Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 Oracle. All rights reserved. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public |
| 6 | * License v2 as published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 11 | * General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public |
| 14 | * License along with this program; if not, write to the |
| 15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 16 | * Boston, MA 021110-1307, USA. |
| 17 | */ |
| 18 | |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/bio.h> |
| 21 | #include <linux/buffer_head.h> |
| 22 | #include <linux/file.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/pagemap.h> |
| 25 | #include <linux/highmem.h> |
| 26 | #include <linux/time.h> |
| 27 | #include <linux/init.h> |
| 28 | #include <linux/string.h> |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 29 | #include <linux/backing-dev.h> |
| 30 | #include <linux/mpage.h> |
| 31 | #include <linux/swap.h> |
| 32 | #include <linux/writeback.h> |
| 33 | #include <linux/bit_spinlock.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 34 | #include <linux/slab.h> |
Chris Mason | 4b4e25f | 2008-11-20 10:22:27 -0500 | [diff] [blame] | 35 | #include "compat.h" |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 36 | #include "ctree.h" |
| 37 | #include "disk-io.h" |
| 38 | #include "transaction.h" |
| 39 | #include "btrfs_inode.h" |
| 40 | #include "volumes.h" |
| 41 | #include "ordered-data.h" |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 42 | #include "compression.h" |
| 43 | #include "extent_io.h" |
| 44 | #include "extent_map.h" |
| 45 | |
| 46 | struct compressed_bio { |
| 47 | /* number of bios pending for this compressed extent */ |
| 48 | atomic_t pending_bios; |
| 49 | |
| 50 | /* the pages with the compressed data on them */ |
| 51 | struct page **compressed_pages; |
| 52 | |
| 53 | /* inode that owns this data */ |
| 54 | struct inode *inode; |
| 55 | |
| 56 | /* starting offset in the inode for our pages */ |
| 57 | u64 start; |
| 58 | |
| 59 | /* number of bytes in the inode we're working on */ |
| 60 | unsigned long len; |
| 61 | |
| 62 | /* number of bytes on disk */ |
| 63 | unsigned long compressed_len; |
| 64 | |
Li Zefan | 261507a0 | 2010-12-17 14:21:50 +0800 | [diff] [blame] | 65 | /* the compression algorithm for this bio */ |
| 66 | int compress_type; |
| 67 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 68 | /* number of compressed pages in the array */ |
| 69 | unsigned long nr_pages; |
| 70 | |
| 71 | /* IO errors */ |
| 72 | int errors; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 73 | int mirror_num; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 74 | |
| 75 | /* for reads, this is the bio we are copying the data into */ |
| 76 | struct bio *orig_bio; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 77 | |
| 78 | /* |
| 79 | * the start of a variable length array of checksums only |
| 80 | * used by reads |
| 81 | */ |
| 82 | u32 sums; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 83 | }; |
| 84 | |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 85 | static inline int compressed_bio_size(struct btrfs_root *root, |
| 86 | unsigned long disk_size) |
| 87 | { |
| 88 | u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); |
| 89 | return sizeof(struct compressed_bio) + |
| 90 | ((disk_size + root->sectorsize - 1) / root->sectorsize) * |
| 91 | csum_size; |
| 92 | } |
| 93 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 94 | static struct bio *compressed_bio_alloc(struct block_device *bdev, |
| 95 | u64 first_byte, gfp_t gfp_flags) |
| 96 | { |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 97 | int nr_vecs; |
| 98 | |
| 99 | nr_vecs = bio_get_nr_vecs(bdev); |
Miao Xie | 88f794e | 2010-11-22 03:02:55 +0000 | [diff] [blame] | 100 | return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, gfp_flags); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 101 | } |
| 102 | |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 103 | static int check_compressed_csum(struct inode *inode, |
| 104 | struct compressed_bio *cb, |
| 105 | u64 disk_start) |
| 106 | { |
| 107 | int ret; |
| 108 | struct btrfs_root *root = BTRFS_I(inode)->root; |
| 109 | struct page *page; |
| 110 | unsigned long i; |
| 111 | char *kaddr; |
| 112 | u32 csum; |
| 113 | u32 *cb_sum = &cb->sums; |
| 114 | |
Christoph Hellwig | 6cbff00 | 2009-04-17 10:37:41 +0200 | [diff] [blame] | 115 | if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 116 | return 0; |
| 117 | |
| 118 | for (i = 0; i < cb->nr_pages; i++) { |
| 119 | page = cb->compressed_pages[i]; |
| 120 | csum = ~(u32)0; |
| 121 | |
| 122 | kaddr = kmap_atomic(page, KM_USER0); |
| 123 | csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE); |
| 124 | btrfs_csum_final(csum, (char *)&csum); |
| 125 | kunmap_atomic(kaddr, KM_USER0); |
| 126 | |
| 127 | if (csum != *cb_sum) { |
Chris Mason | d397712 | 2009-01-05 21:25:51 -0500 | [diff] [blame] | 128 | printk(KERN_INFO "btrfs csum failed ino %lu " |
| 129 | "extent %llu csum %u " |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 130 | "wanted %u mirror %d\n", inode->i_ino, |
| 131 | (unsigned long long)disk_start, |
| 132 | csum, *cb_sum, cb->mirror_num); |
| 133 | ret = -EIO; |
| 134 | goto fail; |
| 135 | } |
| 136 | cb_sum++; |
| 137 | |
| 138 | } |
| 139 | ret = 0; |
| 140 | fail: |
| 141 | return ret; |
| 142 | } |
| 143 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 144 | /* when we finish reading compressed pages from the disk, we |
| 145 | * decompress them and then run the bio end_io routines on the |
| 146 | * decompressed pages (in the inode address space). |
| 147 | * |
| 148 | * This allows the checksumming and other IO error handling routines |
| 149 | * to work normally |
| 150 | * |
| 151 | * The compressed pages are freed here, and it must be run |
| 152 | * in process context |
| 153 | */ |
| 154 | static void end_compressed_bio_read(struct bio *bio, int err) |
| 155 | { |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 156 | struct compressed_bio *cb = bio->bi_private; |
| 157 | struct inode *inode; |
| 158 | struct page *page; |
| 159 | unsigned long index; |
| 160 | int ret; |
| 161 | |
| 162 | if (err) |
| 163 | cb->errors = 1; |
| 164 | |
| 165 | /* if there are more bios still pending for this compressed |
| 166 | * extent, just exit |
| 167 | */ |
| 168 | if (!atomic_dec_and_test(&cb->pending_bios)) |
| 169 | goto out; |
| 170 | |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 171 | inode = cb->inode; |
| 172 | ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); |
| 173 | if (ret) |
| 174 | goto csum_failed; |
| 175 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 176 | /* ok, we're the last bio for this extent, lets start |
| 177 | * the decompression. |
| 178 | */ |
Li Zefan | 261507a0 | 2010-12-17 14:21:50 +0800 | [diff] [blame] | 179 | ret = btrfs_decompress_biovec(cb->compress_type, |
| 180 | cb->compressed_pages, |
| 181 | cb->start, |
| 182 | cb->orig_bio->bi_io_vec, |
| 183 | cb->orig_bio->bi_vcnt, |
| 184 | cb->compressed_len); |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 185 | csum_failed: |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 186 | if (ret) |
| 187 | cb->errors = 1; |
| 188 | |
| 189 | /* release the compressed pages */ |
| 190 | index = 0; |
| 191 | for (index = 0; index < cb->nr_pages; index++) { |
| 192 | page = cb->compressed_pages[index]; |
| 193 | page->mapping = NULL; |
| 194 | page_cache_release(page); |
| 195 | } |
| 196 | |
| 197 | /* do io completion on the original bio */ |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 198 | if (cb->errors) { |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 199 | bio_io_error(cb->orig_bio); |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 200 | } else { |
| 201 | int bio_index = 0; |
| 202 | struct bio_vec *bvec = cb->orig_bio->bi_io_vec; |
| 203 | |
| 204 | /* |
| 205 | * we have verified the checksum already, set page |
| 206 | * checked so the end_io handlers know about it |
| 207 | */ |
Chris Mason | d397712 | 2009-01-05 21:25:51 -0500 | [diff] [blame] | 208 | while (bio_index < cb->orig_bio->bi_vcnt) { |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 209 | SetPageChecked(bvec->bv_page); |
| 210 | bvec++; |
| 211 | bio_index++; |
| 212 | } |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 213 | bio_endio(cb->orig_bio, 0); |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 214 | } |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 215 | |
| 216 | /* finally free the cb struct */ |
| 217 | kfree(cb->compressed_pages); |
| 218 | kfree(cb); |
| 219 | out: |
| 220 | bio_put(bio); |
| 221 | } |
| 222 | |
| 223 | /* |
| 224 | * Clear the writeback bits on all of the file |
| 225 | * pages for a compressed write |
| 226 | */ |
| 227 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, |
| 228 | unsigned long ram_size) |
| 229 | { |
| 230 | unsigned long index = start >> PAGE_CACHE_SHIFT; |
| 231 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; |
| 232 | struct page *pages[16]; |
| 233 | unsigned long nr_pages = end_index - index + 1; |
| 234 | int i; |
| 235 | int ret; |
| 236 | |
Chris Mason | d397712 | 2009-01-05 21:25:51 -0500 | [diff] [blame] | 237 | while (nr_pages > 0) { |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 238 | ret = find_get_pages_contig(inode->i_mapping, index, |
Chris Mason | 5b050f0 | 2008-11-11 09:34:41 -0500 | [diff] [blame] | 239 | min_t(unsigned long, |
| 240 | nr_pages, ARRAY_SIZE(pages)), pages); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 241 | if (ret == 0) { |
| 242 | nr_pages -= 1; |
| 243 | index += 1; |
| 244 | continue; |
| 245 | } |
| 246 | for (i = 0; i < ret; i++) { |
| 247 | end_page_writeback(pages[i]); |
| 248 | page_cache_release(pages[i]); |
| 249 | } |
| 250 | nr_pages -= ret; |
| 251 | index += ret; |
| 252 | } |
| 253 | /* the inode may be gone now */ |
| 254 | return 0; |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * do the cleanup once all the compressed pages hit the disk. |
| 259 | * This will clear writeback on the file pages and free the compressed |
| 260 | * pages. |
| 261 | * |
| 262 | * This also calls the writeback end hooks for the file pages so that |
| 263 | * metadata and checksums can be updated in the file. |
| 264 | */ |
| 265 | static void end_compressed_bio_write(struct bio *bio, int err) |
| 266 | { |
| 267 | struct extent_io_tree *tree; |
| 268 | struct compressed_bio *cb = bio->bi_private; |
| 269 | struct inode *inode; |
| 270 | struct page *page; |
| 271 | unsigned long index; |
| 272 | |
| 273 | if (err) |
| 274 | cb->errors = 1; |
| 275 | |
| 276 | /* if there are more bios still pending for this compressed |
| 277 | * extent, just exit |
| 278 | */ |
| 279 | if (!atomic_dec_and_test(&cb->pending_bios)) |
| 280 | goto out; |
| 281 | |
| 282 | /* ok, we're the last bio for this extent, step one is to |
| 283 | * call back into the FS and do all the end_io operations |
| 284 | */ |
| 285 | inode = cb->inode; |
| 286 | tree = &BTRFS_I(inode)->io_tree; |
Chris Mason | 70b99e6 | 2008-10-31 12:46:39 -0400 | [diff] [blame] | 287 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 288 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
| 289 | cb->start, |
| 290 | cb->start + cb->len - 1, |
| 291 | NULL, 1); |
Chris Mason | 70b99e6 | 2008-10-31 12:46:39 -0400 | [diff] [blame] | 292 | cb->compressed_pages[0]->mapping = NULL; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 293 | |
| 294 | end_compressed_writeback(inode, cb->start, cb->len); |
| 295 | /* note, our inode could be gone now */ |
| 296 | |
| 297 | /* |
| 298 | * release the compressed pages, these came from alloc_page and |
| 299 | * are not attached to the inode at all |
| 300 | */ |
| 301 | index = 0; |
| 302 | for (index = 0; index < cb->nr_pages; index++) { |
| 303 | page = cb->compressed_pages[index]; |
| 304 | page->mapping = NULL; |
| 305 | page_cache_release(page); |
| 306 | } |
| 307 | |
| 308 | /* finally free the cb struct */ |
| 309 | kfree(cb->compressed_pages); |
| 310 | kfree(cb); |
| 311 | out: |
| 312 | bio_put(bio); |
| 313 | } |
| 314 | |
| 315 | /* |
| 316 | * worker function to build and submit bios for previously compressed pages. |
| 317 | * The corresponding pages in the inode should be marked for writeback |
| 318 | * and the compressed pages should have a reference on them for dropping |
| 319 | * when the IO is complete. |
| 320 | * |
| 321 | * This also checksums the file bytes and gets things ready for |
| 322 | * the end io hooks. |
| 323 | */ |
| 324 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, |
| 325 | unsigned long len, u64 disk_start, |
| 326 | unsigned long compressed_len, |
| 327 | struct page **compressed_pages, |
| 328 | unsigned long nr_pages) |
| 329 | { |
| 330 | struct bio *bio = NULL; |
| 331 | struct btrfs_root *root = BTRFS_I(inode)->root; |
| 332 | struct compressed_bio *cb; |
| 333 | unsigned long bytes_left; |
| 334 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; |
| 335 | int page_index = 0; |
| 336 | struct page *page; |
| 337 | u64 first_byte = disk_start; |
| 338 | struct block_device *bdev; |
| 339 | int ret; |
| 340 | |
| 341 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 342 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); |
Yoshinori Sano | dac97e51 | 2011-02-15 12:01:42 +0000 | [diff] [blame^] | 343 | if (!cb) |
| 344 | return -ENOMEM; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 345 | atomic_set(&cb->pending_bios, 0); |
| 346 | cb->errors = 0; |
| 347 | cb->inode = inode; |
| 348 | cb->start = start; |
| 349 | cb->len = len; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 350 | cb->mirror_num = 0; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 351 | cb->compressed_pages = compressed_pages; |
| 352 | cb->compressed_len = compressed_len; |
| 353 | cb->orig_bio = NULL; |
| 354 | cb->nr_pages = nr_pages; |
| 355 | |
| 356 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; |
| 357 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 358 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
Yoshinori Sano | dac97e51 | 2011-02-15 12:01:42 +0000 | [diff] [blame^] | 359 | if(!bio) { |
| 360 | kfree(cb); |
| 361 | return -ENOMEM; |
| 362 | } |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 363 | bio->bi_private = cb; |
| 364 | bio->bi_end_io = end_compressed_bio_write; |
| 365 | atomic_inc(&cb->pending_bios); |
| 366 | |
| 367 | /* create and submit bios for the compressed pages */ |
| 368 | bytes_left = compressed_len; |
Chris Mason | cfbc246 | 2008-10-30 13:22:14 -0400 | [diff] [blame] | 369 | for (page_index = 0; page_index < cb->nr_pages; page_index++) { |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 370 | page = compressed_pages[page_index]; |
| 371 | page->mapping = inode->i_mapping; |
| 372 | if (bio->bi_size) |
| 373 | ret = io_tree->ops->merge_bio_hook(page, 0, |
| 374 | PAGE_CACHE_SIZE, |
| 375 | bio, 0); |
| 376 | else |
| 377 | ret = 0; |
| 378 | |
Chris Mason | 70b99e6 | 2008-10-31 12:46:39 -0400 | [diff] [blame] | 379 | page->mapping = NULL; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 380 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < |
| 381 | PAGE_CACHE_SIZE) { |
| 382 | bio_get(bio); |
| 383 | |
Chris Mason | af09abf | 2008-11-07 12:35:44 -0500 | [diff] [blame] | 384 | /* |
| 385 | * inc the count before we submit the bio so |
| 386 | * we know the end IO handler won't happen before |
| 387 | * we inc the count. Otherwise, the cb might get |
| 388 | * freed before we're done setting it up |
| 389 | */ |
| 390 | atomic_inc(&cb->pending_bios); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 391 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); |
| 392 | BUG_ON(ret); |
| 393 | |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 394 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
| 395 | BUG_ON(ret); |
| 396 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 397 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
| 398 | BUG_ON(ret); |
| 399 | |
| 400 | bio_put(bio); |
| 401 | |
| 402 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 403 | bio->bi_private = cb; |
| 404 | bio->bi_end_io = end_compressed_bio_write; |
| 405 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); |
| 406 | } |
Chris Mason | cfbc246 | 2008-10-30 13:22:14 -0400 | [diff] [blame] | 407 | if (bytes_left < PAGE_CACHE_SIZE) { |
| 408 | printk("bytes left %lu compress len %lu nr %lu\n", |
| 409 | bytes_left, cb->compressed_len, cb->nr_pages); |
| 410 | } |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 411 | bytes_left -= PAGE_CACHE_SIZE; |
| 412 | first_byte += PAGE_CACHE_SIZE; |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 413 | cond_resched(); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 414 | } |
| 415 | bio_get(bio); |
| 416 | |
| 417 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); |
| 418 | BUG_ON(ret); |
| 419 | |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 420 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
| 421 | BUG_ON(ret); |
| 422 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 423 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
| 424 | BUG_ON(ret); |
| 425 | |
| 426 | bio_put(bio); |
| 427 | return 0; |
| 428 | } |
| 429 | |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 430 | static noinline int add_ra_bio_pages(struct inode *inode, |
| 431 | u64 compressed_end, |
| 432 | struct compressed_bio *cb) |
| 433 | { |
| 434 | unsigned long end_index; |
| 435 | unsigned long page_index; |
| 436 | u64 last_offset; |
| 437 | u64 isize = i_size_read(inode); |
| 438 | int ret; |
| 439 | struct page *page; |
| 440 | unsigned long nr_pages = 0; |
| 441 | struct extent_map *em; |
| 442 | struct address_space *mapping = inode->i_mapping; |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 443 | struct extent_map_tree *em_tree; |
| 444 | struct extent_io_tree *tree; |
| 445 | u64 end; |
| 446 | int misses = 0; |
| 447 | |
| 448 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; |
| 449 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); |
| 450 | em_tree = &BTRFS_I(inode)->extent_tree; |
| 451 | tree = &BTRFS_I(inode)->io_tree; |
| 452 | |
| 453 | if (isize == 0) |
| 454 | return 0; |
| 455 | |
| 456 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; |
| 457 | |
Chris Mason | d397712 | 2009-01-05 21:25:51 -0500 | [diff] [blame] | 458 | while (last_offset < compressed_end) { |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 459 | page_index = last_offset >> PAGE_CACHE_SHIFT; |
| 460 | |
| 461 | if (page_index > end_index) |
| 462 | break; |
| 463 | |
| 464 | rcu_read_lock(); |
| 465 | page = radix_tree_lookup(&mapping->page_tree, page_index); |
| 466 | rcu_read_unlock(); |
| 467 | if (page) { |
| 468 | misses++; |
| 469 | if (misses > 4) |
| 470 | break; |
| 471 | goto next; |
| 472 | } |
| 473 | |
Nick Piggin | 28ecb609 | 2010-03-17 13:31:04 +0000 | [diff] [blame] | 474 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & |
| 475 | ~__GFP_FS); |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 476 | if (!page) |
| 477 | break; |
| 478 | |
Nick Piggin | 28ecb609 | 2010-03-17 13:31:04 +0000 | [diff] [blame] | 479 | if (add_to_page_cache_lru(page, mapping, page_index, |
| 480 | GFP_NOFS)) { |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 481 | page_cache_release(page); |
| 482 | goto next; |
| 483 | } |
| 484 | |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 485 | end = last_offset + PAGE_CACHE_SIZE - 1; |
| 486 | /* |
| 487 | * at this point, we have a locked page in the page cache |
| 488 | * for these bytes in the file. But, we have to make |
| 489 | * sure they map to this compressed extent on disk. |
| 490 | */ |
| 491 | set_page_extent_mapped(page); |
| 492 | lock_extent(tree, last_offset, end, GFP_NOFS); |
Chris Mason | 890871b | 2009-09-02 16:24:52 -0400 | [diff] [blame] | 493 | read_lock(&em_tree->lock); |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 494 | em = lookup_extent_mapping(em_tree, last_offset, |
| 495 | PAGE_CACHE_SIZE); |
Chris Mason | 890871b | 2009-09-02 16:24:52 -0400 | [diff] [blame] | 496 | read_unlock(&em_tree->lock); |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 497 | |
| 498 | if (!em || last_offset < em->start || |
| 499 | (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || |
| 500 | (em->block_start >> 9) != cb->orig_bio->bi_sector) { |
| 501 | free_extent_map(em); |
| 502 | unlock_extent(tree, last_offset, end, GFP_NOFS); |
| 503 | unlock_page(page); |
| 504 | page_cache_release(page); |
| 505 | break; |
| 506 | } |
| 507 | free_extent_map(em); |
| 508 | |
| 509 | if (page->index == end_index) { |
| 510 | char *userpage; |
| 511 | size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); |
| 512 | |
| 513 | if (zero_offset) { |
| 514 | int zeros; |
| 515 | zeros = PAGE_CACHE_SIZE - zero_offset; |
| 516 | userpage = kmap_atomic(page, KM_USER0); |
| 517 | memset(userpage + zero_offset, 0, zeros); |
| 518 | flush_dcache_page(page); |
| 519 | kunmap_atomic(userpage, KM_USER0); |
| 520 | } |
| 521 | } |
| 522 | |
| 523 | ret = bio_add_page(cb->orig_bio, page, |
| 524 | PAGE_CACHE_SIZE, 0); |
| 525 | |
| 526 | if (ret == PAGE_CACHE_SIZE) { |
| 527 | nr_pages++; |
| 528 | page_cache_release(page); |
| 529 | } else { |
| 530 | unlock_extent(tree, last_offset, end, GFP_NOFS); |
| 531 | unlock_page(page); |
| 532 | page_cache_release(page); |
| 533 | break; |
| 534 | } |
| 535 | next: |
| 536 | last_offset += PAGE_CACHE_SIZE; |
| 537 | } |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 538 | return 0; |
| 539 | } |
| 540 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 541 | /* |
| 542 | * for a compressed read, the bio we get passed has all the inode pages |
| 543 | * in it. We don't actually do IO on those pages but allocate new ones |
| 544 | * to hold the compressed pages on disk. |
| 545 | * |
| 546 | * bio->bi_sector points to the compressed extent on disk |
| 547 | * bio->bi_io_vec points to all of the inode pages |
| 548 | * bio->bi_vcnt is a count of pages |
| 549 | * |
| 550 | * After the compressed pages are read, we copy the bytes into the |
| 551 | * bio we were passed and then call the bio end_io calls |
| 552 | */ |
| 553 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, |
| 554 | int mirror_num, unsigned long bio_flags) |
| 555 | { |
| 556 | struct extent_io_tree *tree; |
| 557 | struct extent_map_tree *em_tree; |
| 558 | struct compressed_bio *cb; |
| 559 | struct btrfs_root *root = BTRFS_I(inode)->root; |
| 560 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; |
| 561 | unsigned long compressed_len; |
| 562 | unsigned long nr_pages; |
| 563 | unsigned long page_index; |
| 564 | struct page *page; |
| 565 | struct block_device *bdev; |
| 566 | struct bio *comp_bio; |
| 567 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; |
Chris Mason | e04ca62 | 2008-11-10 11:44:58 -0500 | [diff] [blame] | 568 | u64 em_len; |
| 569 | u64 em_start; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 570 | struct extent_map *em; |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 571 | int ret = -ENOMEM; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 572 | u32 *sums; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 573 | |
| 574 | tree = &BTRFS_I(inode)->io_tree; |
| 575 | em_tree = &BTRFS_I(inode)->extent_tree; |
| 576 | |
| 577 | /* we need the actual starting offset of this extent in the file */ |
Chris Mason | 890871b | 2009-09-02 16:24:52 -0400 | [diff] [blame] | 578 | read_lock(&em_tree->lock); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 579 | em = lookup_extent_mapping(em_tree, |
| 580 | page_offset(bio->bi_io_vec->bv_page), |
| 581 | PAGE_CACHE_SIZE); |
Chris Mason | 890871b | 2009-09-02 16:24:52 -0400 | [diff] [blame] | 582 | read_unlock(&em_tree->lock); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 583 | |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 584 | compressed_len = em->block_len; |
| 585 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 586 | if (!cb) |
| 587 | goto out; |
| 588 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 589 | atomic_set(&cb->pending_bios, 0); |
| 590 | cb->errors = 0; |
| 591 | cb->inode = inode; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 592 | cb->mirror_num = mirror_num; |
| 593 | sums = &cb->sums; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 594 | |
Yan Zheng | ff5b7ee | 2008-11-10 07:34:43 -0500 | [diff] [blame] | 595 | cb->start = em->orig_start; |
Chris Mason | e04ca62 | 2008-11-10 11:44:58 -0500 | [diff] [blame] | 596 | em_len = em->len; |
| 597 | em_start = em->start; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 598 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 599 | free_extent_map(em); |
Chris Mason | e04ca62 | 2008-11-10 11:44:58 -0500 | [diff] [blame] | 600 | em = NULL; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 601 | |
| 602 | cb->len = uncompressed_len; |
| 603 | cb->compressed_len = compressed_len; |
Li Zefan | 261507a0 | 2010-12-17 14:21:50 +0800 | [diff] [blame] | 604 | cb->compress_type = extent_compress_type(bio_flags); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 605 | cb->orig_bio = bio; |
| 606 | |
| 607 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / |
| 608 | PAGE_CACHE_SIZE; |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 609 | cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages, |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 610 | GFP_NOFS); |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 611 | if (!cb->compressed_pages) |
| 612 | goto fail1; |
| 613 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 614 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; |
| 615 | |
| 616 | for (page_index = 0; page_index < nr_pages; page_index++) { |
| 617 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | |
| 618 | __GFP_HIGHMEM); |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 619 | if (!cb->compressed_pages[page_index]) |
| 620 | goto fail2; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 621 | } |
| 622 | cb->nr_pages = nr_pages; |
| 623 | |
Chris Mason | e04ca62 | 2008-11-10 11:44:58 -0500 | [diff] [blame] | 624 | add_ra_bio_pages(inode, em_start + em_len, cb); |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 625 | |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 626 | /* include any pages we added in add_ra-bio_pages */ |
| 627 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; |
| 628 | cb->len = uncompressed_len; |
| 629 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 630 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 631 | if (!comp_bio) |
| 632 | goto fail2; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 633 | comp_bio->bi_private = cb; |
| 634 | comp_bio->bi_end_io = end_compressed_bio_read; |
| 635 | atomic_inc(&cb->pending_bios); |
| 636 | |
| 637 | for (page_index = 0; page_index < nr_pages; page_index++) { |
| 638 | page = cb->compressed_pages[page_index]; |
| 639 | page->mapping = inode->i_mapping; |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 640 | page->index = em_start >> PAGE_CACHE_SHIFT; |
| 641 | |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 642 | if (comp_bio->bi_size) |
| 643 | ret = tree->ops->merge_bio_hook(page, 0, |
| 644 | PAGE_CACHE_SIZE, |
| 645 | comp_bio, 0); |
| 646 | else |
| 647 | ret = 0; |
| 648 | |
Chris Mason | 70b99e6 | 2008-10-31 12:46:39 -0400 | [diff] [blame] | 649 | page->mapping = NULL; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 650 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < |
| 651 | PAGE_CACHE_SIZE) { |
| 652 | bio_get(comp_bio); |
| 653 | |
| 654 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); |
| 655 | BUG_ON(ret); |
| 656 | |
Chris Mason | af09abf | 2008-11-07 12:35:44 -0500 | [diff] [blame] | 657 | /* |
| 658 | * inc the count before we submit the bio so |
| 659 | * we know the end IO handler won't happen before |
| 660 | * we inc the count. Otherwise, the cb might get |
| 661 | * freed before we're done setting it up |
| 662 | */ |
| 663 | atomic_inc(&cb->pending_bios); |
| 664 | |
Christoph Hellwig | 6cbff00 | 2009-04-17 10:37:41 +0200 | [diff] [blame] | 665 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 666 | btrfs_lookup_bio_sums(root, inode, comp_bio, |
| 667 | sums); |
| 668 | } |
| 669 | sums += (comp_bio->bi_size + root->sectorsize - 1) / |
| 670 | root->sectorsize; |
| 671 | |
| 672 | ret = btrfs_map_bio(root, READ, comp_bio, |
| 673 | mirror_num, 0); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 674 | BUG_ON(ret); |
| 675 | |
| 676 | bio_put(comp_bio); |
| 677 | |
| 678 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, |
| 679 | GFP_NOFS); |
Chris Mason | 771ed68 | 2008-11-06 22:02:51 -0500 | [diff] [blame] | 680 | comp_bio->bi_private = cb; |
| 681 | comp_bio->bi_end_io = end_compressed_bio_read; |
| 682 | |
| 683 | bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 684 | } |
| 685 | cur_disk_byte += PAGE_CACHE_SIZE; |
| 686 | } |
| 687 | bio_get(comp_bio); |
| 688 | |
| 689 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); |
| 690 | BUG_ON(ret); |
| 691 | |
Christoph Hellwig | 6cbff00 | 2009-04-17 10:37:41 +0200 | [diff] [blame] | 692 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 693 | btrfs_lookup_bio_sums(root, inode, comp_bio, sums); |
Chris Mason | d20f704 | 2008-12-08 16:58:54 -0500 | [diff] [blame] | 694 | |
| 695 | ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 696 | BUG_ON(ret); |
| 697 | |
| 698 | bio_put(comp_bio); |
| 699 | return 0; |
liubo | 6b82ce8 | 2011-01-26 06:21:39 +0000 | [diff] [blame] | 700 | |
| 701 | fail2: |
| 702 | for (page_index = 0; page_index < nr_pages; page_index++) |
| 703 | free_page((unsigned long)cb->compressed_pages[page_index]); |
| 704 | |
| 705 | kfree(cb->compressed_pages); |
| 706 | fail1: |
| 707 | kfree(cb); |
| 708 | out: |
| 709 | free_extent_map(em); |
| 710 | return ret; |
Chris Mason | c8b9781 | 2008-10-29 14:49:59 -0400 | [diff] [blame] | 711 | } |
Li Zefan | 261507a0 | 2010-12-17 14:21:50 +0800 | [diff] [blame] | 712 | |
| 713 | static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES]; |
| 714 | static spinlock_t comp_workspace_lock[BTRFS_COMPRESS_TYPES]; |
| 715 | static int comp_num_workspace[BTRFS_COMPRESS_TYPES]; |
| 716 | static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES]; |
| 717 | static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES]; |
| 718 | |
| 719 | struct btrfs_compress_op *btrfs_compress_op[] = { |
| 720 | &btrfs_zlib_compress, |
Li Zefan | a6fa6fa | 2010-10-25 15:12:26 +0800 | [diff] [blame] | 721 | &btrfs_lzo_compress, |
Li Zefan | 261507a0 | 2010-12-17 14:21:50 +0800 | [diff] [blame] | 722 | }; |
| 723 | |
| 724 | int __init btrfs_init_compress(void) |
| 725 | { |
| 726 | int i; |
| 727 | |
| 728 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { |
| 729 | INIT_LIST_HEAD(&comp_idle_workspace[i]); |
| 730 | spin_lock_init(&comp_workspace_lock[i]); |
| 731 | atomic_set(&comp_alloc_workspace[i], 0); |
| 732 | init_waitqueue_head(&comp_workspace_wait[i]); |
| 733 | } |
| 734 | return 0; |
| 735 | } |
| 736 | |
| 737 | /* |
| 738 | * this finds an available workspace or allocates a new one |
| 739 | * ERR_PTR is returned if things go bad. |
| 740 | */ |
| 741 | static struct list_head *find_workspace(int type) |
| 742 | { |
| 743 | struct list_head *workspace; |
| 744 | int cpus = num_online_cpus(); |
| 745 | int idx = type - 1; |
| 746 | |
| 747 | struct list_head *idle_workspace = &comp_idle_workspace[idx]; |
| 748 | spinlock_t *workspace_lock = &comp_workspace_lock[idx]; |
| 749 | atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; |
| 750 | wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; |
| 751 | int *num_workspace = &comp_num_workspace[idx]; |
| 752 | again: |
| 753 | spin_lock(workspace_lock); |
| 754 | if (!list_empty(idle_workspace)) { |
| 755 | workspace = idle_workspace->next; |
| 756 | list_del(workspace); |
| 757 | (*num_workspace)--; |
| 758 | spin_unlock(workspace_lock); |
| 759 | return workspace; |
| 760 | |
| 761 | } |
| 762 | if (atomic_read(alloc_workspace) > cpus) { |
| 763 | DEFINE_WAIT(wait); |
| 764 | |
| 765 | spin_unlock(workspace_lock); |
| 766 | prepare_to_wait(workspace_wait, &wait, TASK_UNINTERRUPTIBLE); |
| 767 | if (atomic_read(alloc_workspace) > cpus && !*num_workspace) |
| 768 | schedule(); |
| 769 | finish_wait(workspace_wait, &wait); |
| 770 | goto again; |
| 771 | } |
| 772 | atomic_inc(alloc_workspace); |
| 773 | spin_unlock(workspace_lock); |
| 774 | |
| 775 | workspace = btrfs_compress_op[idx]->alloc_workspace(); |
| 776 | if (IS_ERR(workspace)) { |
| 777 | atomic_dec(alloc_workspace); |
| 778 | wake_up(workspace_wait); |
| 779 | } |
| 780 | return workspace; |
| 781 | } |
| 782 | |
| 783 | /* |
| 784 | * put a workspace struct back on the list or free it if we have enough |
| 785 | * idle ones sitting around |
| 786 | */ |
| 787 | static void free_workspace(int type, struct list_head *workspace) |
| 788 | { |
| 789 | int idx = type - 1; |
| 790 | struct list_head *idle_workspace = &comp_idle_workspace[idx]; |
| 791 | spinlock_t *workspace_lock = &comp_workspace_lock[idx]; |
| 792 | atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; |
| 793 | wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; |
| 794 | int *num_workspace = &comp_num_workspace[idx]; |
| 795 | |
| 796 | spin_lock(workspace_lock); |
| 797 | if (*num_workspace < num_online_cpus()) { |
| 798 | list_add_tail(workspace, idle_workspace); |
| 799 | (*num_workspace)++; |
| 800 | spin_unlock(workspace_lock); |
| 801 | goto wake; |
| 802 | } |
| 803 | spin_unlock(workspace_lock); |
| 804 | |
| 805 | btrfs_compress_op[idx]->free_workspace(workspace); |
| 806 | atomic_dec(alloc_workspace); |
| 807 | wake: |
| 808 | if (waitqueue_active(workspace_wait)) |
| 809 | wake_up(workspace_wait); |
| 810 | } |
| 811 | |
| 812 | /* |
| 813 | * cleanup function for module exit |
| 814 | */ |
| 815 | static void free_workspaces(void) |
| 816 | { |
| 817 | struct list_head *workspace; |
| 818 | int i; |
| 819 | |
| 820 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { |
| 821 | while (!list_empty(&comp_idle_workspace[i])) { |
| 822 | workspace = comp_idle_workspace[i].next; |
| 823 | list_del(workspace); |
| 824 | btrfs_compress_op[i]->free_workspace(workspace); |
| 825 | atomic_dec(&comp_alloc_workspace[i]); |
| 826 | } |
| 827 | } |
| 828 | } |
| 829 | |
| 830 | /* |
| 831 | * given an address space and start/len, compress the bytes. |
| 832 | * |
| 833 | * pages are allocated to hold the compressed result and stored |
| 834 | * in 'pages' |
| 835 | * |
| 836 | * out_pages is used to return the number of pages allocated. There |
| 837 | * may be pages allocated even if we return an error |
| 838 | * |
| 839 | * total_in is used to return the number of bytes actually read. It |
| 840 | * may be smaller then len if we had to exit early because we |
| 841 | * ran out of room in the pages array or because we cross the |
| 842 | * max_out threshold. |
| 843 | * |
| 844 | * total_out is used to return the total number of compressed bytes |
| 845 | * |
| 846 | * max_out tells us the max number of bytes that we're allowed to |
| 847 | * stuff into pages |
| 848 | */ |
| 849 | int btrfs_compress_pages(int type, struct address_space *mapping, |
| 850 | u64 start, unsigned long len, |
| 851 | struct page **pages, |
| 852 | unsigned long nr_dest_pages, |
| 853 | unsigned long *out_pages, |
| 854 | unsigned long *total_in, |
| 855 | unsigned long *total_out, |
| 856 | unsigned long max_out) |
| 857 | { |
| 858 | struct list_head *workspace; |
| 859 | int ret; |
| 860 | |
| 861 | workspace = find_workspace(type); |
| 862 | if (IS_ERR(workspace)) |
| 863 | return -1; |
| 864 | |
| 865 | ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, |
| 866 | start, len, pages, |
| 867 | nr_dest_pages, out_pages, |
| 868 | total_in, total_out, |
| 869 | max_out); |
| 870 | free_workspace(type, workspace); |
| 871 | return ret; |
| 872 | } |
| 873 | |
| 874 | /* |
| 875 | * pages_in is an array of pages with compressed data. |
| 876 | * |
| 877 | * disk_start is the starting logical offset of this array in the file |
| 878 | * |
| 879 | * bvec is a bio_vec of pages from the file that we want to decompress into |
| 880 | * |
| 881 | * vcnt is the count of pages in the biovec |
| 882 | * |
| 883 | * srclen is the number of bytes in pages_in |
| 884 | * |
| 885 | * The basic idea is that we have a bio that was created by readpages. |
| 886 | * The pages in the bio are for the uncompressed data, and they may not |
| 887 | * be contiguous. They all correspond to the range of bytes covered by |
| 888 | * the compressed extent. |
| 889 | */ |
| 890 | int btrfs_decompress_biovec(int type, struct page **pages_in, u64 disk_start, |
| 891 | struct bio_vec *bvec, int vcnt, size_t srclen) |
| 892 | { |
| 893 | struct list_head *workspace; |
| 894 | int ret; |
| 895 | |
| 896 | workspace = find_workspace(type); |
| 897 | if (IS_ERR(workspace)) |
| 898 | return -ENOMEM; |
| 899 | |
| 900 | ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in, |
| 901 | disk_start, |
| 902 | bvec, vcnt, srclen); |
| 903 | free_workspace(type, workspace); |
| 904 | return ret; |
| 905 | } |
| 906 | |
| 907 | /* |
| 908 | * a less complex decompression routine. Our compressed data fits in a |
| 909 | * single page, and we want to read a single page out of it. |
| 910 | * start_byte tells us the offset into the compressed data we're interested in |
| 911 | */ |
| 912 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, |
| 913 | unsigned long start_byte, size_t srclen, size_t destlen) |
| 914 | { |
| 915 | struct list_head *workspace; |
| 916 | int ret; |
| 917 | |
| 918 | workspace = find_workspace(type); |
| 919 | if (IS_ERR(workspace)) |
| 920 | return -ENOMEM; |
| 921 | |
| 922 | ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, |
| 923 | dest_page, start_byte, |
| 924 | srclen, destlen); |
| 925 | |
| 926 | free_workspace(type, workspace); |
| 927 | return ret; |
| 928 | } |
| 929 | |
Alexey Charkov | 8e4eef7 | 2011-02-02 21:15:35 +0000 | [diff] [blame] | 930 | void btrfs_exit_compress(void) |
Li Zefan | 261507a0 | 2010-12-17 14:21:50 +0800 | [diff] [blame] | 931 | { |
| 932 | free_workspaces(); |
| 933 | } |
Li Zefan | 3a39c18 | 2010-11-08 15:22:19 +0800 | [diff] [blame] | 934 | |
| 935 | /* |
| 936 | * Copy uncompressed data from working buffer to pages. |
| 937 | * |
| 938 | * buf_start is the byte offset we're of the start of our workspace buffer. |
| 939 | * |
| 940 | * total_out is the last byte of the buffer |
| 941 | */ |
| 942 | int btrfs_decompress_buf2page(char *buf, unsigned long buf_start, |
| 943 | unsigned long total_out, u64 disk_start, |
| 944 | struct bio_vec *bvec, int vcnt, |
| 945 | unsigned long *page_index, |
| 946 | unsigned long *pg_offset) |
| 947 | { |
| 948 | unsigned long buf_offset; |
| 949 | unsigned long current_buf_start; |
| 950 | unsigned long start_byte; |
| 951 | unsigned long working_bytes = total_out - buf_start; |
| 952 | unsigned long bytes; |
| 953 | char *kaddr; |
| 954 | struct page *page_out = bvec[*page_index].bv_page; |
| 955 | |
| 956 | /* |
| 957 | * start byte is the first byte of the page we're currently |
| 958 | * copying into relative to the start of the compressed data. |
| 959 | */ |
| 960 | start_byte = page_offset(page_out) - disk_start; |
| 961 | |
| 962 | /* we haven't yet hit data corresponding to this page */ |
| 963 | if (total_out <= start_byte) |
| 964 | return 1; |
| 965 | |
| 966 | /* |
| 967 | * the start of the data we care about is offset into |
| 968 | * the middle of our working buffer |
| 969 | */ |
| 970 | if (total_out > start_byte && buf_start < start_byte) { |
| 971 | buf_offset = start_byte - buf_start; |
| 972 | working_bytes -= buf_offset; |
| 973 | } else { |
| 974 | buf_offset = 0; |
| 975 | } |
| 976 | current_buf_start = buf_start; |
| 977 | |
| 978 | /* copy bytes from the working buffer into the pages */ |
| 979 | while (working_bytes > 0) { |
| 980 | bytes = min(PAGE_CACHE_SIZE - *pg_offset, |
| 981 | PAGE_CACHE_SIZE - buf_offset); |
| 982 | bytes = min(bytes, working_bytes); |
| 983 | kaddr = kmap_atomic(page_out, KM_USER0); |
| 984 | memcpy(kaddr + *pg_offset, buf + buf_offset, bytes); |
| 985 | kunmap_atomic(kaddr, KM_USER0); |
| 986 | flush_dcache_page(page_out); |
| 987 | |
| 988 | *pg_offset += bytes; |
| 989 | buf_offset += bytes; |
| 990 | working_bytes -= bytes; |
| 991 | current_buf_start += bytes; |
| 992 | |
| 993 | /* check if we need to pick another page */ |
| 994 | if (*pg_offset == PAGE_CACHE_SIZE) { |
| 995 | (*page_index)++; |
| 996 | if (*page_index >= vcnt) |
| 997 | return 0; |
| 998 | |
| 999 | page_out = bvec[*page_index].bv_page; |
| 1000 | *pg_offset = 0; |
| 1001 | start_byte = page_offset(page_out) - disk_start; |
| 1002 | |
| 1003 | /* |
| 1004 | * make sure our new page is covered by this |
| 1005 | * working buffer |
| 1006 | */ |
| 1007 | if (total_out <= start_byte) |
| 1008 | return 1; |
| 1009 | |
| 1010 | /* |
| 1011 | * the next page in the biovec might not be adjacent |
| 1012 | * to the last page, but it might still be found |
| 1013 | * inside this working buffer. bump our offset pointer |
| 1014 | */ |
| 1015 | if (total_out > start_byte && |
| 1016 | current_buf_start < start_byte) { |
| 1017 | buf_offset = start_byte - buf_start; |
| 1018 | working_bytes = total_out - start_byte; |
| 1019 | current_buf_start = buf_start + buf_offset; |
| 1020 | } |
| 1021 | } |
| 1022 | } |
| 1023 | |
| 1024 | return 1; |
| 1025 | } |