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-rw-r--r--fs/ext4/page-io.c559
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;
+}