diff options
| -rw-r--r-- | fs/xfs/xfs_bmap.h | 13 | ||||
| -rw-r--r-- | fs/xfs/xfs_bmap_btree.c | 8 |
2 files changed, 18 insertions, 3 deletions
diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h index 6ff70cda451..9f3e3a836d1 100644 --- a/fs/xfs/xfs_bmap.h +++ b/fs/xfs/xfs_bmap.h @@ -54,12 +54,23 @@ typedef struct xfs_bmap_free_item /* * Header for free extent list. + * + * xbf_low is used by the allocator to activate the lowspace algorithm - + * when free space is running low the extent allocator may choose to + * allocate an extent from an AG without leaving sufficient space for + * a btree split when inserting the new extent. In this case the allocator + * will enable the lowspace algorithm which is supposed to allow further + * allocations (such as btree splits and newroots) to allocate from + * sequential AGs. In order to avoid locking AGs out of order the lowspace + * algorithm will start searching for free space from AG 0. If the correct + * transaction reservations have been made then this algorithm will eventually + * find all the space it needs. */ typedef struct xfs_bmap_free { xfs_bmap_free_item_t *xbf_first; /* list of to-be-free extents */ int xbf_count; /* count of items on list */ - int xbf_low; /* kludge: alloc in low mode */ + int xbf_low; /* alloc in low mode */ } xfs_bmap_free_t; #define XFS_BMAP_MAX_NMAP 4 diff --git a/fs/xfs/xfs_bmap_btree.c b/fs/xfs/xfs_bmap_btree.c index 3fc09cd8d51..1140cef4ba9 100644 --- a/fs/xfs/xfs_bmap_btree.c +++ b/fs/xfs/xfs_bmap_btree.c @@ -1509,7 +1509,9 @@ xfs_bmbt_split( * block allocation here and corrupt the filesystem. */ args.minleft = xfs_trans_get_block_res(args.tp); - } else + } else if (cur->bc_private.b.flist->xbf_low) + args.type = XFS_ALLOCTYPE_START_BNO; + else args.type = XFS_ALLOCTYPE_NEAR_BNO; args.mod = args.alignment = args.total = args.isfl = args.userdata = args.minalignslop = 0; @@ -2237,7 +2239,9 @@ xfs_bmbt_newroot( #endif args.fsbno = be64_to_cpu(*pp); args.type = XFS_ALLOCTYPE_START_BNO; - } else + } else if (cur->bc_private.b.flist->xbf_low) + args.type = XFS_ALLOCTYPE_START_BNO; + else args.type = XFS_ALLOCTYPE_NEAR_BNO; if ((error = xfs_alloc_vextent(&args))) { XFS_BMBT_TRACE_CURSOR(cur, ERROR); |