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Commit 7ad9bb65 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: Fix initalization of s_flex_groups 



The s_flex_groups array should have been initialized using atomic_add
to sum up the free counts from the block groups that make up a
flex_bg.  By using atomic_set, the value of the s_flex_groups array
was set to the values of the last block group in the flex_bg.  

The impact of this bug is that the block and inode allocation
algorithms might not pick the best flex_bg for new allocation.

Thanks to Damien Guibouret for pointing out this problem!

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 1f7bebb9

fs/ext4/super.c

+6 −6
Original line number Diff line number Diff line
@@ -1694,12 +1694,12 @@ static int ext4_fill_flex_info(struct super_block *sb) 
		gdp = ext4_get_group_desc(sb, i, NULL);



		flex_group = ext4_flex_group(sbi, i);

		atomic_set(&sbi->s_flex_groups[flex_group].free_inodes,

			   ext4_free_inodes_count(sb, gdp));

		atomic_set(&sbi->s_flex_groups[flex_group].free_blocks,

			   ext4_free_blks_count(sb, gdp));

		atomic_set(&sbi->s_flex_groups[flex_group].used_dirs,

			   ext4_used_dirs_count(sb, gdp));

		atomic_add(ext4_free_inodes_count(sb, gdp),

			   &sbi->s_flex_groups[flex_group].free_inodes);

		atomic_add(ext4_free_blks_count(sb, gdp),

			   &sbi->s_flex_groups[flex_group].free_blocks);

		atomic_add(ext4_used_dirs_count(sb, gdp),

			   &sbi->s_flex_groups[flex_group].used_dirs);

	}



	return 1;