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 if (prune
->nelms
< 0 || prune
->nelms
> HAMMER_MAX_PRUNE_ELMS
)
67 if ((prune
->key_beg
.localization
| prune
->key_end
.localization
) &
68 HAMMER_LOCALIZE_PSEUDOFS_MASK
) {
71 if (prune
->key_beg
.localization
> prune
->key_end
.localization
)
73 if (prune
->key_beg
.localization
== prune
->key_end
.localization
) {
74 if (prune
->key_beg
.obj_id
> prune
->key_end
.obj_id
)
76 /* key-space limitations - no check needed */
78 if ((prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) && prune
->nelms
)
81 prune
->key_cur
.localization
= (prune
->key_end
.localization
&
82 HAMMER_LOCALIZE_MASK
) +
84 prune
->key_cur
.obj_id
= prune
->key_end
.obj_id
;
85 prune
->key_cur
.key
= HAMMER_MAX_KEY
;
88 * Copy element array from userland
90 elm_array_size
= sizeof(*copy_elms
) * prune
->nelms
;
91 user_elms
= prune
->elms
;
92 copy_elms
= kmalloc(elm_array_size
, M_TEMP
, M_WAITOK
);
93 if ((error
= copyin(user_elms
, copy_elms
, elm_array_size
)) != 0)
95 prune
->elms
= copy_elms
;
97 seq
= trans
->hmp
->flusher
.act
;
100 * Scan backwards. Retries typically occur if a deadlock is detected.
103 error
= hammer_init_cursor(trans
, &cursor
, NULL
, NULL
);
105 hammer_done_cursor(&cursor
);
108 cursor
.key_beg
.localization
= (prune
->key_beg
.localization
&
109 HAMMER_LOCALIZE_MASK
) +
110 ip
->obj_localization
;
111 cursor
.key_beg
.obj_id
= prune
->key_beg
.obj_id
;
112 cursor
.key_beg
.key
= HAMMER_MIN_KEY
;
113 cursor
.key_beg
.create_tid
= 1;
114 cursor
.key_beg
.delete_tid
= 0;
115 cursor
.key_beg
.rec_type
= HAMMER_MIN_RECTYPE
;
116 cursor
.key_beg
.obj_type
= 0;
118 cursor
.key_end
.localization
= prune
->key_cur
.localization
;
119 cursor
.key_end
.obj_id
= prune
->key_cur
.obj_id
;
120 cursor
.key_end
.key
= prune
->key_cur
.key
;
121 cursor
.key_end
.create_tid
= HAMMER_MAX_TID
- 1;
122 cursor
.key_end
.delete_tid
= 0;
123 cursor
.key_end
.rec_type
= HAMMER_MAX_RECTYPE
;
124 cursor
.key_end
.obj_type
= 0;
126 cursor
.flags
|= HAMMER_CURSOR_END_INCLUSIVE
;
127 cursor
.flags
|= HAMMER_CURSOR_BACKEND
;
130 * This flag allows the B-Tree code to clean up loose ends. At
131 * the moment (XXX) it also means we have to hold the sync lock
132 * through the iteration.
134 cursor
.flags
|= HAMMER_CURSOR_PRUNING
;
136 hammer_sync_lock_sh(trans
);
137 error
= hammer_btree_last(&cursor
);
138 hammer_sync_unlock(trans
);
144 elm
= &cursor
.node
->ondisk
->elms
[cursor
.index
].leaf
;
145 prune
->key_cur
= elm
->base
;
148 * Yield to more important tasks
150 if ((error
= hammer_signal_check(trans
->hmp
)) != 0)
153 if (prune
->stat_oldest_tid
> elm
->base
.create_tid
)
154 prune
->stat_oldest_tid
= elm
->base
.create_tid
;
156 if (hammer_debug_general
& 0x0200) {
157 kprintf("check %016llx %016llx cre=%016llx del=%016llx\n",
158 (long long)elm
->base
.obj_id
,
159 (long long)elm
->base
.key
,
160 (long long)elm
->base
.create_tid
,
161 (long long)elm
->base
.delete_tid
);
164 if (prune_should_delete(prune
, elm
)) {
165 if (hammer_debug_general
& 0x0200) {
166 kprintf("check %016llx %016llx: DELETE\n",
167 (long long)elm
->base
.obj_id
,
168 (long long)elm
->base
.key
);
172 * NOTE: This can return EDEADLK
174 * Acquiring the sync lock guarantees that the
175 * operation will not cross a synchronization
176 * boundary (see the flusher).
178 * We dont need to track inodes or next_tid when
179 * we are destroying deleted records.
181 isdir
= (elm
->base
.rec_type
== HAMMER_RECTYPE_DIRENTRY
);
183 hammer_sync_lock_sh(trans
);
184 error
= hammer_delete_at_cursor(&cursor
,
185 HAMMER_DELETE_DESTROY
,
187 cursor
.trans
->time32
,
188 0, &prune
->stat_bytes
);
189 hammer_sync_unlock(trans
);
194 ++prune
->stat_dirrecords
;
196 ++prune
->stat_rawrecords
;
199 * The current record might now be the one after
200 * the one we deleted, set ATEDISK to force us
201 * to skip it (since we are iterating backwards).
203 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
206 * Nothing to delete, but we may have to check other
209 prune_check_nlinks(&cursor
, elm
);
210 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
211 if (hammer_debug_general
& 0x0100) {
212 kprintf("check %016llx %016llx: SKIP\n",
213 (long long)elm
->base
.obj_id
,
214 (long long)elm
->base
.key
);
217 ++prune
->stat_scanrecords
;
219 while (hammer_flusher_meta_halflimit(trans
->hmp
) ||
220 hammer_flusher_undo_exhausted(trans
, 2)) {
221 hammer_unlock_cursor(&cursor
);
222 hammer_flusher_wait(trans
->hmp
, seq
);
223 hammer_lock_cursor(&cursor
);
224 seq
= hammer_flusher_async_one(trans
->hmp
);
226 hammer_sync_lock_sh(trans
);
227 error
= hammer_btree_iterate_reverse(&cursor
);
228 hammer_sync_unlock(trans
);
232 hammer_done_cursor(&cursor
);
233 if (error
== EDEADLK
)
235 if (error
== EINTR
) {
236 prune
->head
.flags
|= HAMMER_IOC_HEAD_INTR
;
240 prune
->key_cur
.localization
&= HAMMER_LOCALIZE_MASK
;
241 prune
->elms
= user_elms
;
242 kfree(copy_elms
, M_TEMP
);
247 * Check pruning list. The list must be sorted in descending order.
249 * Return non-zero if the record should be deleted.
252 prune_should_delete(struct hammer_ioc_prune
*prune
, hammer_btree_leaf_elm_t elm
)
254 struct hammer_ioc_prune_elm
*scan
;
258 * If pruning everything remove all records with a non-zero
261 if (prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) {
262 if (elm
->base
.delete_tid
!= 0)
267 for (i
= 0; i
< prune
->nelms
; ++i
) {
268 scan
= &prune
->elms
[i
];
271 * Check for loop termination.
273 if (elm
->base
.create_tid
>= scan
->end_tid
||
274 elm
->base
.delete_tid
> scan
->end_tid
) {
279 * Determine if we can delete the record.
281 if (elm
->base
.delete_tid
&&
282 elm
->base
.create_tid
>= scan
->beg_tid
&&
283 elm
->base
.delete_tid
<= scan
->end_tid
&&
284 (elm
->base
.create_tid
- scan
->beg_tid
) / scan
->mod_tid
==
285 (elm
->base
.delete_tid
- scan
->beg_tid
) / scan
->mod_tid
) {
293 * Dangling inodes can occur if processes are holding open descriptors on
294 * deleted files as-of when a machine crashes. When we find one simply
295 * acquire the inode and release it. The inode handling code will then
296 * do the right thing.
300 prune_check_nlinks(hammer_cursor_t cursor
, hammer_btree_leaf_elm_t elm
)
305 if (elm
->base
.rec_type
!= HAMMER_RECTYPE_INODE
)
307 if (elm
->base
.delete_tid
!= 0)
309 if (hammer_btree_extract(cursor
, HAMMER_CURSOR_GET_DATA
))
311 if (cursor
->data
->inode
.nlinks
)
313 hammer_cursor_downgrade(cursor
);
314 ip
= hammer_get_inode(cursor
->trans
, NULL
, elm
->base
.obj_id
,
316 elm
->base
.localization
& HAMMER_LOCALIZE_PSEUDOFS_MASK
,
319 if (hammer_debug_general
& 0x0001) {
320 kprintf("pruning disconnected inode %016llx\n",
321 (long long)elm
->base
.obj_id
);
323 hammer_rel_inode(ip
, 0);
324 hammer_inode_waitreclaims(cursor
->trans
->hmp
);
326 kprintf("unable to prune disconnected inode %016llx\n",
327 (long long)elm
->base
.obj_id
);
334 * NOTE: THIS CODE HAS BEEN REMOVED! Pruning no longer attempts to realign
335 * adjacent records because it seriously interferes with every
336 * mirroring algorithm I could come up with.
338 * This means that historical accesses beyond the first snapshot
339 * softlink should be on snapshot boundaries only. Historical
340 * accesses from "now" to the first snapshot softlink continue to
343 * NOTE: It also looks like there's a bug in the removed code. It is believed
344 * that create_tid can sometimes get set to 0xffffffffffffffff. Just as
345 * well we no longer try to do this fancy shit. Probably the attempt to
346 * correct the rhb is blowing up the cursor's indexing or addressing mapping.
348 * Align the record to cover any gaps created through the deletion of
349 * records within the pruning space. If we were to just delete the records
350 * there would be gaps which in turn would cause a snapshot that is NOT on
351 * a pruning boundary to appear corrupt to the user. Forcing alignment
352 * of the create_tid and delete_tid for retained records 'reconnects'
353 * the previously contiguous space, making it contiguous again after the
356 * The use of a reverse iteration allows us to safely align the records and
357 * related elements without creating temporary overlaps. XXX we should
358 * add ordering dependancies for record buffers to guarantee consistency
362 realign_prune(struct hammer_ioc_prune
*prune
,
363 hammer_cursor_t cursor
, int realign_cre
, int realign_del
)
365 struct hammer_ioc_prune_elm
*scan
;
366 hammer_btree_elm_t elm
;
371 hammer_cursor_downgrade(cursor
);
373 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
];
374 ++prune
->stat_realignments
;
377 * Align the create_tid. By doing a reverse iteration we guarantee
378 * that all records after our current record have already been
379 * aligned, allowing us to safely correct the right-hand-boundary
380 * (because no record to our right is otherwise exactly matching
381 * will have a create_tid to the left of our aligned create_tid).
384 if (realign_cre
>= 0) {
385 scan
= &prune
->elms
[realign_cre
];
387 delta
= (elm
->leaf
.base
.create_tid
- scan
->beg_tid
) %
390 tid
= elm
->leaf
.base
.create_tid
- delta
+ scan
->mod_tid
;
393 error
= hammer_btree_correct_rhb(cursor
, tid
+ 1);
395 error
= hammer_btree_extract(cursor
,
396 HAMMER_CURSOR_GET_LEAF
);
400 error
= hammer_cursor_upgrade(cursor
);
403 hammer_modify_node(cursor
->trans
, cursor
->node
,
404 &elm
->leaf
.base
.create_tid
,
405 sizeof(elm
->leaf
.base
.create_tid
));
406 elm
->leaf
.base
.create_tid
= tid
;
407 hammer_modify_node_done(cursor
->node
);
413 * Align the delete_tid. This only occurs if the record is historical
414 * was deleted at some point. Realigning the delete_tid does not
415 * move the record within the B-Tree but may cause it to temporarily
416 * overlap a record that has not yet been pruned.
418 if (error
== 0 && realign_del
>= 0) {
419 scan
= &prune
->elms
[realign_del
];
421 delta
= (elm
->leaf
.base
.delete_tid
- scan
->beg_tid
) %
424 error
= hammer_btree_extract(cursor
,
425 HAMMER_CURSOR_GET_LEAF
);
427 hammer_modify_node(cursor
->trans
, cursor
->node
,
428 &elm
->leaf
.base
.delete_tid
,
429 sizeof(elm
->leaf
.base
.delete_tid
));
430 elm
->leaf
.base
.delete_tid
=
431 elm
->leaf
.base
.delete_tid
-
432 delta
+ scan
->mod_tid
;
433 hammer_modify_node_done(cursor
->node
);