From: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
To: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH RESEND v2 19/25] vfs: Handle case-exact lookup in d_add_ci
Date: Tue, 09 Oct 2018 10:40:39 -0400 [thread overview]
Message-ID: <87va6bmbdk.fsf@collabora.co.uk> (raw)
In-Reply-To: <20181007180953.GA10662@thunk.org> (Theodore Y. Ts'o's message of "Sun, 7 Oct 2018 14:09:53 -0400")
"Theodore Y. Ts'o" <tytso@mit.edu> writes:
> On Mon, Sep 24, 2018 at 05:56:49PM -0400, Gabriel Krisman Bertazi wrote:
>> This prevents a soft hang if called d_add_ci is called from the FS
>> layer, when doing a CI search but the result dentry is the exact match.
>
> This isn't the right way to fix this problem. Take a look at how xfs
> handles this in fs/xfs/xfs_iops.c:xfs_vn_ci_lookup(). This logic
> should be in the file system, not in d_add_ci(). Also, we don't want
> to use d_same_name(), since that is *not* guaranteed to do an exact
> match. It happens to do so for ext4 since we don't provide d_compare,
> but it's better just check for an exact match and call
> d_splice_alias() instead of d_add_ci() in ext4_lookup().
>
> Also note that d_same_name() is *not* guaranteeed to do an exact
> match, in particular if the file system provides d_compare (which
> granted, ext4 doesn't right now). It's simpler to just do a direct
> strcmp in ext4_lookup.
>
> - Ted
>
> P.S. Apologies for not having a chance to look at this series in
> detail until now. It's been a crazy month...
Hey Ted,
No worries. Thanks for the review.
I'm aware of how xfs does it. I was looking for a generic way but I see
its problems now. I will have it addressed in the next iteration.
thanks.
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2018-10-09 21:57 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-24 21:56 [PATCH RESEND v2 00/25] Ext4 Encoding and Case-insensitive support Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 01/25] nls: Wrap uni2char/char2uni callers Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 02/25] nls: Wrap charset field access Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 03/25] nls: Wrap charset hooks in ops structure Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 04/25] nls: Split default charset from NLS core Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 05/25] nls: Split struct nls_charset from struct nls_table Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 06/25] nls: Add support for multiple versions of an encoding Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 07/25] nls: Implement NLS_STRICT_MODE flag Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 08/25] nls: Let charsets define the behavior of tolower/toupper Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 09/25] nls: Add new interface for string comparisons Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 10/25] nls: Add optional normalization and casefold hooks Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 11/25] nls: ascii: Support validation and normalization operations Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 12/25] nls: utf8n: Add unicode character database files Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 13/25] scripts: add trie generator for UTF-8 Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 14/25] nls: utf8: Move nls-utf8{,-core}.c Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 15/25] nls: utf8: Introduce code for UTF-8 normalization Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 16/25] nls: utf8n: reduce the size of utf8data[] Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 17/25] nls: utf8: Integrate utf8 normalization code with utf8 charset Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 18/25] nls: utf8: Introduce test module for normalized utf8 implementation Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 19/25] vfs: Handle case-exact lookup in d_add_ci Gabriel Krisman Bertazi
2018-10-07 18:09 ` Theodore Y. Ts'o
2018-10-09 14:40 ` Gabriel Krisman Bertazi [this message]
2018-09-24 21:56 ` [PATCH RESEND v2 20/25] ext4: Include encoding information in the superblock Gabriel Krisman Bertazi
2018-10-11 22:26 ` Darrick J. Wong
2018-10-12 15:36 ` Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 21/25] ext4: Add encoding mount options Gabriel Krisman Bertazi
2018-10-07 19:22 ` Theodore Y. Ts'o
2018-10-09 14:53 ` Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 22/25] ext4: Support encoding-aware file name lookups Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 23/25] ext4: Implement encoding-aware dcache hooks Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 24/25] ext4: Implement EXT4_CASEFOLD_FL flag Gabriel Krisman Bertazi
2018-09-24 21:56 ` [PATCH RESEND v2 25/25] docs: ext4.rst: Document encoding and case-insensitive lookups Gabriel Krisman Bertazi
2018-10-11 22:23 ` [PATCH RESEND v2 00/25] Ext4 Encoding and Case-insensitive support Darrick J. Wong
2018-10-12 15:29 ` Gabriel Krisman Bertazi
2018-10-12 19:24 ` Theodore Y. Ts'o
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