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authorDavid S. Miller <davem@davemloft.net>2011-02-19 19:17:35 -0800
committerDavid S. Miller <davem@davemloft.net>2011-02-19 19:17:35 -0800
commitda935c66bacb3ed9ada984b053297f87c2dff63a (patch)
tree46278da2b312c73f1375b830d7e5912bf23abd78 /fs/xfs/xfs_alloc.h
parent9435eb1cf0b76b323019cebf8d16762a50a12a19 (diff)
parent2205a6ea93fea76f88b43727fea53f3ce3790d6f (diff)
downloadlinux-da935c66bacb3ed9ada984b053297f87c2dff63a.tar.bz2
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts: Documentation/feature-removal-schedule.txt drivers/net/e1000e/netdev.c net/xfrm/xfrm_policy.c
Diffstat (limited to 'fs/xfs/xfs_alloc.h')
-rw-r--r--fs/xfs/xfs_alloc.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/xfs/xfs_alloc.h b/fs/xfs/xfs_alloc.h
index 0ab56b32c7eb..d0b3bc72005b 100644
--- a/fs/xfs/xfs_alloc.h
+++ b/fs/xfs/xfs_alloc.h
@@ -75,6 +75,22 @@ typedef unsigned int xfs_alloctype_t;
#define XFS_ALLOC_SET_ASIDE(mp) (4 + ((mp)->m_sb.sb_agcount * 4))
/*
+ * When deciding how much space to allocate out of an AG, we limit the
+ * allocation maximum size to the size the AG. However, we cannot use all the
+ * blocks in the AG - some are permanently used by metadata. These
+ * blocks are generally:
+ * - the AG superblock, AGF, AGI and AGFL
+ * - the AGF (bno and cnt) and AGI btree root blocks
+ * - 4 blocks on the AGFL according to XFS_ALLOC_SET_ASIDE() limits
+ *
+ * The AG headers are sector sized, so the amount of space they take up is
+ * dependent on filesystem geometry. The others are all single blocks.
+ */
+#define XFS_ALLOC_AG_MAX_USABLE(mp) \
+ ((mp)->m_sb.sb_agblocks - XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)) - 7)
+
+
+/*
* Argument structure for xfs_alloc routines.
* This is turned into a structure to avoid having 20 arguments passed
* down several levels of the stack.