fs/ocfs2/extent_map.c

Source file repositories/reference/linux-study-clean/fs/ocfs2/extent_map.c

File Facts

System
Linux kernel
Corpus path
fs/ocfs2/extent_map.c
Extension
.c
Size
24866 bytes
Lines
1048
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source 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 (cpos >= emi->ei_cpos && cpos < range) {
			list_move(&emi->ei_list, &em->em_list);

			*ret_emi = emi;
			break;
		}
	}
}

static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
				   unsigned int *phys, unsigned int *len,
				   unsigned int *flags)
{
	unsigned int coff;
	struct ocfs2_inode_info *oi = OCFS2_I(inode);
	struct ocfs2_extent_map_item *emi;

	spin_lock(&oi->ip_lock);

	__ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
	if (emi) {
		coff = cpos - emi->ei_cpos;
		*phys = emi->ei_phys + coff;
		if (len)
			*len = emi->ei_clusters - coff;
		if (flags)
			*flags = emi->ei_flags;
	}

	spin_unlock(&oi->ip_lock);

	if (emi == NULL)
		return -ENOENT;

	return 0;
}

/*
 * Forget about all clusters equal to or greater than cpos.
 */
void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
{
	struct ocfs2_extent_map_item *emi, *n;
	struct ocfs2_inode_info *oi = OCFS2_I(inode);
	struct ocfs2_extent_map *em = &oi->ip_extent_map;
	LIST_HEAD(tmp_list);
	unsigned int range;

	spin_lock(&oi->ip_lock);
	list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
		if (emi->ei_cpos >= cpos) {
			/* Full truncate of this record. */
			list_move(&emi->ei_list, &tmp_list);
			BUG_ON(em->em_num_items == 0);
			em->em_num_items--;
			continue;
		}

		range = emi->ei_cpos + emi->ei_clusters;
		if (range > cpos) {
			/* Partial truncate */
			emi->ei_clusters = cpos - emi->ei_cpos;
		}
	}
	spin_unlock(&oi->ip_lock);

	list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
		list_del(&emi->ei_list);
		kfree(emi);
	}
}

/*
 * Is any part of emi2 contained within emi1
 */
static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
				 struct ocfs2_extent_map_item *emi2)
{
	unsigned int range1, range2;

	/*
	 * Check if logical start of emi2 is inside emi1
	 */
	range1 = emi1->ei_cpos + emi1->ei_clusters;
	if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
		return 1;

	/*
	 * Check if logical end of emi2 is inside emi1
	 */

Annotation

Implementation Notes