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Commit df22291f authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
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ext4: Retry block allocation if we have free blocks left 



When we truncate files, the meta-data blocks released are not reused
untill we commit the truncate transaction.  That means delayed get_block
request will return ENOSPC even if we have free blocks left.  Force a
journal commit and retry block allocation if we get ENOSPC with free
blocks left.

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMingming Cao <cmm@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 166348dd

fs/ext4/inode.c

+57 −24
Original line number Diff line number Diff line
@@ -1634,6 +1634,7 @@ struct mpage_da_data { 
	struct writeback_control *wbc;

	int io_done;

	long pages_written;

	int retval;

};



/*
@@ -1820,6 +1821,24 @@ static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd, 
	return;

}



static void ext4_print_free_blocks(struct inode *inode)

{

	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

	printk(KERN_EMERG "Total free blocks count %lld\n",

			ext4_count_free_blocks(inode->i_sb));

	printk(KERN_EMERG "Free/Dirty block details\n");

	printk(KERN_EMERG "free_blocks=%lld\n",

			percpu_counter_sum(&sbi->s_freeblocks_counter));

	printk(KERN_EMERG "dirty_blocks=%lld\n",

			percpu_counter_sum(&sbi->s_dirtyblocks_counter));

	printk(KERN_EMERG "Block reservation details\n");

	printk(KERN_EMERG "i_reserved_data_blocks=%lu\n",

			EXT4_I(inode)->i_reserved_data_blocks);

	printk(KERN_EMERG "i_reserved_meta_blocks=%lu\n",

			EXT4_I(inode)->i_reserved_meta_blocks);

	return;

}



/*

 * mpage_da_map_blocks - go through given space

 *
@@ -1834,7 +1853,7 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd) 
	int err = 0;

	struct buffer_head new;

	struct buffer_head *lbh = &mpd->lbh;

	sector_t next = lbh->b_blocknr;

	sector_t next;



	/*

	 * We consider only non-mapped and non-allocated blocks
@@ -1844,6 +1863,7 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd) 
	new.b_state = lbh->b_state;

	new.b_blocknr = 0;

	new.b_size = lbh->b_size;

	next = lbh->b_blocknr;

	/*

	 * If we didn't accumulate anything

	 * to write simply return
@@ -1860,6 +1880,13 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd) 
		 */

		if (err == -EAGAIN)

			return 0;



		if (err == -ENOSPC &&

				ext4_count_free_blocks(mpd->inode->i_sb)) {

			mpd->retval = err;

			return 0;

		}



		/*

		 * get block failure will cause us

		 * to loop in writepages. Because
@@ -1877,8 +1904,7 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd) 
		printk(KERN_EMERG "This should not happen.!! "

					"Data will be lost\n");

		if (err == -ENOSPC) {

			printk(KERN_CRIT "Total free blocks count %lld\n",

				ext4_count_free_blocks(mpd->inode->i_sb));

			ext4_print_free_blocks(mpd->inode);

		}

		/* invlaidate all the pages */

		ext4_da_block_invalidatepages(mpd, next,
@@ -2085,39 +2111,36 @@ static int __mpage_da_writepage(struct page *page, 
 */

static int mpage_da_writepages(struct address_space *mapping,

			       struct writeback_control *wbc,

			       get_block_t get_block)

			       struct mpage_da_data *mpd)

{

	struct mpage_da_data mpd;

	long to_write;

	int ret;



	if (!get_block)

	if (!mpd->get_block)

		return generic_writepages(mapping, wbc);



	mpd.wbc = wbc;

	mpd.inode = mapping->host;

	mpd.lbh.b_size = 0;

	mpd.lbh.b_state = 0;

	mpd.lbh.b_blocknr = 0;

	mpd.first_page = 0;

	mpd.next_page = 0;

	mpd.get_block = get_block;

	mpd.io_done = 0;

	mpd.pages_written = 0;

	mpd->lbh.b_size = 0;

	mpd->lbh.b_state = 0;

	mpd->lbh.b_blocknr = 0;

	mpd->first_page = 0;

	mpd->next_page = 0;

	mpd->io_done = 0;

	mpd->pages_written = 0;

	mpd->retval = 0;



	to_write = wbc->nr_to_write;



	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd);

	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);



	/*

	 * Handle last extent of pages

	 */

	if (!mpd.io_done && mpd.next_page != mpd.first_page) {

		if (mpage_da_map_blocks(&mpd) == 0)

			mpage_da_submit_io(&mpd);

	if (!mpd->io_done && mpd->next_page != mpd->first_page) {

		if (mpage_da_map_blocks(mpd) == 0)

			mpage_da_submit_io(mpd);

	}



	wbc->nr_to_write = to_write - mpd.pages_written;

	wbc->nr_to_write = to_write - mpd->pages_written;

	return ret;

}
@@ -2357,6 +2380,7 @@ static int ext4_da_writepages(struct address_space *mapping, 
{

	handle_t *handle = NULL;

	loff_t range_start = 0;

	struct mpage_da_data mpd;

	struct inode *inode = mapping->host;

	int needed_blocks, ret = 0, nr_to_writebump = 0;

	long to_write, pages_skipped = 0;
@@ -2390,6 +2414,9 @@ static int ext4_da_writepages(struct address_space *mapping, 
	range_start =  wbc->range_start;

	pages_skipped = wbc->pages_skipped;



	mpd.wbc = wbc;

	mpd.inode = mapping->host;



restart_loop:

	to_write = wbc->nr_to_write;

	while (!ret && to_write > 0) {
@@ -2413,11 +2440,17 @@ restart_loop: 
			dump_stack();

			goto out_writepages;

		}



		to_write -= wbc->nr_to_write;

		ret = mpage_da_writepages(mapping, wbc,

					  ext4_da_get_block_write);



		mpd.get_block = ext4_da_get_block_write;

		ret = mpage_da_writepages(mapping, wbc, &mpd);



		ext4_journal_stop(handle);



		if (mpd.retval == -ENOSPC)

			jbd2_journal_force_commit_nested(sbi->s_journal);



		/* reset the retry count */

		if (ret == MPAGE_DA_EXTENT_TAIL) {

			/*

			 * got one extent now try with