diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /fs/ext4/page-io.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/ext4/page-io.c')
-rw-r--r-- | fs/ext4/page-io.c | 559 |
1 files changed, 559 insertions, 0 deletions
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c new file mode 100644 index 000000000..d0302b66c --- /dev/null +++ b/fs/ext4/page-io.c @@ -0,0 +1,559 @@ +// 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 *pagecache_page, + struct page *bounce_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, bounce_page ?: pagecache_page, + bh->b_size, bh_offset(bh)); + if (ret != bh->b_size) + goto submit_and_retry; + wbc_account_cgroup_owner(io->io_wbc, pagecache_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_end_bio() 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, page, bounce_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; +} |