![Linus Torvalds](/assets/img/avatar_default.png)
primarily used for testing, but which can be useful on production systems when a scratch volume is being destroyed and the data on it doesn't need to be saved. This found (and we fixed) a number of bugs with ext4's recovery to corrupted file system --- the bugs increased the amount of data that could be potentially lost, and in the case of the inline data feature, could cause the kernel to BUG. Also included are a number of other bug fixes, including in ext4's fscrypt, DAX, inline data support. -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAlirXesACgkQ8vlZVpUN gaMOzQf8Ct6uPatV+m855oR4dAbZr2+lY4A4C+vHDzBtSMkPRyLX8cuo8XcwfTIm vPVyDnL6EPyhXPxxfItu+92wAq1m5mVpKo57d0Ft5lw0rHxNtJTgVSRzsQ7VDRjj 5qMHW2K7Bk7EjzTeW3SF8/3+hqpzkAvRtNCntcomk5h08+cWMC8JSnn1kqw+naIn EcbrC72GZb8JUELogVXC2vU58lp50SSBdr3l005jqKc5BvljMvdJ0Izn/3RVyU7u q7vtynhe2ScFcHe/UzL1QgmQOy32tJpbS0NHalW47aw3Ynmn4cSX0YhhT9FDjRNQ VOOfo1m1sAg166x0E+Nn7FeghTSSyA== =cPIf -----END PGP SIGNATURE----- Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "For this cycle we add support for the shutdown ioctl, which is primarily used for testing, but which can be useful on production systems when a scratch volume is being destroyed and the data on it doesn't need to be saved. This found (and we fixed) a number of bugs with ext4's recovery to corrupted file system --- the bugs increased the amount of data that could be potentially lost, and in the case of the inline data feature, could cause the kernel to BUG. Also included are a number of other bug fixes, including in ext4's fscrypt, DAX, inline data support" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (26 commits) ext4: rename EXT4_IOC_GOINGDOWN to EXT4_IOC_SHUTDOWN ext4: fix fencepost in s_first_meta_bg validation ext4: don't BUG when truncating encrypted inodes on the orphan list ext4: do not use stripe_width if it is not set ext4: fix stripe-unaligned allocations dax: assert that i_rwsem is held exclusive for writes ext4: fix DAX write locking ext4: add EXT4_IOC_GOINGDOWN ioctl ext4: add shutdown bit and check for it ext4: rename s_resize_flags to s_ext4_flags ext4: return EROFS if device is r/o and journal replay is needed ext4: preserve the needs_recovery flag when the journal is aborted jbd2: don't leak modified metadata buffers on an aborted journal ext4: fix inline data error paths ext4: move halfmd4 into hash.c directly ext4: fix use-after-iput when fscrypt contexts are inconsistent jbd2: fix use after free in kjournald2() ext4: fix data corruption in data=journal mode ext4: trim allocation requests to group size ext4: replace BUG_ON with WARN_ON in mb_find_extent() ...
525 lines
13 KiB
C
525 lines
13 KiB
C
/*
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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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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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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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}
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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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int i;
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struct bio_vec *bvec;
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bio_for_each_segment_all(bvec, bio, i) {
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struct page *page = bvec->bv_page;
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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struct page *data_page = NULL;
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#endif
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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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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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if (!page->mapping) {
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/* The bounce data pages are unmapped. */
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data_page = page;
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fscrypt_pullback_bio_page(&page, false);
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}
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#endif
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if (bio->bi_error) {
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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 BH_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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local_irq_save(flags);
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bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
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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_error)
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buffer_io_error(bh);
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} while ((bh = bh->b_this_page) != head);
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bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
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local_irq_restore(flags);
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if (!under_io) {
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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if (data_page)
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fscrypt_restore_control_page(data_page);
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#endif
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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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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(ext4_io_end_t *io)
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{
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struct inode *inode = io->inode;
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loff_t offset = io->offset;
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ssize_t size = io->size;
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handle_t *handle = io->handle;
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int ret = 0;
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ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
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"list->prev 0x%p\n",
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io, inode->i_ino, io->list.next, io->list.prev);
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io->handle = NULL; /* Following call will use up the handle */
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ret = ext4_convert_unwritten_extents(handle, inode, offset, size);
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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, offset %llu, size %zd, error %d)",
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inode->i_ino, offset, size, ret);
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}
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ext4_clear_io_unwritten_flag(io);
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ext4_release_io_end(io);
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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, *io0, *io1;
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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, head, list) {
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cur = &io->list;
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before = cur->prev;
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io0 = container_of(before, ext4_io_end_t, list);
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after = cur->next;
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io1 = 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, inode->i_ino, io0, io1);
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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;
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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 = list_entry(unwritten.next, ext4_io_end_t, list);
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BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
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list_del_init(&io->list);
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err = ext4_end_io(io);
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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 = kmem_cache_zalloc(io_end_cachep, flags);
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if (io) {
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io->inode = inode;
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INIT_LIST_HEAD(&io->list);
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atomic_set(&io->count, 1);
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}
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return io;
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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) || !io_end->size) {
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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_extents(io_end->handle,
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io_end->inode, io_end->offset,
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io_end->size);
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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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BUG_ON(!io_end);
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bio->bi_end_io = NULL;
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if (bio->bi_error) {
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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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"(offset %llu size %ld starting block %llu)",
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bio->bi_error, inode->i_ino,
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(unsigned long long) io_end->offset,
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(long) io_end->size,
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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, bio->bi_error);
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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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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 int 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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bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
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if (!bio)
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return -ENOMEM;
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wbc_init_bio(io->io_wbc, bio);
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bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
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bio->bi_bdev = 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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return 0;
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}
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static int 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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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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ret = io_submit_init_bio(io, bh);
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if (ret)
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return ret;
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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_io(io->io_wbc, page, bh->b_size);
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io->io_next_block++;
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return 0;
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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 *data_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));
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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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* 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."
|
|
*/
|
|
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);
|
|
clean_bdev_bh_alias(bh);
|
|
}
|
|
set_buffer_async_write(bh);
|
|
nr_to_submit++;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
|
|
bh = head = page_buffers(page);
|
|
|
|
if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) &&
|
|
nr_to_submit) {
|
|
gfp_t gfp_flags = GFP_NOFS;
|
|
|
|
retry_encrypt:
|
|
data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0,
|
|
page->index, gfp_flags);
|
|
if (IS_ERR(data_page)) {
|
|
ret = PTR_ERR(data_page);
|
|
if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
|
|
if (io->io_bio) {
|
|
ext4_io_submit(io);
|
|
congestion_wait(BLK_RW_ASYNC, HZ/50);
|
|
}
|
|
gfp_flags |= __GFP_NOFAIL;
|
|
goto retry_encrypt;
|
|
}
|
|
data_page = NULL;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/* Now submit buffers to write */
|
|
do {
|
|
if (!buffer_async_write(bh))
|
|
continue;
|
|
ret = io_submit_add_bh(io, inode,
|
|
data_page ? data_page : page, bh);
|
|
if (ret) {
|
|
/*
|
|
* We only get here on ENOMEM. Not much else
|
|
* we can do but mark the page as dirty, and
|
|
* better luck next time.
|
|
*/
|
|
break;
|
|
}
|
|
nr_submitted++;
|
|
clear_buffer_dirty(bh);
|
|
} while ((bh = bh->b_this_page) != head);
|
|
|
|
/* Error stopped previous loop? Clean up buffers... */
|
|
if (ret) {
|
|
out:
|
|
if (data_page)
|
|
fscrypt_restore_control_page(data_page);
|
|
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);
|
|
}
|
|
unlock_page(page);
|
|
/* Nothing submitted - we have to end page writeback */
|
|
if (!nr_submitted)
|
|
end_page_writeback(page);
|
|
return ret;
|
|
}
|