fs/ext4/mballoc.c

Source file repositories/reference/linux-study-clean/fs/ext4/mballoc.c

File Facts

System
Linux kernel
Corpus path
fs/ext4/mballoc.c
Extension
.c
Size
209641 bytes
Lines
7284
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
			ext4_fsblk_t blocknr;

			blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
			blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
			ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
			ext4_grp_locked_error(sb, e4b->bd_group,
					      inode ? inode->i_ino : 0,
					      blocknr,
					      "freeing block already freed "
					      "(bit %u)",
					      first + i);
		}
		mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
	}
}

static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
	int i;

	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
		return;
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
	for (i = 0; i < count; i++) {
		BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
		mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
	}
}

static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
		return;
	if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
		unsigned char *b1, *b2;
		int i;
		b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
		b2 = (unsigned char *) bitmap;
		for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
			if (b1[i] != b2[i]) {
				ext4_msg(e4b->bd_sb, KERN_ERR,
					 "corruption in group %u "
					 "at byte %u(%u): %x in copy != %x "
					 "on disk/prealloc",
					 e4b->bd_group, i, i * 8, b1[i], b2[i]);
				BUG();
			}
		}
	}
}

static void mb_group_bb_bitmap_alloc(struct super_block *sb,
			struct ext4_group_info *grp, ext4_group_t group)
{
	struct buffer_head *bh;

	grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
	if (!grp->bb_bitmap)
		return;

	bh = ext4_read_block_bitmap(sb, group);
	if (IS_ERR_OR_NULL(bh)) {
		kfree(grp->bb_bitmap);
		grp->bb_bitmap = NULL;
		return;
	}

	memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
	put_bh(bh);
}

static void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
{
	kfree(grp->bb_bitmap);
}

#else
static inline void mb_free_blocks_double(struct inode *inode,
				struct ext4_buddy *e4b, int first, int count)
{
	return;
}
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
						int first, int count)
{
	return;
}
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)

Annotation

Implementation Notes