[18/23] xfs_info: use findmnt to handle mounted block devices

Commit Message

Darrick J. Wong March 1, 2019, 11:28 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Use findmnt to determine if the passed-in argument is associated with a
mount point, and if so, use spaceman to query the mounted filesystem.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 debian/control       |    2 +-
 spaceman/xfs_info.sh |   14 +++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

Patch

diff --git a/debian/control b/debian/control
index f4f807b0..0b3205f5 100644
--- a/debian/control
+++ b/debian/control
@@ -8,7 +8,7 @@  Standards-Version: 4.0.0
 Homepage: https://xfs.wiki.kernel.org/
 
 Package: xfsprogs
-Depends: ${shlibs:Depends}, ${misc:Depends}, python3:any
+Depends: ${shlibs:Depends}, ${misc:Depends}, python3:any, util-linux
 Provides: fsck-backend
 Suggests: xfsdump, acl, attr, quota
 Breaks: xfsdump (<< 3.0.0)
diff --git a/spaceman/xfs_info.sh b/spaceman/xfs_info.sh
index ecf17f61..70978164 100755
--- a/spaceman/xfs_info.sh
+++ b/spaceman/xfs_info.sh
@@ -24,11 +24,19 @@  set -- extra "$@"
 shift $OPTIND
 case $# in
 	1)
-		if [ -b "$1" ] || [ -f "$1" ]; then
-			xfs_db -p xfs_info -c "info" $OPTS "$1"
+		arg="$1"
+
+		# See if we can map the arg to a loop device
+		loopdev="$(losetup -n -O NAME -j "${arg}" 2> /dev/null)"
+		test -n "${loopdev}" && arg="${loopdev}"
+
+		# If we find a mountpoint for the device, do a live query;
+		# otherwise try reading the fs with xfs_db.
+		if mountpt="$(findmnt -f -n -o TARGET "${arg}" 2> /dev/null)"; then
+			xfs_spaceman -p xfs_info -c "info" $OPTS "${mountpt}"
 			status=$?
 		else
-			xfs_spaceman -p xfs_info -c "info" $OPTS "$1"
+			xfs_db -p xfs_info -c "info" $OPTS "${arg}"
 			status=$?
 		fi
 		;;