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authorDavid Sterba <dsterba@suse.com>2015-10-10 17:16:50 +0200
committerChris Mason <clm@fb.com>2015-10-26 19:38:28 -0700
commit12907fc79818a62a2478f84f7795afa774bf7f9c (patch)
treec7df6fd783c99feef090a00c38e7268515488430 /fs/btrfs/ctree.h
parent2849a854224487bc578b73b64422c3cb3ef93ff5 (diff)
downloadop-kernel-dev-12907fc79818a62a2478f84f7795afa774bf7f9c.zip
op-kernel-dev-12907fc79818a62a2478f84f7795afa774bf7f9c.tar.gz
btrfs: extend balance filter limit to take minimum and maximum
The 'limit' filter is underdesigned, it should have been a range for [min,max], with some relaxed semantics when one of the bounds is missing. Besides that, using a full u64 for a single value is a waste of bytes. Let's fix both by extending the use of the u64 bytes for the [min,max] range. This can be done in a backward compatible way, the range will be interpreted only if the appropriate flag is set (BTRFS_BALANCE_ARGS_LIMIT_RANGE). Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/ctree.h')
-rw-r--r--fs/btrfs/ctree.h14
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3fa3c3b..460cd69 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -846,8 +846,18 @@ struct btrfs_disk_balance_args {
/* BTRFS_BALANCE_ARGS_* */
__le64 flags;
- /* BTRFS_BALANCE_ARGS_LIMIT value */
- __le64 limit;
+ /*
+ * BTRFS_BALANCE_ARGS_LIMIT with value 'limit'
+ * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum
+ * and maximum
+ */
+ union {
+ __le64 limit;
+ struct {
+ __le32 limit_min;
+ __le32 limit_max;
+ };
+ };
__le64 unused[7];
} __attribute__ ((__packed__));
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