fs/hpfs/buffer.c

Source file repositories/reference/linux-study-clean/fs/hpfs/buffer.c

File Facts

System
Linux kernel
Corpus path
fs/hpfs/buffer.c
Extension
.c
Size
5441 bytes
Lines
233
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 (sbi->hotfix_from[i] == sec) {
			return sbi->hotfix_to[i];
		}
	}
	return sec;
}

unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n)
{
	unsigned i;
	struct hpfs_sb_info *sbi = hpfs_sb(s);
	for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
		if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) {
			n = sbi->hotfix_from[i] - sec;
		}
	}
	return n;
}

void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
{
	struct buffer_head *bh;
	struct blk_plug plug;

	if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))
		return;

	if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n))
		return;

	bh = sb_find_get_block(s, secno);
	if (bh) {
		if (buffer_uptodate(bh)) {
			brelse(bh);
			return;
		}
		brelse(bh);
	}

	blk_start_plug(&plug);
	while (n > 0) {
		if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))
			break;
		sb_breadahead(s, secno);
		secno++;
		n--;
	}
	blk_finish_plug(&plug);
}

/* Map a sector into a buffer and return pointers to it and to the buffer. */

void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
		 int ahead)
{
	struct buffer_head *bh;

	hpfs_lock_assert(s);

	hpfs_prefetch_sectors(s, secno, ahead);

	cond_resched();

	*bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno));
	if (bh != NULL)
		return bh->b_data;
	else {
		pr_err("%s(): read error\n", __func__);
		return NULL;
	}
}

/* Like hpfs_map_sector but don't read anything */

void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
{
	struct buffer_head *bh;
	/*return hpfs_map_sector(s, secno, bhp, 0);*/

	hpfs_lock_assert(s);

	cond_resched();

	if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) {
		if (!buffer_uptodate(bh)) wait_on_buffer(bh);
		set_buffer_uptodate(bh);
		return bh->b_data;
	} else {
		pr_err("%s(): getblk failed\n", __func__);
		return NULL;

Annotation

Implementation Notes