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btrfs-progs: check metadata redundancy

PATCH Applied sam tygier 2 participants 2 messages May 30, 2015 – Jun 2, 2015 Btrfs file system

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sam tygier

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#0 lore raw

PATCH v2 1/1 btrfs-progs: check metadata redundancy

Currently BTRFS allows you to make bad choices of data and metadata levels. For example -d raid1 -m raid0 means you can only use half your total disk space, but will loose everything if 1 disk fails. It should give a warning in these cases.

When making a filesystem check that metadata mode is at least as redundant as the data mode. For example give warning when:
-d raid1 -m raid0

V1 -> V2 Downgrade from error to warning as requested by David Sterba.

Signed-off-by Sam Tygier <[email protected]>
Quoted 1 line

From fdfcb5f733ff5ed48562366bda6f1a9c740b031a Mon Sep 17 00:00:00 2001

From: Sam Tygier <[email protected]>
Date: Sat, 30 May 2015 15:37:37 +0100
Subject: [PATCH] When making a filesystem check that metadata mode is at least
as redundant as the data mode. For example give warning when:
-d raid1 -m raid0

---
 mkfs.c  |  6 ++++++
 utils.c | 18 ++++++++++++++++++
 utils.h |  1 +
 3 files changed, 25 insertions(+)
mkfs.c +6 -0
index 14e0fed..938840d 100644
@@ -1367,6 +1367,12 @@ int main(int ac, char **av)
 		exit(1);
 	}
 
+	if (group_profile_max_safe_loss(metadata_profile) <
+		group_profile_max_safe_loss(data_profile)){
+		fprintf(stderr,
+			"Warning: metatdata has lower redundancy than data\n");
+	}
+
 	/* if we are here that means all devs are good to btrfsify */
 	printf("%s\n", PACKAGE_STRING);
 	printf("See %s for more information.\n\n", PACKAGE_URL);
utils.c +18 -0
index 4b8a826..ba35b34 100644
@@ -2354,6 +2354,24 @@ int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
 	return 0;
 }
 
+int group_profile_max_safe_loss(u64 flag)
+{
+	switch (flag & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+	case 0: /* single */
+	case BTRFS_BLOCK_GROUP_DUP:
+	case BTRFS_BLOCK_GROUP_RAID0:
+		return 0;
+	case BTRFS_BLOCK_GROUP_RAID1:
+	case BTRFS_BLOCK_GROUP_RAID5:
+	case BTRFS_BLOCK_GROUP_RAID10:
+		return 1;
+	case BTRFS_BLOCK_GROUP_RAID6:
+		return 2;
+	default:
+		return -1;
+	}
+}
+
 /* Check if disk is suitable for btrfs
  * returns:
  *  1: something is wrong, estr provides the error
utils.h +1 -0
index 5657c74..98fd812 100644
@@ -144,6 +144,7 @@ int test_dev_for_mkfs(char *file, int force_overwrite, char *estr);
 int get_label_mounted(const char *mount_path, char *labelp);
 int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
 	u64 dev_cnt, int mixed, char *estr);
+int group_profile_max_safe_loss(u64 flag);
 int is_vol_small(char *file);
 int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 			   int verify);
Signature · 1 line
2.1.4
Applied
#1 lore raw
Quoted 5 lines · sam tygier

Currently BTRFS allows you to make bad choices of data and metadata levels. For example -d raid1 -m raid0 means you can only use half your total disk space, but will loose everything if 1 disk fails. It should give a warning in these cases.

Quoted 8 lines

When making a filesystem check that metadata mode is at least as redundant as the data mode. For example give warning when:
-d raid1 -m raid0

V1 -> V2 Downgrade from error to warning as requested by David Sterba.

Signed-off-by Sam Tygier <[email protected]>

Applied, thanks.