linux/fs/ext4/page-io.c
Linus Torvalds 93061f390f These changes contains a fix for overlayfs interacting with some
(badly behaved) dentry code in various file systems.  These have been
 reviewed by Al and the respective file system mtinainers and are going
 through the ext4 tree for convenience.
 
 This also has a few ext4 encryption bug fixes that were discovered in
 Android testing (yes, we will need to get these sync'ed up with the
 fs/crypto code; I'll take care of that).  It also has some bug fixes
 and a change to ignore the legacy quota options to allow for xfstests
 regression testing of ext4's internal quota feature and to be more
 consistent with how xfs handles this case.
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Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 bugfixes from Ted Ts'o:
 "These changes contains a fix for overlayfs interacting with some
  (badly behaved) dentry code in various file systems.  These have been
  reviewed by Al and the respective file system mtinainers and are going
  through the ext4 tree for convenience.

  This also has a few ext4 encryption bug fixes that were discovered in
  Android testing (yes, we will need to get these sync'ed up with the
  fs/crypto code; I'll take care of that).  It also has some bug fixes
  and a change to ignore the legacy quota options to allow for xfstests
  regression testing of ext4's internal quota feature and to be more
  consistent with how xfs handles this case"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: ignore quota mount options if the quota feature is enabled
  ext4 crypto: fix some error handling
  ext4: avoid calling dquot_get_next_id() if quota is not enabled
  ext4: retry block allocation for failed DIO and DAX writes
  ext4: add lockdep annotations for i_data_sem
  ext4: allow readdir()'s of large empty directories to be interrupted
  btrfs: fix crash/invalid memory access on fsync when using overlayfs
  ext4 crypto: use dget_parent() in ext4_d_revalidate()
  ext4: use file_dentry()
  ext4: use dget_parent() in ext4_file_open()
  nfs: use file_dentry()
  fs: add file_dentry()
  ext4 crypto: don't let data integrity writebacks fail with ENOMEM
  ext4: check if in-inode xattr is corrupted in ext4_expand_extra_isize_ea()
2016-04-07 17:22:20 -07:00

529 lines
14 KiB
C

/*
* 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/backing-dev.h>
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
static struct kmem_cache *io_end_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;
return 0;
}
void ext4_exit_pageio(void)
{
kmem_cache_destroy(io_end_cachep);
}
/*
* 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)
{
int i;
struct bio_vec *bvec;
bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
struct page *data_page = NULL;
struct ext4_crypto_ctx *ctx = NULL;
#endif
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 (!page)
continue;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
if (!page->mapping) {
/* The bounce data pages are unmapped. */
data_page = page;
ctx = (struct ext4_crypto_ctx *)page_private(data_page);
page = ctx->w.control_page;
}
#endif
if (bio->bi_error) {
SetPageError(page);
set_bit(AS_EIO, &page->mapping->flags);
}
bh = head = page_buffers(page);
/*
* We check all buffers in the page under BH_Uptodate_Lock
* to avoid races with other end io clearing async_write flags
*/
local_irq_save(flags);
bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
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_error)
buffer_io_error(bh);
} while ((bh = bh->b_this_page) != head);
bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
local_irq_restore(flags);
if (!under_io) {
#ifdef CONFIG_EXT4_FS_ENCRYPTION
if (ctx)
ext4_restore_control_page(data_page);
#endif
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);
}
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(ext4_io_end_t *io)
{
struct inode *inode = io->inode;
loff_t offset = io->offset;
ssize_t size = io->size;
handle_t *handle = io->handle;
int ret = 0;
ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
"list->prev 0x%p\n",
io, inode->i_ino, io->list.next, io->list.prev);
io->handle = NULL; /* Following call will use up the handle */
ret = ext4_convert_unwritten_extents(handle, inode, offset, size);
if (ret < 0) {
ext4_msg(inode->i_sb, KERN_EMERG,
"failed to convert unwritten extents to written "
"extents -- potential data loss! "
"(inode %lu, offset %llu, size %zd, error %d)",
inode->i_ino, offset, size, ret);
}
ext4_clear_io_unwritten_flag(io);
ext4_release_io_end(io);
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, *io0, *io1;
if (list_empty(head))
return;
ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
list_for_each_entry(io, head, list) {
cur = &io->list;
before = cur->prev;
io0 = container_of(before, ext4_io_end_t, list);
after = cur->next;
io1 = container_of(after, ext4_io_end_t, list);
ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
io, inode->i_ino, io0, io1);
}
#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;
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 = list_entry(unwritten.next, ext4_io_end_t, list);
BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
list_del_init(&io->list);
err = ext4_end_io(io);
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 = kmem_cache_zalloc(io_end_cachep, flags);
if (io) {
io->inode = inode;
INIT_LIST_HEAD(&io->list);
atomic_set(&io->count, 1);
}
return io;
}
void ext4_put_io_end_defer(ext4_io_end_t *io_end)
{
if (atomic_dec_and_test(&io_end->count)) {
if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) {
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 (atomic_dec_and_test(&io_end->count)) {
if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
err = ext4_convert_unwritten_extents(io_end->handle,
io_end->inode, io_end->offset,
io_end->size);
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)
{
atomic_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;
BUG_ON(!io_end);
bio->bi_end_io = NULL;
if (bio->bi_error) {
struct inode *inode = io_end->inode;
ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
"(offset %llu size %ld starting block %llu)",
bio->bi_error, inode->i_ino,
(unsigned long long) io_end->offset,
(long) io_end->size,
(unsigned long long)
bi_sector >> (inode->i_blkbits - 9));
mapping_set_error(inode->i_mapping, bio->bi_error);
}
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) {
int io_op = io->io_wbc->sync_mode == WB_SYNC_ALL ?
WRITE_SYNC : WRITE;
bio_get(io->io_bio);
submit_bio(io_op, io->io_bio);
bio_put(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 int io_submit_init_bio(struct ext4_io_submit *io,
struct buffer_head *bh)
{
struct bio *bio;
bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
if (!bio)
return -ENOMEM;
wbc_init_bio(io->io_wbc, bio);
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio->bi_bdev = bh->b_bdev;
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;
return 0;
}
static int io_submit_add_bh(struct ext4_io_submit *io,
struct inode *inode,
struct page *page,
struct buffer_head *bh)
{
int ret;
if (io->io_bio && bh->b_blocknr != io->io_next_block) {
submit_and_retry:
ext4_io_submit(io);
}
if (io->io_bio == NULL) {
ret = io_submit_init_bio(io, bh);
if (ret)
return ret;
}
ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
if (ret != bh->b_size)
goto submit_and_retry;
wbc_account_io(io->io_wbc, page, bh->b_size);
io->io_next_block++;
return 0;
}
int ext4_bio_write_page(struct ext4_io_submit *io,
struct page *page,
int len,
struct writeback_control *wbc,
bool keep_towrite)
{
struct page *data_page = NULL;
struct inode *inode = page->mapping->host;
unsigned block_start, blocksize;
struct buffer_head *bh, *head;
int ret = 0;
int nr_submitted = 0;
int nr_to_submit = 0;
blocksize = 1 << inode->i_blkbits;
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);
unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
}
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 = ext4_encrypt(inode, page, 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)
ext4_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;
}