| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/fs/ext4/page-io.c |
| * |
| * This contains the new page_io functions for ext4 |
| * |
| * Written by Theodore Ts'o, 2010. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/time.h> |
| #include <linux/highuid.h> |
| #include <linux/pagemap.h> |
| #include <linux/quotaops.h> |
| #include <linux/string.h> |
| #include <linux/buffer_head.h> |
| #include <linux/writeback.h> |
| #include <linux/pagevec.h> |
| #include <linux/mpage.h> |
| #include <linux/namei.h> |
| #include <linux/uio.h> |
| #include <linux/bio.h> |
| #include <linux/workqueue.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/mm.h> |
| #include <linux/sched/mm.h> |
| |
| #include "ext4_jbd2.h" |
| #include "xattr.h" |
| #include "acl.h" |
| |
| static struct kmem_cache *io_end_cachep; |
| static struct kmem_cache *io_end_vec_cachep; |
| |
| int __init ext4_init_pageio(void) |
| { |
| io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); |
| if (io_end_cachep == NULL) |
| return -ENOMEM; |
| |
| io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0); |
| if (io_end_vec_cachep == NULL) { |
| kmem_cache_destroy(io_end_cachep); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| void ext4_exit_pageio(void) |
| { |
| kmem_cache_destroy(io_end_cachep); |
| kmem_cache_destroy(io_end_vec_cachep); |
| } |
| |
| struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end) |
| { |
| struct ext4_io_end_vec *io_end_vec; |
| |
| io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS); |
| if (!io_end_vec) |
| return ERR_PTR(-ENOMEM); |
| INIT_LIST_HEAD(&io_end_vec->list); |
| list_add_tail(&io_end_vec->list, &io_end->list_vec); |
| return io_end_vec; |
| } |
| |
| static void ext4_free_io_end_vec(ext4_io_end_t *io_end) |
| { |
| struct ext4_io_end_vec *io_end_vec, *tmp; |
| |
| if (list_empty(&io_end->list_vec)) |
| return; |
| list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) { |
| list_del(&io_end_vec->list); |
| kmem_cache_free(io_end_vec_cachep, io_end_vec); |
| } |
| } |
| |
| struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end) |
| { |
| BUG_ON(list_empty(&io_end->list_vec)); |
| return list_last_entry(&io_end->list_vec, struct ext4_io_end_vec, list); |
| } |
| |
| /* |
| * Print an buffer I/O error compatible with the fs/buffer.c. This |
| * provides compatibility with dmesg scrapers that look for a specific |
| * buffer I/O error message. We really need a unified error reporting |
| * structure to userspace ala Digital Unix's uerf system, but it's |
| * probably not going to happen in my lifetime, due to LKML politics... |
| */ |
| static void buffer_io_error(struct buffer_head *bh) |
| { |
| printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n", |
| bh->b_bdev, |
| (unsigned long long)bh->b_blocknr); |
| } |
| |
| static void ext4_finish_bio(struct bio *bio) |
| { |
| struct bio_vec *bvec; |
| struct bvec_iter_all iter_all; |
| |
| bio_for_each_segment_all(bvec, bio, iter_all) { |
| struct page *page = bvec->bv_page; |
| struct page *bounce_page = NULL; |
| struct buffer_head *bh, *head; |
| unsigned bio_start = bvec->bv_offset; |
| unsigned bio_end = bio_start + bvec->bv_len; |
| unsigned under_io = 0; |
| unsigned long flags; |
| |
| if (fscrypt_is_bounce_page(page)) { |
| bounce_page = page; |
| page = fscrypt_pagecache_page(bounce_page); |
| } |
| |
| if (bio->bi_status) { |
| SetPageError(page); |
| mapping_set_error(page->mapping, -EIO); |
| } |
| bh = head = page_buffers(page); |
| /* |
| * We check all buffers in the page under b_uptodate_lock |
| * to avoid races with other end io clearing async_write flags |
| */ |
| spin_lock_irqsave(&head->b_uptodate_lock, flags); |
| do { |
| if (bh_offset(bh) < bio_start || |
| bh_offset(bh) + bh->b_size > bio_end) { |
| if (buffer_async_write(bh)) |
| under_io++; |
| continue; |
| } |
| clear_buffer_async_write(bh); |
| if (bio->bi_status) { |
| set_buffer_write_io_error(bh); |
| buffer_io_error(bh); |
| } |
| } while ((bh = bh->b_this_page) != head); |
| spin_unlock_irqrestore(&head->b_uptodate_lock, flags); |
| if (!under_io) { |
| fscrypt_free_bounce_page(bounce_page); |
| end_page_writeback(page); |
| } |
| } |
| } |
| |
| static void ext4_release_io_end(ext4_io_end_t *io_end) |
| { |
| struct bio *bio, *next_bio; |
| |
| BUG_ON(!list_empty(&io_end->list)); |
| BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN); |
| WARN_ON(io_end->handle); |
| |
| for (bio = io_end->bio; bio; bio = next_bio) { |
| next_bio = bio->bi_private; |
| ext4_finish_bio(bio); |
| bio_put(bio); |
| } |
| ext4_free_io_end_vec(io_end); |
| kmem_cache_free(io_end_cachep, io_end); |
| } |
| |
| /* |
| * Check a range of space and convert unwritten extents to written. Note that |
| * we are protected from truncate touching same part of extent tree by the |
| * fact that truncate code waits for all DIO to finish (thus exclusion from |
| * direct IO is achieved) and also waits for PageWriteback bits. Thus we |
| * cannot get to ext4_ext_truncate() before all IOs overlapping that range are |
| * completed (happens from ext4_free_ioend()). |
| */ |
| static int ext4_end_io_end(ext4_io_end_t *io_end) |
| { |
| struct inode *inode = io_end->inode; |
| handle_t *handle = io_end->handle; |
| int ret = 0; |
| |
| ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p," |
| "list->prev 0x%p\n", |
| io_end, inode->i_ino, io_end->list.next, io_end->list.prev); |
| |
| io_end->handle = NULL; /* Following call will use up the handle */ |
| ret = ext4_convert_unwritten_io_end_vec(handle, io_end); |
| if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) { |
| ext4_msg(inode->i_sb, KERN_EMERG, |
| "failed to convert unwritten extents to written " |
| "extents -- potential data loss! " |
| "(inode %lu, error %d)", inode->i_ino, ret); |
| } |
| ext4_clear_io_unwritten_flag(io_end); |
| ext4_release_io_end(io_end); |
| return ret; |
| } |
| |
| static void dump_completed_IO(struct inode *inode, struct list_head *head) |
| { |
| #ifdef EXT4FS_DEBUG |
| struct list_head *cur, *before, *after; |
| ext4_io_end_t *io_end, *io_end0, *io_end1; |
| |
| if (list_empty(head)) |
| return; |
| |
| ext4_debug("Dump inode %lu completed io list\n", inode->i_ino); |
| list_for_each_entry(io_end, head, list) { |
| cur = &io_end->list; |
| before = cur->prev; |
| io_end0 = container_of(before, ext4_io_end_t, list); |
| after = cur->next; |
| io_end1 = container_of(after, ext4_io_end_t, list); |
| |
| ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n", |
| io_end, inode->i_ino, io_end0, io_end1); |
| } |
| #endif |
| } |
| |
| /* Add the io_end to per-inode completed end_io list. */ |
| static void ext4_add_complete_io(ext4_io_end_t *io_end) |
| { |
| struct ext4_inode_info *ei = EXT4_I(io_end->inode); |
| struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb); |
| struct workqueue_struct *wq; |
| unsigned long flags; |
| |
| /* Only reserved conversions from writeback should enter here */ |
| WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN)); |
| WARN_ON(!io_end->handle && sbi->s_journal); |
| spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
| wq = sbi->rsv_conversion_wq; |
| if (list_empty(&ei->i_rsv_conversion_list)) |
| queue_work(wq, &ei->i_rsv_conversion_work); |
| list_add_tail(&io_end->list, &ei->i_rsv_conversion_list); |
| spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
| } |
| |
| static int ext4_do_flush_completed_IO(struct inode *inode, |
| struct list_head *head) |
| { |
| ext4_io_end_t *io_end; |
| struct list_head unwritten; |
| unsigned long flags; |
| struct ext4_inode_info *ei = EXT4_I(inode); |
| int err, ret = 0; |
| |
| spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
| dump_completed_IO(inode, head); |
| list_replace_init(head, &unwritten); |
| spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
| |
| while (!list_empty(&unwritten)) { |
| io_end = list_entry(unwritten.next, ext4_io_end_t, list); |
| BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN)); |
| list_del_init(&io_end->list); |
| |
| err = ext4_end_io_end(io_end); |
| if (unlikely(!ret && err)) |
| ret = err; |
| } |
| return ret; |
| } |
| |
| /* |
| * work on completed IO, to convert unwritten extents to extents |
| */ |
| void ext4_end_io_rsv_work(struct work_struct *work) |
| { |
| struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info, |
| i_rsv_conversion_work); |
| ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list); |
| } |
| |
| ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) |
| { |
| ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags); |
| |
| if (io_end) { |
| io_end->inode = inode; |
| INIT_LIST_HEAD(&io_end->list); |
| INIT_LIST_HEAD(&io_end->list_vec); |
| refcount_set(&io_end->count, 1); |
| } |
| return io_end; |
| } |
| |
| void ext4_put_io_end_defer(ext4_io_end_t *io_end) |
| { |
| if (refcount_dec_and_test(&io_end->count)) { |
| if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || |
| list_empty(&io_end->list_vec)) { |
| ext4_release_io_end(io_end); |
| return; |
| } |
| ext4_add_complete_io(io_end); |
| } |
| } |
| |
| int ext4_put_io_end(ext4_io_end_t *io_end) |
| { |
| int err = 0; |
| |
| if (refcount_dec_and_test(&io_end->count)) { |
| if (io_end->flag & EXT4_IO_END_UNWRITTEN) { |
| err = ext4_convert_unwritten_io_end_vec(io_end->handle, |
| io_end); |
| io_end->handle = NULL; |
| ext4_clear_io_unwritten_flag(io_end); |
| } |
| ext4_release_io_end(io_end); |
| } |
| return err; |
| } |
| |
| ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end) |
| { |
| refcount_inc(&io_end->count); |
| return io_end; |
| } |
| |
| /* BIO completion function for page writeback */ |
| static void ext4_end_bio(struct bio *bio) |
| { |
| ext4_io_end_t *io_end = bio->bi_private; |
| sector_t bi_sector = bio->bi_iter.bi_sector; |
| |
| if (WARN_ONCE(!io_end, "io_end is NULL: %pg: sector %Lu len %u err %d\n", |
| bio->bi_bdev, |
| (long long) bio->bi_iter.bi_sector, |
| (unsigned) bio_sectors(bio), |
| bio->bi_status)) { |
| ext4_finish_bio(bio); |
| bio_put(bio); |
| return; |
| } |
| bio->bi_end_io = NULL; |
| |
| if (bio->bi_status) { |
| struct inode *inode = io_end->inode; |
| |
| ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu " |
| "starting block %llu)", |
| bio->bi_status, inode->i_ino, |
| (unsigned long long) |
| bi_sector >> (inode->i_blkbits - 9)); |
| mapping_set_error(inode->i_mapping, |
| blk_status_to_errno(bio->bi_status)); |
| } |
| |
| if (io_end->flag & EXT4_IO_END_UNWRITTEN) { |
| /* |
| * Link bio into list hanging from io_end. We have to do it |
| * atomically as bio completions can be racing against each |
| * other. |
| */ |
| bio->bi_private = xchg(&io_end->bio, bio); |
| ext4_put_io_end_defer(io_end); |
| } else { |
| /* |
| * Drop io_end reference early. Inode can get freed once |
| * we finish the bio. |
| */ |
| ext4_put_io_end_defer(io_end); |
| ext4_finish_bio(bio); |
| bio_put(bio); |
| } |
| } |
| |
| void ext4_io_submit(struct ext4_io_submit *io) |
| { |
| struct bio *bio = io->io_bio; |
| |
| if (bio) { |
| if (io->io_wbc->sync_mode == WB_SYNC_ALL) |
| io->io_bio->bi_opf |= REQ_SYNC; |
| submit_bio(io->io_bio); |
| } |
| io->io_bio = NULL; |
| } |
| |
| void ext4_io_submit_init(struct ext4_io_submit *io, |
| struct writeback_control *wbc) |
| { |
| io->io_wbc = wbc; |
| io->io_bio = NULL; |
| io->io_end = NULL; |
| } |
| |
| static void io_submit_init_bio(struct ext4_io_submit *io, |
| struct buffer_head *bh) |
| { |
| struct bio *bio; |
| |
| /* |
| * bio_alloc will _always_ be able to allocate a bio if |
| * __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset(). |
| */ |
| bio = bio_alloc(bh->b_bdev, BIO_MAX_VECS, REQ_OP_WRITE, GFP_NOIO); |
| fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO); |
| bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
| bio->bi_end_io = ext4_end_bio; |
| bio->bi_private = ext4_get_io_end(io->io_end); |
| io->io_bio = bio; |
| io->io_next_block = bh->b_blocknr; |
| wbc_init_bio(io->io_wbc, bio); |
| } |
| |
| static void io_submit_add_bh(struct ext4_io_submit *io, |
| struct inode *inode, |
| struct page *page, |
| struct buffer_head *bh) |
| { |
| int ret; |
| |
| if (io->io_bio && (bh->b_blocknr != io->io_next_block || |
| !fscrypt_mergeable_bio_bh(io->io_bio, bh))) { |
| submit_and_retry: |
| ext4_io_submit(io); |
| } |
| if (io->io_bio == NULL) |
| io_submit_init_bio(io, bh); |
| ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh)); |
| if (ret != bh->b_size) |
| goto submit_and_retry; |
| wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size); |
| io->io_next_block++; |
| } |
| |
| int ext4_bio_write_page(struct ext4_io_submit *io, |
| struct page *page, |
| int len, |
| bool keep_towrite) |
| { |
| struct page *bounce_page = NULL; |
| struct inode *inode = page->mapping->host; |
| unsigned block_start; |
| struct buffer_head *bh, *head; |
| int ret = 0; |
| int nr_submitted = 0; |
| int nr_to_submit = 0; |
| struct writeback_control *wbc = io->io_wbc; |
| |
| BUG_ON(!PageLocked(page)); |
| BUG_ON(PageWriteback(page)); |
| |
| if (keep_towrite) |
| set_page_writeback_keepwrite(page); |
| else |
| set_page_writeback(page); |
| ClearPageError(page); |
| |
| /* |
| * Comments copied from block_write_full_page: |
| * |
| * The page straddles i_size. It must be zeroed out on each and every |
| * writepage invocation because it may be mmapped. "A file is mapped |
| * in multiples of the page size. For a file that is not a multiple of |
| * the page size, the remaining memory is zeroed when mapped, and |
| * writes to that region are not written out to the file." |
| */ |
| if (len < PAGE_SIZE) |
| zero_user_segment(page, len, PAGE_SIZE); |
| /* |
| * In the first loop we prepare and mark buffers to submit. We have to |
| * mark all buffers in the page before submitting so that |
| * end_page_writeback() cannot be called from ext4_bio_end_io() when IO |
| * on the first buffer finishes and we are still working on submitting |
| * the second buffer. |
| */ |
| bh = head = page_buffers(page); |
| do { |
| block_start = bh_offset(bh); |
| if (block_start >= len) { |
| clear_buffer_dirty(bh); |
| set_buffer_uptodate(bh); |
| continue; |
| } |
| if (!buffer_dirty(bh) || buffer_delay(bh) || |
| !buffer_mapped(bh) || buffer_unwritten(bh)) { |
| /* A hole? We can safely clear the dirty bit */ |
| if (!buffer_mapped(bh)) |
| clear_buffer_dirty(bh); |
| if (io->io_bio) |
| ext4_io_submit(io); |
| continue; |
| } |
| if (buffer_new(bh)) |
| clear_buffer_new(bh); |
| set_buffer_async_write(bh); |
| nr_to_submit++; |
| } while ((bh = bh->b_this_page) != head); |
| |
| bh = head = page_buffers(page); |
| |
| /* |
| * If any blocks are being written to an encrypted file, encrypt them |
| * into a bounce page. For simplicity, just encrypt until the last |
| * block which might be needed. This may cause some unneeded blocks |
| * (e.g. holes) to be unnecessarily encrypted, but this is rare and |
| * can't happen in the common case of blocksize == PAGE_SIZE. |
| */ |
| if (fscrypt_inode_uses_fs_layer_crypto(inode) && nr_to_submit) { |
| gfp_t gfp_flags = GFP_NOFS; |
| unsigned int enc_bytes = round_up(len, i_blocksize(inode)); |
| |
| /* |
| * Since bounce page allocation uses a mempool, we can only use |
| * a waiting mask (i.e. request guaranteed allocation) on the |
| * first page of the bio. Otherwise it can deadlock. |
| */ |
| if (io->io_bio) |
| gfp_flags = GFP_NOWAIT | __GFP_NOWARN; |
| retry_encrypt: |
| bounce_page = fscrypt_encrypt_pagecache_blocks(page, enc_bytes, |
| 0, gfp_flags); |
| if (IS_ERR(bounce_page)) { |
| ret = PTR_ERR(bounce_page); |
| if (ret == -ENOMEM && |
| (io->io_bio || wbc->sync_mode == WB_SYNC_ALL)) { |
| gfp_t new_gfp_flags = GFP_NOFS; |
| if (io->io_bio) |
| ext4_io_submit(io); |
| else |
| new_gfp_flags |= __GFP_NOFAIL; |
| memalloc_retry_wait(gfp_flags); |
| gfp_flags = new_gfp_flags; |
| goto retry_encrypt; |
| } |
| |
| printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret); |
| redirty_page_for_writepage(wbc, page); |
| do { |
| clear_buffer_async_write(bh); |
| bh = bh->b_this_page; |
| } while (bh != head); |
| goto unlock; |
| } |
| } |
| |
| /* Now submit buffers to write */ |
| do { |
| if (!buffer_async_write(bh)) |
| continue; |
| io_submit_add_bh(io, inode, |
| bounce_page ? bounce_page : page, bh); |
| nr_submitted++; |
| clear_buffer_dirty(bh); |
| } while ((bh = bh->b_this_page) != head); |
| |
| unlock: |
| unlock_page(page); |
| /* Nothing submitted - we have to end page writeback */ |
| if (!nr_submitted) |
| end_page_writeback(page); |
| return ret; |
| } |