common/xfs: FITRIM now supports realtime volumes

XFS now supports FITRIM to the realtime volume.  Detect this support and
enable it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zorro Lang <zlang@kernel.org>

diff --git a/common/xfs b/common/xfs
index 7ee6fbec84672b8a9f841770278054ca97224f64..de557ebd90beaaee321471d4dd53ac111bca9ba7 100644 (file)
--- a/common/xfs
+++ b/common/xfs
@@ -1777,8 +1777,44 @@ _require_xfs_scratch_atomicswap()
 # of 1024 byte blocks.
 _xfs_discard_max_offset_kb()
 {
-       $XFS_IO_PROG -c 'statfs' "$1" | \
-               awk '{g[$1] = $3} END {print (g["geom.bsize"] * g["geom.datablocks"] / 1024)}'
+       local statfs
+
+       # Use awk to read the statfs output for the XFS filesystem, compute
+       # the two possible FITRIM offset maximums, and then use some horrid
+       # bash magic to import the five numbers as an indexed array.  There's
+       # no better way to do this in bash since you can't readarray to build
+       # an associative array.  Elements are as follows:
+       #
+       # 0: fsblock size in bytes
+       # 1: Data volume size in fsblocks.
+       # 2: Realtime volume size in fsblocks.
+       # 3: Max FITRIM offset if we can only trim the data volume
+       # 4: Max FITRIM offset if we can trim the data and rt volumes
+       readarray -t statfs < <($XFS_IO_PROG -c 'statfs' "$1" | \
+               awk '{g[$1] = $3} END {printf("%d\n%d\n%d\n%d\n%d\n",
+                       g["geom.bsize"],
+                       g["geom.datablocks"],
+                       g["geom.rtblocks"],
+                       g["geom.bsize"] * g["geom.datablocks"] / 1024,
+                       g["geom.bsize"] * (g["geom.datablocks"] + g["geom.rtblocks"]) / 1024);}')
+
+       # If the kernel supports discarding the realtime volume, then it will
+       # not reject a FITRIM for fsblock dblks+1, even if the len/minlen
+       # arguments are absurd.
+       if [ "${statfs[2]}" -gt 0 ]; then
+               if $FSTRIM_PROG -o "$((statfs[0] * statfs[1]))" \
+                               -l "${statfs[0]}" \
+                               -m "$((statfs[0] * 2))" "$1" &>/dev/null; then
+                       # The kernel supports discarding the rt volume, so
+                       # print out the second answer from above.
+                       echo "${statfs[4]}"
+                       return
+               fi
+       fi
+
+       # The kernel does not support discarding the rt volume or there is no
+       # rt volume.  Print out the first answer from above.
+       echo "${statfs[3]}"
 }
 
 # check if mkfs and the kernel support nocrc (v4) file systems