[PATCH v2 1/2] btrfs: add replace missing and replace RAID 5/6 to profile configs

[Omar Sandoval <osandov@osandov.com>]

From: Omar Sandoval <osandov@fb.com>

Replacing and scrubbing RAID 5/6 is now supported on Btrfs. Enable it in
_btrfs_get_profile_configs while making it more generic to also support
replace missing.

Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 common/rc | 95 ++++++++++++++++++++++++++++++++-------------------------------
 1 file changed, 48 insertions(+), 47 deletions(-)

diff --git a/common/rc b/common/rc
index 8bec836805c6..91e8f1c8e693 100644
--- a/common/rc
+++ b/common/rc
@@ -3207,60 +3207,61 @@ _btrfs_get_profile_configs()
 		return
 	fi
 
-	# no user specified btrfs profile configs, export the default configs
 	if [ -z "$BTRFS_PROFILE_CONFIGS" ]; then
-		# default configs
-		_btrfs_profile_configs=(
-			"-m single -d single"
-			"-m dup -d single"
-			"-m raid0 -d raid0"
-			"-m raid1 -d raid0"
-			"-m raid1 -d raid1"
-			"-m raid10 -d raid10"
-			"-m raid5 -d raid5"
-			"-m raid6 -d raid6"
+		# Default configurations to test.
+		local configs=(
+			"single:single"
+			"dup:single"
+			"raid0:raid0"
+			"raid1:raid0"
+			"raid1:raid1"
+			"raid10:raid10"
+			"raid5:raid5"
+			"raid6:raid6"
 		)
+	else
+		# User-provided configurations.
+		local configs=(${BTRFS_PROFILE_CONFIGS[@]})
+	fi
 
-		# remove dup/raid5/raid6 profiles if we're doing device replace
-		# dup profile indicates only one device being used (SCRATCH_DEV),
-		# but we don't want to replace SCRATCH_DEV, which will be used in
-		# _scratch_mount/_check_scratch_fs etc.
-		# and raid5/raid6 doesn't support replace yet
+	_btrfs_profile_configs=()
+	for cfg in "${configs[@]}"; do
+		local supported=true
+		local profiles=(${cfg/:/ })
 		if [ "$1" == "replace" ]; then
-			_btrfs_profile_configs=(
-				"-m single -d single"
-				"-m raid0 -d raid0"
-				"-m raid1 -d raid0"
-				"-m raid1 -d raid1"
-				"-m raid10 -d raid10"
-				# add these back when raid5/6 is working with replace
-				#"-m raid5 -d raid5"
-				#"-m raid6 -d raid6"
+			# We can't do replace with these profiles because they
+			# imply only one device ($SCRATCH_DEV), and we need to
+			# keep $SCRATCH_DEV around for _scratch_mount
+			# and _check_scratch_fs.
+			local unsupported=(
+				"dup"
 			)
+		elif [ "$1" == "replace-missing" ]; then
+			# We can't replace missing devices with these profiles
+			# because there isn't enough redundancy.
+			local unsupported=(
+				"single"
+				"dup"
+				"raid0"
+			)
+		else
+			local unsupported=()
 		fi
-		export _btrfs_profile_configs
-		return
-	fi
-
-	# parse user specified btrfs profile configs
-	local i=0
-	local cfg=""
-	for cfg in $BTRFS_PROFILE_CONFIGS; do
-		# turn "metadata:data" format to "-m metadata -d data"
-		# and assign it to _btrfs_profile_configs array
-		cfg=`echo "$cfg" | sed -e 's/^/-m /' -e 's/:/ -d /'`
-		_btrfs_profile_configs[$i]="$cfg"
-		let i=i+1
-	done
-
-	if [ "$1" == "replace" ]; then
-		if echo ${_btrfs_profile_configs[*]} | grep -q raid[56]; then
-			_notrun "RAID5/6 doesn't support btrfs device replace yet"
-		fi
-		if echo ${_btrfs_profile_configs[*]} | grep -q dup; then
-			_notrun "Do not set dup profile in btrfs device replace test"
+		for unsupp in "${unsupported[@]}"; do
+			if [ "${profiles[0]}" == "$unsupp" -o "${profiles[1]}" == "$unsupp" ]; then
+			     if [ -z "$BTRFS_PROFILE_CONFIGS" ]; then
+				     # For the default config, just omit it.
+				     supported=false
+			     else
+				     # For user-provided config, don't run the test.
+				     _notrun "Profile $unsupp not supported for $1"
+			     fi
+			fi
+		done
+		if "$supported"; then
+			_btrfs_profile_configs+=("-m ${profiles[0]} -d ${profiles[1]}")
 		fi
-	fi
+	done
 	export _btrfs_profile_configs
 }
 
-- 
2.8.0