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1 /*
2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_log.h"
23 #include "xfs_inum.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_mount.h"
28 #include "xfs_bmap_btree.h"
29 #include "xfs_alloc_btree.h"
30 #include "xfs_ialloc_btree.h"
31 #include "xfs_dinode.h"
32 #include "xfs_inode.h"
33 #include "xfs_buf_item.h"
34 #include "xfs_trans_priv.h"
35 #include "xfs_error.h"
36 #include "xfs_rw.h"
37 #include "xfs_trace.h"
38 
39 /*
40  * Check to see if a buffer matching the given parameters is already
41  * a part of the given transaction.
42  */
43 STATIC struct xfs_buf *
xfs_trans_buf_item_match(struct xfs_trans * tp,struct xfs_buftarg * target,xfs_daddr_t blkno,int len)44 xfs_trans_buf_item_match(
45 	struct xfs_trans	*tp,
46 	struct xfs_buftarg	*target,
47 	xfs_daddr_t		blkno,
48 	int			len)
49 {
50 	struct xfs_log_item_desc *lidp;
51 	struct xfs_buf_log_item	*blip;
52 
53 	len = BBTOB(len);
54 	list_for_each_entry(lidp, &tp->t_items, lid_trans) {
55 		blip = (struct xfs_buf_log_item *)lidp->lid_item;
56 		if (blip->bli_item.li_type == XFS_LI_BUF &&
57 		    blip->bli_buf->b_target == target &&
58 		    XFS_BUF_ADDR(blip->bli_buf) == blkno &&
59 		    XFS_BUF_COUNT(blip->bli_buf) == len)
60 			return blip->bli_buf;
61 	}
62 
63 	return NULL;
64 }
65 
66 /*
67  * Add the locked buffer to the transaction.
68  *
69  * The buffer must be locked, and it cannot be associated with any
70  * transaction.
71  *
72  * If the buffer does not yet have a buf log item associated with it,
73  * then allocate one for it.  Then add the buf item to the transaction.
74  */
75 STATIC void
_xfs_trans_bjoin(struct xfs_trans * tp,struct xfs_buf * bp,int reset_recur)76 _xfs_trans_bjoin(
77 	struct xfs_trans	*tp,
78 	struct xfs_buf		*bp,
79 	int			reset_recur)
80 {
81 	struct xfs_buf_log_item	*bip;
82 
83 	ASSERT(bp->b_transp == NULL);
84 
85 	/*
86 	 * The xfs_buf_log_item pointer is stored in b_fsprivate.  If
87 	 * it doesn't have one yet, then allocate one and initialize it.
88 	 * The checks to see if one is there are in xfs_buf_item_init().
89 	 */
90 	xfs_buf_item_init(bp, tp->t_mountp);
91 	bip = bp->b_fspriv;
92 	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
93 	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));
94 	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
95 	if (reset_recur)
96 		bip->bli_recur = 0;
97 
98 	/*
99 	 * Take a reference for this transaction on the buf item.
100 	 */
101 	atomic_inc(&bip->bli_refcount);
102 
103 	/*
104 	 * Get a log_item_desc to point at the new item.
105 	 */
106 	xfs_trans_add_item(tp, &bip->bli_item);
107 
108 	/*
109 	 * Initialize b_fsprivate2 so we can find it with incore_match()
110 	 * in xfs_trans_get_buf() and friends above.
111 	 */
112 	bp->b_transp = tp;
113 
114 }
115 
116 void
xfs_trans_bjoin(struct xfs_trans * tp,struct xfs_buf * bp)117 xfs_trans_bjoin(
118 	struct xfs_trans	*tp,
119 	struct xfs_buf		*bp)
120 {
121 	_xfs_trans_bjoin(tp, bp, 0);
122 	trace_xfs_trans_bjoin(bp->b_fspriv);
123 }
124 
125 /*
126  * Get and lock the buffer for the caller if it is not already
127  * locked within the given transaction.  If it is already locked
128  * within the transaction, just increment its lock recursion count
129  * and return a pointer to it.
130  *
131  * If the transaction pointer is NULL, make this just a normal
132  * get_buf() call.
133  */
134 xfs_buf_t *
xfs_trans_get_buf(xfs_trans_t * tp,xfs_buftarg_t * target_dev,xfs_daddr_t blkno,int len,uint flags)135 xfs_trans_get_buf(xfs_trans_t	*tp,
136 		  xfs_buftarg_t	*target_dev,
137 		  xfs_daddr_t	blkno,
138 		  int		len,
139 		  uint		flags)
140 {
141 	xfs_buf_t		*bp;
142 	xfs_buf_log_item_t	*bip;
143 
144 	if (flags == 0)
145 		flags = XBF_LOCK | XBF_MAPPED;
146 
147 	/*
148 	 * Default to a normal get_buf() call if the tp is NULL.
149 	 */
150 	if (tp == NULL)
151 		return xfs_buf_get(target_dev, blkno, len,
152 				   flags | XBF_DONT_BLOCK);
153 
154 	/*
155 	 * If we find the buffer in the cache with this transaction
156 	 * pointer in its b_fsprivate2 field, then we know we already
157 	 * have it locked.  In this case we just increment the lock
158 	 * recursion count and return the buffer to the caller.
159 	 */
160 	bp = xfs_trans_buf_item_match(tp, target_dev, blkno, len);
161 	if (bp != NULL) {
162 		ASSERT(xfs_buf_islocked(bp));
163 		if (XFS_FORCED_SHUTDOWN(tp->t_mountp)) {
164 			xfs_buf_stale(bp);
165 			XFS_BUF_DONE(bp);
166 		}
167 
168 		/*
169 		 * If the buffer is stale then it was binval'ed
170 		 * since last read.  This doesn't matter since the
171 		 * caller isn't allowed to use the data anyway.
172 		 */
173 		else if (XFS_BUF_ISSTALE(bp))
174 			ASSERT(!XFS_BUF_ISDELAYWRITE(bp));
175 
176 		ASSERT(bp->b_transp == tp);
177 		bip = bp->b_fspriv;
178 		ASSERT(bip != NULL);
179 		ASSERT(atomic_read(&bip->bli_refcount) > 0);
180 		bip->bli_recur++;
181 		trace_xfs_trans_get_buf_recur(bip);
182 		return (bp);
183 	}
184 
185 	/*
186 	 * We always specify the XBF_DONT_BLOCK flag within a transaction
187 	 * so that get_buf does not try to push out a delayed write buffer
188 	 * which might cause another transaction to take place (if the
189 	 * buffer was delayed alloc).  Such recursive transactions can
190 	 * easily deadlock with our current transaction as well as cause
191 	 * us to run out of stack space.
192 	 */
193 	bp = xfs_buf_get(target_dev, blkno, len, flags | XBF_DONT_BLOCK);
194 	if (bp == NULL) {
195 		return NULL;
196 	}
197 
198 	ASSERT(!bp->b_error);
199 
200 	_xfs_trans_bjoin(tp, bp, 1);
201 	trace_xfs_trans_get_buf(bp->b_fspriv);
202 	return (bp);
203 }
204 
205 /*
206  * Get and lock the superblock buffer of this file system for the
207  * given transaction.
208  *
209  * We don't need to use incore_match() here, because the superblock
210  * buffer is a private buffer which we keep a pointer to in the
211  * mount structure.
212  */
213 xfs_buf_t *
xfs_trans_getsb(xfs_trans_t * tp,struct xfs_mount * mp,int flags)214 xfs_trans_getsb(xfs_trans_t	*tp,
215 		struct xfs_mount *mp,
216 		int		flags)
217 {
218 	xfs_buf_t		*bp;
219 	xfs_buf_log_item_t	*bip;
220 
221 	/*
222 	 * Default to just trying to lock the superblock buffer
223 	 * if tp is NULL.
224 	 */
225 	if (tp == NULL) {
226 		return (xfs_getsb(mp, flags));
227 	}
228 
229 	/*
230 	 * If the superblock buffer already has this transaction
231 	 * pointer in its b_fsprivate2 field, then we know we already
232 	 * have it locked.  In this case we just increment the lock
233 	 * recursion count and return the buffer to the caller.
234 	 */
235 	bp = mp->m_sb_bp;
236 	if (bp->b_transp == tp) {
237 		bip = bp->b_fspriv;
238 		ASSERT(bip != NULL);
239 		ASSERT(atomic_read(&bip->bli_refcount) > 0);
240 		bip->bli_recur++;
241 		trace_xfs_trans_getsb_recur(bip);
242 		return (bp);
243 	}
244 
245 	bp = xfs_getsb(mp, flags);
246 	if (bp == NULL)
247 		return NULL;
248 
249 	_xfs_trans_bjoin(tp, bp, 1);
250 	trace_xfs_trans_getsb(bp->b_fspriv);
251 	return (bp);
252 }
253 
254 #ifdef DEBUG
255 xfs_buftarg_t *xfs_error_target;
256 int	xfs_do_error;
257 int	xfs_req_num;
258 int	xfs_error_mod = 33;
259 #endif
260 
261 /*
262  * Get and lock the buffer for the caller if it is not already
263  * locked within the given transaction.  If it has not yet been
264  * read in, read it from disk. If it is already locked
265  * within the transaction and already read in, just increment its
266  * lock recursion count and return a pointer to it.
267  *
268  * If the transaction pointer is NULL, make this just a normal
269  * read_buf() call.
270  */
271 int
xfs_trans_read_buf(xfs_mount_t * mp,xfs_trans_t * tp,xfs_buftarg_t * target,xfs_daddr_t blkno,int len,uint flags,xfs_buf_t ** bpp)272 xfs_trans_read_buf(
273 	xfs_mount_t	*mp,
274 	xfs_trans_t	*tp,
275 	xfs_buftarg_t	*target,
276 	xfs_daddr_t	blkno,
277 	int		len,
278 	uint		flags,
279 	xfs_buf_t	**bpp)
280 {
281 	xfs_buf_t		*bp;
282 	xfs_buf_log_item_t	*bip;
283 	int			error;
284 
285 	if (flags == 0)
286 		flags = XBF_LOCK | XBF_MAPPED;
287 
288 	/*
289 	 * Default to a normal get_buf() call if the tp is NULL.
290 	 */
291 	if (tp == NULL) {
292 		bp = xfs_buf_read(target, blkno, len, flags | XBF_DONT_BLOCK);
293 		if (!bp)
294 			return (flags & XBF_TRYLOCK) ?
295 					EAGAIN : XFS_ERROR(ENOMEM);
296 
297 		if (bp->b_error) {
298 			error = bp->b_error;
299 			xfs_buf_ioerror_alert(bp, __func__);
300 			xfs_buf_relse(bp);
301 			return error;
302 		}
303 #ifdef DEBUG
304 		if (xfs_do_error) {
305 			if (xfs_error_target == target) {
306 				if (((xfs_req_num++) % xfs_error_mod) == 0) {
307 					xfs_buf_relse(bp);
308 					xfs_debug(mp, "Returning error!");
309 					return XFS_ERROR(EIO);
310 				}
311 			}
312 		}
313 #endif
314 		if (XFS_FORCED_SHUTDOWN(mp))
315 			goto shutdown_abort;
316 		*bpp = bp;
317 		return 0;
318 	}
319 
320 	/*
321 	 * If we find the buffer in the cache with this transaction
322 	 * pointer in its b_fsprivate2 field, then we know we already
323 	 * have it locked.  If it is already read in we just increment
324 	 * the lock recursion count and return the buffer to the caller.
325 	 * If the buffer is not yet read in, then we read it in, increment
326 	 * the lock recursion count, and return it to the caller.
327 	 */
328 	bp = xfs_trans_buf_item_match(tp, target, blkno, len);
329 	if (bp != NULL) {
330 		ASSERT(xfs_buf_islocked(bp));
331 		ASSERT(bp->b_transp == tp);
332 		ASSERT(bp->b_fspriv != NULL);
333 		ASSERT(!bp->b_error);
334 		if (!(XFS_BUF_ISDONE(bp))) {
335 			trace_xfs_trans_read_buf_io(bp, _RET_IP_);
336 			ASSERT(!XFS_BUF_ISASYNC(bp));
337 			XFS_BUF_READ(bp);
338 			xfsbdstrat(tp->t_mountp, bp);
339 			error = xfs_buf_iowait(bp);
340 			if (error) {
341 				xfs_buf_ioerror_alert(bp, __func__);
342 				xfs_buf_relse(bp);
343 				/*
344 				 * We can gracefully recover from most read
345 				 * errors. Ones we can't are those that happen
346 				 * after the transaction's already dirty.
347 				 */
348 				if (tp->t_flags & XFS_TRANS_DIRTY)
349 					xfs_force_shutdown(tp->t_mountp,
350 							SHUTDOWN_META_IO_ERROR);
351 				return error;
352 			}
353 		}
354 		/*
355 		 * We never locked this buf ourselves, so we shouldn't
356 		 * brelse it either. Just get out.
357 		 */
358 		if (XFS_FORCED_SHUTDOWN(mp)) {
359 			trace_xfs_trans_read_buf_shut(bp, _RET_IP_);
360 			*bpp = NULL;
361 			return XFS_ERROR(EIO);
362 		}
363 
364 
365 		bip = bp->b_fspriv;
366 		bip->bli_recur++;
367 
368 		ASSERT(atomic_read(&bip->bli_refcount) > 0);
369 		trace_xfs_trans_read_buf_recur(bip);
370 		*bpp = bp;
371 		return 0;
372 	}
373 
374 	/*
375 	 * We always specify the XBF_DONT_BLOCK flag within a transaction
376 	 * so that get_buf does not try to push out a delayed write buffer
377 	 * which might cause another transaction to take place (if the
378 	 * buffer was delayed alloc).  Such recursive transactions can
379 	 * easily deadlock with our current transaction as well as cause
380 	 * us to run out of stack space.
381 	 */
382 	bp = xfs_buf_read(target, blkno, len, flags | XBF_DONT_BLOCK);
383 	if (bp == NULL) {
384 		*bpp = NULL;
385 		return (flags & XBF_TRYLOCK) ?
386 					0 : XFS_ERROR(ENOMEM);
387 	}
388 	if (bp->b_error) {
389 		error = bp->b_error;
390 		xfs_buf_stale(bp);
391 		XFS_BUF_DONE(bp);
392 		xfs_buf_ioerror_alert(bp, __func__);
393 		if (tp->t_flags & XFS_TRANS_DIRTY)
394 			xfs_force_shutdown(tp->t_mountp, SHUTDOWN_META_IO_ERROR);
395 		xfs_buf_relse(bp);
396 		return error;
397 	}
398 #ifdef DEBUG
399 	if (xfs_do_error && !(tp->t_flags & XFS_TRANS_DIRTY)) {
400 		if (xfs_error_target == target) {
401 			if (((xfs_req_num++) % xfs_error_mod) == 0) {
402 				xfs_force_shutdown(tp->t_mountp,
403 						   SHUTDOWN_META_IO_ERROR);
404 				xfs_buf_relse(bp);
405 				xfs_debug(mp, "Returning trans error!");
406 				return XFS_ERROR(EIO);
407 			}
408 		}
409 	}
410 #endif
411 	if (XFS_FORCED_SHUTDOWN(mp))
412 		goto shutdown_abort;
413 
414 	_xfs_trans_bjoin(tp, bp, 1);
415 	trace_xfs_trans_read_buf(bp->b_fspriv);
416 
417 	*bpp = bp;
418 	return 0;
419 
420 shutdown_abort:
421 	/*
422 	 * the theory here is that buffer is good but we're
423 	 * bailing out because the filesystem is being forcibly
424 	 * shut down.  So we should leave the b_flags alone since
425 	 * the buffer's not staled and just get out.
426 	 */
427 #if defined(DEBUG)
428 	if (XFS_BUF_ISSTALE(bp) && XFS_BUF_ISDELAYWRITE(bp))
429 		xfs_notice(mp, "about to pop assert, bp == 0x%p", bp);
430 #endif
431 	ASSERT((bp->b_flags & (XBF_STALE|XBF_DELWRI)) !=
432 				     (XBF_STALE|XBF_DELWRI));
433 
434 	trace_xfs_trans_read_buf_shut(bp, _RET_IP_);
435 	xfs_buf_relse(bp);
436 	*bpp = NULL;
437 	return XFS_ERROR(EIO);
438 }
439 
440 
441 /*
442  * Release the buffer bp which was previously acquired with one of the
443  * xfs_trans_... buffer allocation routines if the buffer has not
444  * been modified within this transaction.  If the buffer is modified
445  * within this transaction, do decrement the recursion count but do
446  * not release the buffer even if the count goes to 0.  If the buffer is not
447  * modified within the transaction, decrement the recursion count and
448  * release the buffer if the recursion count goes to 0.
449  *
450  * If the buffer is to be released and it was not modified before
451  * this transaction began, then free the buf_log_item associated with it.
452  *
453  * If the transaction pointer is NULL, make this just a normal
454  * brelse() call.
455  */
456 void
xfs_trans_brelse(xfs_trans_t * tp,xfs_buf_t * bp)457 xfs_trans_brelse(xfs_trans_t	*tp,
458 		 xfs_buf_t	*bp)
459 {
460 	xfs_buf_log_item_t	*bip;
461 
462 	/*
463 	 * Default to a normal brelse() call if the tp is NULL.
464 	 */
465 	if (tp == NULL) {
466 		ASSERT(bp->b_transp == NULL);
467 		xfs_buf_relse(bp);
468 		return;
469 	}
470 
471 	ASSERT(bp->b_transp == tp);
472 	bip = bp->b_fspriv;
473 	ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
474 	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
475 	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));
476 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
477 
478 	trace_xfs_trans_brelse(bip);
479 
480 	/*
481 	 * If the release is just for a recursive lock,
482 	 * then decrement the count and return.
483 	 */
484 	if (bip->bli_recur > 0) {
485 		bip->bli_recur--;
486 		return;
487 	}
488 
489 	/*
490 	 * If the buffer is dirty within this transaction, we can't
491 	 * release it until we commit.
492 	 */
493 	if (bip->bli_item.li_desc->lid_flags & XFS_LID_DIRTY)
494 		return;
495 
496 	/*
497 	 * If the buffer has been invalidated, then we can't release
498 	 * it until the transaction commits to disk unless it is re-dirtied
499 	 * as part of this transaction.  This prevents us from pulling
500 	 * the item from the AIL before we should.
501 	 */
502 	if (bip->bli_flags & XFS_BLI_STALE)
503 		return;
504 
505 	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
506 
507 	/*
508 	 * Free up the log item descriptor tracking the released item.
509 	 */
510 	xfs_trans_del_item(&bip->bli_item);
511 
512 	/*
513 	 * Clear the hold flag in the buf log item if it is set.
514 	 * We wouldn't want the next user of the buffer to
515 	 * get confused.
516 	 */
517 	if (bip->bli_flags & XFS_BLI_HOLD) {
518 		bip->bli_flags &= ~XFS_BLI_HOLD;
519 	}
520 
521 	/*
522 	 * Drop our reference to the buf log item.
523 	 */
524 	atomic_dec(&bip->bli_refcount);
525 
526 	/*
527 	 * If the buf item is not tracking data in the log, then
528 	 * we must free it before releasing the buffer back to the
529 	 * free pool.  Before releasing the buffer to the free pool,
530 	 * clear the transaction pointer in b_fsprivate2 to dissolve
531 	 * its relation to this transaction.
532 	 */
533 	if (!xfs_buf_item_dirty(bip)) {
534 /***
535 		ASSERT(bp->b_pincount == 0);
536 ***/
537 		ASSERT(atomic_read(&bip->bli_refcount) == 0);
538 		ASSERT(!(bip->bli_item.li_flags & XFS_LI_IN_AIL));
539 		ASSERT(!(bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF));
540 		xfs_buf_item_relse(bp);
541 	}
542 
543 	bp->b_transp = NULL;
544 	xfs_buf_relse(bp);
545 }
546 
547 /*
548  * Mark the buffer as not needing to be unlocked when the buf item's
549  * IOP_UNLOCK() routine is called.  The buffer must already be locked
550  * and associated with the given transaction.
551  */
552 /* ARGSUSED */
553 void
xfs_trans_bhold(xfs_trans_t * tp,xfs_buf_t * bp)554 xfs_trans_bhold(xfs_trans_t	*tp,
555 		xfs_buf_t	*bp)
556 {
557 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
558 
559 	ASSERT(bp->b_transp == tp);
560 	ASSERT(bip != NULL);
561 	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
562 	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));
563 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
564 
565 	bip->bli_flags |= XFS_BLI_HOLD;
566 	trace_xfs_trans_bhold(bip);
567 }
568 
569 /*
570  * Cancel the previous buffer hold request made on this buffer
571  * for this transaction.
572  */
573 void
xfs_trans_bhold_release(xfs_trans_t * tp,xfs_buf_t * bp)574 xfs_trans_bhold_release(xfs_trans_t	*tp,
575 			xfs_buf_t	*bp)
576 {
577 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
578 
579 	ASSERT(bp->b_transp == tp);
580 	ASSERT(bip != NULL);
581 	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
582 	ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_CANCEL));
583 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
584 	ASSERT(bip->bli_flags & XFS_BLI_HOLD);
585 
586 	bip->bli_flags &= ~XFS_BLI_HOLD;
587 	trace_xfs_trans_bhold_release(bip);
588 }
589 
590 /*
591  * This is called to mark bytes first through last inclusive of the given
592  * buffer as needing to be logged when the transaction is committed.
593  * The buffer must already be associated with the given transaction.
594  *
595  * First and last are numbers relative to the beginning of this buffer,
596  * so the first byte in the buffer is numbered 0 regardless of the
597  * value of b_blkno.
598  */
599 void
xfs_trans_log_buf(xfs_trans_t * tp,xfs_buf_t * bp,uint first,uint last)600 xfs_trans_log_buf(xfs_trans_t	*tp,
601 		  xfs_buf_t	*bp,
602 		  uint		first,
603 		  uint		last)
604 {
605 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
606 
607 	ASSERT(bp->b_transp == tp);
608 	ASSERT(bip != NULL);
609 	ASSERT((first <= last) && (last < XFS_BUF_COUNT(bp)));
610 	ASSERT(bp->b_iodone == NULL ||
611 	       bp->b_iodone == xfs_buf_iodone_callbacks);
612 
613 	/*
614 	 * Mark the buffer as needing to be written out eventually,
615 	 * and set its iodone function to remove the buffer's buf log
616 	 * item from the AIL and free it when the buffer is flushed
617 	 * to disk.  See xfs_buf_attach_iodone() for more details
618 	 * on li_cb and xfs_buf_iodone_callbacks().
619 	 * If we end up aborting this transaction, we trap this buffer
620 	 * inside the b_bdstrat callback so that this won't get written to
621 	 * disk.
622 	 */
623 	XFS_BUF_DONE(bp);
624 
625 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
626 	bp->b_iodone = xfs_buf_iodone_callbacks;
627 	bip->bli_item.li_cb = xfs_buf_iodone;
628 
629 	xfs_buf_delwri_queue(bp);
630 
631 	trace_xfs_trans_log_buf(bip);
632 
633 	/*
634 	 * If we invalidated the buffer within this transaction, then
635 	 * cancel the invalidation now that we're dirtying the buffer
636 	 * again.  There are no races with the code in xfs_buf_item_unpin(),
637 	 * because we have a reference to the buffer this entire time.
638 	 */
639 	if (bip->bli_flags & XFS_BLI_STALE) {
640 		bip->bli_flags &= ~XFS_BLI_STALE;
641 		ASSERT(XFS_BUF_ISSTALE(bp));
642 		XFS_BUF_UNSTALE(bp);
643 		bip->bli_format.blf_flags &= ~XFS_BLF_CANCEL;
644 	}
645 
646 	tp->t_flags |= XFS_TRANS_DIRTY;
647 	bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY;
648 	bip->bli_flags |= XFS_BLI_LOGGED;
649 	xfs_buf_item_log(bip, first, last);
650 }
651 
652 
653 /*
654  * This called to invalidate a buffer that is being used within
655  * a transaction.  Typically this is because the blocks in the
656  * buffer are being freed, so we need to prevent it from being
657  * written out when we're done.  Allowing it to be written again
658  * might overwrite data in the free blocks if they are reallocated
659  * to a file.
660  *
661  * We prevent the buffer from being written out by clearing the
662  * B_DELWRI flag.  We can't always
663  * get rid of the buf log item at this point, though, because
664  * the buffer may still be pinned by another transaction.  If that
665  * is the case, then we'll wait until the buffer is committed to
666  * disk for the last time (we can tell by the ref count) and
667  * free it in xfs_buf_item_unpin().  Until it is cleaned up we
668  * will keep the buffer locked so that the buffer and buf log item
669  * are not reused.
670  */
671 void
xfs_trans_binval(xfs_trans_t * tp,xfs_buf_t * bp)672 xfs_trans_binval(
673 	xfs_trans_t	*tp,
674 	xfs_buf_t	*bp)
675 {
676 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
677 
678 	ASSERT(bp->b_transp == tp);
679 	ASSERT(bip != NULL);
680 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
681 
682 	trace_xfs_trans_binval(bip);
683 
684 	if (bip->bli_flags & XFS_BLI_STALE) {
685 		/*
686 		 * If the buffer is already invalidated, then
687 		 * just return.
688 		 */
689 		ASSERT(!(XFS_BUF_ISDELAYWRITE(bp)));
690 		ASSERT(XFS_BUF_ISSTALE(bp));
691 		ASSERT(!(bip->bli_flags & (XFS_BLI_LOGGED | XFS_BLI_DIRTY)));
692 		ASSERT(!(bip->bli_format.blf_flags & XFS_BLF_INODE_BUF));
693 		ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL);
694 		ASSERT(bip->bli_item.li_desc->lid_flags & XFS_LID_DIRTY);
695 		ASSERT(tp->t_flags & XFS_TRANS_DIRTY);
696 		return;
697 	}
698 
699 	/*
700 	 * Clear the dirty bit in the buffer and set the STALE flag
701 	 * in the buf log item.  The STALE flag will be used in
702 	 * xfs_buf_item_unpin() to determine if it should clean up
703 	 * when the last reference to the buf item is given up.
704 	 * We set the XFS_BLF_CANCEL flag in the buf log format structure
705 	 * and log the buf item.  This will be used at recovery time
706 	 * to determine that copies of the buffer in the log before
707 	 * this should not be replayed.
708 	 * We mark the item descriptor and the transaction dirty so
709 	 * that we'll hold the buffer until after the commit.
710 	 *
711 	 * Since we're invalidating the buffer, we also clear the state
712 	 * about which parts of the buffer have been logged.  We also
713 	 * clear the flag indicating that this is an inode buffer since
714 	 * the data in the buffer will no longer be valid.
715 	 *
716 	 * We set the stale bit in the buffer as well since we're getting
717 	 * rid of it.
718 	 */
719 	xfs_buf_stale(bp);
720 	bip->bli_flags |= XFS_BLI_STALE;
721 	bip->bli_flags &= ~(XFS_BLI_INODE_BUF | XFS_BLI_LOGGED | XFS_BLI_DIRTY);
722 	bip->bli_format.blf_flags &= ~XFS_BLF_INODE_BUF;
723 	bip->bli_format.blf_flags |= XFS_BLF_CANCEL;
724 	memset((char *)(bip->bli_format.blf_data_map), 0,
725 	      (bip->bli_format.blf_map_size * sizeof(uint)));
726 	bip->bli_item.li_desc->lid_flags |= XFS_LID_DIRTY;
727 	tp->t_flags |= XFS_TRANS_DIRTY;
728 }
729 
730 /*
731  * This call is used to indicate that the buffer contains on-disk inodes which
732  * must be handled specially during recovery.  They require special handling
733  * because only the di_next_unlinked from the inodes in the buffer should be
734  * recovered.  The rest of the data in the buffer is logged via the inodes
735  * themselves.
736  *
737  * All we do is set the XFS_BLI_INODE_BUF flag in the items flags so it can be
738  * transferred to the buffer's log format structure so that we'll know what to
739  * do at recovery time.
740  */
741 void
xfs_trans_inode_buf(xfs_trans_t * tp,xfs_buf_t * bp)742 xfs_trans_inode_buf(
743 	xfs_trans_t	*tp,
744 	xfs_buf_t	*bp)
745 {
746 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
747 
748 	ASSERT(bp->b_transp == tp);
749 	ASSERT(bip != NULL);
750 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
751 
752 	bip->bli_flags |= XFS_BLI_INODE_BUF;
753 }
754 
755 /*
756  * This call is used to indicate that the buffer is going to
757  * be staled and was an inode buffer. This means it gets
758  * special processing during unpin - where any inodes
759  * associated with the buffer should be removed from ail.
760  * There is also special processing during recovery,
761  * any replay of the inodes in the buffer needs to be
762  * prevented as the buffer may have been reused.
763  */
764 void
xfs_trans_stale_inode_buf(xfs_trans_t * tp,xfs_buf_t * bp)765 xfs_trans_stale_inode_buf(
766 	xfs_trans_t	*tp,
767 	xfs_buf_t	*bp)
768 {
769 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
770 
771 	ASSERT(bp->b_transp == tp);
772 	ASSERT(bip != NULL);
773 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
774 
775 	bip->bli_flags |= XFS_BLI_STALE_INODE;
776 	bip->bli_item.li_cb = xfs_buf_iodone;
777 }
778 
779 /*
780  * Mark the buffer as being one which contains newly allocated
781  * inodes.  We need to make sure that even if this buffer is
782  * relogged as an 'inode buf' we still recover all of the inode
783  * images in the face of a crash.  This works in coordination with
784  * xfs_buf_item_committed() to ensure that the buffer remains in the
785  * AIL at its original location even after it has been relogged.
786  */
787 /* ARGSUSED */
788 void
xfs_trans_inode_alloc_buf(xfs_trans_t * tp,xfs_buf_t * bp)789 xfs_trans_inode_alloc_buf(
790 	xfs_trans_t	*tp,
791 	xfs_buf_t	*bp)
792 {
793 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
794 
795 	ASSERT(bp->b_transp == tp);
796 	ASSERT(bip != NULL);
797 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
798 
799 	bip->bli_flags |= XFS_BLI_INODE_ALLOC_BUF;
800 }
801 
802 
803 /*
804  * Similar to xfs_trans_inode_buf(), this marks the buffer as a cluster of
805  * dquots. However, unlike in inode buffer recovery, dquot buffers get
806  * recovered in their entirety. (Hence, no XFS_BLI_DQUOT_ALLOC_BUF flag).
807  * The only thing that makes dquot buffers different from regular
808  * buffers is that we must not replay dquot bufs when recovering
809  * if a _corresponding_ quotaoff has happened. We also have to distinguish
810  * between usr dquot bufs and grp dquot bufs, because usr and grp quotas
811  * can be turned off independently.
812  */
813 /* ARGSUSED */
814 void
xfs_trans_dquot_buf(xfs_trans_t * tp,xfs_buf_t * bp,uint type)815 xfs_trans_dquot_buf(
816 	xfs_trans_t	*tp,
817 	xfs_buf_t	*bp,
818 	uint		type)
819 {
820 	xfs_buf_log_item_t	*bip = bp->b_fspriv;
821 
822 	ASSERT(bp->b_transp == tp);
823 	ASSERT(bip != NULL);
824 	ASSERT(type == XFS_BLF_UDQUOT_BUF ||
825 	       type == XFS_BLF_PDQUOT_BUF ||
826 	       type == XFS_BLF_GDQUOT_BUF);
827 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
828 
829 	bip->bli_format.blf_flags |= type;
830 }
831