2 * Copyright (c) 2008 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/vfs/hammer/hammer_prune.c,v 1.19 2008/09/23 21:03:52 dillon Exp $
40 * Iterate through the specified range of object ids and remove any
41 * deleted records that fall entirely within a prune modulo.
43 * A reverse iteration is used to prevent overlapping records from being
44 * created during the iteration due to alignments. This also allows us
45 * to adjust alignments without blowing up the B-Tree.
47 static int prune_should_delete(struct hammer_ioc_prune
*prune
,
48 hammer_btree_leaf_elm_t elm
);
49 static void prune_check_nlinks(hammer_cursor_t cursor
,
50 hammer_btree_leaf_elm_t elm
);
53 hammer_ioc_prune(hammer_transaction_t trans
, hammer_inode_t ip
,
54 struct hammer_ioc_prune
*prune
)
56 struct hammer_cursor cursor
;
57 hammer_btree_leaf_elm_t elm
;
58 struct hammer_ioc_prune_elm
*copy_elms
;
59 struct hammer_ioc_prune_elm
*user_elms
;
65 uint32_t key_beg_localization
;
67 if (prune
->nelms
< 0 || prune
->nelms
> HAMMER_MAX_PRUNE_ELMS
)
69 if ((prune
->key_beg
.localization
| prune
->key_end
.localization
) &
70 HAMMER_LOCALIZE_PSEUDOFS_MASK
) {
73 if (prune
->key_beg
.localization
> prune
->key_end
.localization
)
75 if (prune
->key_beg
.localization
== prune
->key_end
.localization
) {
76 if (prune
->key_beg
.obj_id
> prune
->key_end
.obj_id
)
78 /* key-space limitations - no check needed */
80 if ((prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) && prune
->nelms
)
84 * Ioctl caller has only set localization type to prune.
85 * Initialize cursor key localization with ip localization.
87 key_beg_localization
= prune
->key_beg
.localization
;
88 key_beg_localization
&= HAMMER_LOCALIZE_MASK
;
89 key_beg_localization
|= ip
->obj_localization
;
91 prune
->key_cur
.localization
= prune
->key_end
.localization
;
92 prune
->key_cur
.localization
&= HAMMER_LOCALIZE_MASK
;
93 prune
->key_cur
.localization
|= ip
->obj_localization
;
95 prune
->key_cur
.obj_id
= prune
->key_end
.obj_id
;
96 prune
->key_cur
.key
= HAMMER_MAX_KEY
;
99 * Copy element array from userland
101 elm_array_size
= sizeof(*copy_elms
) * prune
->nelms
;
102 user_elms
= prune
->elms
;
103 copy_elms
= kmalloc(elm_array_size
, M_TEMP
, M_WAITOK
);
104 if ((error
= copyin(user_elms
, copy_elms
, elm_array_size
)) != 0)
106 prune
->elms
= copy_elms
;
108 seq
= trans
->hmp
->flusher
.done
;
111 * Scan backwards. Retries typically occur if a deadlock is detected.
114 error
= hammer_init_cursor(trans
, &cursor
, NULL
, NULL
);
116 hammer_done_cursor(&cursor
);
119 cursor
.key_beg
.localization
= key_beg_localization
;
120 cursor
.key_beg
.obj_id
= prune
->key_beg
.obj_id
;
121 cursor
.key_beg
.key
= HAMMER_MIN_KEY
;
122 cursor
.key_beg
.create_tid
= 1;
123 cursor
.key_beg
.delete_tid
= 0;
124 cursor
.key_beg
.rec_type
= HAMMER_MIN_RECTYPE
;
125 cursor
.key_beg
.obj_type
= 0;
127 cursor
.key_end
.localization
= prune
->key_cur
.localization
;
128 cursor
.key_end
.obj_id
= prune
->key_cur
.obj_id
;
129 cursor
.key_end
.key
= prune
->key_cur
.key
;
130 cursor
.key_end
.create_tid
= HAMMER_MAX_TID
- 1;
131 cursor
.key_end
.delete_tid
= 0;
132 cursor
.key_end
.rec_type
= HAMMER_MAX_RECTYPE
;
133 cursor
.key_end
.obj_type
= 0;
135 cursor
.flags
|= HAMMER_CURSOR_END_INCLUSIVE
;
136 cursor
.flags
|= HAMMER_CURSOR_BACKEND
;
139 * This flag allows the B-Tree code to clean up loose ends. At
140 * the moment (XXX) it also means we have to hold the sync lock
141 * through the iteration.
143 cursor
.flags
|= HAMMER_CURSOR_PRUNING
;
145 hammer_sync_lock_sh(trans
);
146 error
= hammer_btree_last(&cursor
);
147 hammer_sync_unlock(trans
);
153 elm
= &cursor
.node
->ondisk
->elms
[cursor
.index
].leaf
;
154 prune
->key_cur
= elm
->base
;
157 * Filesystem went read-only during rebalancing
159 if (trans
->hmp
->ronly
) {
165 * Yield to more important tasks
167 if ((error
= hammer_signal_check(trans
->hmp
)) != 0)
170 if (prune
->stat_oldest_tid
> elm
->base
.create_tid
)
171 prune
->stat_oldest_tid
= elm
->base
.create_tid
;
173 if (hammer_debug_general
& 0x0200) {
174 hdkprintf("check %016jx %016jx cre=%016jx del=%016jx\n",
175 (intmax_t)elm
->base
.obj_id
,
176 (intmax_t)elm
->base
.key
,
177 (intmax_t)elm
->base
.create_tid
,
178 (intmax_t)elm
->base
.delete_tid
);
181 if (prune_should_delete(prune
, elm
)) {
182 if (hammer_debug_general
& 0x0200) {
183 hdkprintf("check %016jx %016jx: DELETE\n",
184 (intmax_t)elm
->base
.obj_id
,
185 (intmax_t)elm
->base
.key
);
189 * NOTE: This can return EDEADLK
191 * Acquiring the sync lock guarantees that the
192 * operation will not cross a synchronization
193 * boundary (see the flusher).
195 * We dont need to track inodes or next_tid when
196 * we are destroying deleted records.
198 isdir
= (elm
->base
.rec_type
== HAMMER_RECTYPE_DIRENTRY
);
200 hammer_sync_lock_sh(trans
);
201 error
= hammer_delete_at_cursor(&cursor
,
202 HAMMER_DELETE_DESTROY
,
204 cursor
.trans
->time32
,
206 hammer_sync_unlock(trans
);
211 ++prune
->stat_dirrecords
;
213 ++prune
->stat_rawrecords
;
214 prune
->stat_bytes
+= bytes
;
217 * The current record might now be the one after
218 * the one we deleted, set ATEDISK to force us
219 * to skip it (since we are iterating backwards).
221 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
224 * Nothing to delete, but we may have to check other
227 prune_check_nlinks(&cursor
, elm
);
228 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
229 if (hammer_debug_general
& 0x0100) {
230 hdkprintf("check %016jx %016jx: SKIP\n",
231 (intmax_t)elm
->base
.obj_id
,
232 (intmax_t)elm
->base
.key
);
235 ++prune
->stat_scanrecords
;
238 * WARNING: See warnings in hammer_unlock_cursor() function.
240 while (hammer_flusher_meta_halflimit(trans
->hmp
) ||
241 hammer_flusher_undo_exhausted(trans
, 2)) {
242 hammer_unlock_cursor(&cursor
);
243 hammer_flusher_wait(trans
->hmp
, seq
);
244 hammer_lock_cursor(&cursor
);
245 seq
= hammer_flusher_async_one(trans
->hmp
);
247 hammer_sync_lock_sh(trans
);
248 error
= hammer_btree_iterate_reverse(&cursor
);
249 hammer_sync_unlock(trans
);
253 hammer_done_cursor(&cursor
);
254 if (error
== EDEADLK
)
256 if (error
== EINTR
) {
257 prune
->head
.flags
|= HAMMER_IOC_HEAD_INTR
;
261 prune
->key_cur
.localization
&= HAMMER_LOCALIZE_MASK
;
262 prune
->elms
= user_elms
;
263 kfree(copy_elms
, M_TEMP
);
268 * Check pruning list. The list must be sorted in descending order.
270 * Return non-zero if the record should be deleted.
273 prune_should_delete(struct hammer_ioc_prune
*prune
, hammer_btree_leaf_elm_t elm
)
275 struct hammer_ioc_prune_elm
*scan
;
279 * If pruning everything remove all records with a non-zero
282 if (prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) {
283 if (elm
->base
.delete_tid
!= 0)
288 for (i
= 0; i
< prune
->nelms
; ++i
) {
289 scan
= &prune
->elms
[i
];
292 * Check for loop termination.
294 if (elm
->base
.create_tid
>= scan
->end_tid
||
295 elm
->base
.delete_tid
> scan
->end_tid
) {
300 * Determine if we can delete the record.
302 if (elm
->base
.delete_tid
&&
303 elm
->base
.create_tid
>= scan
->beg_tid
&&
304 elm
->base
.delete_tid
<= scan
->end_tid
&&
305 (elm
->base
.create_tid
- scan
->beg_tid
) / scan
->mod_tid
==
306 (elm
->base
.delete_tid
- scan
->beg_tid
) / scan
->mod_tid
) {
314 * Dangling inodes can occur if processes are holding open descriptors on
315 * deleted files as-of when a machine crashes. When we find one simply
316 * acquire the inode and release it. The inode handling code will then
317 * do the right thing.
321 prune_check_nlinks(hammer_cursor_t cursor
, hammer_btree_leaf_elm_t elm
)
326 if (elm
->base
.rec_type
!= HAMMER_RECTYPE_INODE
)
328 if (elm
->base
.delete_tid
!= 0)
330 if (hammer_btree_extract_data(cursor
))
332 if (cursor
->data
->inode
.nlinks
)
334 hammer_cursor_downgrade(cursor
);
335 ip
= hammer_get_inode(cursor
->trans
, NULL
, elm
->base
.obj_id
,
337 elm
->base
.localization
& HAMMER_LOCALIZE_PSEUDOFS_MASK
,
340 if (hammer_debug_general
& 0x0001) {
341 hdkprintf("pruning disconnected inode %016jx\n",
342 (intmax_t)elm
->base
.obj_id
);
344 hammer_rel_inode(ip
, 0);
345 hammer_inode_waitreclaims(cursor
->trans
);
347 hkprintf("unable to prune disconnected inode %016jx\n",
348 (intmax_t)elm
->base
.obj_id
);
355 * NOTE: THIS CODE HAS BEEN REMOVED! Pruning no longer attempts to realign
356 * adjacent records because it seriously interferes with every
357 * mirroring algorithm I could come up with.
359 * This means that historical accesses beyond the first snapshot
360 * softlink should be on snapshot boundaries only. Historical
361 * accesses from "now" to the first snapshot softlink continue to
364 * NOTE: It also looks like there's a bug in the removed code. It is believed
365 * that create_tid can sometimes get set to 0xffffffffffffffff. Just as
366 * well we no longer try to do this fancy shit. Probably the attempt to
367 * correct the rhb is blowing up the cursor's indexing or addressing mapping.
369 * Align the record to cover any gaps created through the deletion of
370 * records within the pruning space. If we were to just delete the records
371 * there would be gaps which in turn would cause a snapshot that is NOT on
372 * a pruning boundary to appear corrupt to the user. Forcing alignment
373 * of the create_tid and delete_tid for retained records 'reconnects'
374 * the previously contiguous space, making it contiguous again after the
377 * The use of a reverse iteration allows us to safely align the records and
378 * related elements without creating temporary overlaps. XXX we should
379 * add ordering dependancies for record buffers to guarantee consistency
383 realign_prune(struct hammer_ioc_prune
*prune
,
384 hammer_cursor_t cursor
, int realign_cre
, int realign_del
)
386 struct hammer_ioc_prune_elm
*scan
;
387 hammer_btree_elm_t elm
;
392 hammer_cursor_downgrade(cursor
);
394 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
];
395 ++prune
->stat_realignments
;
398 * Align the create_tid. By doing a reverse iteration we guarantee
399 * that all records after our current record have already been
400 * aligned, allowing us to safely correct the right-hand-boundary
401 * (because no record to our right is otherwise exactly matching
402 * will have a create_tid to the left of our aligned create_tid).
405 if (realign_cre
>= 0) {
406 scan
= &prune
->elms
[realign_cre
];
408 delta
= (elm
->leaf
.base
.create_tid
- scan
->beg_tid
) %
411 tid
= elm
->leaf
.base
.create_tid
- delta
+ scan
->mod_tid
;
414 error
= hammer_btree_correct_rhb(cursor
, tid
+ 1);
416 error
= hammer_btree_extract_leaf(cursor
);
420 error
= hammer_cursor_upgrade(cursor
);
423 hammer_modify_node(cursor
->trans
, cursor
->node
,
424 &elm
->leaf
.base
.create_tid
,
425 sizeof(elm
->leaf
.base
.create_tid
));
426 elm
->leaf
.base
.create_tid
= tid
;
427 hammer_modify_node_done(cursor
->node
);
433 * Align the delete_tid. This only occurs if the record is historical
434 * was deleted at some point. Realigning the delete_tid does not
435 * move the record within the B-Tree but may cause it to temporarily
436 * overlap a record that has not yet been pruned.
438 if (error
== 0 && realign_del
>= 0) {
439 scan
= &prune
->elms
[realign_del
];
441 delta
= (elm
->leaf
.base
.delete_tid
- scan
->beg_tid
) %
444 error
= hammer_btree_extract_leaf(cursor
);
446 hammer_modify_node(cursor
->trans
, cursor
->node
,
447 &elm
->leaf
.base
.delete_tid
,
448 sizeof(elm
->leaf
.base
.delete_tid
));
449 elm
->leaf
.base
.delete_tid
=
450 elm
->leaf
.base
.delete_tid
-
451 delta
+ scan
->mod_tid
;
452 hammer_modify_node_done(cursor
->node
);