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_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 /** 191 * gfs2_meta_read - Read a block from disk 192 * @gl: The glock covering the block 193 * @blkno: The block number 194 * @flags: flags 195 * @bhp: the place where the buffer is returned (NULL on failure) 196 * 197 * Returns: errno 198 */ 199 200 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, 201 struct buffer_head **bhp) 202 { 203 struct gfs2_sbd *sdp = gl->gl_sbd; 204 struct buffer_head *bh; 205 206 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) { 207 *bhp = NULL; 208 return -EIO; 209 } 210 211 *bhp = bh = gfs2_getbuf(gl, blkno, CREATE); 212 213 lock_buffer(bh); 214 if (buffer_uptodate(bh)) { 215 unlock_buffer(bh); 216 return 0; 217 } 218 bh->b_end_io = end_buffer_read_sync; 219 get_bh(bh); 220 submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh); 221 if (!(flags & DIO_WAIT)) 222 return 0; 223 224 wait_on_buffer(bh); 225 if (unlikely(!buffer_uptodate(bh))) { 226 struct gfs2_trans *tr = current->journal_info; 227 if (tr && tr->tr_touched) 228 gfs2_io_error_bh(sdp, bh); 229 brelse(bh); 230 *bhp = NULL; 231 return -EIO; 232 } 233 234 return 0; 235 } 236 237 /** 238 * gfs2_meta_wait - Reread a block from disk 239 * @sdp: the filesystem 240 * @bh: The block to wait for 241 * 242 * Returns: errno 243 */ 244 245 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh) 246 { 247 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 248 return -EIO; 249 250 wait_on_buffer(bh); 251 252 if (!buffer_uptodate(bh)) { 253 struct gfs2_trans *tr = current->journal_info; 254 if (tr && tr->tr_touched) 255 gfs2_io_error_bh(sdp, bh); 256 return -EIO; 257 } 258 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 259 return -EIO; 260 261 return 0; 262 } 263 264 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta) 265 { 266 struct address_space *mapping = bh->b_page->mapping; 267 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); 268 struct gfs2_bufdata *bd = bh->b_private; 269 int was_pinned = 0; 270 271 if (test_clear_buffer_pinned(bh)) { 272 trace_gfs2_pin(bd, 0); 273 atomic_dec(&sdp->sd_log_pinned); 274 list_del_init(&bd->bd_list); 275 if (meta) 276 tr->tr_num_buf_rm++; 277 else 278 tr->tr_num_databuf_rm++; 279 tr->tr_touched = 1; 280 was_pinned = 1; 281 brelse(bh); 282 } 283 if (bd) { 284 spin_lock(&sdp->sd_ail_lock); 285 if (bd->bd_tr) { 286 gfs2_trans_add_revoke(sdp, bd); 287 } else if (was_pinned) { 288 bh->b_private = NULL; 289 kmem_cache_free(gfs2_bufdata_cachep, bd); 290 } 291 spin_unlock(&sdp->sd_ail_lock); 292 } 293 clear_buffer_dirty(bh); 294 clear_buffer_uptodate(bh); 295 } 296 297 /** 298 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore 299 * @ip: the inode who owns the buffers 300 * @bstart: the first buffer in the run 301 * @blen: the number of buffers in the run 302 * 303 */ 304 305 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen) 306 { 307 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); 308 struct buffer_head *bh; 309 310 while (blen) { 311 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE); 312 if (bh) { 313 lock_buffer(bh); 314 gfs2_log_lock(sdp); 315 gfs2_remove_from_journal(bh, current->journal_info, 1); 316 gfs2_log_unlock(sdp); 317 unlock_buffer(bh); 318 brelse(bh); 319 } 320 321 bstart++; 322 blen--; 323 } 324 } 325 326 /** 327 * gfs2_meta_indirect_buffer - Get a metadata buffer 328 * @ip: The GFS2 inode 329 * @height: The level of this buf in the metadata (indir addr) tree (if any) 330 * @num: The block number (device relative) of the buffer 331 * @bhp: the buffer is returned here 332 * 333 * Returns: errno 334 */ 335 336 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num, 337 struct buffer_head **bhp) 338 { 339 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); 340 struct gfs2_glock *gl = ip->i_gl; 341 struct buffer_head *bh; 342 int ret = 0; 343 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI; 344 345 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh); 346 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) { 347 brelse(bh); 348 ret = -EIO; 349 } 350 *bhp = bh; 351 return ret; 352 } 353 354 /** 355 * gfs2_meta_ra - start readahead on an extent of a file 356 * @gl: the glock the blocks belong to 357 * @dblock: the starting disk block 358 * @extlen: the number of blocks in the extent 359 * 360 * returns: the first buffer in the extent 361 */ 362 363 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen) 364 { 365 struct gfs2_sbd *sdp = gl->gl_sbd; 366 struct buffer_head *first_bh, *bh; 367 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >> 368 sdp->sd_sb.sb_bsize_shift; 369 370 BUG_ON(!extlen); 371 372 if (max_ra < 1) 373 max_ra = 1; 374 if (extlen > max_ra) 375 extlen = max_ra; 376 377 first_bh = gfs2_getbuf(gl, dblock, CREATE); 378 379 if (buffer_uptodate(first_bh)) 380 goto out; 381 if (!buffer_locked(first_bh)) 382 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh); 383 384 dblock++; 385 extlen--; 386 387 while (extlen) { 388 bh = gfs2_getbuf(gl, dblock, CREATE); 389 390 if (!buffer_uptodate(bh) && !buffer_locked(bh)) 391 ll_rw_block(READA | REQ_META, 1, &bh); 392 brelse(bh); 393 dblock++; 394 extlen--; 395 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh)) 396 goto out; 397 } 398 399 wait_on_buffer(first_bh); 400 out: 401 return first_bh; 402 } 403 404