[mirror_ubuntu-artful-kernel.git] / fs / ext4 / page-io.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/jbd2.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/aio.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 "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);
}

/*
 * This function is called by ext4_evict_inode() to make sure there is
 * no more pending I/O completion work left to do.
 */
void ext4_ioend_shutdown(struct inode *inode)
{
	wait_queue_head_t *wq = ext4_ioend_wq(inode);

	wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0));
	/*
	 * We need to make sure the work structure is finished being
	 * used before we let the inode get destroyed.
	 */
	if (work_pending(&EXT4_I(inode)->i_unwritten_work))
		cancel_work_sync(&EXT4_I(inode)->i_unwritten_work);
}

static void ext4_release_io_end(ext4_io_end_t *io_end)
{
	BUG_ON(!list_empty(&io_end->list));
	BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);

	if (atomic_dec_and_test(&EXT4_I(io_end->inode)->i_ioend_count))
		wake_up_all(ext4_ioend_wq(io_end->inode));
	if (io_end->flag & EXT4_IO_END_DIRECT)
		inode_dio_done(io_end->inode);
	if (io_end->iocb)
		aio_complete(io_end->iocb, io_end->result, 0);
	kmem_cache_free(io_end_cachep, io_end);
}

static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
{
	struct inode *inode = io_end->inode;

	io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
	/* Wake up anyone waiting on unwritten extent conversion */
	if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
		wake_up_all(ext4_ioend_wq(inode));
}

/* check a range of space and convert unwritten extents to written. */
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;
	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);

	ret = ext4_convert_unwritten_extents(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)
{
#ifdef	EXT4FS_DEBUG
	struct list_head *cur, *before, *after;
	ext4_io_end_t *io, *io0, *io1;

	if (list_empty(&EXT4_I(inode)->i_completed_io_list)) {
		ext4_debug("inode %lu completed_io list is empty\n",
			   inode->i_ino);
		return;
	}

	ext4_debug("Dump inode %lu completed_io list\n", inode->i_ino);
	list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, 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 workqueue_struct *wq;
	unsigned long flags;

	BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
	wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;

	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
	if (list_empty(&ei->i_completed_io_list))
		queue_work(wq, &ei->i_unwritten_work);
	list_add_tail(&io_end->list, &ei->i_completed_io_list);
	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
}

static int ext4_do_flush_completed_IO(struct inode *inode)
{
	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);
	list_replace_init(&ei->i_completed_io_list, &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 aio dio IO, to convert unwritten extents to extents
 */
void ext4_end_io_work(struct work_struct *work)
{
	struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
						  i_unwritten_work);
	ext4_do_flush_completed_IO(&ei->vfs_inode);
}

int ext4_flush_unwritten_io(struct inode *inode)
{
	int ret;
	WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex) &&
		     !(inode->i_state & I_FREEING));
	ret = ext4_do_flush_completed_IO(inode);
	ext4_unwritten_wait(inode);
	return ret;
}

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) {
		atomic_inc(&EXT4_I(inode)->i_ioend_count);
		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->inode,
						io_end->offset, io_end->size);
			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;
}

/*
 * 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)
{
	char b[BDEVNAME_SIZE];
	printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n",
			bdevname(bh->b_bdev, b),
			(unsigned long long)bh->b_blocknr);
}

static void ext4_end_bio(struct bio *bio, int error)
{
	ext4_io_end_t *io_end = bio->bi_private;
	struct inode *inode;
	int i;
	int blocksize;
	sector_t bi_sector = bio->bi_sector;

	BUG_ON(!io_end);
	inode = io_end->inode;
	blocksize = 1 << inode->i_blkbits;
	bio->bi_private = NULL;
	bio->bi_end_io = NULL;
	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
		error = 0;
	for (i = 0; i < bio->bi_vcnt; i++) {
		struct bio_vec *bvec = &bio->bi_io_vec[i];
		struct page *page = bvec->bv_page;
		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;

		if (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) + blocksize > bio_end) {
				if (buffer_async_write(bh))
					under_io++;
				continue;
			}
			clear_buffer_async_write(bh);
			if (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)
			end_page_writeback(page);
	}
	bio_put(bio);

	if (error) {
		io_end->flag |= EXT4_IO_END_ERROR;
		ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
			     "(offset %llu size %ld starting block %llu)",
			     inode->i_ino,
			     (unsigned long long) io_end->offset,
			     (long) io_end->size,
			     (unsigned long long)
			     bi_sector >> (inode->i_blkbits - 9));
	}

	ext4_put_io_end_defer(io_end);
}

void ext4_io_submit(struct ext4_io_submit *io)
{
	struct bio *bio = io->io_bio;

	if (bio) {
		bio_get(io->io_bio);
		submit_bio(io->io_op, io->io_bio);
		BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
		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_op = (wbc->sync_mode == WB_SYNC_ALL ?  WRITE_SYNC : WRITE);
	io->io_bio = NULL;
	io->io_end = NULL;
}

static int io_submit_init_bio(struct ext4_io_submit *io,
			      struct buffer_head *bh)
{
	int nvecs = bio_get_nr_vecs(bh->b_bdev);
	struct bio *bio;

	bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES));
	bio->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 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, bh->b_page, bh->b_size, bh_offset(bh));
	if (ret != bh->b_size)
		goto submit_and_retry;
	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)
{
	struct inode *inode = page->mapping->host;
	unsigned block_start, blocksize;
	struct buffer_head *bh, *head;
	int ret = 0;
	int nr_submitted = 0;

	blocksize = 1 << inode->i_blkbits;

	BUG_ON(!PageLocked(page));
	BUG_ON(PageWriteback(page));

	set_page_writeback(page);
	ClearPageError(page);

	/*
	 * 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) {
			/*
			 * Comments copied from block_write_full_page_endio:
			 *
			 * 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."
			 */
			zero_user_segment(page, block_start,
					  block_start + blocksize);
			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);
	} while ((bh = bh->b_this_page) != head);

	/* Now submit buffers to write */
	bh = head = page_buffers(page);
	do {
		if (!buffer_async_write(bh))
			continue;
		ret = io_submit_add_bh(io, inode, 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.
			 */
			redirty_page_for_writepage(wbc, page);
			break;
		}
		nr_submitted++;
		clear_buffer_dirty(bh);
	} while ((bh = bh->b_this_page) != head);

	/* Error stopped previous loop? Clean up buffers... */
	if (ret) {
		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;
}
Commit	Line	Data
bd2d0210 TT	1	/*
	2	* linux/fs/ext4/page-io.c
	3	*
	4	* This contains the new page_io functions for ext4
	5	*
	6	* Written by Theodore Ts'o, 2010.
	7	*/
	8
bd2d0210 TT	9	#include <linux/fs.h>
	10	#include <linux/time.h>
	11	#include <linux/jbd2.h>
	12	#include <linux/highuid.h>
	13	#include <linux/pagemap.h>
	14	#include <linux/quotaops.h>
	15	#include <linux/string.h>
	16	#include <linux/buffer_head.h>
	17	#include <linux/writeback.h>
	18	#include <linux/pagevec.h>
	19	#include <linux/mpage.h>
	20	#include <linux/namei.h>
a27bb332	21	#include <linux/aio.h>
bd2d0210 TT	22	#include <linux/uio.h>
	23	#include <linux/bio.h>
	24	#include <linux/workqueue.h>
	25	#include <linux/kernel.h>
	26	#include <linux/slab.h>
1ae48a63	27	#include <linux/mm.h>
bd2d0210 TT	28
	29	#include "ext4_jbd2.h"
	30	#include "xattr.h"
	31	#include "acl.h"
bd2d0210	32
0058f965	33	static struct kmem_cache *io_end_cachep;
bd2d0210	34
5dabfc78	35	int __init ext4_init_pageio(void)
bd2d0210	36	{
bd2d0210	37	io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
0058f965	38	if (io_end_cachep == NULL)
bd2d0210	39	return -ENOMEM;
bd2d0210 TT	40	return 0;
	41	}
	42
5dabfc78	43	void ext4_exit_pageio(void)
bd2d0210 TT	44	{
bd2d0210 TT	45	kmem_cache_destroy(io_end_cachep);
bd2d0210 TT	46	}
bd2d0210 TT	47
1ada47d9 TT	48	/*
	49	* This function is called by ext4_evict_inode() to make sure there is
	50	* no more pending I/O completion work left to do.
	51	*/
	52	void ext4_ioend_shutdown(struct inode *inode)
f7ad6d2e	53	{
e9e3bcec	54	wait_queue_head_t *wq = ext4_ioend_wq(inode);
f7ad6d2e TT	55
f7ad6d2e TT	56	wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0));
1ada47d9 TT	57	/*
	58	* We need to make sure the work structure is finished being
	59	* used before we let the inode get destroyed.
	60	*/
	61	if (work_pending(&EXT4_I(inode)->i_unwritten_work))
	62	cancel_work_sync(&EXT4_I(inode)->i_unwritten_work);
f7ad6d2e TT	63	}
f7ad6d2e TT	64
97a851ed	65	static void ext4_release_io_end(ext4_io_end_t *io_end)
bd2d0210	66	{
97a851ed JK	67	BUG_ON(!list_empty(&io_end->list));
	68	BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
	69
	70	if (atomic_dec_and_test(&EXT4_I(io_end->inode)->i_ioend_count))
	71	wake_up_all(ext4_ioend_wq(io_end->inode));
	72	if (io_end->flag & EXT4_IO_END_DIRECT)
	73	inode_dio_done(io_end->inode);
	74	if (io_end->iocb)
	75	aio_complete(io_end->iocb, io_end->result, 0);
	76	kmem_cache_free(io_end_cachep, io_end);
	77	}
	78
	79	static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
	80	{
	81	struct inode *inode = io_end->inode;
82e54229	82
97a851ed JK	83	io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
	84	/* Wake up anyone waiting on unwritten extent conversion */
	85	if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
	86	wake_up_all(ext4_ioend_wq(inode));
bd2d0210 TT	87	}
bd2d0210 TT	88
28a535f9 DM	89	/* check a range of space and convert unwritten extents to written. */
28a535f9 DM	90	static int ext4_end_io(ext4_io_end_t *io)
bd2d0210 TT	91	{
	92	struct inode *inode = io->inode;
	93	loff_t offset = io->offset;
	94	ssize_t size = io->size;
	95	int ret = 0;
	96
	97	ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
	98	"list->prev 0x%p\n",
	99	io, inode->i_ino, io->list.next, io->list.prev);
	100
bd2d0210 TT	101	ret = ext4_convert_unwritten_extents(inode, offset, size);
bd2d0210 TT	102	if (ret < 0) {
b82e384c TT	103	ext4_msg(inode->i_sb, KERN_EMERG,
	104	"failed to convert unwritten extents to written "
	105	"extents -- potential data loss! "
	106	"(inode %lu, offset %llu, size %zd, error %d)",
	107	inode->i_ino, offset, size, ret);
bd2d0210	108	}
97a851ed JK	109	ext4_clear_io_unwritten_flag(io);
97a851ed JK	110	ext4_release_io_end(io);
bd2d0210 TT	111	return ret;
	112	}
	113
28a535f9 DM	114	static void dump_completed_IO(struct inode *inode)
	115	{
	116	#ifdef EXT4FS_DEBUG
	117	struct list_head cur, before, *after;
	118	ext4_io_end_t io, io0, *io1;
28a535f9 DM	119
	120	if (list_empty(&EXT4_I(inode)->i_completed_io_list)) {
	121	ext4_debug("inode %lu completed_io list is empty\n",
	122	inode->i_ino);
	123	return;
	124	}
	125
	126	ext4_debug("Dump inode %lu completed_io list\n", inode->i_ino);
	127	list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list) {
	128	cur = &io->list;
	129	before = cur->prev;
	130	io0 = container_of(before, ext4_io_end_t, list);
	131	after = cur->next;
	132	io1 = container_of(after, ext4_io_end_t, list);
	133
	134	ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
	135	io, inode->i_ino, io0, io1);
	136	}
	137	#endif
	138	}
	139
	140	/* Add the io_end to per-inode completed end_io list. */
97a851ed	141	static void ext4_add_complete_io(ext4_io_end_t *io_end)
bd2d0210	142	{
28a535f9 DM	143	struct ext4_inode_info *ei = EXT4_I(io_end->inode);
	144	struct workqueue_struct *wq;
	145	unsigned long flags;
	146
	147	BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
	148	wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
bd2d0210	149
d73d5046	150	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
84c17543 JK	151	if (list_empty(&ei->i_completed_io_list))
84c17543 JK	152	queue_work(wq, &ei->i_unwritten_work);
28a535f9 DM	153	list_add_tail(&io_end->list, &ei->i_completed_io_list);
	154	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
	155	}
d73d5046	156
84c17543	157	static int ext4_do_flush_completed_IO(struct inode *inode)
28a535f9 DM	158	{
28a535f9 DM	159	ext4_io_end_t *io;
002bd7fa	160	struct list_head unwritten;
28a535f9 DM	161	unsigned long flags;
	162	struct ext4_inode_info *ei = EXT4_I(inode);
	163	int err, ret = 0;
	164
28a535f9 DM	165	spin_lock_irqsave(&ei->i_completed_io_lock, flags);
	166	dump_completed_IO(inode);
	167	list_replace_init(&ei->i_completed_io_list, &unwritten);
	168	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
	169
	170	while (!list_empty(&unwritten)) {
	171	io = list_entry(unwritten.next, ext4_io_end_t, list);
	172	BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
	173	list_del_init(&io->list);
	174
	175	err = ext4_end_io(io);
	176	if (unlikely(!ret && err))
	177	ret = err;
28a535f9 DM	178	}
	179	return ret;
	180	}
	181
	182	/*
	183	* work on completed aio dio IO, to convert unwritten extents to extents
	184	*/
84c17543	185	void ext4_end_io_work(struct work_struct *work)
28a535f9	186	{
84c17543 JK	187	struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
	188	i_unwritten_work);
	189	ext4_do_flush_completed_IO(&ei->vfs_inode);
28a535f9 DM	190	}
28a535f9 DM	191
c278531d	192	int ext4_flush_unwritten_io(struct inode *inode)
28a535f9	193	{
c278531d DM	194	int ret;
	195	WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex) &&
	196	!(inode->i_state & I_FREEING));
84c17543	197	ret = ext4_do_flush_completed_IO(inode);
c278531d DM	198	ext4_unwritten_wait(inode);
c278531d DM	199	return ret;
bd2d0210 TT	200	}
	201
	202	ext4_io_end_t ext4_init_io_end(struct inode inode, gfp_t flags)
	203	{
b17b35ec	204	ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
bd2d0210	205	if (io) {
f7ad6d2e TT	206	atomic_inc(&EXT4_I(inode)->i_ioend_count);
f7ad6d2e TT	207	io->inode = inode;
bd2d0210	208	INIT_LIST_HEAD(&io->list);
97a851ed	209	atomic_set(&io->count, 1);
bd2d0210 TT	210	}
	211	return io;
	212	}
	213
97a851ed JK	214	void ext4_put_io_end_defer(ext4_io_end_t *io_end)
	215	{
	216	if (atomic_dec_and_test(&io_end->count)) {
	217	if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) \|\| !io_end->size) {
	218	ext4_release_io_end(io_end);
	219	return;
	220	}
	221	ext4_add_complete_io(io_end);
	222	}
	223	}
	224
	225	int ext4_put_io_end(ext4_io_end_t *io_end)
	226	{
	227	int err = 0;
	228
	229	if (atomic_dec_and_test(&io_end->count)) {
	230	if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
	231	err = ext4_convert_unwritten_extents(io_end->inode,
	232	io_end->offset, io_end->size);
	233	ext4_clear_io_unwritten_flag(io_end);
	234	}
	235	ext4_release_io_end(io_end);
	236	}
	237	return err;
	238	}
	239
	240	ext4_io_end_t ext4_get_io_end(ext4_io_end_t io_end)
	241	{
	242	atomic_inc(&io_end->count);
	243	return io_end;
	244	}
	245
bd2d0210 TT	246	/*
	247	* Print an buffer I/O error compatible with the fs/buffer.c. This
	248	* provides compatibility with dmesg scrapers that look for a specific
	249	* buffer I/O error message. We really need a unified error reporting
	250	* structure to userspace ala Digital Unix's uerf system, but it's
	251	* probably not going to happen in my lifetime, due to LKML politics...
	252	*/
	253	static void buffer_io_error(struct buffer_head *bh)
	254	{
	255	char b[BDEVNAME_SIZE];
	256	printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n",
	257	bdevname(bh->b_bdev, b),
	258	(unsigned long long)bh->b_blocknr);
	259	}
	260
	261	static void ext4_end_bio(struct bio *bio, int error)
	262	{
	263	ext4_io_end_t *io_end = bio->bi_private;
bd2d0210	264	struct inode *inode;
bd2d0210	265	int i;
0058f965	266	int blocksize;
d50bdd5a	267	sector_t bi_sector = bio->bi_sector;
bd2d0210 TT	268
bd2d0210 TT	269	BUG_ON(!io_end);
0058f965 JK	270	inode = io_end->inode;
0058f965 JK	271	blocksize = 1 << inode->i_blkbits;
bd2d0210 TT	272	bio->bi_private = NULL;
	273	bio->bi_end_io = NULL;
	274	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
	275	error = 0;
0058f965 JK	276	for (i = 0; i < bio->bi_vcnt; i++) {
	277	struct bio_vec *bvec = &bio->bi_io_vec[i];
	278	struct page *page = bvec->bv_page;
bd2d0210	279	struct buffer_head bh, head;
0058f965 JK	280	unsigned bio_start = bvec->bv_offset;
	281	unsigned bio_end = bio_start + bvec->bv_len;
	282	unsigned under_io = 0;
	283	unsigned long flags;
	284
	285	if (!page)
	286	continue;
bd2d0210	287
39db00f1	288	if (error) {
bd2d0210	289	SetPageError(page);
39db00f1	290	set_bit(AS_EIO, &page->mapping->flags);
bd2d0210	291	}
0058f965 JK	292	bh = head = page_buffers(page);
	293	/*
	294	* We check all buffers in the page under BH_Uptodate_Lock
	295	* to avoid races with other end io clearing async_write flags
	296	*/
	297	local_irq_save(flags);
	298	bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
	299	do {
	300	if (bh_offset(bh) < bio_start \|\|
	301	bh_offset(bh) + blocksize > bio_end) {
	302	if (buffer_async_write(bh))
	303	under_io++;
	304	continue;
	305	}
	306	clear_buffer_async_write(bh);
	307	if (error)
	308	buffer_io_error(bh);
	309	} while ((bh = bh->b_this_page) != head);
	310	bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
	311	local_irq_restore(flags);
	312	if (!under_io)
	313	end_page_writeback(page);
bd2d0210	314	}
0058f965	315	bio_put(bio);
f7ad6d2e TT	316
	317	if (error) {
	318	io_end->flag \|= EXT4_IO_END_ERROR;
	319	ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
	320	"(offset %llu size %ld starting block %llu)",
	321	inode->i_ino,
	322	(unsigned long long) io_end->offset,
	323	(long) io_end->size,
	324	(unsigned long long)
d50bdd5a	325	bi_sector >> (inode->i_blkbits - 9));
f7ad6d2e	326	}
bd2d0210	327
97a851ed	328	ext4_put_io_end_defer(io_end);
bd2d0210 TT	329	}
	330
	331	void ext4_io_submit(struct ext4_io_submit *io)
	332	{
	333	struct bio *bio = io->io_bio;
	334
	335	if (bio) {
	336	bio_get(io->io_bio);
	337	submit_bio(io->io_op, io->io_bio);
	338	BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
	339	bio_put(io->io_bio);
	340	}
7dc57615	341	io->io_bio = NULL;
97a851ed JK	342	}
	343
	344	void ext4_io_submit_init(struct ext4_io_submit *io,
	345	struct writeback_control *wbc)
	346	{
	347	io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
	348	io->io_bio = NULL;
7dc57615	349	io->io_end = NULL;
bd2d0210 TT	350	}
bd2d0210 TT	351
97a851ed JK	352	static int io_submit_init_bio(struct ext4_io_submit *io,
97a851ed JK	353	struct buffer_head *bh)
bd2d0210	354	{
bd2d0210 TT	355	int nvecs = bio_get_nr_vecs(bh->b_bdev);
	356	struct bio *bio;
	357
275d3ba6	358	bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES));
bd2d0210 TT	359	bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bd2d0210 TT	360	bio->bi_bdev = bh->b_bdev;
bd2d0210	361	bio->bi_end_io = ext4_end_bio;
97a851ed	362	bio->bi_private = ext4_get_io_end(io->io_end);
bd2d0210	363	io->io_bio = bio;
bd2d0210 TT	364	io->io_next_block = bh->b_blocknr;
	365	return 0;
	366	}
	367
	368	static int io_submit_add_bh(struct ext4_io_submit *io,
bd2d0210	369	struct inode *inode,
bd2d0210 TT	370	struct buffer_head *bh)
bd2d0210 TT	371	{
bd2d0210 TT	372	int ret;
bd2d0210 TT	373
bd2d0210 TT	374	if (io->io_bio && bh->b_blocknr != io->io_next_block) {
	375	submit_and_retry:
	376	ext4_io_submit(io);
	377	}
	378	if (io->io_bio == NULL) {
97a851ed	379	ret = io_submit_init_bio(io, bh);
bd2d0210 TT	380	if (ret)
	381	return ret;
	382	}
97a851ed JK	383	ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));
	384	if (ret != bh->b_size)
	385	goto submit_and_retry;
bd2d0210	386	io->io_next_block++;
bd2d0210 TT	387	return 0;
	388	}
	389
	390	int ext4_bio_write_page(struct ext4_io_submit *io,
	391	struct page *page,
	392	int len,
	393	struct writeback_control *wbc)
	394	{
	395	struct inode *inode = page->mapping->host;
0058f965	396	unsigned block_start, blocksize;
bd2d0210 TT	397	struct buffer_head bh, head;
bd2d0210 TT	398	int ret = 0;
0058f965	399	int nr_submitted = 0;
bd2d0210 TT	400
	401	blocksize = 1 << inode->i_blkbits;
	402
d50bdd5a	403	BUG_ON(!PageLocked(page));
bd2d0210	404	BUG_ON(PageWriteback(page));
bd2d0210	405
a54aa761 TT	406	set_page_writeback(page);
a54aa761 TT	407	ClearPageError(page);
bd2d0210	408
0058f965 JK	409	/*
	410	* In the first loop we prepare and mark buffers to submit. We have to
	411	* mark all buffers in the page before submitting so that
	412	* end_page_writeback() cannot be called from ext4_bio_end_io() when IO
	413	* on the first buffer finishes and we are still working on submitting
	414	* the second buffer.
	415	*/
	416	bh = head = page_buffers(page);
	417	do {
	418	block_start = bh_offset(bh);
bd2d0210	419	if (block_start >= len) {
5a0dc736 YY	420	/*
	421	* Comments copied from block_write_full_page_endio:
	422	*
	423	* The page straddles i_size. It must be zeroed out on
	424	* each and every writepage invocation because it may
	425	* be mmapped. "A file is mapped in multiples of the
	426	* page size. For a file that is not a multiple of
	427	* the page size, the remaining memory is zeroed when
	428	* mapped, and writes to that region are not written
	429	* out to the file."
	430	*/
0058f965 JK	431	zero_user_segment(page, block_start,
0058f965 JK	432	block_start + blocksize);
bd2d0210 TT	433	clear_buffer_dirty(bh);
	434	set_buffer_uptodate(bh);
	435	continue;
	436	}
8a850c3f JK	437	if (!buffer_dirty(bh) \|\| buffer_delay(bh) \|\|
	438	!buffer_mapped(bh) \|\| buffer_unwritten(bh)) {
	439	/* A hole? We can safely clear the dirty bit */
	440	if (!buffer_mapped(bh))
	441	clear_buffer_dirty(bh);
	442	if (io->io_bio)
	443	ext4_io_submit(io);
	444	continue;
	445	}
0058f965 JK	446	if (buffer_new(bh)) {
	447	clear_buffer_new(bh);
	448	unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
	449	}
	450	set_buffer_async_write(bh);
	451	} while ((bh = bh->b_this_page) != head);
	452
	453	/* Now submit buffers to write */
	454	bh = head = page_buffers(page);
	455	do {
	456	if (!buffer_async_write(bh))
	457	continue;
97a851ed	458	ret = io_submit_add_bh(io, inode, bh);
bd2d0210 TT	459	if (ret) {
	460	/*
	461	* We only get here on ENOMEM. Not much else
	462	* we can do but mark the page as dirty, and
	463	* better luck next time.
	464	*/
1ae48a63	465	redirty_page_for_writepage(wbc, page);
bd2d0210 TT	466	break;
bd2d0210 TT	467	}
0058f965	468	nr_submitted++;
1ae48a63	469	clear_buffer_dirty(bh);
0058f965 JK	470	} while ((bh = bh->b_this_page) != head);
	471
	472	/* Error stopped previous loop? Clean up buffers... */
	473	if (ret) {
	474	do {
	475	clear_buffer_async_write(bh);
	476	bh = bh->b_this_page;
	477	} while (bh != head);
bd2d0210 TT	478	}
bd2d0210 TT	479	unlock_page(page);
0058f965 JK	480	/* Nothing submitted - we have to end page writeback */
	481	if (!nr_submitted)
	482	end_page_writeback(page);
bd2d0210 TT	483	return ret;
bd2d0210 TT	484	}