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4f74d15fe4
Wire up ext4 to support inline encryption via the helper functions which fs/crypto/ now provides. This includes: - Adding a mount option 'inlinecrypt' which enables inline encryption on encrypted files where it can be used. - Setting the bio_crypt_ctx on bios that will be submitted to an inline-encrypted file. Note: submit_bh_wbc() in fs/buffer.c also needed to be patched for this part, since ext4 sometimes uses ll_rw_block() on file data. - Not adding logically discontiguous data to bios that will be submitted to an inline-encrypted file. - Not doing filesystem-layer crypto on inline-encrypted files. Co-developed-by: Satya Tangirala <satyat@google.com> Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Theodore Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/20200702015607.1215430-5-satyat@google.com Signed-off-by: Eric Biggers <ebiggers@google.com>
565 lines
15 KiB
C
565 lines
15 KiB
C
// 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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#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 (!page)
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continue;
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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_PAGES);
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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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struct writeback_control *wbc,
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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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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_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;
|
|
}
|