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Commit 79893c17 authored by Al Viro's avatar Al Viro
Browse files

fix prune_dcache()/umount() race 



... and get rid of the last __put_super_and_need_restart() caller

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent df40c01a

fs/dcache.c

+6 −11
Original line number Diff line number Diff line
@@ -536,7 +536,7 @@ static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags) 
 */

static void prune_dcache(int count)

{

	struct super_block *sb;

	struct super_block *sb, *n;

	int w_count;

	int unused = dentry_stat.nr_unused;

	int prune_ratio;
@@ -545,13 +545,12 @@ static void prune_dcache(int count) 
	if (unused == 0 || count == 0)

		return;

	spin_lock(&dcache_lock);

restart:

	if (count >= unused)

		prune_ratio = 1;

	else

		prune_ratio = unused / count;

	spin_lock(&sb_lock);

	list_for_each_entry(sb, &super_blocks, s_list) {

	list_for_each_entry_safe(sb, n, &super_blocks, s_list) {

		if (list_empty(&sb->s_instances))

			continue;

		if (sb->s_nr_dentry_unused == 0)
@@ -592,14 +591,10 @@ static void prune_dcache(int count) 
		}

		spin_lock(&sb_lock);

		count -= pruned;

		/*

		 * restart only when sb is no longer on the list and

		 * we have more work to do.

		 */

		if (__put_super_and_need_restart(sb) && count > 0) {

			spin_unlock(&sb_lock);

			goto restart;

		}

		__put_super(sb);

		/* more work left to do? */

		if (count <= 0)

			break;

	}

	spin_unlock(&sb_lock);

	spin_unlock(&dcache_lock);