1 /* 2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This copyrighted material is made available to anyone wishing to use, 6 * modify, copy, or redistribute it subject to the terms and conditions 7 * of the GNU General Public License version 2. 8 */ 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> 20 #include <linux/bio.h> 21 #include <linux/gfs2_ondisk.h> 22 23 #include "gfs2.h" 24 #include "incore.h" 25 #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" 33 #include "util.h" 34 #include "trace_gfs2.h" 35 36 static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc) 37 { 38 struct buffer_head *bh, *head; 39 int nr_underway = 0; 40 int write_op = REQ_META | REQ_PRIO | 41 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE); 42 43 BUG_ON(!PageLocked(page)); 44 BUG_ON(!page_has_buffers(page)); 45 46 head = page_buffers(page); 47 bh = head; 48 49 do { 50 if (!buffer_mapped(bh)) 51 continue; 52 /* 53 * If it's a fully non-blocking write attempt and we cannot 54 * lock the buffer then redirty the page. Note that this can 55 * potentially cause a busy-wait loop from flusher thread and kswapd 56 * activity, but those code paths have their own higher-level 57 * throttling. 58 */ 59 if (wbc->sync_mode != WB_SYNC_NONE) { 60 lock_buffer(bh); 61 } else if (!trylock_buffer(bh)) { 62 redirty_page_for_writepage(wbc, page); 63 continue; 64 } 65 if (test_clear_buffer_dirty(bh)) { 66 mark_buffer_async_write(bh); 67 } else { 68 unlock_buffer(bh); 69 } 70 } while ((bh = bh->b_this_page) != head); 71 72 /* 73 * The page and its buffers are protected by PageWriteback(), so we can 74 * drop the bh refcounts early. 75 */ 76 BUG_ON(PageWriteback(page)); 77 set_page_writeback(page); 78 79 do { 80 struct buffer_head *next = bh->b_this_page; 81 if (buffer_async_write(bh)) { 82 submit_bh(write_op, bh); 83 nr_underway++; 84 } 85 bh = next; 86 } while (bh != head); 87 unlock_page(page); 88 89 if (nr_underway == 0) 90 end_page_writeback(page); 91 92 return 0; 93 } 94 95 const struct address_space_operations gfs2_meta_aops = { 96 .writepage = gfs2_aspace_writepage, 97 .releasepage = gfs2_releasepage, 98 }; 99 100 const struct address_space_operations gfs2_rgrp_aops = { 101 .writepage = gfs2_aspace_writepage, 102 .releasepage = gfs2_releasepage, 103 }; 104 105 /** 106 * gfs2_getbuf - Get a buffer with a given address space 107 * @gl: the glock 108 * @blkno: the block number (filesystem scope) 109 * @create: 1 if the buffer should be created 110 * 111 * Returns: the buffer 112 */ 113 114 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create) 115 { 116 struct address_space *mapping = gfs2_glock2aspace(gl); 117 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; 118 struct page *page; 119 struct buffer_head *bh; 120 unsigned int shift; 121 unsigned long index; 122 unsigned int bufnum; 123 124 if (mapping == NULL) 125 mapping = &sdp->sd_aspace; 126 127 shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift; 128 index = blkno >> shift; /* convert block to page */ 129 bufnum = blkno - (index << shift); /* block buf index within page */ 130 131 if (create) { 132 for (;;) { 133 page = grab_cache_page(mapping, index); 134 if (page) 135 break; 136 yield(); 137 } 138 } else { 139 page = find_get_page_flags(mapping, index, 140 FGP_LOCK|FGP_ACCESSED); 141 if (!page) 142 return NULL; 143 } 144 145 if (!page_has_buffers(page)) 146 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0); 147 148 /* Locate header for our buffer within our page */ 149 for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page) 150 /* Do nothing */; 151 get_bh(bh); 152 153 if (!buffer_mapped(bh)) 154 map_bh(bh, sdp->sd_vfs, blkno); 155 156 unlock_page(page); 157 page_cache_release(page); 158 159 return bh; 160 } 161 162 static void meta_prep_new(struct buffer_head *bh) 163 { 164 struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data; 165 166 lock_buffer(bh); 167 clear_buffer_dirty(bh); 168 set_buffer_uptodate(bh); 169 unlock_buffer(bh); 170 171 mh->mh_magic = cpu_to_be32(GFS2_MAGIC); 172 } 173 174 /** 175 * gfs2_meta_new - Get a block 176 * @gl: The glock associated with this block 177 * @blkno: The block number 178 * 179 * Returns: The buffer 180 */ 181 182 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno) 183 { 184 struct buffer_head *bh; 185 bh = gfs2_getbuf(gl, blkno, CREATE); 186 meta_prep_new(bh); 187 return bh; 188 } 189 190 static void gfs2_meta_read_endio(struct bio *bio) 191 { 192 struct bio_vec *bvec; 193 int i; 194 195 bio_for_each_segment_all(bvec, bio, i) { 196 struct page *page = bvec->bv_page; 197 struct buffer_head *bh = page_buffers(page); 198 unsigned int len = bvec->bv_len; 199 200 while (bh_offset(bh) < bvec->bv_offset) 201 bh = bh->b_this_page; 202 do { 203 struct buffer_head *next = bh->b_this_page; 204 len -= bh->b_size; 205 bh->b_end_io(bh, !bio->bi_error); 206 bh = next; 207 } while (bh && len); 208 } 209 bio_put(bio); 210 } 211 212 /* 213 * Submit several consecutive buffer head I/O requests as a single bio I/O 214 * request. (See submit_bh_wbc.) 215 */ 216 static void gfs2_submit_bhs(int rw, struct buffer_head *bhs[], int num) 217 { 218 struct buffer_head *bh = bhs[0]; 219 struct bio *bio; 220 int i; 221 222 if (!num) 223 return; 224 225 bio = bio_alloc(GFP_NOIO, num); 226 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); 227 bio->bi_bdev = bh->b_bdev; 228 for (i = 0; i < num; i++) { 229 bh = bhs[i]; 230 bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh)); 231 } 232 bio->bi_end_io = gfs2_meta_read_endio; 233 submit_bio(rw, bio); 234 } 235 236 /** 237 * gfs2_meta_read - Read a block from disk 238 * @gl: The glock covering the block 239 * @blkno: The block number 240 * @flags: flags 241 * @bhp: the place where the buffer is returned (NULL on failure) 242 * 243 * Returns: errno 244 */ 245 246 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, 247 int rahead, struct buffer_head **bhp) 248 { 249 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; 250 struct buffer_head *bh, *bhs[2]; 251 int num = 0; 252 253 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) { 254 *bhp = NULL; 255 return -EIO; 256 } 257 258 *bhp = bh = gfs2_getbuf(gl, blkno, CREATE); 259 260 lock_buffer(bh); 261 if (buffer_uptodate(bh)) { 262 unlock_buffer(bh); 263 flags &= ~DIO_WAIT; 264 } else { 265 bh->b_end_io = end_buffer_read_sync; 266 get_bh(bh); 267 bhs[num++] = bh; 268 } 269 270 if (rahead) { 271 bh = gfs2_getbuf(gl, blkno + 1, CREATE); 272 273 lock_buffer(bh); 274 if (buffer_uptodate(bh)) { 275 unlock_buffer(bh); 276 brelse(bh); 277 } else { 278 bh->b_end_io = end_buffer_read_sync; 279 bhs[num++] = bh; 280 } 281 } 282 283 gfs2_submit_bhs(READ_SYNC | REQ_META | REQ_PRIO, bhs, num); 284 if (!(flags & DIO_WAIT)) 285 return 0; 286 287 bh = *bhp; 288 wait_on_buffer(bh); 289 if (unlikely(!buffer_uptodate(bh))) { 290 struct gfs2_trans *tr = current->journal_info; 291 if (tr && tr->tr_touched) 292 gfs2_io_error_bh(sdp, bh); 293 brelse(bh); 294 *bhp = NULL; 295 return -EIO; 296 } 297 298 return 0; 299 } 300 301 /** 302 * gfs2_meta_wait - Reread a block from disk 303 * @sdp: the filesystem 304 * @bh: The block to wait for 305 * 306 * Returns: errno 307 */ 308 309 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh) 310 { 311 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 312 return -EIO; 313 314 wait_on_buffer(bh); 315 316 if (!buffer_uptodate(bh)) { 317 struct gfs2_trans *tr = current->journal_info; 318 if (tr && tr->tr_touched) 319 gfs2_io_error_bh(sdp, bh); 320 return -EIO; 321 } 322 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 323 return -EIO; 324 325 return 0; 326 } 327 328 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta) 329 { 330 struct address_space *mapping = bh->b_page->mapping; 331 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); 332 struct gfs2_bufdata *bd = bh->b_private; 333 int was_pinned = 0; 334 335 if (test_clear_buffer_pinned(bh)) { 336 trace_gfs2_pin(bd, 0); 337 atomic_dec(&sdp->sd_log_pinned); 338 list_del_init(&bd->bd_list); 339 if (meta) 340 tr->tr_num_buf_rm++; 341 else 342 tr->tr_num_databuf_rm++; 343 tr->tr_touched = 1; 344 was_pinned = 1; 345 brelse(bh); 346 } 347 if (bd) { 348 spin_lock(&sdp->sd_ail_lock); 349 if (bd->bd_tr) { 350 gfs2_trans_add_revoke(sdp, bd); 351 } else if (was_pinned) { 352 bh->b_private = NULL; 353 kmem_cache_free(gfs2_bufdata_cachep, bd); 354 } 355 spin_unlock(&sdp->sd_ail_lock); 356 } 357 clear_buffer_dirty(bh); 358 clear_buffer_uptodate(bh); 359 } 360 361 /** 362 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore 363 * @ip: the inode who owns the buffers 364 * @bstart: the first buffer in the run 365 * @blen: the number of buffers in the run 366 * 367 */ 368 369 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen) 370 { 371 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); 372 struct buffer_head *bh; 373 374 while (blen) { 375 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE); 376 if (bh) { 377 lock_buffer(bh); 378 gfs2_log_lock(sdp); 379 gfs2_remove_from_journal(bh, current->journal_info, 1); 380 gfs2_log_unlock(sdp); 381 unlock_buffer(bh); 382 brelse(bh); 383 } 384 385 bstart++; 386 blen--; 387 } 388 } 389 390 /** 391 * gfs2_meta_indirect_buffer - Get a metadata buffer 392 * @ip: The GFS2 inode 393 * @height: The level of this buf in the metadata (indir addr) tree (if any) 394 * @num: The block number (device relative) of the buffer 395 * @bhp: the buffer is returned here 396 * 397 * Returns: errno 398 */ 399 400 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num, 401 struct buffer_head **bhp) 402 { 403 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); 404 struct gfs2_glock *gl = ip->i_gl; 405 struct buffer_head *bh; 406 int ret = 0; 407 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI; 408 int rahead = 0; 409 410 if (num == ip->i_no_addr) 411 rahead = ip->i_rahead; 412 413 ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh); 414 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) { 415 brelse(bh); 416 ret = -EIO; 417 } 418 *bhp = bh; 419 return ret; 420 } 421 422 /** 423 * gfs2_meta_ra - start readahead on an extent of a file 424 * @gl: the glock the blocks belong to 425 * @dblock: the starting disk block 426 * @extlen: the number of blocks in the extent 427 * 428 * returns: the first buffer in the extent 429 */ 430 431 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen) 432 { 433 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; 434 struct buffer_head *first_bh, *bh; 435 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >> 436 sdp->sd_sb.sb_bsize_shift; 437 438 BUG_ON(!extlen); 439 440 if (max_ra < 1) 441 max_ra = 1; 442 if (extlen > max_ra) 443 extlen = max_ra; 444 445 first_bh = gfs2_getbuf(gl, dblock, CREATE); 446 447 if (buffer_uptodate(first_bh)) 448 goto out; 449 if (!buffer_locked(first_bh)) 450 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh); 451 452 dblock++; 453 extlen--; 454 455 while (extlen) { 456 bh = gfs2_getbuf(gl, dblock, CREATE); 457 458 if (!buffer_uptodate(bh) && !buffer_locked(bh)) 459 ll_rw_block(READA | REQ_META, 1, &bh); 460 brelse(bh); 461 dblock++; 462 extlen--; 463 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh)) 464 goto out; 465 } 466 467 wait_on_buffer(first_bh); 468 out: 469 return first_bh; 470 } 471 472