[v4] btrfs: make block group flags in balance printks human-readable

Commit Message

Adam Borowski Nov. 14, 2016, 5:44 p.m. UTC

They're not even documented anywhere, letting users with no recourse but
to RTFS.  It's no big burden to output the bitfield as words.

Also, display unknown flags as hex.

Signed-off-by: Adam Borowski <[e-mail]>
---
 fs/btrfs/relocation.c | 42 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 3 deletions(-)

Comments

David Sterba Nov. 14, 2016, 6:24 p.m. UTC | #1

On Mon, Nov 14, 2016 at 06:44:34PM +0100, Adam Borowski wrote:
> They're not even documented anywhere, letting users with no recourse but
> to RTFS.  It's no big burden to output the bitfield as words.
> 
> Also, display unknown flags as hex.
> 
> Signed-off-by: Adam Borowski <[e-mail]>

Added to 4.10 queue, thanks.
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Patch

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index c4af0cd..9a3abf3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4333,6 +4333,44 @@  static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
 }
 
 /*
+ * printk the block group being relocated
+ */
+static void describe_relocation(struct btrfs_fs_info *fs_info,
+				struct btrfs_block_group_cache *block_group)
+{
+	char buf[128]; /* prefixed by a '|' that'll be dropped */
+	u64 flags = block_group->flags;
+
+	if (!flags) { /* shouldn't happen */
+		strcpy(buf, "|NONE");
+	} else {
+		char *bp = buf;
+
+#define DESCRIBE_FLAG(f, d) \
+		if (flags & BTRFS_BLOCK_GROUP_##f) { \
+			bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
+			flags &= ~BTRFS_BLOCK_GROUP_##f; \
+		}
+		DESCRIBE_FLAG(DATA,     "data");
+		DESCRIBE_FLAG(SYSTEM,   "system");
+		DESCRIBE_FLAG(METADATA, "metadata");
+		DESCRIBE_FLAG(RAID0,    "raid0");
+		DESCRIBE_FLAG(RAID1,    "raid1");
+		DESCRIBE_FLAG(DUP,      "dup");
+		DESCRIBE_FLAG(RAID10,   "raid10");
+		DESCRIBE_FLAG(RAID5,    "raid5");
+		DESCRIBE_FLAG(RAID6,    "raid6");
+		if (flags)
+			snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
+#undef DESCRIBE_FLAG
+	}
+
+	btrfs_info(fs_info,
+		   "relocating block group %llu flags %s",
+		   block_group->key.objectid, buf + 1);
+}
+
+/*
  * function to relocate all extents in a block group.
  */
 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
@@ -4388,9 +4426,7 @@  int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
 		goto out;
 	}
 
-	btrfs_info(extent_root->fs_info,
-		   "relocating block group %llu flags %llu",
-		   rc->block_group->key.objectid, rc->block_group->flags);
+	describe_relocation(extent_root->fs_info, rc->block_group);
 
 	btrfs_wait_block_group_reservations(rc->block_group);
 	btrfs_wait_nocow_writers(rc->block_group);