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authorXie Xiaobo <xiaobo.xie@nxp.com>2017-12-12 08:12:33 (GMT)
committerXie Xiaobo <xiaobo.xie@nxp.com>2017-12-12 08:12:33 (GMT)
commitc0246a9ec4d461ef4dd7647f94005380bb9e7f0b (patch)
tree7588601aa6ce98f5e9fd083a1b351d9023c0b295 /fs/xfs/libxfs/xfs_refcount.h
parent50fd1a6d79d48a7c35890aecce5a5d6b872a461d (diff)
parent56f4a560c6d6318b5a8e18a1b3e44909a5158d1e (diff)
downloadlinux-c0246a9ec4d461ef4dd7647f94005380bb9e7f0b.tar.xz
Merge Linaro linux 4.9.62 into linux-4.9
Signed-off-by: Xiaobo Xie <xiaobo.xie@nxp.com>
Diffstat (limited to 'fs/xfs/libxfs/xfs_refcount.h')
-rw-r--r--fs/xfs/libxfs/xfs_refcount.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_refcount.h b/fs/xfs/libxfs/xfs_refcount.h
index 098dc66..eafb9d1 100644
--- a/fs/xfs/libxfs/xfs_refcount.h
+++ b/fs/xfs/libxfs/xfs_refcount.h
@@ -67,4 +67,20 @@ extern int xfs_refcount_free_cow_extent(struct xfs_mount *mp,
extern int xfs_refcount_recover_cow_leftovers(struct xfs_mount *mp,
xfs_agnumber_t agno);
+/*
+ * While we're adjusting the refcounts records of an extent, we have
+ * to keep an eye on the number of extents we're dirtying -- run too
+ * many in a single transaction and we'll exceed the transaction's
+ * reservation and crash the fs. Each record adds 12 bytes to the
+ * log (plus any key updates) so we'll conservatively assume 32 bytes
+ * per record. We must also leave space for btree splits on both ends
+ * of the range and space for the CUD and a new CUI.
+ */
+#define XFS_REFCOUNT_ITEM_OVERHEAD 32
+
+static inline xfs_fileoff_t xfs_refcount_max_unmap(int log_res)
+{
+ return (log_res * 3 / 4) / XFS_REFCOUNT_ITEM_OVERHEAD;
+}
+
#endif /* __XFS_REFCOUNT_H__ */