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1// SPDX-License-Identifier: GPL-2.02/*3 * linux/fs/ext4/page-io.c4 *5 * This contains the new page_io functions for ext46 *7 * Written by Theodore Ts'o, 2010.8 */9 10#include <linux/fs.h>11#include <linux/time.h>12#include <linux/highuid.h>13#include <linux/pagemap.h>14#include <linux/quotaops.h>15#include <linux/string.h>16#include <linux/buffer_head.h>17#include <linux/writeback.h>18#include <linux/pagevec.h>19#include <linux/mpage.h>20#include <linux/namei.h>21#include <linux/uio.h>22#include <linux/bio.h>23#include <linux/workqueue.h>24#include <linux/kernel.h>25#include <linux/slab.h>26#include <linux/mm.h>27#include <linux/sched/mm.h>28 29#include "ext4_jbd2.h"30#include "xattr.h"31#include "acl.h"32 33static struct kmem_cache *io_end_cachep;34static struct kmem_cache *io_end_vec_cachep;35 36int __init ext4_init_pageio(void)37{38 io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);39 if (io_end_cachep == NULL)40 return -ENOMEM;41 42 io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0);43 if (io_end_vec_cachep == NULL) {44 kmem_cache_destroy(io_end_cachep);45 return -ENOMEM;46 }47 return 0;48}49 50void ext4_exit_pageio(void)51{52 kmem_cache_destroy(io_end_cachep);53 kmem_cache_destroy(io_end_vec_cachep);54}55 56struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end)57{58 struct ext4_io_end_vec *io_end_vec;59 60 io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS);61 if (!io_end_vec)62 return ERR_PTR(-ENOMEM);63 INIT_LIST_HEAD(&io_end_vec->list);64 list_add_tail(&io_end_vec->list, &io_end->list_vec);65 return io_end_vec;66}67 68static void ext4_free_io_end_vec(ext4_io_end_t *io_end)69{70 struct ext4_io_end_vec *io_end_vec, *tmp;71 72 if (list_empty(&io_end->list_vec))73 return;74 list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) {75 list_del(&io_end_vec->list);76 kmem_cache_free(io_end_vec_cachep, io_end_vec);77 }78}79 80struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end)81{82 BUG_ON(list_empty(&io_end->list_vec));83 return list_last_entry(&io_end->list_vec, struct ext4_io_end_vec, list);84}85 86/*87 * Print an buffer I/O error compatible with the fs/buffer.c. This88 * provides compatibility with dmesg scrapers that look for a specific89 * buffer I/O error message. We really need a unified error reporting90 * structure to userspace ala Digital Unix's uerf system, but it's91 * probably not going to happen in my lifetime, due to LKML politics...92 */93static void buffer_io_error(struct buffer_head *bh)94{95 printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n",96 bh->b_bdev,97 (unsigned long long)bh->b_blocknr);98}99 100static void ext4_finish_bio(struct bio *bio)101{102 struct folio_iter fi;103 104 bio_for_each_folio_all(fi, bio) {105 struct folio *folio = fi.folio;106 struct folio *io_folio = NULL;107 struct buffer_head *bh, *head;108 size_t bio_start = fi.offset;109 size_t bio_end = bio_start + fi.length;110 unsigned under_io = 0;111 unsigned long flags;112 113 if (fscrypt_is_bounce_folio(folio)) {114 io_folio = folio;115 folio = fscrypt_pagecache_folio(folio);116 }117 118 if (bio->bi_status) {119 int err = blk_status_to_errno(bio->bi_status);120 mapping_set_error(folio->mapping, err);121 }122 bh = head = folio_buffers(folio);123 /*124 * We check all buffers in the folio under b_uptodate_lock125 * to avoid races with other end io clearing async_write flags126 */127 spin_lock_irqsave(&head->b_uptodate_lock, flags);128 do {129 if (bh_offset(bh) < bio_start ||130 bh_offset(bh) + bh->b_size > bio_end) {131 if (buffer_async_write(bh))132 under_io++;133 continue;134 }135 clear_buffer_async_write(bh);136 if (bio->bi_status) {137 set_buffer_write_io_error(bh);138 buffer_io_error(bh);139 }140 } while ((bh = bh->b_this_page) != head);141 spin_unlock_irqrestore(&head->b_uptodate_lock, flags);142 if (!under_io) {143 fscrypt_free_bounce_page(&io_folio->page);144 folio_end_writeback(folio);145 }146 }147}148 149static void ext4_release_io_end(ext4_io_end_t *io_end)150{151 struct bio *bio, *next_bio;152 153 BUG_ON(!list_empty(&io_end->list));154 BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);155 WARN_ON(io_end->handle);156 157 for (bio = io_end->bio; bio; bio = next_bio) {158 next_bio = bio->bi_private;159 ext4_finish_bio(bio);160 bio_put(bio);161 }162 ext4_free_io_end_vec(io_end);163 kmem_cache_free(io_end_cachep, io_end);164}165 166/*167 * Check a range of space and convert unwritten extents to written. Note that168 * we are protected from truncate touching same part of extent tree by the169 * fact that truncate code waits for all DIO to finish (thus exclusion from170 * direct IO is achieved) and also waits for PageWriteback bits. Thus we171 * cannot get to ext4_ext_truncate() before all IOs overlapping that range are172 * completed (happens from ext4_free_ioend()).173 */174static int ext4_end_io_end(ext4_io_end_t *io_end)175{176 struct inode *inode = io_end->inode;177 handle_t *handle = io_end->handle;178 int ret = 0;179 180 ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p,"181 "list->prev 0x%p\n",182 io_end, inode->i_ino, io_end->list.next, io_end->list.prev);183 184 io_end->handle = NULL; /* Following call will use up the handle */185 ret = ext4_convert_unwritten_io_end_vec(handle, io_end);186 if (ret < 0 && !ext4_forced_shutdown(inode->i_sb)) {187 ext4_msg(inode->i_sb, KERN_EMERG,188 "failed to convert unwritten extents to written "189 "extents -- potential data loss! "190 "(inode %lu, error %d)", inode->i_ino, ret);191 }192 ext4_clear_io_unwritten_flag(io_end);193 ext4_release_io_end(io_end);194 return ret;195}196 197static void dump_completed_IO(struct inode *inode, struct list_head *head)198{199#ifdef EXT4FS_DEBUG200 struct list_head *cur, *before, *after;201 ext4_io_end_t *io_end, *io_end0, *io_end1;202 203 if (list_empty(head))204 return;205 206 ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);207 list_for_each_entry(io_end, head, list) {208 cur = &io_end->list;209 before = cur->prev;210 io_end0 = container_of(before, ext4_io_end_t, list);211 after = cur->next;212 io_end1 = container_of(after, ext4_io_end_t, list);213 214 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",215 io_end, inode->i_ino, io_end0, io_end1);216 }217#endif218}219 220/* Add the io_end to per-inode completed end_io list. */221static void ext4_add_complete_io(ext4_io_end_t *io_end)222{223 struct ext4_inode_info *ei = EXT4_I(io_end->inode);224 struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);225 struct workqueue_struct *wq;226 unsigned long flags;227 228 /* Only reserved conversions from writeback should enter here */229 WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));230 WARN_ON(!io_end->handle && sbi->s_journal);231 spin_lock_irqsave(&ei->i_completed_io_lock, flags);232 wq = sbi->rsv_conversion_wq;233 if (list_empty(&ei->i_rsv_conversion_list))234 queue_work(wq, &ei->i_rsv_conversion_work);235 list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);236 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);237}238 239static int ext4_do_flush_completed_IO(struct inode *inode,240 struct list_head *head)241{242 ext4_io_end_t *io_end;243 struct list_head unwritten;244 unsigned long flags;245 struct ext4_inode_info *ei = EXT4_I(inode);246 int err, ret = 0;247 248 spin_lock_irqsave(&ei->i_completed_io_lock, flags);249 dump_completed_IO(inode, head);250 list_replace_init(head, &unwritten);251 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);252 253 while (!list_empty(&unwritten)) {254 io_end = list_entry(unwritten.next, ext4_io_end_t, list);255 BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));256 list_del_init(&io_end->list);257 258 err = ext4_end_io_end(io_end);259 if (unlikely(!ret && err))260 ret = err;261 }262 return ret;263}264 265/*266 * work on completed IO, to convert unwritten extents to extents267 */268void ext4_end_io_rsv_work(struct work_struct *work)269{270 struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,271 i_rsv_conversion_work);272 ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);273}274 275ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)276{277 ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);278 279 if (io_end) {280 io_end->inode = inode;281 INIT_LIST_HEAD(&io_end->list);282 INIT_LIST_HEAD(&io_end->list_vec);283 refcount_set(&io_end->count, 1);284 }285 return io_end;286}287 288void ext4_put_io_end_defer(ext4_io_end_t *io_end)289{290 if (refcount_dec_and_test(&io_end->count)) {291 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) ||292 list_empty(&io_end->list_vec)) {293 ext4_release_io_end(io_end);294 return;295 }296 ext4_add_complete_io(io_end);297 }298}299 300int ext4_put_io_end(ext4_io_end_t *io_end)301{302 int err = 0;303 304 if (refcount_dec_and_test(&io_end->count)) {305 if (io_end->flag & EXT4_IO_END_UNWRITTEN) {306 err = ext4_convert_unwritten_io_end_vec(io_end->handle,307 io_end);308 io_end->handle = NULL;309 ext4_clear_io_unwritten_flag(io_end);310 }311 ext4_release_io_end(io_end);312 }313 return err;314}315 316ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)317{318 refcount_inc(&io_end->count);319 return io_end;320}321 322/* BIO completion function for page writeback */323static void ext4_end_bio(struct bio *bio)324{325 ext4_io_end_t *io_end = bio->bi_private;326 sector_t bi_sector = bio->bi_iter.bi_sector;327 328 if (WARN_ONCE(!io_end, "io_end is NULL: %pg: sector %Lu len %u err %d\n",329 bio->bi_bdev,330 (long long) bio->bi_iter.bi_sector,331 (unsigned) bio_sectors(bio),332 bio->bi_status)) {333 ext4_finish_bio(bio);334 bio_put(bio);335 return;336 }337 bio->bi_end_io = NULL;338 339 if (bio->bi_status) {340 struct inode *inode = io_end->inode;341 342 ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "343 "starting block %llu)",344 bio->bi_status, inode->i_ino,345 (unsigned long long)346 bi_sector >> (inode->i_blkbits - 9));347 mapping_set_error(inode->i_mapping,348 blk_status_to_errno(bio->bi_status));349 }350 351 if (io_end->flag & EXT4_IO_END_UNWRITTEN) {352 /*353 * Link bio into list hanging from io_end. We have to do it354 * atomically as bio completions can be racing against each355 * other.356 */357 bio->bi_private = xchg(&io_end->bio, bio);358 ext4_put_io_end_defer(io_end);359 } else {360 /*361 * Drop io_end reference early. Inode can get freed once362 * we finish the bio.363 */364 ext4_put_io_end_defer(io_end);365 ext4_finish_bio(bio);366 bio_put(bio);367 }368}369 370void ext4_io_submit(struct ext4_io_submit *io)371{372 struct bio *bio = io->io_bio;373 374 if (bio) {375 if (io->io_wbc->sync_mode == WB_SYNC_ALL)376 io->io_bio->bi_opf |= REQ_SYNC;377 submit_bio(io->io_bio);378 }379 io->io_bio = NULL;380}381 382void ext4_io_submit_init(struct ext4_io_submit *io,383 struct writeback_control *wbc)384{385 io->io_wbc = wbc;386 io->io_bio = NULL;387 io->io_end = NULL;388}389 390static void io_submit_init_bio(struct ext4_io_submit *io,391 struct buffer_head *bh)392{393 struct bio *bio;394 395 /*396 * bio_alloc will _always_ be able to allocate a bio if397 * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset().398 */399 bio = bio_alloc(bh->b_bdev, BIO_MAX_VECS, REQ_OP_WRITE, GFP_NOIO);400 fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);401 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);402 bio->bi_end_io = ext4_end_bio;403 bio->bi_private = ext4_get_io_end(io->io_end);404 io->io_bio = bio;405 io->io_next_block = bh->b_blocknr;406 wbc_init_bio(io->io_wbc, bio);407}408 409static void io_submit_add_bh(struct ext4_io_submit *io,410 struct inode *inode,411 struct folio *folio,412 struct folio *io_folio,413 struct buffer_head *bh)414{415 if (io->io_bio && (bh->b_blocknr != io->io_next_block ||416 !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {417submit_and_retry:418 ext4_io_submit(io);419 }420 if (io->io_bio == NULL)421 io_submit_init_bio(io, bh);422 if (!bio_add_folio(io->io_bio, io_folio, bh->b_size, bh_offset(bh)))423 goto submit_and_retry;424 wbc_account_cgroup_owner(io->io_wbc, &folio->page, bh->b_size);425 io->io_next_block++;426}427 428int ext4_bio_write_folio(struct ext4_io_submit *io, struct folio *folio,429 size_t len)430{431 struct folio *io_folio = folio;432 struct inode *inode = folio->mapping->host;433 unsigned block_start;434 struct buffer_head *bh, *head;435 int ret = 0;436 int nr_to_submit = 0;437 struct writeback_control *wbc = io->io_wbc;438 bool keep_towrite = false;439 440 BUG_ON(!folio_test_locked(folio));441 BUG_ON(folio_test_writeback(folio));442 443 /*444 * Comments copied from block_write_full_folio:445 *446 * The folio straddles i_size. It must be zeroed out on each and every447 * writepage invocation because it may be mmapped. "A file is mapped448 * in multiples of the page size. For a file that is not a multiple of449 * the page size, the remaining memory is zeroed when mapped, and450 * writes to that region are not written out to the file."451 */452 if (len < folio_size(folio))453 folio_zero_segment(folio, len, folio_size(folio));454 /*455 * In the first loop we prepare and mark buffers to submit. We have to456 * mark all buffers in the folio before submitting so that457 * folio_end_writeback() cannot be called from ext4_end_bio() when IO458 * on the first buffer finishes and we are still working on submitting459 * the second buffer.460 */461 bh = head = folio_buffers(folio);462 do {463 block_start = bh_offset(bh);464 if (block_start >= len) {465 clear_buffer_dirty(bh);466 set_buffer_uptodate(bh);467 continue;468 }469 if (!buffer_dirty(bh) || buffer_delay(bh) ||470 !buffer_mapped(bh) || buffer_unwritten(bh)) {471 /* A hole? We can safely clear the dirty bit */472 if (!buffer_mapped(bh))473 clear_buffer_dirty(bh);474 /*475 * Keeping dirty some buffer we cannot write? Make sure476 * to redirty the folio and keep TOWRITE tag so that477 * racing WB_SYNC_ALL writeback does not skip the folio.478 * This happens e.g. when doing writeout for479 * transaction commit or when journalled data is not480 * yet committed.481 */482 if (buffer_dirty(bh) ||483 (buffer_jbd(bh) && buffer_jbddirty(bh))) {484 if (!folio_test_dirty(folio))485 folio_redirty_for_writepage(wbc, folio);486 keep_towrite = true;487 }488 continue;489 }490 if (buffer_new(bh))491 clear_buffer_new(bh);492 set_buffer_async_write(bh);493 clear_buffer_dirty(bh);494 nr_to_submit++;495 } while ((bh = bh->b_this_page) != head);496 497 /* Nothing to submit? Just unlock the folio... */498 if (!nr_to_submit)499 return 0;500 501 bh = head = folio_buffers(folio);502 503 /*504 * If any blocks are being written to an encrypted file, encrypt them505 * into a bounce page. For simplicity, just encrypt until the last506 * block which might be needed. This may cause some unneeded blocks507 * (e.g. holes) to be unnecessarily encrypted, but this is rare and508 * can't happen in the common case of blocksize == PAGE_SIZE.509 */510 if (fscrypt_inode_uses_fs_layer_crypto(inode)) {511 gfp_t gfp_flags = GFP_NOFS;512 unsigned int enc_bytes = round_up(len, i_blocksize(inode));513 struct page *bounce_page;514 515 /*516 * Since bounce page allocation uses a mempool, we can only use517 * a waiting mask (i.e. request guaranteed allocation) on the518 * first page of the bio. Otherwise it can deadlock.519 */520 if (io->io_bio)521 gfp_flags = GFP_NOWAIT | __GFP_NOWARN;522 retry_encrypt:523 bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page,524 enc_bytes, 0, gfp_flags);525 if (IS_ERR(bounce_page)) {526 ret = PTR_ERR(bounce_page);527 if (ret == -ENOMEM &&528 (io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) {529 gfp_t new_gfp_flags = GFP_NOFS;530 if (io->io_bio)531 ext4_io_submit(io);532 else533 new_gfp_flags |= __GFP_NOFAIL;534 memalloc_retry_wait(gfp_flags);535 gfp_flags = new_gfp_flags;536 goto retry_encrypt;537 }538 539 printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);540 folio_redirty_for_writepage(wbc, folio);541 do {542 if (buffer_async_write(bh)) {543 clear_buffer_async_write(bh);544 set_buffer_dirty(bh);545 }546 bh = bh->b_this_page;547 } while (bh != head);548 549 return ret;550 }551 io_folio = page_folio(bounce_page);552 }553 554 __folio_start_writeback(folio, keep_towrite);555 556 /* Now submit buffers to write */557 do {558 if (!buffer_async_write(bh))559 continue;560 io_submit_add_bh(io, inode, folio, io_folio, bh);561 } while ((bh = bh->b_this_page) != head);562 563 return 0;564}565