fs/xfs/xfs_buf_item_recover.c

Source file repositories/reference/linux-study-clean/fs/xfs/xfs_buf_item_recover.c

File Facts

System
Linux kernel
Corpus path
fs/xfs/xfs_buf_item_recover.c
Extension
.c
Size
34797 bytes
Lines
1217
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

struct xfs_buf_cancel {
	xfs_daddr_t		bc_blkno;
	uint			bc_len;
	int			bc_refcount;
	struct list_head	bc_list;
};

static struct xfs_buf_cancel *
xlog_find_buffer_cancelled(
	struct xlog		*log,
	xfs_daddr_t		blkno,
	uint			len)
{
	struct list_head	*bucket;
	struct xfs_buf_cancel	*bcp;

	if (!log->l_buf_cancel_table)
		return NULL;

	bucket = XLOG_BUF_CANCEL_BUCKET(log, blkno);
	list_for_each_entry(bcp, bucket, bc_list) {
		if (bcp->bc_blkno == blkno && bcp->bc_len == len)
			return bcp;
	}

	return NULL;
}

static bool
xlog_add_buffer_cancelled(
	struct xlog		*log,
	xfs_daddr_t		blkno,
	uint			len)
{
	struct xfs_buf_cancel	*bcp;

	/*
	 * If we find an existing cancel record, this indicates that the buffer
	 * was cancelled multiple times.  To ensure that during pass 2 we keep
	 * the record in the table until we reach its last occurrence in the
	 * log, a reference count is kept to tell how many times we expect to
	 * see this record during the second pass.
	 */
	bcp = xlog_find_buffer_cancelled(log, blkno, len);
	if (bcp) {
		bcp->bc_refcount++;
		return false;
	}

	bcp = kmalloc_obj(struct xfs_buf_cancel, GFP_KERNEL | __GFP_NOFAIL);
	bcp->bc_blkno = blkno;
	bcp->bc_len = len;
	bcp->bc_refcount = 1;
	list_add_tail(&bcp->bc_list, XLOG_BUF_CANCEL_BUCKET(log, blkno));
	return true;
}

/*
 * Check if there is and entry for blkno, len in the buffer cancel record table.
 */
bool
xlog_is_buffer_cancelled(
	struct xlog		*log,
	xfs_daddr_t		blkno,
	uint			len)
{
	return xlog_find_buffer_cancelled(log, blkno, len) != NULL;
}

/*
 * Check if there is and entry for blkno, len in the buffer cancel record table,
 * and decremented the reference count on it if there is one.
 *
 * Remove the cancel record once the refcount hits zero, so that if the same
 * buffer is re-used again after its last cancellation we actually replay the
 * changes made at that point.
 */
static bool
xlog_put_buffer_cancelled(
	struct xlog		*log,
	xfs_daddr_t		blkno,
	uint			len)
{
	struct xfs_buf_cancel	*bcp;

	bcp = xlog_find_buffer_cancelled(log, blkno, len);
	if (!bcp) {
		ASSERT(0);
		return false;
	}

Annotation

Implementation Notes