cvs commit: src/sys/cam/scsi scsi_cd.c scsi_da.c src/sys/geom geom_disk.c geom_disk.h geom_subr.c

[Jeremie Le Hen]

Hi, John,

On Fri, Nov 18, 2005 at 02:43:49AM +0000, John Polstra wrote:
> jdp         2005-11-18 02:43:49 UTC
> 
>   FreeBSD src repository
> 
>   Modified files:
>     sys/cam/scsi         scsi_cd.c scsi_da.c 
>     sys/geom             geom_disk.c geom_disk.h geom_subr.c 
>   Log:
>   Fix a bug that caused some /dev entries to continue to exist after
>   the underlying drive had been hot-unplugged from the system.  Here
>   is a specific example.  Filesystem code had opened /dev/da1s1e.
>   Subsequently, the drive was hot-unplugged.  This (correctly) caused
>   all of the associated /dev/da1* entries to be deleted.  When the
>   filesystem later realized that the drive was gone it closed the
>   device, reducing the write-access counts to 0 on the geom providers
>   for da1s1e, da1s1, and da1.  This caused geom to re-taste the
>   providers, resulting in the devices being created again.  When the
>   drive was hot-plugged back in, it resulted in duplicate /dev entries
>   for da1s1e, da1s1, and da1.
>   
>   This fix adds a new disk_gone() function which is called by CAM when a
>   drive goes away.  It orphans all of the providers associated with the
>   drive, setting an error condition of ENXIO in each one.  In addition,
>   we prevent a re-taste on last close for writing if an error condition
>   has been set in the provider.

This commit stirred my memory up about panicking when hot-unplugging
an USB key while it is still mounted.  I have not been able to track
HEAD source changes attentively for some time recently but it
appears from the above description that this awkard behaviour has been
replaced by a smarter one (IOW, return ENXIO on all pending filesystem
actions).

Thanks in advance for explanations.

Best regards,
-- 
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >