xfs: cap longest free extent to maximum allocatable

Cap longest extent to the largest we can allocate based on limits
calculated at mount time. Dynamic state (such as finobt blocks)
can result in the longest free extent exceeding the size we can
allocate, and that results in failure to align full AG allocations
when the AG is empty.

Result:

xfs_io-4413  [003]   426.412459: xfs_alloc_vextent_loopfailed: dev 8:96 agno 0 agbno 32 minlen 243968 maxlen 244000 mod 0 prod 1 minleft 1 total 262148 alignment 32 minalignslop 0 len 0 type NEAR_BNO otype START_BNO wasdel 0 wasfromfl 0 resv 0 datatype 0x5 firstblock 0xffffffffffffffff

minlen and maxlen are now separated by the alignment size, and
allocation fails because args.total > free space in the AG.

[bfoster: Added xfs_bmap_btalloc() changes.]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Dave Chinner
2019-10-21 09:26:34 -07:00
committed by Darrick J. Wong
parent 3fb21fc8cc
commit 1c743574de
2 changed files with 11 additions and 10 deletions

View File

@@ -2116,7 +2116,8 @@ xfs_alloc_longest_free_extent(
* reservations and AGFL rules in place, we can return this extent.
*/
if (pag->pagf_longest > delta)
return pag->pagf_longest - delta;
return min_t(xfs_extlen_t, pag->pag_mount->m_ag_max_usable,
pag->pagf_longest - delta);
/* Otherwise, let the caller try for 1 block if there's space. */
return pag->pagf_flcount > 0 || pag->pagf_longest > 0;