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 1.12 2008/07/04 07:25:36 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
;
64 if (prune
->nelms
< 0 || prune
->nelms
> HAMMER_MAX_PRUNE_ELMS
)
66 if ((prune
->key_beg
.localization
| prune
->key_end
.localization
) &
67 HAMMER_LOCALIZE_PSEUDOFS_MASK
) {
70 if (prune
->key_beg
.localization
> prune
->key_end
.localization
)
72 if (prune
->key_beg
.localization
== prune
->key_end
.localization
) {
73 if (prune
->key_beg
.obj_id
> prune
->key_end
.obj_id
)
75 /* key-space limitations - no check needed */
77 if ((prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) && prune
->nelms
)
80 prune
->key_cur
.localization
= prune
->key_end
.localization
+
82 prune
->key_cur
.obj_id
= prune
->key_end
.obj_id
;
83 prune
->key_cur
.key
= HAMMER_MAX_KEY
;
86 * Copy element array from userland
88 elm_array_size
= sizeof(*copy_elms
) * prune
->nelms
;
89 user_elms
= prune
->elms
;
90 copy_elms
= kmalloc(elm_array_size
, M_TEMP
, M_WAITOK
);
91 if ((error
= copyin(user_elms
, copy_elms
, elm_array_size
)) != 0)
93 prune
->elms
= copy_elms
;
96 * Scan backwards. Retries typically occur if a deadlock is detected.
99 error
= hammer_init_cursor(trans
, &cursor
, NULL
, NULL
);
101 hammer_done_cursor(&cursor
);
104 cursor
.key_beg
.localization
= prune
->key_beg
.localization
+
105 ip
->obj_localization
;
106 cursor
.key_beg
.obj_id
= prune
->key_beg
.obj_id
;
107 cursor
.key_beg
.key
= HAMMER_MIN_KEY
;
108 cursor
.key_beg
.create_tid
= 1;
109 cursor
.key_beg
.delete_tid
= 0;
110 cursor
.key_beg
.rec_type
= HAMMER_MIN_RECTYPE
;
111 cursor
.key_beg
.obj_type
= 0;
113 cursor
.key_end
.localization
= prune
->key_cur
.localization
;
114 cursor
.key_end
.obj_id
= prune
->key_cur
.obj_id
;
115 cursor
.key_end
.key
= prune
->key_cur
.key
;
116 cursor
.key_end
.create_tid
= HAMMER_MAX_TID
- 1;
117 cursor
.key_end
.delete_tid
= 0;
118 cursor
.key_end
.rec_type
= HAMMER_MAX_RECTYPE
;
119 cursor
.key_end
.obj_type
= 0;
121 cursor
.flags
|= HAMMER_CURSOR_END_INCLUSIVE
;
122 cursor
.flags
|= HAMMER_CURSOR_BACKEND
;
125 * This flag allows the B-Tree code to clean up loose ends.
127 cursor
.flags
|= HAMMER_CURSOR_PRUNING
;
129 hammer_sync_lock_sh(trans
);
130 error
= hammer_btree_last(&cursor
);
136 elm
= &cursor
.node
->ondisk
->elms
[cursor
.index
].leaf
;
137 prune
->key_cur
= elm
->base
;
140 * Yield to more important tasks
142 if ((error
= hammer_signal_check(trans
->hmp
)) != 0)
144 if (trans
->hmp
->sync_lock
.wanted
) {
145 hammer_sync_unlock(trans
);
146 tsleep(trans
, 0, "hmrslo", hz
/ 10);
147 hammer_sync_lock_sh(trans
);
149 if (hammer_flusher_meta_limit(trans
->hmp
) ||
150 hammer_flusher_undo_exhausted(trans
, 2)) {
155 if (prune
->stat_oldest_tid
> elm
->base
.create_tid
)
156 prune
->stat_oldest_tid
= elm
->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 (prune_should_delete(prune
, elm
)) {
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
,
182 HAMMER_DELETE_DESTROY
,
188 ++prune
->stat_dirrecords
;
190 ++prune
->stat_rawrecords
;
193 * The current record might now be the one after
194 * the one we deleted, set ATEDISK to force us
195 * to skip it (since we are iterating backwards).
197 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
200 * Nothing to delete, but we may have to check other
203 prune_check_nlinks(&cursor
, elm
);
204 cursor
.flags
|= HAMMER_CURSOR_ATEDISK
;
205 if (hammer_debug_general
& 0x0100) {
206 kprintf("check %016llx %016llx: SKIP\n",
207 elm
->base
.obj_id
, elm
->base
.key
);
210 ++prune
->stat_scanrecords
;
211 error
= hammer_btree_iterate_reverse(&cursor
);
213 hammer_sync_unlock(trans
);
216 hammer_done_cursor(&cursor
);
217 if (error
== EWOULDBLOCK
) {
218 hammer_flusher_sync(trans
->hmp
);
221 if (error
== EDEADLK
)
223 if (error
== EINTR
) {
224 prune
->head
.flags
|= HAMMER_IOC_HEAD_INTR
;
228 prune
->key_cur
.localization
&= HAMMER_LOCALIZE_MASK
;
229 prune
->elms
= user_elms
;
230 kfree(copy_elms
, M_TEMP
);
235 * Check pruning list. The list must be sorted in descending order.
237 * Return non-zero if the record should be deleted.
240 prune_should_delete(struct hammer_ioc_prune
*prune
, hammer_btree_leaf_elm_t elm
)
242 struct hammer_ioc_prune_elm
*scan
;
246 * If pruning everything remove all records with a non-zero
249 if (prune
->head
.flags
& HAMMER_IOC_PRUNE_ALL
) {
250 if (elm
->base
.delete_tid
!= 0)
255 for (i
= 0; i
< prune
->nelms
; ++i
) {
256 scan
= &prune
->elms
[i
];
259 * Check for loop termination.
261 if (elm
->base
.create_tid
>= scan
->end_tid
||
262 elm
->base
.delete_tid
> scan
->end_tid
) {
267 * Determine if we can delete the record.
269 if (elm
->base
.delete_tid
&&
270 elm
->base
.create_tid
>= scan
->beg_tid
&&
271 elm
->base
.delete_tid
<= scan
->end_tid
&&
272 (elm
->base
.create_tid
- scan
->beg_tid
) / scan
->mod_tid
==
273 (elm
->base
.delete_tid
- scan
->beg_tid
) / scan
->mod_tid
) {
281 * Dangling inodes can occur if processes are holding open descriptors on
282 * deleted files as-of when a machine crashes. When we find one simply
283 * acquire the inode and release it. The inode handling code will then
284 * do the right thing.
288 prune_check_nlinks(hammer_cursor_t cursor
, hammer_btree_leaf_elm_t elm
)
293 if (elm
->base
.rec_type
!= HAMMER_RECTYPE_INODE
)
295 if (elm
->base
.delete_tid
!= 0)
297 if (hammer_btree_extract(cursor
, HAMMER_CURSOR_GET_DATA
))
299 if (cursor
->data
->inode
.nlinks
)
301 hammer_cursor_downgrade(cursor
);
302 hammer_sync_unlock(cursor
->trans
);
303 ip
= hammer_get_inode(cursor
->trans
, NULL
, elm
->base
.obj_id
,
305 elm
->base
.localization
& HAMMER_LOCALIZE_PSEUDOFS_MASK
,
308 kprintf("pruning disconnected inode %016llx\n",
310 hammer_rel_inode(ip
, 0);
312 kprintf("unable to prune disconnected inode %016llx\n",
315 hammer_sync_lock_sh(cursor
->trans
);
321 * NOTE: THIS CODE HAS BEEN REMOVED! Pruning no longer attempts to realign
322 * adjacent records because it seriously interferes with every
323 * mirroring algorithm I could come up with.
325 * This means that historical accesses beyond the first snapshot
326 * softlink should be on snapshot boundaries only. Historical
327 * accesses from "now" to the first snapshot softlink continue to
330 * NOTE: It also looks like there's a bug in the removed code. It is believed
331 * that create_tid can sometimes get set to 0xffffffffffffffff. Just as
332 * well we no longer try to do this fancy shit. Probably the attempt to
333 * correct the rhb is blowing up the cursor's indexing or addressing mapping.
335 * Align the record to cover any gaps created through the deletion of
336 * records within the pruning space. If we were to just delete the records
337 * there would be gaps which in turn would cause a snapshot that is NOT on
338 * a pruning boundary to appear corrupt to the user. Forcing alignment
339 * of the create_tid and delete_tid for retained records 'reconnects'
340 * the previously contiguous space, making it contiguous again after the
343 * The use of a reverse iteration allows us to safely align the records and
344 * related elements without creating temporary overlaps. XXX we should
345 * add ordering dependancies for record buffers to guarantee consistency
349 realign_prune(struct hammer_ioc_prune
*prune
,
350 hammer_cursor_t cursor
, int realign_cre
, int realign_del
)
352 struct hammer_ioc_prune_elm
*scan
;
353 hammer_btree_elm_t elm
;
358 hammer_cursor_downgrade(cursor
);
360 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
];
361 ++prune
->stat_realignments
;
364 * Align the create_tid. By doing a reverse iteration we guarantee
365 * that all records after our current record have already been
366 * aligned, allowing us to safely correct the right-hand-boundary
367 * (because no record to our right is otherwise exactly matching
368 * will have a create_tid to the left of our aligned create_tid).
371 if (realign_cre
>= 0) {
372 scan
= &prune
->elms
[realign_cre
];
374 delta
= (elm
->leaf
.base
.create_tid
- scan
->beg_tid
) %
377 tid
= elm
->leaf
.base
.create_tid
- delta
+ scan
->mod_tid
;
380 error
= hammer_btree_correct_rhb(cursor
, tid
+ 1);
382 error
= hammer_btree_extract(cursor
,
383 HAMMER_CURSOR_GET_LEAF
);
387 error
= hammer_cursor_upgrade(cursor
);
390 hammer_modify_node(cursor
->trans
, cursor
->node
,
391 &elm
->leaf
.base
.create_tid
,
392 sizeof(elm
->leaf
.base
.create_tid
));
393 elm
->leaf
.base
.create_tid
= tid
;
394 hammer_modify_node_done(cursor
->node
);
400 * Align the delete_tid. This only occurs if the record is historical
401 * was deleted at some point. Realigning the delete_tid does not
402 * move the record within the B-Tree but may cause it to temporarily
403 * overlap a record that has not yet been pruned.
405 if (error
== 0 && realign_del
>= 0) {
406 scan
= &prune
->elms
[realign_del
];
408 delta
= (elm
->leaf
.base
.delete_tid
- scan
->beg_tid
) %
411 error
= hammer_btree_extract(cursor
,
412 HAMMER_CURSOR_GET_LEAF
);
414 hammer_modify_node(cursor
->trans
, cursor
->node
,
415 &elm
->leaf
.base
.delete_tid
,
416 sizeof(elm
->leaf
.base
.delete_tid
));
417 elm
->leaf
.base
.delete_tid
=
418 elm
->leaf
.base
.delete_tid
-
419 delta
+ scan
->mod_tid
;
420 hammer_modify_node_done(cursor
->node
);