Commit df9ad5cc authored by Chandan Babu R's avatar Chandan Babu R
Browse files

xfs: Introduce macros to represent new maximum extent counts for data/attr forks 



This commit defines new macros to represent maximum extent counts allowed by
filesystems which have support for large per-inode extent counters.

Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarChandan Babu R <chandan.babu@oracle.com>
parent 0c35e7ba

fs/xfs/libxfs/xfs_bmap.c

+4 −5
Original line number Diff line number Diff line
@@ -61,10 +61,8 @@ xfs_bmap_compute_maxlevels( 
	int		sz;		/* root block size */



	/*

	 * The maximum number of extents in a file, hence the maximum number of

	 * leaf entries, is controlled by the size of the on-disk extent count,

	 * either a signed 32-bit number for the data fork, or a signed 16-bit

	 * number for the attr fork.

	 * The maximum number of extents in a fork, hence the maximum number of

	 * leaf entries, is controlled by the size of the on-disk extent count.

	 *

	 * Note that we can no longer assume that if we are in ATTR1 that the

	 * fork offset of all the inodes will be
@@ -74,7 +72,8 @@ xfs_bmap_compute_maxlevels( 
	 * ATTR2 we have to assume the worst case scenario of a minimum size

	 * available.

	 */

	maxleafents = xfs_iext_max_nextents(whichfork);

	maxleafents = xfs_iext_max_nextents(xfs_has_large_extent_counts(mp),

				whichfork);

	if (whichfork == XFS_DATA_FORK)

		sz = XFS_BMDR_SPACE_CALC(MINDBTPTRS);

	else

fs/xfs/libxfs/xfs_bmap_btree.c

+7 −2
Original line number Diff line number Diff line
@@ -597,7 +597,11 @@ xfs_bmbt_maxrecs( 
	return xfs_bmbt_block_maxrecs(blocklen, leaf);

}



/* Compute the max possible height for block mapping btrees. */

/*

 * Calculate the maximum possible height of the btree that the on-disk format

 * supports. This is used for sizing structures large enough to support every

 * possible configuration of a filesystem that might get mounted.

 */

unsigned int

xfs_bmbt_maxlevels_ondisk(void)

{
@@ -611,7 +615,8 @@ xfs_bmbt_maxlevels_ondisk(void) 
	minrecs[1] = xfs_bmbt_block_maxrecs(blocklen, false) / 2;



	/* One extra level for the inode root. */

	return xfs_btree_compute_maxlevels(minrecs, MAXEXTNUM) + 1;

	return xfs_btree_compute_maxlevels(minrecs,

			XFS_MAX_EXTCNT_DATA_FORK_LARGE) + 1;

}



/*

fs/xfs/libxfs/xfs_format.h

+22 −2
Original line number Diff line number Diff line
@@ -872,9 +872,29 @@ enum xfs_dinode_fmt { 


/*

 * Max values for extnum and aextnum.

 *

 * The original on-disk extent counts were held in signed fields, resulting in

 * maximum extent counts of 2^31 and 2^15 for the data and attr forks

 * respectively. Similarly the maximum extent length is limited to 2^21 blocks

 * by the 21-bit wide blockcount field of a BMBT extent record.

 *

 * The newly introduced data fork extent counter can hold a 64-bit value,

 * however the maximum number of extents in a file is also limited to 2^54

 * extents by the 54-bit wide startoff field of a BMBT extent record.

 *

 * It is further limited by the maximum supported file size of 2^63

 * *bytes*. This leads to a maximum extent count for maximally sized filesystem

 * blocks (64kB) of:

 *

 * 2^63 bytes / 2^16 bytes per block = 2^47 blocks

 *

 * Rounding up 47 to the nearest multiple of bits-per-byte results in 48. Hence

 * 2^48 was chosen as the maximum data fork extent count.

 */

#define	MAXEXTNUM	((xfs_extnum_t)0x7fffffff)	/* signed int */

#define	MAXAEXTNUM	((xfs_aextnum_t)0x7fff)		/* signed short */

#define XFS_MAX_EXTCNT_DATA_FORK_LARGE	((xfs_extnum_t)((1ULL << 48) - 1))

#define XFS_MAX_EXTCNT_ATTR_FORK_LARGE	((xfs_extnum_t)((1ULL << 32) - 1))

#define XFS_MAX_EXTCNT_DATA_FORK_SMALL	((xfs_extnum_t)((1ULL << 31) - 1))

#define XFS_MAX_EXTCNT_ATTR_FORK_SMALL	((xfs_extnum_t)((1ULL << 15) - 1))



/*

 * Inode minimum and maximum sizes.

fs/xfs/libxfs/xfs_inode_buf.c

+3 −1
Original line number Diff line number Diff line
@@ -361,7 +361,9 @@ xfs_dinode_verify_fork( 
			return __this_address;

		break;

	case XFS_DINODE_FMT_BTREE:

		max_extents = xfs_iext_max_nextents(whichfork);

		max_extents = xfs_iext_max_nextents(

					xfs_dinode_has_large_extent_counts(dip),

					whichfork);

		if (di_nextents > max_extents)

			return __this_address;

		break;

fs/xfs/libxfs/xfs_inode_fork.c

+2 −1
Original line number Diff line number Diff line
@@ -744,7 +744,8 @@ xfs_iext_count_may_overflow( 
	if (whichfork == XFS_COW_FORK)

		return 0;



	max_exts = xfs_iext_max_nextents(whichfork);

	max_exts = xfs_iext_max_nextents(xfs_inode_has_large_extent_counts(ip),

				whichfork);



	if (XFS_TEST_ERROR(false, ip->i_mount, XFS_ERRTAG_REDUCE_MAX_IEXTENTS))

		max_exts = 10;