blob: 09853620c95121ecd0b2f8b4dd05397eef969e1d [file] [log] [blame]
David Teiglandb3b94fa2006-01-16 16:50:04 +00001/*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
Bob Peterson091806e2008-04-29 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>
Fabio Massimo Di Nitto7d308592006-09-19 07:56:29 +020022#include <linux/lm_interface.h>
David Teiglandb3b94fa2006-01-16 16:50:04 +000023
24#include "gfs2.h"
Steven Whitehouse5c676f62006-02-27 17:23:27 -050025#include "incore.h"
David Teiglandb3b94fa2006-01-16 16:50:04 +000026#include "glock.h"
27#include "glops.h"
28#include "inode.h"
29#include "log.h"
30#include "lops.h"
31#include "meta_io.h"
32#include "rgrp.h"
33#include "trans.h"
Steven Whitehouse5c676f62006-02-27 17:23:27 -050034#include "util.h"
Steven Whitehouse4340fe62006-07-11 09:46:33 -040035#include "ops_address.h"
David Teiglandb3b94fa2006-01-16 16:50:04 +000036
David Teiglandb3b94fa2006-01-16 16:50:04 +000037static int aspace_get_block(struct inode *inode, sector_t lblock,
38 struct buffer_head *bh_result, int create)
39{
Steven Whitehouse5c676f62006-02-27 17:23:27 -050040 gfs2_assert_warn(inode->i_sb->s_fs_info, 0);
David Teiglandb3b94fa2006-01-16 16:50:04 +000041 return -EOPNOTSUPP;
42}
43
44static int gfs2_aspace_writepage(struct page *page,
45 struct writeback_control *wbc)
46{
47 return block_write_full_page(page, aspace_get_block, wbc);
48}
49
Steven Whitehouse66de0452006-07-03 13:37:30 -040050static const struct address_space_operations aspace_aops = {
David Teiglandb3b94fa2006-01-16 16:50:04 +000051 .writepage = gfs2_aspace_writepage,
Steven Whitehouse4340fe62006-07-11 09:46:33 -040052 .releasepage = gfs2_releasepage,
Steven Whitehouse52d4c742007-11-01 09:34:14 +000053 .sync_page = block_sync_page,
David Teiglandb3b94fa2006-01-16 16:50:04 +000054};
55
56/**
57 * gfs2_aspace_get - Create and initialize a struct inode structure
58 * @sdp: the filesystem the aspace is in
59 *
60 * Right now a struct inode is just a struct inode. Maybe Linux
61 * will supply a more lightweight address space construct (that works)
62 * in the future.
63 *
64 * Make sure pages/buffers in this aspace aren't in high memory.
65 *
66 * Returns: the aspace
67 */
68
69struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
70{
71 struct inode *aspace;
Bob Peterson091806e2008-04-29 12:35:48 -050072 struct gfs2_inode *ip;
David Teiglandb3b94fa2006-01-16 16:50:04 +000073
74 aspace = new_inode(sdp->sd_vfs);
75 if (aspace) {
Steven Whitehousef3bba032006-07-11 09:50:54 -040076 mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
David Teiglandb3b94fa2006-01-16 16:50:04 +000077 aspace->i_mapping->a_ops = &aspace_aops;
78 aspace->i_size = ~0ULL;
Bob Peterson091806e2008-04-29 12:35:48 -050079 ip = GFS2_I(aspace);
80 clear_bit(GIF_USER, &ip->i_flags);
David Teiglandb3b94fa2006-01-16 16:50:04 +000081 insert_inode_hash(aspace);
82 }
David Teiglandb3b94fa2006-01-16 16:50:04 +000083 return aspace;
84}
85
86void gfs2_aspace_put(struct inode *aspace)
87{
88 remove_inode_hash(aspace);
89 iput(aspace);
90}
91
92/**
David Teiglandb3b94fa2006-01-16 16:50:04 +000093 * gfs2_meta_inval - Invalidate all buffers associated with a glock
94 * @gl: the glock
95 *
96 */
97
98void gfs2_meta_inval(struct gfs2_glock *gl)
99{
100 struct gfs2_sbd *sdp = gl->gl_sbd;
101 struct inode *aspace = gl->gl_aspace;
102 struct address_space *mapping = gl->gl_aspace->i_mapping;
103
104 gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
105
106 atomic_inc(&aspace->i_writecount);
107 truncate_inode_pages(mapping, 0);
108 atomic_dec(&aspace->i_writecount);
109
110 gfs2_assert_withdraw(sdp, !mapping->nrpages);
111}
112
113/**
114 * gfs2_meta_sync - Sync all buffers associated with a glock
115 * @gl: The glock
David Teiglandb3b94fa2006-01-16 16:50:04 +0000116 *
117 */
118
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400119void gfs2_meta_sync(struct gfs2_glock *gl)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000120{
121 struct address_space *mapping = gl->gl_aspace->i_mapping;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400122 int error;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000123
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400124 filemap_fdatawrite(mapping);
125 error = filemap_fdatawait(mapping);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000126
127 if (error)
128 gfs2_io_error(gl->gl_sbd);
129}
130
131/**
Steven Whitehouse6802e342008-05-21 17:03:22 +0100132 * gfs2_getbuf - Get a buffer with a given address space
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500133 * @gl: the glock
David Teiglandb3b94fa2006-01-16 16:50:04 +0000134 * @blkno: the block number (filesystem scope)
135 * @create: 1 if the buffer should be created
136 *
137 * Returns: the buffer
138 */
139
Steven Whitehouse6802e342008-05-21 17:03:22 +0100140struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000141{
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500142 struct address_space *mapping = gl->gl_aspace->i_mapping;
143 struct gfs2_sbd *sdp = gl->gl_sbd;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000144 struct page *page;
145 struct buffer_head *bh;
146 unsigned int shift;
147 unsigned long index;
148 unsigned int bufnum;
149
150 shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
151 index = blkno >> shift; /* convert block to page */
152 bufnum = blkno - (index << shift); /* block buf index within page */
153
154 if (create) {
155 for (;;) {
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500156 page = grab_cache_page(mapping, index);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000157 if (page)
158 break;
159 yield();
160 }
161 } else {
Steven Whitehousecb4c0312006-11-23 11:16:32 -0500162 page = find_lock_page(mapping, index);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000163 if (!page)
164 return NULL;
165 }
166
167 if (!page_has_buffers(page))
168 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
169
170 /* Locate header for our buffer within our page */
171 for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
172 /* Do nothing */;
173 get_bh(bh);
174
175 if (!buffer_mapped(bh))
176 map_bh(bh, sdp->sd_vfs, blkno);
177
178 unlock_page(page);
179 mark_page_accessed(page);
180 page_cache_release(page);
181
182 return bh;
183}
184
185static void meta_prep_new(struct buffer_head *bh)
186{
187 struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
188
189 lock_buffer(bh);
190 clear_buffer_dirty(bh);
191 set_buffer_uptodate(bh);
192 unlock_buffer(bh);
193
194 mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
195}
196
197/**
198 * gfs2_meta_new - Get a block
199 * @gl: The glock associated with this block
200 * @blkno: The block number
201 *
202 * Returns: The buffer
203 */
204
Steven Whitehousecd915492006-09-04 12:49:07 -0400205struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000206{
207 struct buffer_head *bh;
Steven Whitehouse6802e342008-05-21 17:03:22 +0100208 bh = gfs2_getbuf(gl, blkno, CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000209 meta_prep_new(bh);
210 return bh;
211}
212
213/**
214 * gfs2_meta_read - Read a block from disk
215 * @gl: The glock covering the block
216 * @blkno: The block number
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400217 * @flags: flags
David Teiglandb3b94fa2006-01-16 16:50:04 +0000218 * @bhp: the place where the buffer is returned (NULL on failure)
219 *
220 * Returns: errno
221 */
222
Steven Whitehousecd915492006-09-04 12:49:07 -0400223int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
David Teiglandb3b94fa2006-01-16 16:50:04 +0000224 struct buffer_head **bhp)
225{
Steven Whitehouse6802e342008-05-21 17:03:22 +0100226 *bhp = gfs2_getbuf(gl, blkno, CREATE);
Bob Peterson15c7cee2007-12-11 19:29:17 -0600227 if (!buffer_uptodate(*bhp)) {
Steven Whitehouse2e565bb2006-10-02 11:38:25 -0400228 ll_rw_block(READ_META, 1, bhp);
Bob Peterson15c7cee2007-12-11 19:29:17 -0600229 if (flags & DIO_WAIT) {
230 int error = gfs2_meta_wait(gl->gl_sbd, *bhp);
231 if (error) {
232 brelse(*bhp);
233 return error;
234 }
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400235 }
236 }
David Teiglandb3b94fa2006-01-16 16:50:04 +0000237
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400238 return 0;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000239}
240
241/**
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400242 * gfs2_meta_wait - Reread a block from disk
David Teiglandb3b94fa2006-01-16 16:50:04 +0000243 * @sdp: the filesystem
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400244 * @bh: The block to wait for
David Teiglandb3b94fa2006-01-16 16:50:04 +0000245 *
246 * Returns: errno
247 */
248
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400249int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000250{
251 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
252 return -EIO;
253
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400254 wait_on_buffer(bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000255
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400256 if (!buffer_uptodate(bh)) {
257 struct gfs2_trans *tr = current->journal_info;
258 if (tr && tr->tr_touched)
259 gfs2_io_error_bh(sdp, bh);
260 return -EIO;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000261 }
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400262 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
263 return -EIO;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000264
265 return 0;
266}
267
268/**
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000269 * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
David Teiglandb3b94fa2006-01-16 16:50:04 +0000270 * @gl: the glock the buffer belongs to
271 * @bh: The buffer to be attached to
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000272 * @meta: Flag to indicate whether its metadata or not
David Teiglandb3b94fa2006-01-16 16:50:04 +0000273 */
274
Steven Whitehouse568f4c92006-02-27 12:00:42 -0500275void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
276 int meta)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000277{
278 struct gfs2_bufdata *bd;
279
Steven Whitehouse18ec7d52006-02-08 11:50:51 +0000280 if (meta)
281 lock_page(bh->b_page);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000282
Steven Whitehouse5c676f62006-02-27 17:23:27 -0500283 if (bh->b_private) {
Steven Whitehouse18ec7d52006-02-08 11:50:51 +0000284 if (meta)
285 unlock_page(bh->b_page);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000286 return;
287 }
288
Bob Peterson3e5cd082008-01-16 08:45:39 -0600289 bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000290 bd->bd_bh = bh;
291 bd->bd_gl = gl;
292
293 INIT_LIST_HEAD(&bd->bd_list_tr);
Steven Whitehouse82ffa512006-09-04 14:47:06 -0400294 if (meta)
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000295 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
Steven Whitehouse82ffa512006-09-04 14:47:06 -0400296 else
Steven Whitehouse586dfda2006-01-18 11:32:00 +0000297 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
Steven Whitehouse5c676f62006-02-27 17:23:27 -0500298 bh->b_private = bd;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000299
Steven Whitehouse18ec7d52006-02-08 11:50:51 +0000300 if (meta)
301 unlock_page(bh->b_page);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000302}
303
Steven Whitehouse16615be2007-09-17 10:59:52 +0100304void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
305{
306 struct gfs2_sbd *sdp = GFS2_SB(bh->b_page->mapping->host);
307 struct gfs2_bufdata *bd = bh->b_private;
308 if (test_clear_buffer_pinned(bh)) {
309 list_del_init(&bd->bd_le.le_list);
310 if (meta) {
311 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
312 sdp->sd_log_num_buf--;
313 tr->tr_num_buf_rm++;
314 } else {
315 gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
316 sdp->sd_log_num_databuf--;
317 tr->tr_num_databuf_rm++;
318 }
319 tr->tr_touched = 1;
320 brelse(bh);
321 }
322 if (bd) {
323 if (bd->bd_ail) {
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100324 gfs2_remove_from_ail(bd);
Steven Whitehouse16615be2007-09-17 10:59:52 +0100325 bh->b_private = NULL;
326 bd->bd_bh = NULL;
327 bd->bd_blkno = bh->b_blocknr;
328 gfs2_trans_add_revoke(sdp, bd);
329 }
330 }
331 clear_buffer_dirty(bh);
332 clear_buffer_uptodate(bh);
333}
334
David Teiglandb3b94fa2006-01-16 16:50:04 +0000335/**
David Teiglandb3b94fa2006-01-16 16:50:04 +0000336 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
337 * @ip: the inode who owns the buffers
338 * @bstart: the first buffer in the run
339 * @blen: the number of buffers in the run
340 *
341 */
342
Steven Whitehousecd915492006-09-04 12:49:07 -0400343void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000344{
Steven Whitehousefeaa7bb2006-06-14 15:32:57 -0400345 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000346 struct buffer_head *bh;
347
348 while (blen) {
Steven Whitehouse6802e342008-05-21 17:03:22 +0100349 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000350 if (bh) {
Steven Whitehouse1ad38c42007-09-03 11:01:33 +0100351 lock_buffer(bh);
352 gfs2_log_lock(sdp);
Steven Whitehouse16615be2007-09-17 10:59:52 +0100353 gfs2_remove_from_journal(bh, current->journal_info, 1);
Steven Whitehouse1ad38c42007-09-03 11:01:33 +0100354 gfs2_log_unlock(sdp);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000355 unlock_buffer(bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000356 brelse(bh);
357 }
358
359 bstart++;
360 blen--;
361 }
362}
363
364/**
David Teiglandb3b94fa2006-01-16 16:50:04 +0000365 * gfs2_meta_indirect_buffer - Get a metadata buffer
366 * @ip: The GFS2 inode
367 * @height: The level of this buf in the metadata (indir addr) tree (if any)
368 * @num: The block number (device relative) of the buffer
369 * @new: Non-zero if we may create a new buffer
370 * @bhp: the buffer is returned here
371 *
David Teiglandb3b94fa2006-01-16 16:50:04 +0000372 * Returns: errno
373 */
374
Steven Whitehousecd915492006-09-04 12:49:07 -0400375int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
David Teiglandb3b94fa2006-01-16 16:50:04 +0000376 int new, struct buffer_head **bhp)
377{
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400378 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
379 struct gfs2_glock *gl = ip->i_gl;
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100380 struct buffer_head *bh;
381 int ret = 0;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000382
383 if (new) {
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100384 BUG_ON(height == 0);
385 bh = gfs2_meta_new(gl, num);
Steven Whitehoused4e9c4c2006-01-18 11:19:28 +0000386 gfs2_trans_add_bh(ip->i_gl, bh, 1);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000387 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
388 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400389 } else {
390 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100391 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
392 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
393 brelse(bh);
394 ret = -EIO;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400395 }
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400396 }
David Teiglandb3b94fa2006-01-16 16:50:04 +0000397 *bhp = bh;
Steven Whitehousef91a0d32007-10-15 16:29:05 +0100398 return ret;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000399}
400
401/**
402 * gfs2_meta_ra - start readahead on an extent of a file
403 * @gl: the glock the blocks belong to
404 * @dblock: the starting disk block
405 * @extlen: the number of blocks in the extent
406 *
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400407 * returns: the first buffer in the extent
David Teiglandb3b94fa2006-01-16 16:50:04 +0000408 */
409
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400410struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
David Teiglandb3b94fa2006-01-16 16:50:04 +0000411{
412 struct gfs2_sbd *sdp = gl->gl_sbd;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000413 struct buffer_head *first_bh, *bh;
Steven Whitehousecd915492006-09-04 12:49:07 -0400414 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
Steven Whitehouse568f4c92006-02-27 12:00:42 -0500415 sdp->sd_sb.sb_bsize_shift;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000416
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400417 BUG_ON(!extlen);
418
419 if (max_ra < 1)
420 max_ra = 1;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000421 if (extlen > max_ra)
422 extlen = max_ra;
423
Steven Whitehouse6802e342008-05-21 17:03:22 +0100424 first_bh = gfs2_getbuf(gl, dblock, CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000425
426 if (buffer_uptodate(first_bh))
427 goto out;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400428 if (!buffer_locked(first_bh))
Steven Whitehouse2e565bb2006-10-02 11:38:25 -0400429 ll_rw_block(READ_META, 1, &first_bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000430
431 dblock++;
432 extlen--;
433
434 while (extlen) {
Steven Whitehouse6802e342008-05-21 17:03:22 +0100435 bh = gfs2_getbuf(gl, dblock, CREATE);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000436
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400437 if (!buffer_uptodate(bh) && !buffer_locked(bh))
438 ll_rw_block(READA, 1, &bh);
439 brelse(bh);
David Teiglandb3b94fa2006-01-16 16:50:04 +0000440 dblock++;
441 extlen--;
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400442 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
443 goto out;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000444 }
445
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400446 wait_on_buffer(first_bh);
Steven Whitehousea91ea692006-09-04 12:04:26 -0400447out:
Steven Whitehouse7276b3b2006-09-21 17:05:23 -0400448 return first_bh;
David Teiglandb3b94fa2006-01-16 16:50:04 +0000449}
450