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561 lines
15 KiB
561 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/fs/ext4/page-io.c |
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* |
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* This contains the new page_io functions for ext4 |
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* |
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* Written by Theodore Ts'o, 2010. |
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*/ |
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|
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#include <linux/fs.h> |
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#include <linux/time.h> |
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#include <linux/highuid.h> |
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#include <linux/pagemap.h> |
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#include <linux/quotaops.h> |
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#include <linux/string.h> |
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#include <linux/buffer_head.h> |
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#include <linux/writeback.h> |
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#include <linux/pagevec.h> |
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#include <linux/mpage.h> |
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#include <linux/namei.h> |
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#include <linux/uio.h> |
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#include <linux/bio.h> |
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#include <linux/workqueue.h> |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/mm.h> |
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#include <linux/backing-dev.h> |
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#include "ext4_jbd2.h" |
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#include "xattr.h" |
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#include "acl.h" |
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static struct kmem_cache *io_end_cachep; |
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static struct kmem_cache *io_end_vec_cachep; |
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int __init ext4_init_pageio(void) |
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{ |
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io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); |
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if (io_end_cachep == NULL) |
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return -ENOMEM; |
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io_end_vec_cachep = KMEM_CACHE(ext4_io_end_vec, 0); |
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if (io_end_vec_cachep == NULL) { |
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kmem_cache_destroy(io_end_cachep); |
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return -ENOMEM; |
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} |
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return 0; |
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} |
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void ext4_exit_pageio(void) |
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{ |
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kmem_cache_destroy(io_end_cachep); |
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kmem_cache_destroy(io_end_vec_cachep); |
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} |
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struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end) |
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{ |
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struct ext4_io_end_vec *io_end_vec; |
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io_end_vec = kmem_cache_zalloc(io_end_vec_cachep, GFP_NOFS); |
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if (!io_end_vec) |
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return ERR_PTR(-ENOMEM); |
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INIT_LIST_HEAD(&io_end_vec->list); |
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list_add_tail(&io_end_vec->list, &io_end->list_vec); |
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return io_end_vec; |
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} |
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static void ext4_free_io_end_vec(ext4_io_end_t *io_end) |
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{ |
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struct ext4_io_end_vec *io_end_vec, *tmp; |
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if (list_empty(&io_end->list_vec)) |
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return; |
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list_for_each_entry_safe(io_end_vec, tmp, &io_end->list_vec, list) { |
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list_del(&io_end_vec->list); |
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kmem_cache_free(io_end_vec_cachep, io_end_vec); |
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} |
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} |
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struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end) |
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{ |
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BUG_ON(list_empty(&io_end->list_vec)); |
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return list_last_entry(&io_end->list_vec, struct ext4_io_end_vec, list); |
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} |
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/* |
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* Print an buffer I/O error compatible with the fs/buffer.c. This |
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* provides compatibility with dmesg scrapers that look for a specific |
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* buffer I/O error message. We really need a unified error reporting |
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* structure to userspace ala Digital Unix's uerf system, but it's |
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* probably not going to happen in my lifetime, due to LKML politics... |
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*/ |
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static void buffer_io_error(struct buffer_head *bh) |
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{ |
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printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n", |
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bh->b_bdev, |
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(unsigned long long)bh->b_blocknr); |
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} |
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static void ext4_finish_bio(struct bio *bio) |
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{ |
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struct bio_vec *bvec; |
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struct bvec_iter_all iter_all; |
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bio_for_each_segment_all(bvec, bio, iter_all) { |
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struct page *page = bvec->bv_page; |
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struct page *bounce_page = NULL; |
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struct buffer_head *bh, *head; |
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unsigned bio_start = bvec->bv_offset; |
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unsigned bio_end = bio_start + bvec->bv_len; |
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unsigned under_io = 0; |
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unsigned long flags; |
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if (fscrypt_is_bounce_page(page)) { |
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bounce_page = page; |
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page = fscrypt_pagecache_page(bounce_page); |
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} |
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if (bio->bi_status) { |
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SetPageError(page); |
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mapping_set_error(page->mapping, -EIO); |
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} |
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bh = head = page_buffers(page); |
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/* |
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* We check all buffers in the page under b_uptodate_lock |
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* to avoid races with other end io clearing async_write flags |
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*/ |
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spin_lock_irqsave(&head->b_uptodate_lock, flags); |
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do { |
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if (bh_offset(bh) < bio_start || |
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bh_offset(bh) + bh->b_size > bio_end) { |
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if (buffer_async_write(bh)) |
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under_io++; |
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continue; |
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} |
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clear_buffer_async_write(bh); |
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if (bio->bi_status) |
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buffer_io_error(bh); |
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} while ((bh = bh->b_this_page) != head); |
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spin_unlock_irqrestore(&head->b_uptodate_lock, flags); |
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if (!under_io) { |
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fscrypt_free_bounce_page(bounce_page); |
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end_page_writeback(page); |
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} |
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} |
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} |
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static void ext4_release_io_end(ext4_io_end_t *io_end) |
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{ |
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struct bio *bio, *next_bio; |
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BUG_ON(!list_empty(&io_end->list)); |
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BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN); |
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WARN_ON(io_end->handle); |
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for (bio = io_end->bio; bio; bio = next_bio) { |
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next_bio = bio->bi_private; |
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ext4_finish_bio(bio); |
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bio_put(bio); |
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} |
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ext4_free_io_end_vec(io_end); |
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kmem_cache_free(io_end_cachep, io_end); |
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} |
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/* |
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* Check a range of space and convert unwritten extents to written. Note that |
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* we are protected from truncate touching same part of extent tree by the |
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* fact that truncate code waits for all DIO to finish (thus exclusion from |
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* direct IO is achieved) and also waits for PageWriteback bits. Thus we |
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* cannot get to ext4_ext_truncate() before all IOs overlapping that range are |
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* completed (happens from ext4_free_ioend()). |
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*/ |
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static int ext4_end_io_end(ext4_io_end_t *io_end) |
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{ |
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struct inode *inode = io_end->inode; |
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handle_t *handle = io_end->handle; |
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int ret = 0; |
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ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p," |
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"list->prev 0x%p\n", |
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io_end, inode->i_ino, io_end->list.next, io_end->list.prev); |
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io_end->handle = NULL; /* Following call will use up the handle */ |
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ret = ext4_convert_unwritten_io_end_vec(handle, io_end); |
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if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) { |
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ext4_msg(inode->i_sb, KERN_EMERG, |
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"failed to convert unwritten extents to written " |
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"extents -- potential data loss! " |
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"(inode %lu, error %d)", inode->i_ino, ret); |
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} |
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ext4_clear_io_unwritten_flag(io_end); |
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ext4_release_io_end(io_end); |
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return ret; |
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} |
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static void dump_completed_IO(struct inode *inode, struct list_head *head) |
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{ |
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#ifdef EXT4FS_DEBUG |
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struct list_head *cur, *before, *after; |
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ext4_io_end_t *io_end, *io_end0, *io_end1; |
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if (list_empty(head)) |
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return; |
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ext4_debug("Dump inode %lu completed io list\n", inode->i_ino); |
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list_for_each_entry(io_end, head, list) { |
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cur = &io_end->list; |
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before = cur->prev; |
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io_end0 = container_of(before, ext4_io_end_t, list); |
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after = cur->next; |
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io_end1 = container_of(after, ext4_io_end_t, list); |
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ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n", |
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io_end, inode->i_ino, io_end0, io_end1); |
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} |
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#endif |
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} |
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/* Add the io_end to per-inode completed end_io list. */ |
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static void ext4_add_complete_io(ext4_io_end_t *io_end) |
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{ |
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struct ext4_inode_info *ei = EXT4_I(io_end->inode); |
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struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb); |
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struct workqueue_struct *wq; |
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unsigned long flags; |
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/* Only reserved conversions from writeback should enter here */ |
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WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN)); |
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WARN_ON(!io_end->handle && sbi->s_journal); |
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spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
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wq = sbi->rsv_conversion_wq; |
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if (list_empty(&ei->i_rsv_conversion_list)) |
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queue_work(wq, &ei->i_rsv_conversion_work); |
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list_add_tail(&io_end->list, &ei->i_rsv_conversion_list); |
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spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
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} |
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static int ext4_do_flush_completed_IO(struct inode *inode, |
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struct list_head *head) |
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{ |
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ext4_io_end_t *io_end; |
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struct list_head unwritten; |
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unsigned long flags; |
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struct ext4_inode_info *ei = EXT4_I(inode); |
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int err, ret = 0; |
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spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
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dump_completed_IO(inode, head); |
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list_replace_init(head, &unwritten); |
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spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
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while (!list_empty(&unwritten)) { |
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io_end = list_entry(unwritten.next, ext4_io_end_t, list); |
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BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN)); |
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list_del_init(&io_end->list); |
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err = ext4_end_io_end(io_end); |
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if (unlikely(!ret && err)) |
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ret = err; |
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} |
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return ret; |
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} |
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/* |
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* work on completed IO, to convert unwritten extents to extents |
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*/ |
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void ext4_end_io_rsv_work(struct work_struct *work) |
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{ |
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struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info, |
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i_rsv_conversion_work); |
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ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list); |
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} |
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ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) |
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{ |
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ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags); |
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if (io_end) { |
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io_end->inode = inode; |
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INIT_LIST_HEAD(&io_end->list); |
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INIT_LIST_HEAD(&io_end->list_vec); |
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atomic_set(&io_end->count, 1); |
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} |
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return io_end; |
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} |
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void ext4_put_io_end_defer(ext4_io_end_t *io_end) |
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{ |
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if (atomic_dec_and_test(&io_end->count)) { |
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if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || |
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list_empty(&io_end->list_vec)) { |
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ext4_release_io_end(io_end); |
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return; |
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} |
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ext4_add_complete_io(io_end); |
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} |
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} |
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int ext4_put_io_end(ext4_io_end_t *io_end) |
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{ |
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int err = 0; |
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if (atomic_dec_and_test(&io_end->count)) { |
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if (io_end->flag & EXT4_IO_END_UNWRITTEN) { |
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err = ext4_convert_unwritten_io_end_vec(io_end->handle, |
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io_end); |
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io_end->handle = NULL; |
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ext4_clear_io_unwritten_flag(io_end); |
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} |
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ext4_release_io_end(io_end); |
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} |
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return err; |
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} |
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ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end) |
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{ |
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atomic_inc(&io_end->count); |
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return io_end; |
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} |
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/* BIO completion function for page writeback */ |
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static void ext4_end_bio(struct bio *bio) |
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{ |
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ext4_io_end_t *io_end = bio->bi_private; |
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sector_t bi_sector = bio->bi_iter.bi_sector; |
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char b[BDEVNAME_SIZE]; |
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if (WARN_ONCE(!io_end, "io_end is NULL: %s: sector %Lu len %u err %d\n", |
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bio_devname(bio, b), |
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(long long) bio->bi_iter.bi_sector, |
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(unsigned) bio_sectors(bio), |
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bio->bi_status)) { |
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ext4_finish_bio(bio); |
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bio_put(bio); |
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return; |
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} |
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bio->bi_end_io = NULL; |
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if (bio->bi_status) { |
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struct inode *inode = io_end->inode; |
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ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu " |
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"starting block %llu)", |
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bio->bi_status, inode->i_ino, |
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(unsigned long long) |
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bi_sector >> (inode->i_blkbits - 9)); |
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mapping_set_error(inode->i_mapping, |
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blk_status_to_errno(bio->bi_status)); |
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} |
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if (io_end->flag & EXT4_IO_END_UNWRITTEN) { |
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/* |
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* Link bio into list hanging from io_end. We have to do it |
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* atomically as bio completions can be racing against each |
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* other. |
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*/ |
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bio->bi_private = xchg(&io_end->bio, bio); |
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ext4_put_io_end_defer(io_end); |
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} else { |
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/* |
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* Drop io_end reference early. Inode can get freed once |
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* we finish the bio. |
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*/ |
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ext4_put_io_end_defer(io_end); |
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ext4_finish_bio(bio); |
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bio_put(bio); |
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} |
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} |
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void ext4_io_submit(struct ext4_io_submit *io) |
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{ |
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struct bio *bio = io->io_bio; |
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if (bio) { |
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int io_op_flags = io->io_wbc->sync_mode == WB_SYNC_ALL ? |
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REQ_SYNC : 0; |
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io->io_bio->bi_write_hint = io->io_end->inode->i_write_hint; |
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bio_set_op_attrs(io->io_bio, REQ_OP_WRITE, io_op_flags); |
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submit_bio(io->io_bio); |
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} |
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io->io_bio = NULL; |
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} |
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void ext4_io_submit_init(struct ext4_io_submit *io, |
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struct writeback_control *wbc) |
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{ |
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io->io_wbc = wbc; |
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io->io_bio = NULL; |
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io->io_end = NULL; |
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} |
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static void io_submit_init_bio(struct ext4_io_submit *io, |
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struct buffer_head *bh) |
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{ |
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struct bio *bio; |
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/* |
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* bio_alloc will _always_ be able to allocate a bio if |
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* __GFP_DIRECT_RECLAIM is set, see comments for bio_alloc_bioset(). |
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*/ |
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bio = bio_alloc(GFP_NOIO, BIO_MAX_VECS); |
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fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO); |
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bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
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bio_set_dev(bio, bh->b_bdev); |
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bio->bi_end_io = ext4_end_bio; |
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bio->bi_private = ext4_get_io_end(io->io_end); |
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io->io_bio = bio; |
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io->io_next_block = bh->b_blocknr; |
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wbc_init_bio(io->io_wbc, bio); |
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} |
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static void io_submit_add_bh(struct ext4_io_submit *io, |
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struct inode *inode, |
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struct page *page, |
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struct buffer_head *bh) |
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{ |
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int ret; |
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if (io->io_bio && (bh->b_blocknr != io->io_next_block || |
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!fscrypt_mergeable_bio_bh(io->io_bio, bh))) { |
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submit_and_retry: |
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ext4_io_submit(io); |
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} |
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if (io->io_bio == NULL) { |
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io_submit_init_bio(io, bh); |
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io->io_bio->bi_write_hint = inode->i_write_hint; |
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} |
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ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh)); |
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if (ret != bh->b_size) |
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goto submit_and_retry; |
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wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size); |
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io->io_next_block++; |
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} |
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int ext4_bio_write_page(struct ext4_io_submit *io, |
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struct page *page, |
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int len, |
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bool keep_towrite) |
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{ |
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struct page *bounce_page = NULL; |
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struct inode *inode = page->mapping->host; |
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unsigned block_start; |
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struct buffer_head *bh, *head; |
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int ret = 0; |
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int nr_submitted = 0; |
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int nr_to_submit = 0; |
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struct writeback_control *wbc = io->io_wbc; |
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BUG_ON(!PageLocked(page)); |
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BUG_ON(PageWriteback(page)); |
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if (keep_towrite) |
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set_page_writeback_keepwrite(page); |
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else |
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set_page_writeback(page); |
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ClearPageError(page); |
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|
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/* |
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* Comments copied from block_write_full_page: |
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* |
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* The page straddles i_size. It must be zeroed out on each and every |
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* writepage invocation because it may be mmapped. "A file is mapped |
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* in multiples of the page size. For a file that is not a multiple of |
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* the page size, the remaining memory is zeroed when mapped, and |
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* writes to that region are not written out to the file." |
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*/ |
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if (len < PAGE_SIZE) |
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zero_user_segment(page, len, PAGE_SIZE); |
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/* |
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* In the first loop we prepare and mark buffers to submit. We have to |
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* mark all buffers in the page before submitting so that |
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* end_page_writeback() cannot be called from ext4_bio_end_io() when IO |
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* on the first buffer finishes and we are still working on submitting |
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* the second buffer. |
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*/ |
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bh = head = page_buffers(page); |
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do { |
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block_start = bh_offset(bh); |
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if (block_start >= len) { |
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clear_buffer_dirty(bh); |
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set_buffer_uptodate(bh); |
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continue; |
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} |
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if (!buffer_dirty(bh) || buffer_delay(bh) || |
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!buffer_mapped(bh) || buffer_unwritten(bh)) { |
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/* A hole? We can safely clear the dirty bit */ |
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if (!buffer_mapped(bh)) |
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clear_buffer_dirty(bh); |
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if (io->io_bio) |
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ext4_io_submit(io); |
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continue; |
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} |
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if (buffer_new(bh)) |
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clear_buffer_new(bh); |
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set_buffer_async_write(bh); |
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nr_to_submit++; |
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} while ((bh = bh->b_this_page) != head); |
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|
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bh = head = page_buffers(page); |
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|
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/* |
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* If any blocks are being written to an encrypted file, encrypt them |
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* into a bounce page. For simplicity, just encrypt until the last |
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* block which might be needed. This may cause some unneeded blocks |
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* (e.g. holes) to be unnecessarily encrypted, but this is rare and |
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* can't happen in the common case of blocksize == PAGE_SIZE. |
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*/ |
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if (fscrypt_inode_uses_fs_layer_crypto(inode) && nr_to_submit) { |
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gfp_t gfp_flags = GFP_NOFS; |
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unsigned int enc_bytes = round_up(len, i_blocksize(inode)); |
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|
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/* |
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* Since bounce page allocation uses a mempool, we can only use |
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* a waiting mask (i.e. request guaranteed allocation) on the |
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* first page of the bio. Otherwise it can deadlock. |
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*/ |
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if (io->io_bio) |
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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_flags = GFP_NOFS; |
|
if (io->io_bio) |
|
ext4_io_submit(io); |
|
else |
|
gfp_flags |= __GFP_NOFAIL; |
|
congestion_wait(BLK_RW_ASYNC, HZ/50); |
|
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; |
|
}
|
|
|