Commit bd721ec7 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Carlos Maiolino
Browse files

xfs: don't set bt_nr_sectors to a negative number 



xfs_daddr_t is a signed type, which means that xfs_buf_map_verify is
using a signed comparison.  This causes problems if bt_nr_sectors is
never overridden (e.g. in the case of an xfbtree for rmap btree repairs)
because even daddr 0 can't pass the verifier test in that case.

Define an explicit max constant and set the initial bt_nr_sectors to a
positive value.

Found by xfs/422.

Cc: stable@vger.kernel.org # v6.18-rc1
Fixes: 42852fe5 ("xfs: track the number of blocks in each buftarg")
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent 0f41997b

fs/xfs/xfs_buf.c

+1 −1
Original line number Diff line number Diff line
@@ -1751,7 +1751,7 @@ xfs_init_buftarg( 
	const char			*descr)

{

	/* The maximum size of the buftarg is only known once the sb is read. */

	btp->bt_nr_sectors = (xfs_daddr_t)-1;

	btp->bt_nr_sectors = XFS_BUF_DADDR_MAX;



	/* Set up device logical sector size mask */

	btp->bt_logical_sectorsize = logical_sectorsize;

fs/xfs/xfs_buf.h

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ extern struct kmem_cache *xfs_buf_cache; 
 */

struct xfs_buf;



#define XFS_BUF_DADDR_MAX	((xfs_daddr_t) S64_MAX)

#define XFS_BUF_DADDR_NULL	((xfs_daddr_t) (-1LL))



#define XBF_READ	 (1u << 0) /* buffer intended for reading from device */