[PATCH] Btrfs: fix 64 bit divide problem
From: Josef Bacik <hidden>
Date: 2011-08-20 12:30:44
Also in:
lkml
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
This fixes a regression introduced by cdcb725c05fe0cb71777c66ddc2445fedbbb3c59 In cases where we need to divide/multiply by 2 we should just left/right shift respectively, and in cases where theres N number of devices use do_div. Also make the counters u64 to match up with rw_devices. Thanks, Signed-off-by: Josef Bacik <redacted> --- fs/btrfs/extent-tree.c | 12 +++++++----- 1 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 44a3107..99ab571 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c@@ -6727,9 +6727,9 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr) struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices; struct btrfs_device *device; u64 min_free; + u64 dev_min = 1; + u64 dev_nr = 0; int index; - int dev_nr = 0; - int dev_min = 1; int full = 0; int ret = 0;
@@ -6788,14 +6788,16 @@ int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr) index = get_block_group_index(block_group); if (index == 0) { dev_min = 4; - min_free /= 2; + /* Divide by 2 */ + min_free >>= 1; } else if (index == 1) { dev_min = 2; } else if (index == 2) { - min_free *= 2; + /* Multiply by 2 */ + min_free <<= 1; } else if (index == 3) { dev_min = fs_devices->rw_devices; - min_free /= dev_min; + do_div(min_free, dev_min); } mutex_lock(&root->fs_info->chunk_mutex);
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1.7.5.2