blob: 18176d0b75d775901268e038f621765a56d54752 [file] [log] [blame]
David Teiglandb3b94fa2006-01-16 16:50:04 +00001/*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
Bob Peterson091806ed2008-04-29 12:35:48 -05003 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
David Teiglandb3b94fa2006-01-16 16:50:04 +00004 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
Steven Whitehousee9fc2aa2006-09-01 11:05:15 -04007 * of the GNU General Public License version 2.
David Teiglandb3b94fa2006-01-16 16:50:04 +00008 */
9
10#include <linux/sched.h>
11#include <linux/slab.h>
12#include <linux/spinlock.h>
13#include <linux/completion.h>
14#include <linux/buffer_head.h>
15#include <linux/mm.h>
16#include <linux/pagemap.h>
17#include <linux/writeback.h>
18#include <linux/swap.h>
19#include <linux/delay.h>
Steven Whitehouse2e565bb2006-10-02 11:38:25 -040020#include <linux/bio.h>
Steven Whitehouse5c676f62006-02-27 17:23:27 -050021#include <linux/gfs2_ondisk.h>
David Teiglandb3b94fa2006-01-16 16:50:04 +000022
23#include "gfs2.h"
Steven Whitehouse5c676f62006-02-27 17:23:27 -050024#include "incore.h"
David Teiglandb3b94fa2006-01-16 16:50:04 +000025#include "glock.h"
26#include "glops.h"
27#include "inode.h"
28#include "log.h"
29#include "lops.h"
30#include "meta_io.h"
31#include "rgrp.h"
32#include "trans.h"
Steven Whitehouse5c676f62006-02-27 17:23:27 -050033#include "util.h"
David Teiglandb3b94fa2006-01-16 16:50:04 +000034
Steven Whitehouse4a0f9a32009-04-20 08:16:26 +010035static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc)
David Teiglandb3b94fa2006-01-16 16:50:04 +000036{
Steven Whitehouse4a0f9a32009-04-20 08:16:26 +010037 struct buffer_head *bh, *head;
38 int nr_underway = 0;
39 int write_op = (1 << BIO_RW_META) | ((wbc->sync_mode == WB_SYNC_ALL ?
40 WRITE_SYNC_PLUG : WRITE));
David Teiglandb3b94fa2006-01-16 16:50:04 +000041
Steven Whitehouse4a0f9a32009-04-20 08:16:26 +010042 BUG_ON(!PageLocked(page));
43 BUG_ON(!page_has_buffers(page));
44
45 head = page_buffers(page);
46 bh = head;
47
48 do {
49 if (!buffer_mapped(bh))
50 continue;
51 /*
52 * If it's a fully non-blocking write attempt and we cannot
53 * lock the buffer then redirty the page. Note that this can
54 * potentially cause a busy-wait loop from pdflush and kswapd
55 * activity, but those code paths have their own higher-level
56 * throttling.
57 */
58 if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
59 lock_buffer(bh);
60 } else if (!trylock_buffer(bh)) {
61 redirty_page_for_writepage(wbc, page);
62 continue;
63 }
64 if (test_clear_buffer_dirty(bh)) {
65 mark_buffer_async_write(bh);
66 } else {
67 unlock_buffer(bh);
68 }
69 } while ((bh = bh->b_this_page) != head);
70
71 /*
72 * The page and its buffers are protected by PageWriteback(), so we can
73 * drop the bh refcounts early.
74 */
75 BUG_ON(PageWriteback(page));
76 set_page_writeback(page);
77
78 do {
79 struct buffer_head *next = bh->b_this_page;
80 if (buffer_async_write(bh)) {
81 submit_bh(write_op, bh);
82 nr_underway++;
83 }
84 bh = next;
85 } while (bh != head);
86 unlock_page(page);
87
Steven Whitehouse4a0f9a32009-04-20 08:16:26 +010088 if (nr_underway == 0)
89 end_page_writeback(page);
90
Bob Petersoneaefbf92010-05-11 17:35:34 -040091 return 0;
David Teiglandb3b94fa2006-01-16 16:50:04 +000092}
93
Steven Whitehouse009d8512009-12-08 12:12:13 +000094const struct address_space_operations gfs2_meta_aops = {
David Teiglandb3b94fa2006-01-16 16:50:04 +000095 .writepage = gfs2_aspace_writepage,
Steven Whitehouse4340fe62006-07-11 09:46:33 -040096 .releasepage = gfs2_releasepage,
Steven Whitehouse52d4c742007-11-01 09:34:14 +000097 .sync_page = block_sync_page,
David Teiglandb3b94fa2006-01-16 16:50:04 +000098};
99
100/**
David Teiglandb3b94fa2006-01-16 16:50:04 +0000101 * gfs2_meta_sync - Sync all buffers associated with a glock
102 * @gl: The glock
David Teiglandb3b94fa2006-01-16 16:50:04 +0000103 *
104 */
105
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400106void gfs2_meta_sync(struct gfs2_glock *gl)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000107{
Steven Whitehouse009d8512009-12-08 12:12:13 +0000108 struct address_space *mapping = gfs2_glock2aspace(gl);
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400109 int error;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000110
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400111 filemap_fdatawrite(mapping);
112 error = filemap_fdatawait(mapping);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000113
114 if (error)
115 gfs2_io_error(gl->gl_sbd);
116}
117
118/**
Steven Whitehouse6802e342008-05-21 17:03:22 +0100119 * gfs2_getbuf - Get a buffer with a given address space
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500120 * @gl: the glock
David Teiglandb3b94fa2006-01-16 16:50:04 +0000121 * @blkno: the block number (filesystem scope)
122 * @create: 1 if the buffer should be created
123 *
124 * Returns: the buffer
125 */
126
Steven Whitehouse6802e342008-05-21 17:03:22 +0100127struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000128{
Steven Whitehouse009d8512009-12-08 12:12:13 +0000129 struct address_space *mapping = gfs2_glock2aspace(gl);
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500130 struct gfs2_sbd *sdp = gl->gl_sbd;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000131 struct page *page;
132 struct buffer_head *bh;
133 unsigned int shift;
134 unsigned long index;
135 unsigned int bufnum;
136
137 shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
138 index = blkno >> shift; /* convert block to page */
139 bufnum = blkno - (index << shift); /* block buf index within page */
140
141 if (create) {
142 for (;;) {
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500143 page = grab_cache_page(mapping, index);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000144 if (page)
145 break;
146 yield();
147 }
148 } else {
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500149 page = find_lock_page(mapping, index);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000150 if (!page)
151 return NULL;
152 }
153
154 if (!page_has_buffers(page))
155 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
156
157 /* Locate header for our buffer within our page */
158 for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
159 /* Do nothing */;
160 get_bh(bh);
161
162 if (!buffer_mapped(bh))
163 map_bh(bh, sdp->sd_vfs, blkno);
164
165 unlock_page(page);
166 mark_page_accessed(page);
167 page_cache_release(page);
168
169 return bh;
170}
171
172static void meta_prep_new(struct buffer_head *bh)
173{
174 struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
175
176 lock_buffer(bh);
177 clear_buffer_dirty(bh);
178 set_buffer_uptodate(bh);
179 unlock_buffer(bh);
180
181 mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
182}
183
184/**
185 * gfs2_meta_new - Get a block
186 * @gl: The glock associated with this block
187 * @blkno: The block number
188 *
189 * Returns: The buffer
190 */
191
Steven Whitehousecd915492006-09-04 12:49:07 -0400192struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000193{
194 struct buffer_head *bh;
Steven Whitehouse6802e342008-05-21 17:03:22 +0100195 bh = gfs2_getbuf(gl, blkno, CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000196 meta_prep_new(bh);
197 return bh;
198}
199
200/**
201 * gfs2_meta_read - Read a block from disk
202 * @gl: The glock covering the block
203 * @blkno: The block number
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400204 * @flags: flags
David Teiglandb3b94fa2006-01-16 16:50:04 +0000205 * @bhp: the place where the buffer is returned (NULL on failure)
206 *
207 * Returns: errno
208 */
209
Steven Whitehousecd915492006-09-04 12:49:07 -0400210int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
David Teiglandb3b94fa2006-01-16 16:50:04 +0000211 struct buffer_head **bhp)
212{
Steven Whitehousec969f58c2009-04-07 14:13:01 +0100213 struct gfs2_sbd *sdp = gl->gl_sbd;
214 struct buffer_head *bh;
215
216 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
217 return -EIO;
218
219 *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
220
221 lock_buffer(bh);
222 if (buffer_uptodate(bh)) {
223 unlock_buffer(bh);
224 return 0;
225 }
226 bh->b_end_io = end_buffer_read_sync;
227 get_bh(bh);
228 submit_bh(READ_SYNC | (1 << BIO_RW_META), bh);
229 if (!(flags & DIO_WAIT))
230 return 0;
231
232 wait_on_buffer(bh);
233 if (unlikely(!buffer_uptodate(bh))) {
234 struct gfs2_trans *tr = current->journal_info;
235 if (tr && tr->tr_touched)
236 gfs2_io_error_bh(sdp, bh);
237 brelse(bh);
238 return -EIO;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400239 }
David Teiglandb3b94fa2006-01-16 16:50:04 +0000240
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400241 return 0;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000242}
243
244/**
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400245 * gfs2_meta_wait - Reread a block from disk
David Teiglandb3b94fa2006-01-16 16:50:04 +0000246 * @sdp: the filesystem
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400247 * @bh: The block to wait for
David Teiglandb3b94fa2006-01-16 16:50:04 +0000248 *
249 * Returns: errno
250 */
251
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400252int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000253{
254 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
255 return -EIO;
256
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400257 wait_on_buffer(bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000258
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400259 if (!buffer_uptodate(bh)) {
260 struct gfs2_trans *tr = current->journal_info;
261 if (tr && tr->tr_touched)
262 gfs2_io_error_bh(sdp, bh);
263 return -EIO;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000264 }
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400265 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
266 return -EIO;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000267
268 return 0;
269}
270
271/**
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000272 * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
David Teiglandb3b94fa2006-01-16 16:50:04 +0000273 * @gl: the glock the buffer belongs to
274 * @bh: The buffer to be attached to
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000275 * @meta: Flag to indicate whether its metadata or not
David Teiglandb3b94fa2006-01-16 16:50:04 +0000276 */
277
Steven Whitehouse568f4c92006-02-27 12:00:42 -0500278void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
279 int meta)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000280{
281 struct gfs2_bufdata *bd;
282
Steven Whitehouse18ec7d52006-02-08 11:50:51 +0000283 if (meta)
284 lock_page(bh->b_page);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000285
Steven Whitehouse5c676f62006-02-27 17:23:27 -0500286 if (bh->b_private) {
Steven Whitehouse18ec7d52006-02-08 11:50:51 +0000287 if (meta)
288 unlock_page(bh->b_page);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000289 return;
290 }
291
Bob Peterson3e5cd082008-01-16 08:45:39 -0600292 bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000293 bd->bd_bh = bh;
294 bd->bd_gl = gl;
295
296 INIT_LIST_HEAD(&bd->bd_list_tr);
Steven Whitehouse82ffa512006-09-04 14:47:06 -0400297 if (meta)
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000298 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
Steven Whitehouse82ffa512006-09-04 14:47:06 -0400299 else
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000300 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
Steven Whitehouse5c676f62006-02-27 17:23:27 -0500301 bh->b_private = bd;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000302
Steven Whitehouse18ec7d52006-02-08 11:50:51 +0000303 if (meta)
304 unlock_page(bh->b_page);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000305}
306
Steven Whitehouse16615be2007-09-17 10:59:52 +0100307void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
308{
Steven Whitehouse009d8512009-12-08 12:12:13 +0000309 struct address_space *mapping = bh->b_page->mapping;
310 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
Steven Whitehouse16615be2007-09-17 10:59:52 +0100311 struct gfs2_bufdata *bd = bh->b_private;
Steven Whitehouse009d8512009-12-08 12:12:13 +0000312
Steven Whitehouse16615be2007-09-17 10:59:52 +0100313 if (test_clear_buffer_pinned(bh)) {
Benjamin Marzinski5e687ea2010-05-04 14:29:16 -0500314 atomic_dec(&sdp->sd_log_pinned);
Steven Whitehouse16615be2007-09-17 10:59:52 +0100315 list_del_init(&bd->bd_le.le_list);
316 if (meta) {
317 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
318 sdp->sd_log_num_buf--;
319 tr->tr_num_buf_rm++;
320 } else {
321 gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
322 sdp->sd_log_num_databuf--;
323 tr->tr_num_databuf_rm++;
324 }
325 tr->tr_touched = 1;
326 brelse(bh);
327 }
328 if (bd) {
329 if (bd->bd_ail) {
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100330 gfs2_remove_from_ail(bd);
Steven Whitehouse16615be2007-09-17 10:59:52 +0100331 bh->b_private = NULL;
332 bd->bd_bh = NULL;
333 bd->bd_blkno = bh->b_blocknr;
334 gfs2_trans_add_revoke(sdp, bd);
335 }
336 }
337 clear_buffer_dirty(bh);
338 clear_buffer_uptodate(bh);
339}
340
David Teiglandb3b94fa2006-01-16 16:50:04 +0000341/**
David Teiglandb3b94fa2006-01-16 16:50:04 +0000342 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
343 * @ip: the inode who owns the buffers
344 * @bstart: the first buffer in the run
345 * @blen: the number of buffers in the run
346 *
347 */
348
Steven Whitehousecd915492006-09-04 12:49:07 -0400349void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000350{
Steven Whitehousefeaa7bb2006-06-14 15:32:57 -0400351 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000352 struct buffer_head *bh;
353
354 while (blen) {
Steven Whitehouse6802e342008-05-21 17:03:22 +0100355 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000356 if (bh) {
Steven Whitehouse1ad38c42007-09-03 11:01:33 +0100357 lock_buffer(bh);
358 gfs2_log_lock(sdp);
Steven Whitehouse16615be2007-09-17 10:59:52 +0100359 gfs2_remove_from_journal(bh, current->journal_info, 1);
Steven Whitehouse1ad38c42007-09-03 11:01:33 +0100360 gfs2_log_unlock(sdp);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000361 unlock_buffer(bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000362 brelse(bh);
363 }
364
365 bstart++;
366 blen--;
367 }
368}
369
370/**
David Teiglandb3b94fa2006-01-16 16:50:04 +0000371 * gfs2_meta_indirect_buffer - Get a metadata buffer
372 * @ip: The GFS2 inode
373 * @height: The level of this buf in the metadata (indir addr) tree (if any)
374 * @num: The block number (device relative) of the buffer
375 * @new: Non-zero if we may create a new buffer
376 * @bhp: the buffer is returned here
377 *
David Teiglandb3b94fa2006-01-16 16:50:04 +0000378 * Returns: errno
379 */
380
Steven Whitehousecd915492006-09-04 12:49:07 -0400381int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
David Teiglandb3b94fa2006-01-16 16:50:04 +0000382 int new, struct buffer_head **bhp)
383{
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400384 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
385 struct gfs2_glock *gl = ip->i_gl;
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100386 struct buffer_head *bh;
387 int ret = 0;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000388
389 if (new) {
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100390 BUG_ON(height == 0);
391 bh = gfs2_meta_new(gl, num);
Steven Whitehoused4e9c4c2006-01-18 11:19:28 +0000392 gfs2_trans_add_bh(ip->i_gl, bh, 1);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000393 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
394 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400395 } else {
396 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100397 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
398 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
399 brelse(bh);
400 ret = -EIO;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400401 }
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400402 }
David Teiglandb3b94fa2006-01-16 16:50:04 +0000403 *bhp = bh;
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100404 return ret;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000405}
406
407/**
408 * gfs2_meta_ra - start readahead on an extent of a file
409 * @gl: the glock the blocks belong to
410 * @dblock: the starting disk block
411 * @extlen: the number of blocks in the extent
412 *
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400413 * returns: the first buffer in the extent
David Teiglandb3b94fa2006-01-16 16:50:04 +0000414 */
415
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400416struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000417{
418 struct gfs2_sbd *sdp = gl->gl_sbd;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000419 struct buffer_head *first_bh, *bh;
Steven Whitehousecd915492006-09-04 12:49:07 -0400420 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
Steven Whitehouse568f4c92006-02-27 12:00:42 -0500421 sdp->sd_sb.sb_bsize_shift;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000422
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400423 BUG_ON(!extlen);
424
425 if (max_ra < 1)
426 max_ra = 1;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000427 if (extlen > max_ra)
428 extlen = max_ra;
429
Steven Whitehouse6802e342008-05-21 17:03:22 +0100430 first_bh = gfs2_getbuf(gl, dblock, CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000431
432 if (buffer_uptodate(first_bh))
433 goto out;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400434 if (!buffer_locked(first_bh))
Steven Whitehousec969f58c2009-04-07 14:13:01 +0100435 ll_rw_block(READ_SYNC | (1 << BIO_RW_META), 1, &first_bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000436
437 dblock++;
438 extlen--;
439
440 while (extlen) {
Steven Whitehouse6802e342008-05-21 17:03:22 +0100441 bh = gfs2_getbuf(gl, dblock, CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000442
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400443 if (!buffer_uptodate(bh) && !buffer_locked(bh))
444 ll_rw_block(READA, 1, &bh);
445 brelse(bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000446 dblock++;
447 extlen--;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400448 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
449 goto out;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000450 }
451
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400452 wait_on_buffer(first_bh);
Steven Whitehousea91ea692006-09-04 12:04:26 -0400453out:
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400454 return first_bh;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000455}
456