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From: Chris Mason <chris.mason@oracle.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Joel Becker <jlbec@evilplan.org>,
	David Miller <davem@davemloft.net>
Subject: Re: [RFC] killing boilerplate checks in ->link/->mkdir/->rename
Date: Fri, 3 Feb 2012 09:57:44 -0500	[thread overview]
Message-ID: <20120203145744.GN16796@shiny> (raw)
In-Reply-To: <20120203011612.GS23916@ZenIV.linux.org.uk>

On Fri, Feb 03, 2012 at 01:16:12AM +0000, Al Viro wrote:
> On Thu, Feb 02, 2012 at 03:46:06PM -0800, Linus Torvalds wrote:
> > On Thu, Feb 2, 2012 at 1:24 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > >
> > > Comments? ?Boilerplate removal follows (22 files changed, 45 insertions(+),
> > > 120 deletions(-)), but it's *not* for immediate merge; it's really completely
> > > untested.
> > 
> > Looks ok to me. Historically, the more things we can check at the VFS
> > layer, the better.
> 
> 
> 	* what's up with btrfs_insert_inode_ref()?  I've tried to trace
> the codepaths around there, but...

Btrfs stores backrefs (the filename, directory inode number) from the
inode to the directory.

In the current format that's a pretty low limit on how many of these we
can store for hard links to the same file in the same directory, but
basically no limit on how many backrefs we can store to the same file
from different directories.

Mark Fasheh was working on a patch to change the backrefs to make the
links-from-the-same-dir case consistent with the
links-from-different-dir case.   With today's code, we'll go -EMLINK at
different times depending on the length of the file name and what links
you've already made.


> Incidentally, when could fixup_low_keys()
> return non-zero?  I don't see any candidates for that in there...  Chris?

A long time ago this one used to cow blocks and so it needed an error
return.  I think Jeff Mahoney has a patch queued up to make it (among
many others) void.

-chris

  parent reply	other threads:[~2012-02-03 14:58 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30 21:56 sysfs regression: wrong link counts Jiri Slaby
2012-01-30 22:06 ` Greg KH
2012-01-30 22:10   ` Alan Cox
2012-01-30 22:27     ` Greg KH
2012-01-30 22:43       ` Al Viro
2012-01-30 22:56         ` Al Viro
2012-01-31  1:27       ` Eric W. Biederman
2012-01-31 10:48         ` Jiri Slaby
2012-01-31 12:44           ` Eric W. Biederman
2012-01-31 16:45             ` Linus Torvalds
2012-01-31 19:18               ` Al Viro
2012-02-01  5:06               ` Eric W. Biederman
2012-02-01 22:21                 ` [PATCH] sysfs: Optionally count subdirectories to support buggy applications Eric W. Biederman
2012-02-01 22:24                   ` Greg Kroah-Hartman
2012-02-01 22:44                     ` Eric W. Biederman
2012-02-01 22:49                       ` Greg Kroah-Hartman
2012-02-01 22:31                   ` Dave Jones
2012-02-01 22:35                   ` Jiri Slaby
2012-02-01 23:15                   ` Linus Torvalds
2012-02-01 23:18                     ` Linus Torvalds
2012-02-02  1:22                       ` Al Viro
2012-02-02 21:24                         ` [RFC] killing boilerplate checks in ->link/->mkdir/->rename Al Viro
2012-02-02 23:46                           ` Linus Torvalds
2012-02-03  1:16                             ` Al Viro
2012-02-03  1:45                               ` Al Viro
2012-02-03  2:00                                 ` Linus Torvalds
2012-02-03 14:57                               ` Chris Mason [this message]
2012-02-03 17:08                               ` Al Viro
2012-02-03 19:34                                 ` Artem Bityutskiy
2012-02-06  8:50                                 ` Artem Bityutskiy
2012-02-06 13:56                                   ` Al Viro
2012-02-06 17:05                                     ` Artem Bityutskiy
2012-02-06 17:11                                       ` Al Viro
2012-02-07  7:21                                         ` Artem Bityutskiy
2012-02-06 22:49                               ` Dave Chinner
2012-02-03  8:25                           ` Andreas Dilger
2012-02-03 17:03                             ` Al Viro
2012-02-04  7:42                               ` Andreas Dilger
2012-03-05 13:30                       ` [PATCH] sysfs: Optionally count subdirectories to support buggy applications Jiri Slaby
2012-03-05 16:09                         ` Greg Kroah-Hartman
2012-03-05 16:47                           ` Linus Torvalds
2012-03-08 21:05                             ` Greg Kroah-Hartman
2012-03-08 22:18                             ` Eric W. Biederman
2012-03-08 23:40                               ` Linus Torvalds
2012-03-08 21:28                           ` Eric W. Biederman
2012-03-08 21:34                           ` [PATCH 1/3] sysfs: Compact sysfs_dirent s_flags into a byte Eric W. Biederman
2012-03-08 21:36                             ` [PATCH 2/3] sysfs: Maintain usable nlink directory counts Eric W. Biederman
2012-03-08 21:37                               ` [PATCH 3/3] sysfs: Remove SYSFS_FLAG_REMOVED and use sd->s_nlink == 0 instead Eric W. Biederman
2012-03-09  3:40                                 ` Linus Torvalds
2012-03-08 22:28                             ` [PATCH 1/3] sysfs: Compact sysfs_dirent s_flags into a byte Greg Kroah-Hartman
2012-03-09  2:49                               ` Eric W. Biederman
2012-01-31  3:45     ` sysfs regression: wrong link counts Eric W. Biederman
2012-01-31 11:54       ` Alan Cox
2012-01-30 22:52 ` Kay Sievers
2012-01-31 10:41   ` network regression: cannot rename netdev twice Jiri Slaby
2012-01-31 10:52     ` Kay Sievers
2012-01-31 11:00       ` Jiri Slaby
2012-01-31 11:13         ` Kay Sievers
2012-01-31 11:17           ` Jiri Slaby
2012-01-31 11:58             ` Kay Sievers
2012-01-31 14:18               ` Eric W. Biederman
2012-01-31 14:40                 ` [PATCH] sysfs: Update the name hash when renaming sysfs entries Eric W. Biederman
2012-01-31 14:41                   ` Jiri Slaby
2012-01-31 14:55                   ` Greg KH
2012-02-04  2:14       ` network regression: cannot rename netdev twice Henrique de Moraes Holschuh
2012-02-06 20:03         ` Kay Sievers
2012-02-08  2:00           ` Henrique de Moraes Holschuh
2012-02-08  3:50             ` Kay Sievers
2012-02-08  6:42               ` Valdis.Kletnieks
2012-02-08 10:57                 ` Kay Sievers
2012-02-08 20:06                   ` Valdis.Kletnieks
2012-02-08 20:27                     ` Stephen Hemminger
2012-02-08 23:48                     ` Kay Sievers
2012-01-31  1:32 ` sysfs regression: wrong link counts Eric W. Biederman
2012-02-01 18:29 ` Maciej Rutecki

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