* do i actually need to update? not if my context seq |
| 319 | matches realm seq, and my parents' does to. (this works |
| 320 | because we rebuild_snap_realms() works _downward_ in |
| 321 | hierarchy after each update.) */ |
| 322 | if (realm->cached_context && |
Sage Weil | ec4318bc | 2010-03-19 13:24:39 -0700 | [diff] [blame] | 323 | realm->cached_context->seq == realm->seq && |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 324 | (!parent || |
Sage Weil | ec4318bc | 2010-03-19 13:24:39 -0700 | [diff] [blame] | 325 | realm->cached_context->seq >= parent->cached_context->seq)) { |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 326 | dout("build_snap_context %llx %p: %p seq %lld (%u snaps)" |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 327 | " (unchanged)\n", |
| 328 | realm->ino, realm, realm->cached_context, |
| 329 | realm->cached_context->seq, |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 330 | (unsigned int) realm->cached_context->num_snaps); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 331 | return 0; |
| 332 | } |
| 333 | |
Yan, Zheng | 97c85a8 | 2014-11-06 15:09:41 +0800 | [diff] [blame] | 334 | if (num == 0 && realm->seq == empty_snapc->seq) { |
| 335 | ceph_get_snap_context(empty_snapc); |
| 336 | snapc = empty_snapc; |
| 337 | goto done; |
| 338 | } |
| 339 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 340 | /* alloc new snap context */ |
| 341 | err = -ENOMEM; |
Xi Wang | a3860c1 | 2012-05-31 16:26:04 -0700 | [diff] [blame] | 342 | if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64)) |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 343 | goto fail; |
Alex Elder | 812164f8 | 2013-04-30 00:44:32 -0500 | [diff] [blame] | 344 | snapc = ceph_create_snap_context(num, GFP_NOFS); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 345 | if (!snapc) |
| 346 | goto fail; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 347 | |
| 348 | /* build (reverse sorted) snap vector */ |
| 349 | num = 0; |
| 350 | snapc->seq = realm->seq; |
| 351 | if (parent) { |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 352 | u32 i; |
| 353 | |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 354 | /* include any of parent's snaps occurring _after_ my |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 355 | parent became my parent */ |
| 356 | for (i = 0; i < parent->cached_context->num_snaps; i++) |
| 357 | if (parent->cached_context->snaps[i] >= |
| 358 | realm->parent_since) |
| 359 | snapc->snaps[num++] = |
| 360 | parent->cached_context->snaps[i]; |
| 361 | if (parent->cached_context->seq > snapc->seq) |
| 362 | snapc->seq = parent->cached_context->seq; |
| 363 | } |
| 364 | memcpy(snapc->snaps + num, realm->snaps, |
| 365 | sizeof(u64)*realm->num_snaps); |
| 366 | num += realm->num_snaps; |
| 367 | memcpy(snapc->snaps + num, realm->prior_parent_snaps, |
| 368 | sizeof(u64)*realm->num_prior_parent_snaps); |
| 369 | num += realm->num_prior_parent_snaps; |
| 370 | |
| 371 | sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL); |
| 372 | snapc->num_snaps = num; |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 373 | dout("build_snap_context %llx %p: %p seq %lld (%u snaps)\n", |
| 374 | realm->ino, realm, snapc, snapc->seq, |
| 375 | (unsigned int) snapc->num_snaps); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 376 | |
Yan, Zheng | 97c85a8 | 2014-11-06 15:09:41 +0800 | [diff] [blame] | 377 | done: |
SF Markus Elfring | e96a650 | 2014-11-02 15:20:59 +0100 | [diff] [blame] | 378 | ceph_put_snap_context(realm->cached_context); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 379 | realm->cached_context = snapc; |
| 380 | return 0; |
| 381 | |
| 382 | fail: |
| 383 | /* |
| 384 | * if we fail, clear old (incorrect) cached_context... hopefully |
| 385 | * we'll have better luck building it later |
| 386 | */ |
| 387 | if (realm->cached_context) { |
| 388 | ceph_put_snap_context(realm->cached_context); |
| 389 | realm->cached_context = NULL; |
| 390 | } |
| 391 | pr_err("build_snap_context %llx %p fail %d\n", realm->ino, |
| 392 | realm, err); |
| 393 | return err; |
| 394 | } |
| 395 | |
| 396 | /* |
| 397 | * rebuild snap context for the given realm and all of its children. |
| 398 | */ |
| 399 | static void rebuild_snap_realms(struct ceph_snap_realm *realm) |
| 400 | { |
| 401 | struct ceph_snap_realm *child; |
| 402 | |
| 403 | dout("rebuild_snap_realms %llx %p\n", realm->ino, realm); |
| 404 | build_snap_context(realm); |
| 405 | |
| 406 | list_for_each_entry(child, &realm->children, child_item) |
| 407 | rebuild_snap_realms(child); |
| 408 | } |
| 409 | |
| 410 | |
| 411 | /* |
| 412 | * helper to allocate and decode an array of snapids. free prior |
| 413 | * instance, if any. |
| 414 | */ |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 415 | static int dup_array(u64 **dst, __le64 *src, u32 num) |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 416 | { |
Alex Elder | aa711ee | 2012-07-13 20:35:11 -0500 | [diff] [blame] | 417 | u32 i; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 418 | |
| 419 | kfree(*dst); |
| 420 | if (num) { |
| 421 | *dst = kcalloc(num, sizeof(u64), GFP_NOFS); |
| 422 | if (!*dst) |
| 423 | return -ENOMEM; |
| 424 | for (i = 0; i < num; i++) |
| 425 | (*dst)[i] = get_unaligned_le64(src + i); |
| 426 | } else { |
| 427 | *dst = NULL; |
| 428 | } |
| 429 | return 0; |
| 430 | } |
| 431 | |
| 432 | |
| 433 | /* |
| 434 | * When a snapshot is applied, the size/mtime inode metadata is queued |
| 435 | * in a ceph_cap_snap (one for each snapshot) until writeback |
| 436 | * completes and the metadata can be flushed back to the MDS. |
| 437 | * |
| 438 | * However, if a (sync) write is currently in-progress when we apply |
| 439 | * the snapshot, we have to wait until the write succeeds or fails |
| 440 | * (and a final size/mtime is known). In this case the |
| 441 | * cap_snap->writing = 1, and is said to be "pending." When the write |
| 442 | * finishes, we __ceph_finish_cap_snap(). |
| 443 | * |
| 444 | * Caller must hold snap_rwsem for read (i.e., the realm topology won't |
| 445 | * change). |
| 446 | */ |
Sage Weil | fc837c8f | 2010-04-13 11:41:22 -0700 | [diff] [blame] | 447 | void ceph_queue_cap_snap(struct ceph_inode_info *ci) |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 448 | { |
| 449 | struct inode *inode = &ci->vfs_inode; |
| 450 | struct ceph_cap_snap *capsnap; |
Sage Weil | 4a625be | 2010-08-22 15:03:56 -0700 | [diff] [blame] | 451 | int used, dirty; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 452 | |
| 453 | capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS); |
| 454 | if (!capsnap) { |
| 455 | pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode); |
| 456 | return; |
| 457 | } |
| 458 | |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 459 | spin_lock(&ci->i_ceph_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 460 | used = __ceph_caps_used(ci); |
Sage Weil | 4a625be | 2010-08-22 15:03:56 -0700 | [diff] [blame] | 461 | dirty = __ceph_caps_dirty(ci); |
Sage Weil | af0ed56 | 2011-07-26 11:26:31 -0700 | [diff] [blame] | 462 | |
| 463 | /* |
| 464 | * If there is a write in progress, treat that as a dirty Fw, |
| 465 | * even though it hasn't completed yet; by the time we finish |
| 466 | * up this capsnap it will be. |
| 467 | */ |
| 468 | if (used & CEPH_CAP_FILE_WR) |
| 469 | dirty |= CEPH_CAP_FILE_WR; |
| 470 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 471 | if (__ceph_have_pending_cap_snap(ci)) { |
| 472 | /* there is no point in queuing multiple "pending" cap_snaps, |
| 473 | as no new writes are allowed to start when pending, so any |
| 474 | writes in progress now were started before the previous |
| 475 | cap_snap. lucky us. */ |
Sage Weil | fc837c8f | 2010-04-13 11:41:22 -0700 | [diff] [blame] | 476 | dout("queue_cap_snap %p already pending\n", inode); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 477 | kfree(capsnap); |
Yan, Zheng | 97c85a8 | 2014-11-06 15:09:41 +0800 | [diff] [blame] | 478 | } else if (ci->i_snap_realm->cached_context == empty_snapc) { |
| 479 | dout("queue_cap_snap %p empty snapc\n", inode); |
| 480 | kfree(capsnap); |
Sage Weil | e77dc3e | 2011-07-26 11:26:41 -0700 | [diff] [blame] | 481 | } else if (dirty & (CEPH_CAP_AUTH_EXCL|CEPH_CAP_XATTR_EXCL| |
| 482 | CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR)) { |
Sage Weil | fc837c8f | 2010-04-13 11:41:22 -0700 | [diff] [blame] | 483 | struct ceph_snap_context *snapc = ci->i_head_snapc; |
| 484 | |
Sage Weil | af0ed56 | 2011-07-26 11:26:31 -0700 | [diff] [blame] | 485 | /* |
| 486 | * if we are a sync write, we may need to go to the snaprealm |
| 487 | * to get the current snapc. |
| 488 | */ |
| 489 | if (!snapc) |
| 490 | snapc = ci->i_snap_realm->cached_context; |
| 491 | |
| 492 | dout("queue_cap_snap %p cap_snap %p queuing under %p %s\n", |
| 493 | inode, capsnap, snapc, ceph_cap_string(dirty)); |
Dave Chinner | 0444d76 | 2011-03-29 18:08:50 +1100 | [diff] [blame] | 494 | ihold(inode); |
| 495 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 496 | atomic_set(&capsnap->nref, 1); |
| 497 | capsnap->ci = ci; |
| 498 | INIT_LIST_HEAD(&capsnap->ci_item); |
| 499 | INIT_LIST_HEAD(&capsnap->flushing_item); |
| 500 | |
Sage Weil | 8bef923 | 2010-09-14 15:45:44 -0700 | [diff] [blame] | 501 | capsnap->follows = snapc->seq; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 502 | capsnap->issued = __ceph_caps_issued(ci, NULL); |
Sage Weil | 4a625be | 2010-08-22 15:03:56 -0700 | [diff] [blame] | 503 | capsnap->dirty = dirty; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 504 | |
| 505 | capsnap->mode = inode->i_mode; |
| 506 | capsnap->uid = inode->i_uid; |
| 507 | capsnap->gid = inode->i_gid; |
| 508 | |
Sage Weil | 4a625be | 2010-08-22 15:03:56 -0700 | [diff] [blame] | 509 | if (dirty & CEPH_CAP_XATTR_EXCL) { |
| 510 | __ceph_build_xattrs_blob(ci); |
| 511 | capsnap->xattr_blob = |
| 512 | ceph_buffer_get(ci->i_xattrs.blob); |
| 513 | capsnap->xattr_version = ci->i_xattrs.version; |
| 514 | } else { |
| 515 | capsnap->xattr_blob = NULL; |
| 516 | capsnap->xattr_version = 0; |
| 517 | } |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 518 | |
Yan, Zheng | e20d258 | 2014-11-14 22:39:13 +0800 | [diff] [blame] | 519 | capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE; |
| 520 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 521 | /* dirty page count moved from _head to this cap_snap; |
| 522 | all subsequent writes page dirties occur _after_ this |
| 523 | snapshot. */ |
| 524 | capsnap->dirty_pages = ci->i_wrbuffer_ref_head; |
| 525 | ci->i_wrbuffer_ref_head = 0; |
Sage Weil | fc837c8f | 2010-04-13 11:41:22 -0700 | [diff] [blame] | 526 | capsnap->context = snapc; |
Sage Weil | 7d8cb26 | 2010-08-24 08:44:16 -0700 | [diff] [blame] | 527 | ci->i_head_snapc = |
| 528 | ceph_get_snap_context(ci->i_snap_realm->cached_context); |
| 529 | dout(" new snapc is %p\n", ci->i_head_snapc); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 530 | list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps); |
| 531 | |
| 532 | if (used & CEPH_CAP_FILE_WR) { |
| 533 | dout("queue_cap_snap %p cap_snap %p snapc %p" |
| 534 | " seq %llu used WR, now pending\n", inode, |
| 535 | capsnap, snapc, snapc->seq); |
| 536 | capsnap->writing = 1; |
| 537 | } else { |
| 538 | /* note mtime, size NOW. */ |
| 539 | __ceph_finish_cap_snap(ci, capsnap); |
| 540 | } |
| 541 | } else { |
| 542 | dout("queue_cap_snap %p nothing dirty|writing\n", inode); |
| 543 | kfree(capsnap); |
| 544 | } |
| 545 | |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 546 | spin_unlock(&ci->i_ceph_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 547 | } |
| 548 | |
| 549 | /* |
| 550 | * Finalize the size, mtime for a cap_snap.. that is, settle on final values |
| 551 | * to be used for the snapshot, to be flushed back to the mds. |
| 552 | * |
| 553 | * If capsnap can now be flushed, add to snap_flush list, and return 1. |
| 554 | * |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 555 | * Caller must hold i_ceph_lock. |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 556 | */ |
| 557 | int __ceph_finish_cap_snap(struct ceph_inode_info *ci, |
| 558 | struct ceph_cap_snap *capsnap) |
| 559 | { |
| 560 | struct inode *inode = &ci->vfs_inode; |
Yehuda Sadeh | 3d14c5d | 2010-04-06 15:14:15 -0700 | [diff] [blame] | 561 | struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 562 | |
| 563 | BUG_ON(capsnap->writing); |
| 564 | capsnap->size = inode->i_size; |
| 565 | capsnap->mtime = inode->i_mtime; |
| 566 | capsnap->atime = inode->i_atime; |
| 567 | capsnap->ctime = inode->i_ctime; |
| 568 | capsnap->time_warp_seq = ci->i_time_warp_seq; |
| 569 | if (capsnap->dirty_pages) { |
Sage Weil | 819ccbf | 2010-04-01 09:33:46 -0700 | [diff] [blame] | 570 | dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu " |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 571 | "still has %d dirty pages\n", inode, capsnap, |
| 572 | capsnap->context, capsnap->context->seq, |
Sage Weil | 819ccbf | 2010-04-01 09:33:46 -0700 | [diff] [blame] | 573 | ceph_cap_string(capsnap->dirty), capsnap->size, |
| 574 | capsnap->dirty_pages); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 575 | return 0; |
| 576 | } |
Sage Weil | 819ccbf | 2010-04-01 09:33:46 -0700 | [diff] [blame] | 577 | dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n", |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 578 | inode, capsnap, capsnap->context, |
Sage Weil | 819ccbf | 2010-04-01 09:33:46 -0700 | [diff] [blame] | 579 | capsnap->context->seq, ceph_cap_string(capsnap->dirty), |
| 580 | capsnap->size); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 581 | |
| 582 | spin_lock(&mdsc->snap_flush_lock); |
| 583 | list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list); |
| 584 | spin_unlock(&mdsc->snap_flush_lock); |
| 585 | return 1; /* caller may want to ceph_flush_snaps */ |
| 586 | } |
| 587 | |
Sage Weil | ed32604 | 2010-08-16 13:37:31 -0700 | [diff] [blame] | 588 | /* |
| 589 | * Queue cap_snaps for snap writeback for this realm and its children. |
| 590 | * Called under snap_rwsem, so realm topology won't change. |
| 591 | */ |
| 592 | static void queue_realm_cap_snaps(struct ceph_snap_realm *realm) |
| 593 | { |
| 594 | struct ceph_inode_info *ci; |
| 595 | struct inode *lastinode = NULL; |
| 596 | struct ceph_snap_realm *child; |
| 597 | |
| 598 | dout("queue_realm_cap_snaps %p %llx inodes\n", realm, realm->ino); |
| 599 | |
| 600 | spin_lock(&realm->inodes_with_caps_lock); |
| 601 | list_for_each_entry(ci, &realm->inodes_with_caps, |
| 602 | i_snap_realm_item) { |
| 603 | struct inode *inode = igrab(&ci->vfs_inode); |
| 604 | if (!inode) |
| 605 | continue; |
| 606 | spin_unlock(&realm->inodes_with_caps_lock); |
SF Markus Elfring | e96a650 | 2014-11-02 15:20:59 +0100 | [diff] [blame] | 607 | iput(lastinode); |
Sage Weil | ed32604 | 2010-08-16 13:37:31 -0700 | [diff] [blame] | 608 | lastinode = inode; |
| 609 | ceph_queue_cap_snap(ci); |
| 610 | spin_lock(&realm->inodes_with_caps_lock); |
| 611 | } |
| 612 | spin_unlock(&realm->inodes_with_caps_lock); |
SF Markus Elfring | e96a650 | 2014-11-02 15:20:59 +0100 | [diff] [blame] | 613 | iput(lastinode); |
Sage Weil | ed32604 | 2010-08-16 13:37:31 -0700 | [diff] [blame] | 614 | |
Sage Weil | e8e1ba96 | 2011-02-04 20:45:58 -0800 | [diff] [blame] | 615 | list_for_each_entry(child, &realm->children, child_item) { |
| 616 | dout("queue_realm_cap_snaps %p %llx queue child %p %llx\n", |
| 617 | realm, realm->ino, child, child->ino); |
| 618 | list_del_init(&child->dirty_item); |
| 619 | list_add(&child->dirty_item, &realm->dirty_item); |
| 620 | } |
Sage Weil | ed32604 | 2010-08-16 13:37:31 -0700 | [diff] [blame] | 621 | |
Sage Weil | e8e1ba96 | 2011-02-04 20:45:58 -0800 | [diff] [blame] | 622 | list_del_init(&realm->dirty_item); |
Sage Weil | ed32604 | 2010-08-16 13:37:31 -0700 | [diff] [blame] | 623 | dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino); |
| 624 | } |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 625 | |
| 626 | /* |
| 627 | * Parse and apply a snapblob "snap trace" from the MDS. This specifies |
| 628 | * the snap realm parameters from a given realm and all of its ancestors, |
| 629 | * up to the root. |
| 630 | * |
| 631 | * Caller must hold snap_rwsem for write. |
| 632 | */ |
| 633 | int ceph_update_snap_trace(struct ceph_mds_client *mdsc, |
| 634 | void *p, void *e, bool deletion) |
| 635 | { |
| 636 | struct ceph_mds_snap_realm *ri; /* encoded */ |
| 637 | __le64 *snaps; /* encoded */ |
| 638 | __le64 *prior_parent_snaps; /* encoded */ |
| 639 | struct ceph_snap_realm *realm; |
| 640 | int invalidate = 0; |
| 641 | int err = -ENOMEM; |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 642 | LIST_HEAD(dirty_realms); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 643 | |
| 644 | dout("update_snap_trace deletion=%d\n", deletion); |
| 645 | more: |
| 646 | ceph_decode_need(&p, e, sizeof(*ri), bad); |
| 647 | ri = p; |
| 648 | p += sizeof(*ri); |
| 649 | ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) + |
| 650 | le32_to_cpu(ri->num_prior_parent_snaps)), bad); |
| 651 | snaps = p; |
| 652 | p += sizeof(u64) * le32_to_cpu(ri->num_snaps); |
| 653 | prior_parent_snaps = p; |
| 654 | p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps); |
| 655 | |
| 656 | realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino)); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 657 | if (!realm) { |
| 658 | realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino)); |
| 659 | if (IS_ERR(realm)) { |
| 660 | err = PTR_ERR(realm); |
| 661 | goto fail; |
| 662 | } |
| 663 | } |
| 664 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 665 | /* ensure the parent is correct */ |
| 666 | err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent)); |
| 667 | if (err < 0) |
| 668 | goto fail; |
| 669 | invalidate += err; |
| 670 | |
| 671 | if (le64_to_cpu(ri->seq) > realm->seq) { |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 672 | dout("update_snap_trace updating %llx %p %lld -> %lld\n", |
| 673 | realm->ino, realm, realm->seq, le64_to_cpu(ri->seq)); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 674 | /* update realm parameters, snap lists */ |
| 675 | realm->seq = le64_to_cpu(ri->seq); |
| 676 | realm->created = le64_to_cpu(ri->created); |
| 677 | realm->parent_since = le64_to_cpu(ri->parent_since); |
| 678 | |
| 679 | realm->num_snaps = le32_to_cpu(ri->num_snaps); |
| 680 | err = dup_array(&realm->snaps, snaps, realm->num_snaps); |
| 681 | if (err < 0) |
| 682 | goto fail; |
| 683 | |
| 684 | realm->num_prior_parent_snaps = |
| 685 | le32_to_cpu(ri->num_prior_parent_snaps); |
| 686 | err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps, |
| 687 | realm->num_prior_parent_snaps); |
| 688 | if (err < 0) |
| 689 | goto fail; |
| 690 | |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 691 | /* queue realm for cap_snap creation */ |
| 692 | list_add(&realm->dirty_item, &dirty_realms); |
| 693 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 694 | invalidate = 1; |
| 695 | } else if (!realm->cached_context) { |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 696 | dout("update_snap_trace %llx %p seq %lld new\n", |
| 697 | realm->ino, realm, realm->seq); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 698 | invalidate = 1; |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 699 | } else { |
| 700 | dout("update_snap_trace %llx %p seq %lld unchanged\n", |
| 701 | realm->ino, realm, realm->seq); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 702 | } |
| 703 | |
| 704 | dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino, |
| 705 | realm, invalidate, p, e); |
| 706 | |
| 707 | if (p < e) |
| 708 | goto more; |
| 709 | |
| 710 | /* invalidate when we reach the _end_ (root) of the trace */ |
| 711 | if (invalidate) |
| 712 | rebuild_snap_realms(realm); |
| 713 | |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 714 | /* |
| 715 | * queue cap snaps _after_ we've built the new snap contexts, |
| 716 | * so that i_head_snapc can be set appropriately. |
| 717 | */ |
Sage Weil | e8e1ba96 | 2011-02-04 20:45:58 -0800 | [diff] [blame] | 718 | while (!list_empty(&dirty_realms)) { |
| 719 | realm = list_first_entry(&dirty_realms, struct ceph_snap_realm, |
| 720 | dirty_item); |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 721 | queue_realm_cap_snaps(realm); |
| 722 | } |
| 723 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 724 | __cleanup_empty_realms(mdsc); |
| 725 | return 0; |
| 726 | |
| 727 | bad: |
| 728 | err = -EINVAL; |
| 729 | fail: |
| 730 | pr_err("update_snap_trace error %d\n", err); |
| 731 | return err; |
| 732 | } |
| 733 | |
| 734 | |
| 735 | /* |
| 736 | * Send any cap_snaps that are queued for flush. Try to carry |
| 737 | * s_mutex across multiple snap flushes to avoid locking overhead. |
| 738 | * |
| 739 | * Caller holds no locks. |
| 740 | */ |
| 741 | static void flush_snaps(struct ceph_mds_client *mdsc) |
| 742 | { |
| 743 | struct ceph_inode_info *ci; |
| 744 | struct inode *inode; |
| 745 | struct ceph_mds_session *session = NULL; |
| 746 | |
| 747 | dout("flush_snaps\n"); |
| 748 | spin_lock(&mdsc->snap_flush_lock); |
| 749 | while (!list_empty(&mdsc->snap_flush_list)) { |
| 750 | ci = list_first_entry(&mdsc->snap_flush_list, |
| 751 | struct ceph_inode_info, i_snap_flush_item); |
| 752 | inode = &ci->vfs_inode; |
Sage Weil | 70b666c | 2011-05-27 09:24:26 -0700 | [diff] [blame] | 753 | ihold(inode); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 754 | spin_unlock(&mdsc->snap_flush_lock); |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 755 | spin_lock(&ci->i_ceph_lock); |
Sage Weil | e835124 | 2010-09-17 08:03:08 -0700 | [diff] [blame] | 756 | __ceph_flush_snaps(ci, &session, 0); |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 757 | spin_unlock(&ci->i_ceph_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 758 | iput(inode); |
| 759 | spin_lock(&mdsc->snap_flush_lock); |
| 760 | } |
| 761 | spin_unlock(&mdsc->snap_flush_lock); |
| 762 | |
| 763 | if (session) { |
| 764 | mutex_unlock(&session->s_mutex); |
| 765 | ceph_put_mds_session(session); |
| 766 | } |
| 767 | dout("flush_snaps done\n"); |
| 768 | } |
| 769 | |
| 770 | |
| 771 | /* |
| 772 | * Handle a snap notification from the MDS. |
| 773 | * |
| 774 | * This can take two basic forms: the simplest is just a snap creation |
| 775 | * or deletion notification on an existing realm. This should update the |
| 776 | * realm and its children. |
| 777 | * |
| 778 | * The more difficult case is realm creation, due to snap creation at a |
| 779 | * new point in the file hierarchy, or due to a rename that moves a file or |
| 780 | * directory into another realm. |
| 781 | */ |
| 782 | void ceph_handle_snap(struct ceph_mds_client *mdsc, |
Sage Weil | 2600d2d | 2010-02-22 15:12:16 -0800 | [diff] [blame] | 783 | struct ceph_mds_session *session, |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 784 | struct ceph_msg *msg) |
| 785 | { |
Yehuda Sadeh | 3d14c5d | 2010-04-06 15:14:15 -0700 | [diff] [blame] | 786 | struct super_block *sb = mdsc->fsc->sb; |
Sage Weil | 2600d2d | 2010-02-22 15:12:16 -0800 | [diff] [blame] | 787 | int mds = session->s_mds; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 788 | u64 split; |
| 789 | int op; |
| 790 | int trace_len; |
| 791 | struct ceph_snap_realm *realm = NULL; |
| 792 | void *p = msg->front.iov_base; |
| 793 | void *e = p + msg->front.iov_len; |
| 794 | struct ceph_mds_snap_head *h; |
| 795 | int num_split_inos, num_split_realms; |
| 796 | __le64 *split_inos = NULL, *split_realms = NULL; |
| 797 | int i; |
| 798 | int locked_rwsem = 0; |
| 799 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 800 | /* decode */ |
| 801 | if (msg->front.iov_len < sizeof(*h)) |
| 802 | goto bad; |
| 803 | h = p; |
| 804 | op = le32_to_cpu(h->op); |
| 805 | split = le64_to_cpu(h->split); /* non-zero if we are splitting an |
| 806 | * existing realm */ |
| 807 | num_split_inos = le32_to_cpu(h->num_split_inos); |
| 808 | num_split_realms = le32_to_cpu(h->num_split_realms); |
| 809 | trace_len = le32_to_cpu(h->trace_len); |
| 810 | p += sizeof(*h); |
| 811 | |
| 812 | dout("handle_snap from mds%d op %s split %llx tracelen %d\n", mds, |
| 813 | ceph_snap_op_name(op), split, trace_len); |
| 814 | |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 815 | mutex_lock(&session->s_mutex); |
| 816 | session->s_seq++; |
| 817 | mutex_unlock(&session->s_mutex); |
| 818 | |
| 819 | down_write(&mdsc->snap_rwsem); |
| 820 | locked_rwsem = 1; |
| 821 | |
| 822 | if (op == CEPH_SNAP_OP_SPLIT) { |
| 823 | struct ceph_mds_snap_realm *ri; |
| 824 | |
| 825 | /* |
| 826 | * A "split" breaks part of an existing realm off into |
| 827 | * a new realm. The MDS provides a list of inodes |
| 828 | * (with caps) and child realms that belong to the new |
| 829 | * child. |
| 830 | */ |
| 831 | split_inos = p; |
| 832 | p += sizeof(u64) * num_split_inos; |
| 833 | split_realms = p; |
| 834 | p += sizeof(u64) * num_split_realms; |
| 835 | ceph_decode_need(&p, e, sizeof(*ri), bad); |
| 836 | /* we will peek at realm info here, but will _not_ |
| 837 | * advance p, as the realm update will occur below in |
| 838 | * ceph_update_snap_trace. */ |
| 839 | ri = p; |
| 840 | |
| 841 | realm = ceph_lookup_snap_realm(mdsc, split); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 842 | if (!realm) { |
| 843 | realm = ceph_create_snap_realm(mdsc, split); |
| 844 | if (IS_ERR(realm)) |
| 845 | goto out; |
| 846 | } |
| 847 | ceph_get_snap_realm(mdsc, realm); |
| 848 | |
| 849 | dout("splitting snap_realm %llx %p\n", realm->ino, realm); |
| 850 | for (i = 0; i < num_split_inos; i++) { |
| 851 | struct ceph_vino vino = { |
| 852 | .ino = le64_to_cpu(split_inos[i]), |
| 853 | .snap = CEPH_NOSNAP, |
| 854 | }; |
| 855 | struct inode *inode = ceph_find_inode(sb, vino); |
| 856 | struct ceph_inode_info *ci; |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 857 | struct ceph_snap_realm *oldrealm; |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 858 | |
| 859 | if (!inode) |
| 860 | continue; |
| 861 | ci = ceph_inode(inode); |
| 862 | |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 863 | spin_lock(&ci->i_ceph_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 864 | if (!ci->i_snap_realm) |
| 865 | goto skip_inode; |
| 866 | /* |
| 867 | * If this inode belongs to a realm that was |
| 868 | * created after our new realm, we experienced |
| 869 | * a race (due to another split notifications |
| 870 | * arriving from a different MDS). So skip |
| 871 | * this inode. |
| 872 | */ |
| 873 | if (ci->i_snap_realm->created > |
| 874 | le64_to_cpu(ri->created)) { |
| 875 | dout(" leaving %p in newer realm %llx %p\n", |
| 876 | inode, ci->i_snap_realm->ino, |
| 877 | ci->i_snap_realm); |
| 878 | goto skip_inode; |
| 879 | } |
| 880 | dout(" will move %p to split realm %llx %p\n", |
| 881 | inode, realm->ino, realm); |
| 882 | /* |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 883 | * Move the inode to the new realm |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 884 | */ |
Sage Weil | 052bb34 | 2010-03-09 12:52:26 -0800 | [diff] [blame] | 885 | spin_lock(&realm->inodes_with_caps_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 886 | list_del_init(&ci->i_snap_realm_item); |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 887 | list_add(&ci->i_snap_realm_item, |
| 888 | &realm->inodes_with_caps); |
| 889 | oldrealm = ci->i_snap_realm; |
| 890 | ci->i_snap_realm = realm; |
Sage Weil | 052bb34 | 2010-03-09 12:52:26 -0800 | [diff] [blame] | 891 | spin_unlock(&realm->inodes_with_caps_lock); |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 892 | spin_unlock(&ci->i_ceph_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 893 | |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 894 | ceph_get_snap_realm(mdsc, realm); |
| 895 | ceph_put_snap_realm(mdsc, oldrealm); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 896 | |
| 897 | iput(inode); |
| 898 | continue; |
| 899 | |
| 900 | skip_inode: |
Sage Weil | be65559 | 2011-11-30 09:47:09 -0800 | [diff] [blame] | 901 | spin_unlock(&ci->i_ceph_lock); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 902 | iput(inode); |
| 903 | } |
| 904 | |
| 905 | /* we may have taken some of the old realm's children. */ |
| 906 | for (i = 0; i < num_split_realms; i++) { |
| 907 | struct ceph_snap_realm *child = |
| 908 | ceph_lookup_snap_realm(mdsc, |
| 909 | le64_to_cpu(split_realms[i])); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 910 | if (!child) |
| 911 | continue; |
| 912 | adjust_snap_realm_parent(mdsc, child, realm->ino); |
| 913 | } |
| 914 | } |
| 915 | |
| 916 | /* |
| 917 | * update using the provided snap trace. if we are deleting a |
| 918 | * snap, we can avoid queueing cap_snaps. |
| 919 | */ |
| 920 | ceph_update_snap_trace(mdsc, p, e, |
| 921 | op == CEPH_SNAP_OP_DESTROY); |
| 922 | |
Sage Weil | ae00d4f | 2010-09-16 16:26:51 -0700 | [diff] [blame] | 923 | if (op == CEPH_SNAP_OP_SPLIT) |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 924 | /* we took a reference when we created the realm, above */ |
| 925 | ceph_put_snap_realm(mdsc, realm); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 926 | |
| 927 | __cleanup_empty_realms(mdsc); |
| 928 | |
| 929 | up_write(&mdsc->snap_rwsem); |
| 930 | |
| 931 | flush_snaps(mdsc); |
| 932 | return; |
| 933 | |
| 934 | bad: |
| 935 | pr_err("corrupt snap message from mds%d\n", mds); |
Sage Weil | 9ec7cab | 2009-12-14 15:13:47 -0800 | [diff] [blame] | 936 | ceph_msg_dump(msg); |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 937 | out: |
| 938 | if (locked_rwsem) |
| 939 | up_write(&mdsc->snap_rwsem); |
| 940 | return; |
| 941 | } |
| 942 | |
Yan, Zheng | 97c85a8 | 2014-11-06 15:09:41 +0800 | [diff] [blame] | 943 | int __init ceph_snap_init(void) |
| 944 | { |
| 945 | empty_snapc = ceph_create_snap_context(0, GFP_NOFS); |
| 946 | if (!empty_snapc) |
| 947 | return -ENOMEM; |
| 948 | empty_snapc->seq = 1; |
| 949 | return 0; |
| 950 | } |
Sage Weil | 963b61e | 2009-10-06 11:31:12 -0700 | [diff] [blame] | 951 | |
Yan, Zheng | 97c85a8 | 2014-11-06 15:09:41 +0800 | [diff] [blame] | 952 | void ceph_snap_exit(void) |
| 953 | { |
| 954 | ceph_put_snap_context(empty_snapc); |
| 955 | } |