From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: "Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger@dilger.ca>,
Tahsin Erdogan <tahsin@google.com>, Jan Kara <jack@suse.cz>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 09/32] ext4: extended attribute value size limit is enforced by vfs
Date: Thu, 22 Jun 2017 16:21:25 -0700 [thread overview]
Message-ID: <20170622232125.GB10237@birch.djwong.org> (raw)
In-Reply-To: <20170622222708.w6uouwzfiihwmlvd@thunk.org>
On Thu, Jun 22, 2017 at 06:27:08PM -0400, Theodore Ts'o wrote:
> On Thu, Jun 22, 2017 at 01:40:25PM -0600, Andreas Dilger wrote:
> >
> > The EXT4_XATTR_MAX_LARGE_EA_SIZE limit of 1MB was also totally arbitrary,
> > but a reasonable upper limit for the atomic get/set interface used by
> > xattrs. The underlying disk format could actually store xattrs of any size.
> >
> > I'd think if we want to get huge xattrs that they should be handled by
> > having separate streams (e.g. open file descriptor, ioctl/syscall to select
> > a different stream number on that file) so that the data doesn't have to be
> > completely rewritten any time it is modified, but streams are frowned upon
> > by many Linux developers for security reasons so will probably be a no-go.
>
> This has been discussed before. Most of the arguments (both pro and
> con) can be found on this thread (2016):
>
> https://www.spinics.net/lists/linux-nfs/msg57055.html
>
> Jeremy Allison used to pester me for alternate data stream support
> many years ago, but he has since completely changed his opinion on the
> matter:
>
> http://www.spinics.net/lists/linux-fsdevel/msg96083.html
>
> So if jra@ doesn't add support for this interface to Samba, the thing
> I'd ask is who is actually going to used such an interface; because if
> there aren't any user space applications lining up to use it, it's
> probably not worth adding it until we can find a flagship user of the
> proposed new API.
Heh, ok, that's about what I expected to hear. :)
> There are plenty of other things we could add that Jeremy has asked
> for, that *would* improve Samba performance. (For example, adding a
> mount option which provides case-insensitive lookup; the one thing
> that makes this hard is that while Android doesn't seem to care about
> I18N --- they are currently using an ascii-only tolower() in their
> sdcardfs hack --- Samba/Windows does care about I18N done right, so we
> wouldn't have to get a Unicode case folding implementation into the
> kernel.) So I'd argue that those are probably more interesting
> projects than O_XATTR support.
--D
>
> - Ted
next prev parent reply other threads:[~2017-06-22 23:21 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 21:21 [PATCH 01/32] ext4: xattr-in-inode support Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 02/32] ext4: fix lockdep warning about recursive inode locking Tahsin Erdogan
2017-06-22 1:18 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 03/32] ext4: lock inode before calling ext4_orphan_add() Tahsin Erdogan
2017-06-22 1:20 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 04/32] ext4: do not set posix acls on xattr inodes Tahsin Erdogan
2017-06-22 1:23 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 05/32] ext4: attach jinode after creation of xattr inode Tahsin Erdogan
2017-06-22 1:26 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 06/32] ext4: ea_inode owner should be the same as the inode owner Tahsin Erdogan
2017-06-22 1:28 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 07/32] ext4: call journal revoke when freeing ea_inode blocks Tahsin Erdogan
2017-06-22 1:38 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 08/32] ext4: fix ref counting for ea_inode Tahsin Erdogan
2017-06-22 1:40 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 09/32] ext4: extended attribute value size limit is enforced by vfs Tahsin Erdogan
2017-06-22 1:42 ` Theodore Ts'o
2017-06-22 18:02 ` Darrick J. Wong
2017-06-22 19:40 ` Andreas Dilger
2017-06-22 22:27 ` Theodore Ts'o
2017-06-22 23:21 ` Darrick J. Wong [this message]
2017-06-21 21:21 ` [PATCH 10/32] ext4: change ext4_xattr_inode_iget() signature Tahsin Erdogan
2017-06-22 1:55 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 11/32] ext4: clean up ext4_xattr_inode_get() Tahsin Erdogan
2017-06-22 1:58 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 12/32] ext4: add missing le32_to_cpu(e_value_inum) conversions Tahsin Erdogan
2017-06-22 2:00 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 13/32] ext4: ext4_xattr_value_same() should return false for external data Tahsin Erdogan
2017-06-22 2:04 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 14/32] ext4: fix ext4_xattr_make_inode_space() value size calculation Tahsin Erdogan
2017-06-22 2:09 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 15/32] ext4: fix ext4_xattr_move_to_block() Tahsin Erdogan
2017-06-22 2:13 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 16/32] ext4: fix ext4_xattr_cmp() Tahsin Erdogan
2017-06-22 2:15 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 17/32] ext4: fix credits calculation for xattr inode Tahsin Erdogan
2017-06-22 2:19 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 18/32] ext4: retry storing value in external inode with xattr block too Tahsin Erdogan
2017-06-22 2:22 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 19/32] ext4: ext4_xattr_delete_inode() should return accurate errors Tahsin Erdogan
2017-06-22 2:27 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 20/32] ext4: improve journal credit handling in set xattr paths Tahsin Erdogan
2017-06-22 2:30 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 21/32] ext4: modify ext4_xattr_ino_array to hold struct inode * Tahsin Erdogan
2017-06-22 14:28 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 22/32] ext4: move struct ext4_xattr_inode_array to xattr.h Tahsin Erdogan
2017-06-22 14:29 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 23/32] mbcache: make mbcache naming more generic Tahsin Erdogan
2017-06-22 14:37 ` Theodore Ts'o
2017-06-21 21:21 ` [PATCH 24/32] ext2, ext4: make mb block cache names more explicit Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 25/32] ext4: add ext4_is_quota_file() Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 26/32] ext4: cleanup transaction restarts during inode deletion Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 27/32] ext4: xattr inode deduplication Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 28/32] quota: add get_inode_usage callback to transfer multi-inode charges Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 29/32] ext4: reserve space for xattr entries/names Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 30/32] ext4: eliminate xattr entry e_hash recalculation for removes Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 31/32] ext4: strong binding of xattr inode references Tahsin Erdogan
2017-06-21 21:21 ` [PATCH 32/32] ext4: add nombcache mount option Tahsin Erdogan
2017-06-22 1:16 ` [PATCH 01/32] ext4: xattr-in-inode support Theodore Ts'o
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