Messages in this thread Patch in this message | | | Date | Sat, 26 Feb 2005 10:48:52 -0300 | From | Marcelo Tosatti <> | Subject | Re: [PATCH] fix units/partition count in sd.c (2.4.x) |
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On Wed, Feb 16, 2005 at 11:23:53AM -0500, Luben Tuikov wrote: > Hi, > > This patch fixes the nr_real count in sd.c, which is also used > in genhd.c to print out the partitions/units. The problem is that > nr_real is decremented on detach, the genhd's nr_sects is > cleared but the entry is still there and is being counted > for when displaying the partitions. Thus when nr_real > is decremented _and_ a 0-ed partition/unit is counted, > we get to not display 1 or more entries of the tail of > the list. > > The solution is to not decrement nr_real on detach, effectively > never decrementing it, and so that it doesn't grow without a bound, > to throttle it on attach, incrementing it only if it would be > smaller than nr_dev. > > This was observed on a RH kernel and on the current BK kernel. > Tested and fixed on 2.4.30-pre1 (BK). This patch is against 2.4.30-pre1. > > To reproduce: assume 4 scsi disks sda, sdb, sdc, sdd. > #echo "scsi remove-single-device <sdb-HCTL>" > /proc/scsi/scsi > #cat /proc/partitions > <<sdb _and_ sdd are not listed>>
Luben,
On James Bottomley advice I have applied Soo Lee's fix, which looks cleaner.
Also as James notice this will increase overhead of /proc/partitions which might be a problem on higher-end systems with many devices.
Testing of it on such systems is highly appreciated.
# 05/02/26 slee@netengine1.com 1.1558 # [PATCH] Fix units/partition count in sd.c # # Symptom: # When a scsi disk is removed other scsi disk with biggest minor # # disapears in /proc/partition at the same time. # # Cause and fix: # sd.c decreases nr_real on disk removal but because nr_real is not # real # of devices but max # of devices of a major #, # it doesn't need to be changed on disk add/remove. # # 2.6 has little different structure but it does like this # # sd.c:sd_probe() # gd->minors = 16; # -------------------------------------------- # diff -Nru a/drivers/scsi/sd.c b/drivers/scsi/sd.c --- a/drivers/scsi/sd.c Sat Feb 26 10:46:42 2005 +++ b/drivers/scsi/sd.c Sat Feb 26 10:46:42 2005 @@ -1220,7 +1220,7 @@ goto cleanup_gendisks_part; memset(sd_gendisks[i].part, 0, (SCSI_DISKS_PER_MAJOR << 4) * sizeof(struct hd_struct)); sd_gendisks[i].sizes = sd_sizes + (i * SCSI_DISKS_PER_MAJOR << 4); - sd_gendisks[i].nr_real = 0; + sd_gendisks[i].nr_real = SCSI_DISKS_PER_MAJOR; sd_gendisks[i].real_devices = (void *) (rscsi_disks + i * SCSI_DISKS_PER_MAJOR); } @@ -1333,7 +1333,6 @@ rscsi_disks[i].device = SDp; rscsi_disks[i].has_part_table = 0; sd_template.nr_dev++; - SD_GENDISK(i).nr_real++; devnum = i % SCSI_DISKS_PER_MAJOR; SD_GENDISK(i).de_arr[devnum] = SDp->de; if (SDp->removable) @@ -1447,7 +1446,6 @@ SDp->attached--; sd_template.dev_noticed--; sd_template.nr_dev--; - SD_GENDISK(i).nr_real--; return; } return;
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