mtd: Allow holes in volume ID table

new file mode 100644
index 0000000..aaed353
@@ -0,0 +1,91 @@
+From 0f833ac73ad631248826386e2918d8571ecf0347 Mon Sep 17 00:00:00 2001
+From: David Oberhollenzer <[email protected]>
+Date: Sat, 9 Jun 2018 16:45:22 +0200
+Subject: [PATCH] Revert "Return correct error number in ubi_get_vol_info1"
+
+This reverts commit dede98ffb706676309488d7cc660f569548d5930.
+
+The original commit tried to fix a descrepancy between the implementation
+and the documentation by making the implementation comply.
+
+When making the change, it was overlooked, that ubinfo and ubirename were
+written against the implementation instead of the behaviour specified by
+the documentation. So were further internal functions like
+ubi_get_vol_info1_nm which further breaks ubirmvol.
+
+A report with an outline of a resulting problem can be read on
+the mailing list:
+
+http://lists.infradead.org/pipermail/linux-mtd/2018-June/081562.html
+
+From the report:
+
+steps to reproduce: have mtd-utils 2.0.1 or 2.0.2
+
+0. make a bunch of ubi volumes in sequential order
+
+ubimkvol /dev/ubi0 -s 64KiB -N test1
+ubimkvol /dev/ubi0 -s 64KiB -N test2
+ubimkvol /dev/ubi0 -s 64KiB -N test3
+ubimkvol /dev/ubi0 -s 64KiB -N test4
+..
+
+1. delete the test1 volume, making a hole in the volume table
+
+ubirmvol /dev/ubi0 -N test1
+
+2. try an affected tool (i.e. "ubirmvol /dev/ubi0 -N test4" )
+
+ |root at mr24:/# ubirmvol /dev/ubi0 -N test4
+ |ubirmvol: error!: cannot find UBI volume "test4"
+ |         error 19 (No such device)
+
+or "ubinfo -a"
+
+ | root at mr24:/# ubinfo -a
+ | UBI version:                    1
+ | Count of UBI devices:           1
+ | UBI control device major/minor: 10:59
+ | Present UBI devices:            ubi0
+ |
+ | ubi0
+ | Volumes count:                           11
+ | Logical eraseblock size:                 15872 bytes, 15.5 KiB
+ | Total amount of logical eraseblocks:     1952 (30982144 bytes, 29.5 MiB)
+ | Amount of available logical eraseblocks: 75 (1190400 bytes, 1.1 MiB)
+ | Maximum count of volumes                 92
+ | Count of bad physical eraseblocks:       0
+ | Count of reserved physical eraseblocks:  40
+ | Current maximum erase counter value:     984
+ | Minimum input/output unit size:          512 bytes
+ | Character device major/minor:            251:0
+ | ubinfo: error!: libubi failed to probe volume 5 on ubi0
+ |        error 19 (No such device)
+ | Present volumes:                         0, 1, 2, 3, 4root at mr24:/#
+
+Reported-by: Christian Lamparter <[email protected]>
+Signed-off-by: David Oberhollenzer <[email protected]>
+---
+ lib/libubi.c | 5 +----
+ 1 file changed, 1 insertion(+), 4 deletions(-)
+
+diff --git a/lib/libubi.c b/lib/libubi.c
+index b50e68a..978b433 100644
+--- a/lib/libubi.c
++++ b/lib/libubi.c
+@@ -1240,11 +1240,8 @@ int ubi_get_vol_info1(libubi_t desc, int dev_num, int vol_id,
+ 	info->dev_num = dev_num;
+ 	info->vol_id = vol_id;
+ 
+-	if (vol_get_major(lib, dev_num, vol_id, &info->major, &info->minor)) {
+-		if (errno == ENOENT)
+-			errno = ENODEV;
++	if (vol_get_major(lib, dev_num, vol_id, &info->major, &info->minor))
+ 		return -1;
+-	}
+ 
+ 	ret = vol_read_data(lib->vol_type, dev_num, vol_id, buf, 50);
+ 	if (ret < 0)
+-- 
+2.14.4
+