File ofpathname-make-goto_dir-canonicalize-directory... of Package powerpc-utils

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File ofpathname-make-goto_dir-canonicalize-directory-argu.patch of Package powerpc-utils (Revision 7114c62ad10f510c4a043fd556b01ac5)

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From 937780a5fcbd887352e458f32a860c67164a2c14 Mon Sep 17 00:00:00 2001
From: Tyrel Datwyler <tyreld@linux.ibm.com>
Date: Wed, 24 Jun 2020 17:25:35 -0500
Subject: [PATCH] ofpathname: make goto_dir canonicalize directory argument

Upstream: accepted, expected v1.3.8
Git-commit: 937780a5fcbd887352e458f32a860c67164a2c14

Commit c97fe35b5b6d "ofpathname: speed up l2of_scsi()" attempted to
optimize the look up of scsi devices by restricting the base directory
input of the 'find' command to /sys/class/block instead of /sys. This
works as intended for raw scsi disks such as sda, but broke for scsi disk
partitions such as sda1.

(0) root @ linux-td1r: /root/powerpc-utils
$ ./scripts/ofpathname /dev/sda1
: Logical device "/dev/sda1" does not appear
            to be configured.

(1) root @ linux-td1r: /root/powerpc-utils
$ ./scripts/ofpathname /dev/sda
/vdevice/v-scsi@30000066/disk@8100000000000000

The differences in looking up sda1 via /sys/class/block vs /sys:

(0) root @ linux-td1r: /root/powerpc-utils
$ find /sys/class/block -name sda1
/sys/class/block/sda1

(0) root @ linux-td1r: /root/powerpc-utils
$ find /sys -name sda1
/sys/devices/vio/30000066/host0/target0:0:1/0:0:1:0/block/sda/sda1
/sys/class/block/sda1

In the end /sys/class/block/sda1 is just a symlink to sda1 under /sys/devices/vio/...

(0) root @ linux-td1r: /root/powerpc-utils
$ ll /sys/class/block/sda1
lrwxrwxrwx 1 root root 0 Jun 22 18:56 /sys/class/block/sda1 ->
	../../devices/vio/30000066/host0/target0:0:1/0:0:1:0/block/sda/sda1

However, ofpathname assumes that by moving up to the parent we will
eventually find the raw disk device, in the above example sda,  and this
will only happen for paths under /sys/devices in the case of scsi disk
partitions.

Fix this regression by using readlink in goto_dir() to canonicalize the
path name of the device while following all symlinks.

Fixes: c97fe35b5b6d ("ofpathname: speed up l2of_scsi()")
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
 scripts/ofpathname | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/ofpathname b/scripts/ofpathname
index cbdaa050eb2d..9c0d047cdf7a 100755
--- a/scripts/ofpathname
+++ b/scripts/ofpathname
@@ -288,7 +288,7 @@ get_usb_storage_no()
 # $3 on_exit behavior on error
 goto_dir()
 {
-    local start_dir=$1
+    local start_dir=$(readlink -f $1)
     local fname=$2
     local found=0
     local on_exit=1
-- 
2.26.2

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File ofpathname-make-goto_dir-canonicalize-directory-argu.patch of Package powerpc-utils (Revision 7114c62ad10f510c4a043fd556b01ac5)

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