RE: mtab and procs not in sync?

* RE: mtab and procs not in sync?
@ 2004-06-09 17:48 Lever, Charles
  2004-06-09 21:20 ` James Pearson
  2004-06-10  1:03 ` Ian Kent
  0 siblings, 2 replies; 11+ messages in thread
From: Lever, Charles @ 2004-06-09 17:48 UTC (permalink / raw)
  To: James Pearson; +Cc: nfs

i would guess that if seq_file is used, then /proc/mounts should be OK.

i was looking at a RHEL AS 2.1 system last week that used the single
page I/O model for /proc/mounts, and it was definitely busted.

> -----Original Message-----
> From: James Pearson [mailto:james-p@moving-picture.com]=20
> Sent: Wednesday, June 09, 2004 11:05 AM
> To: Lever, Charles
> Cc: nfs@lists.sourceforge.net
> Subject: Re: [NFS] mtab and procs not in sync?
>=20
>=20
> On a 2.4.26 kernel on x86 I can get /proc/mounts to go over=20
> 4K (over 8K=20
> with about 100 automounted file systems).
>=20
> Having a quick look through the kernel code I can see=20
> seq_file used in=20
> relation to proc_mounts_operations (fs/proc/base.c) - however=20
> as I don't=20
> pretend to understand the code, I can't say this is the case ...
>=20
> If 2.4.X does use seq_file, then is it safe to say=20
> /proc/mounts doesn't=20
> suffer from a truncation problem?
>=20
> James Pearson
>=20
> Lever, Charles wrote:
> > as far as i can tell, the 4KB limit is common to x86 on 2.2 and 2.4.
> > 2.6 has replaced the old /proc read method with seq_file,=20
> so i believe
> > /proc/mounts on 2.6 kernels will not suffer from this problem.
> >=20
> > it's not a fixed number of mounts, because the length of=20
> each line in
> > /proc/mounts depends on what mount options are in effect. =20
> the limit is
> > the number of characters in the file.
> >=20
> >=20
> >>-----Original Message-----
> >>From: James Pearson [mailto:james-p@moving-picture.com]=20
> >>Sent: Wednesday, June 09, 2004 6:29 AM
> >>To: Lever, Charles
> >>Cc: nfs@lists.sourceforge.net
> >>Subject: Re: [NFS] mtab and procs not in sync?
> >>
> >>
> >>Do you know how many 'a lot of mounts' is?
> >>
> >>I believe there was a problem with /proc/mounts in 2.2=20
> >>kernels (limited=20
> >>to one page) - is there still a limit in 2.4 or 2.6 kernels?
> >>
> >>I currently symlink /proc/mounts to /etc/mtab on diskless=20
> machines to=20
> >>get round the issue that /etc/mtab can not trusted to be=20
> >>correct. I only=20
> >>have a maximum of a few 10's of mounts at any one time.
> >>
> >>James Pearson
> >>
> >>Lever, Charles wrote:
> >>
> >>>if there are a lot of mounts on the system, then=20
> >>
> >>/proc/mounts can be=20
> >>
> >>>truncated and not show all of them.
> >>>
> >>>however, if there are more mounts in /proc/mounts than in=20
> >>
> >>/etc/mtab,=20
> >>
> >>>there is probably a bug in mount.  not unheard of.
> >>>
> >>>
> >>>
> >>>>-----Original Message-----
> >>>>From: Phy Prabab [mailto:phyprabab@yahoo.com]
> >>>>Sent: Tuesday, June 08, 2004 2:21 PM
> >>>>To: nfs@lists.sourceforge.net
> >>>>Subject: [NFS] mtab and procs not in sync?
> >>>>
> >>>>
> >>>>Hello,
> >>>>
> >>>>Have run into a situation where mtab does not match=20
> /proc/mounts in=20
> >>>>that mtab has numerous entries that have expired off and=20
> >>
> >>removed, yet=20
> >>
> >>>>does not show that it has been removed from mtab.  Is this=20
> >>
> >>known and=20
> >>
> >>>>is there a fix?
> >>>>
> >>>>Kernel 2.4.21 and 23
> >>>>nfs-utils 1.06
> >>>>automount 4.1.2
> >>>>
> >>>>Thanks!
> >>>>Phy
> >>>>
> >>>>
> >>>>=09
> >>>>	=09
> >>>>__________________________________
> >>>>Do you Yahoo!?
> >>>>Friends.  Fun.  Try the all-new Yahoo! Messenger.=20
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> >>>>
> >>>>
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> >>
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> >>
> >>_______________________________________________
> >>
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> >>>>https://lists.sourceforge.net/lists/listinfo/nfs
> >>>>
> >>>
> >>>
> >>>
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> >>_______________________________________________
> >>
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> >>>
> >>
> >=20
> >=20
>=20
>=20

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