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Revision ce93ec548cfa02f9cd6b70d546d5f36f4d160f57 authored by Josef Bacik on 17 November 2014, 20:45:48 UTC, committed by Chris Mason on 22 January 2015, 01:36:52 UTC 
Btrfs: track dirty block groups on their own list
 
Currently any time we try to update the block groups on disk we will walk _all_
block groups and check for the ->dirty flag to see if it is set.  This function
can get called several times during a commit.  So if you have several terabytes
of data you will be a very sad panda as we will loop through _all_ of the block
groups several times, which makes the commit take a while which slows down the
rest of the file system operations.

This patch introduces a dirty list for the block groups that we get added to
when we dirty the block group for the first time.  Then we simply update any
block groups that have been dirtied since the last time we called
btrfs_write_dirty_block_groups.  This allows us to clean up how we write the
free space cache out so it is much cleaner.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
1 parent e7070be
Raw File
failslab.c 
#include <linux/fault-inject.h>
#include <linux/slab.h>

static struct {
	struct fault_attr attr;
	u32 ignore_gfp_wait;
	int cache_filter;
} failslab = {
	.attr = FAULT_ATTR_INITIALIZER,
	.ignore_gfp_wait = 1,
	.cache_filter = 0,
};

bool should_failslab(size_t size, gfp_t gfpflags, unsigned long cache_flags)
{
	if (gfpflags & __GFP_NOFAIL)
		return false;

        if (failslab.ignore_gfp_wait && (gfpflags & __GFP_WAIT))
		return false;

	if (failslab.cache_filter && !(cache_flags & SLAB_FAILSLAB))
		return false;

	return should_fail(&failslab.attr, size);
}

static int __init setup_failslab(char *str)
{
	return setup_fault_attr(&failslab.attr, str);
}
__setup("failslab=", setup_failslab);

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int __init failslab_debugfs_init(void)
{
	struct dentry *dir;
	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;

	dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
	if (IS_ERR(dir))
		return PTR_ERR(dir);

	if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
				&failslab.ignore_gfp_wait))
		goto fail;
	if (!debugfs_create_bool("cache-filter", mode, dir,
				&failslab.cache_filter))
		goto fail;

	return 0;
fail:
	debugfs_remove_recursive(dir);

	return -ENOMEM;
}

late_initcall(failslab_debugfs_init);

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
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