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 1.6 2008/06/10 00:40:31 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 check_prune(struct hammer_ioc_prune
*prune
, hammer_btree_elm_t elm
,
48 int *realign_cre
, int *realign_del
);
49 static int realign_prune(struct hammer_ioc_prune
*prune
, hammer_cursor_t cursor
,
50 int realign_cre
, int realign_del
);
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_elm_t elm
;
58 struct hammer_ioc_prune_elm
*copy_elms
;
59 struct hammer_ioc_prune_elm
*user_elms
;
66 if (prune
->nelms
< 0 || prune
->nelms
> HAMMER_MAX_PRUNE_ELMS
)
68 if (prune
->beg_localization
> prune
->end_localization
)
70 if (prune
->beg_localization
== prune
->end_localization
) {
71 if (prune
->beg_obj_id
> prune
->end_obj_id
)
73 /* key-space limitations - no check needed */
75 if ((prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) && prune
->nelms
)
78 prune
->cur_localization
= prune
->end_localization
;
79 prune
->cur_obj_id
= prune
->end_obj_id
;
80 prune
->cur_key
= HAMMER_MAX_KEY
;
83 * Copy element array from userland
85 elm_array_size
= sizeof(*copy_elms
) * prune
->nelms
;
86 user_elms
= prune
->elms
;
87 copy_elms
= kmalloc(elm_array_size
, M_TEMP
, M_WAITOK
);
88 if ((error
= copyin(user_elms
, copy_elms
, elm_array_size
)) != 0)
90 prune
->elms
= copy_elms
;
93 * Scan backwards. Retries typically occur if a deadlock is detected.
96 error
= hammer_init_cursor(trans
, &cursor
, NULL
, NULL
);
98 hammer_done_cursor(&cursor
);
101 cursor
.key_beg
.localization
= prune
->beg_localization
;
102 cursor
.key_beg
.obj_id
= prune
->beg_obj_id
;
103 cursor
.key_beg
.key
= HAMMER_MIN_KEY
;
104 cursor
.key_beg
.create_tid
= 1;
105 cursor
.key_beg
.delete_tid
= 0;
106 cursor
.key_beg
.rec_type
= HAMMER_MIN_RECTYPE
;
107 cursor
.key_beg
.obj_type
= 0;
109 cursor
.key_end
.localization
= prune
->cur_localization
;
110 cursor
.key_end
.obj_id
= prune
->cur_obj_id
;
111 cursor
.key_end
.key
= prune
->cur_key
;
112 cursor
.key_end
.create_tid
= HAMMER_MAX_TID
- 1;
113 cursor
.key_end
.delete_tid
= 0;
114 cursor
.key_end
.rec_type
= HAMMER_MAX_RECTYPE
;
115 cursor
.key_end
.obj_type
= 0;
117 cursor
.flags
|= HAMMER_CURSOR_END_INCLUSIVE
;
118 cursor
.flags
|= HAMMER_CURSOR_BACKEND
;
121 * This flag allows the B-Tree code to clean up loose ends.
123 cursor
.flags
|= HAMMER_CURSOR_PRUNING
;
125 hammer_sync_lock_sh(trans
);
126 error
= hammer_btree_last(&cursor
);
130 * Yield to more important tasks
132 if ((error
= hammer_signal_check(trans
->hmp
)) != 0)
134 if (trans
->hmp
->sync_lock
.wanted
) {
135 hammer_sync_unlock(trans
);
136 tsleep(trans
, 0, "hmrslo", hz
/ 10);
137 hammer_sync_lock_sh(trans
);
139 if (trans
->hmp
->locked_dirty_count
+
140 trans
->hmp
->io_running_count
> hammer_limit_dirtybufs
) {
141 hammer_sync_unlock(trans
);
142 hammer_flusher_async(trans
->hmp
);
143 tsleep(trans
, 0, "hmrslo", hz
/ 10);
144 hammer_sync_lock_sh(trans
);
150 elm
= &cursor
.node
->ondisk
->elms
[cursor
.index
];
151 prune
->cur_localization
= elm
->base
.localization
;
152 prune
->cur_obj_id
= elm
->base
.obj_id
;
153 prune
->cur_key
= elm
->base
.key
;
155 if (prune
->stat_oldest_tid
> elm
->leaf
.base
.create_tid
)
156 prune
->stat_oldest_tid
= elm
->leaf
.base
.create_tid
;
158 if (hammer_debug_general
& 0x0200) {
159 kprintf("check %016llx %016llx cre=%016llx del=%016llx\n",
162 elm
->base
.create_tid
,
163 elm
->base
.delete_tid
);
166 if (check_prune(prune
, elm
, &realign_cre
, &realign_del
) == 0) {
167 if (hammer_debug_general
& 0x0200) {
168 kprintf("check %016llx %016llx: DELETE\n",
169 elm
->base
.obj_id
, elm
->base
.key
);
173 * NOTE: This can return EDEADLK
175 * Acquiring the sync lock guarantees that the
176 * operation will not cross a synchronization
177 * boundary (see the flusher).
179 isdir
= (elm
->base
.rec_type
== HAMMER_RECTYPE_DIRENTRY
);
181 error
= hammer_delete_at_cursor(&cursor
,
187 ++prune
->stat_dirrecords
;
189 ++prune
->stat_rawrecords
;
192 * The current record might now be the one after
193 * the one we deleted, set ATEDISK to force us
194 * to skip it (since we are iterating backwards).
196 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
197 } else if (realign_cre
>= 0 || realign_del
>= 0) {
198 error
= realign_prune(prune
, &cursor
,
199 realign_cre
, realign_del
);
201 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
202 if (hammer_debug_general
& 0x0200) {
203 kprintf("check %016llx %016llx: "
210 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
211 if (hammer_debug_general
& 0x0100) {
212 kprintf("check %016llx %016llx: SKIP\n",
213 elm
->base
.obj_id
, elm
->base
.key
);
216 ++prune
->stat_scanrecords
;
217 error
= hammer_btree_iterate_reverse(&cursor
);
219 hammer_sync_unlock(trans
);
222 hammer_done_cursor(&cursor
);
223 if (error
== EDEADLK
)
225 if (error
== EINTR
) {
226 prune
->head
.flags
|= HAMMER_IOC_HEAD_INTR
;
230 prune
->elms
= user_elms
;
231 kfree(copy_elms
, M_TEMP
);
236 * Check pruning list. The list must be sorted in descending order.
239 check_prune(struct hammer_ioc_prune
*prune
, hammer_btree_elm_t elm
,
240 int *realign_cre
, int *realign_del
)
242 struct hammer_ioc_prune_elm
*scan
;
249 * If pruning everything remove all records with a non-zero
252 if (prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) {
253 if (elm
->base
.delete_tid
!= 0)
258 for (i
= 0; i
< prune
->nelms
; ++i
) {
259 scan
= &prune
->elms
[i
];
262 * Locate the scan index covering the create and delete TIDs.
264 if (*realign_cre
< 0 &&
265 elm
->base
.create_tid
>= scan
->beg_tid
&&
266 elm
->base
.create_tid
< scan
->end_tid
) {
269 if (*realign_del
< 0 && elm
->base
.delete_tid
&&
270 elm
->base
.delete_tid
> scan
->beg_tid
&&
271 elm
->base
.delete_tid
<= scan
->end_tid
) {
276 * Now check for loop termination.
278 if (elm
->base
.create_tid
>= scan
->end_tid
||
279 elm
->base
.delete_tid
> scan
->end_tid
) {
284 * Now determine if we can delete the record.
286 if (elm
->base
.delete_tid
&&
287 elm
->base
.create_tid
>= scan
->beg_tid
&&
288 elm
->base
.delete_tid
<= scan
->end_tid
&&
289 (elm
->base
.create_tid
- scan
->beg_tid
) / scan
->mod_tid
==
290 (elm
->base
.delete_tid
- scan
->beg_tid
) / scan
->mod_tid
) {
298 * Align the record to cover any gaps created through the deletion of
299 * records within the pruning space. If we were to just delete the records
300 * there would be gaps which in turn would cause a snapshot that is NOT on
301 * a pruning boundary to appear corrupt to the user. Forcing alignment
302 * of the create_tid and delete_tid for retained records 'reconnects'
303 * the previously contiguous space, making it contiguous again after the
306 * The use of a reverse iteration allows us to safely align the records and
307 * related elements without creating temporary overlaps. XXX we should
308 * add ordering dependancies for record buffers to guarantee consistency
312 realign_prune(struct hammer_ioc_prune
*prune
,
313 hammer_cursor_t cursor
, int realign_cre
, int realign_del
)
315 struct hammer_ioc_prune_elm
*scan
;
316 hammer_btree_elm_t elm
;
321 hammer_cursor_downgrade(cursor
);
323 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
];
324 ++prune
->stat_realignments
;
327 * Align the create_tid. By doing a reverse iteration we guarantee
328 * that all records after our current record have already been
329 * aligned, allowing us to safely correct the right-hand-boundary
330 * (because no record to our right is otherwise exactly matching
331 * will have a create_tid to the left of our aligned create_tid).
334 if (realign_cre
>= 0) {
335 scan
= &prune
->elms
[realign_cre
];
337 delta
= (elm
->leaf
.base
.create_tid
- scan
->beg_tid
) %
340 tid
= elm
->leaf
.base
.create_tid
- delta
+ scan
->mod_tid
;
343 error
= hammer_btree_correct_rhb(cursor
, tid
+ 1);
345 error
= hammer_btree_extract(cursor
,
346 HAMMER_CURSOR_GET_LEAF
);
350 error
= hammer_cursor_upgrade(cursor
);
353 hammer_modify_node(cursor
->trans
, cursor
->node
,
354 &elm
->leaf
.base
.create_tid
,
355 sizeof(elm
->leaf
.base
.create_tid
));
356 elm
->leaf
.base
.create_tid
= tid
;
357 hammer_modify_node_done(cursor
->node
);
363 * Align the delete_tid. This only occurs if the record is historical
364 * was deleted at some point. Realigning the delete_tid does not
365 * move the record within the B-Tree but may cause it to temporarily
366 * overlap a record that has not yet been pruned.
368 if (error
== 0 && realign_del
>= 0) {
369 scan
= &prune
->elms
[realign_del
];
371 delta
= (elm
->leaf
.base
.delete_tid
- scan
->beg_tid
) %
374 error
= hammer_btree_extract(cursor
,
375 HAMMER_CURSOR_GET_LEAF
);
377 hammer_modify_node(cursor
->trans
, cursor
->node
,
378 &elm
->leaf
.base
.delete_tid
,
379 sizeof(elm
->leaf
.base
.delete_tid
));
380 elm
->leaf
.base
.delete_tid
=
381 elm
->leaf
.base
.delete_tid
-
382 delta
+ scan
->mod_tid
;
383 hammer_modify_node_done(cursor
->node
);