From: Al Viro <viro@zeniv.linux.org.uk>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH] fscrypt: cache decrypted symlink target in ->i_link
Date: Wed, 10 Apr 2019 01:33:46 +0100 [thread overview]
Message-ID: <20190410003346.GT2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190409233544.156665-1-ebiggers@kernel.org>
On Tue, Apr 09, 2019 at 04:35:44PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> Path lookups that traverse encrypted symlink(s) are very slow because
> each encrypted symlink needs to be decrypted each time it's followed.
>
> Make encrypted symlinks faster by caching the decrypted symlink target
> in ->i_link. The first call to ->get_link() sets it; later calls simply
> return it. ->symlink() also sets it when the symlink is created.
>
> When the inode's ->i_crypt_info is freed, ->i_link is freed too.
>
> Note: RCU-delayed freeing of ->i_link is not yet implemented.
> Therefore, for now even when ->i_link is set, path lookups must continue
> to drop out of RCU-walk mode when following an encrypted symlink.
And how the devil would they continue to do that, if I might ask?
->get_link() is *NOT* called if ->i_link is non-NULL, period.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH] fscrypt: cache decrypted symlink target in ->i_link
Date: Wed, 10 Apr 2019 01:33:46 +0100 [thread overview]
Message-ID: <20190410003346.GT2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190409233544.156665-1-ebiggers@kernel.org>
On Tue, Apr 09, 2019 at 04:35:44PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> Path lookups that traverse encrypted symlink(s) are very slow because
> each encrypted symlink needs to be decrypted each time it's followed.
>
> Make encrypted symlinks faster by caching the decrypted symlink target
> in ->i_link. The first call to ->get_link() sets it; later calls simply
> return it. ->symlink() also sets it when the symlink is created.
>
> When the inode's ->i_crypt_info is freed, ->i_link is freed too.
>
> Note: RCU-delayed freeing of ->i_link is not yet implemented.
> Therefore, for now even when ->i_link is set, path lookups must continue
> to drop out of RCU-walk mode when following an encrypted symlink.
And how the devil would they continue to do that, if I might ask?
->get_link() is *NOT* called if ->i_link is non-NULL, period.
next prev parent reply other threads:[~2019-04-10 0:33 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-09 23:35 [PATCH] fscrypt: cache decrypted symlink target in ->i_link Eric Biggers
2019-04-09 23:35 ` [f2fs-dev] " Eric Biggers
2019-04-10 0:33 ` Al Viro [this message]
2019-04-10 0:33 ` Al Viro
2019-04-10 0:45 ` Eric Biggers
2019-04-10 0:45 ` Eric Biggers
2019-04-10 1:04 ` Al Viro
2019-04-10 1:04 ` Al Viro
2019-04-10 1:22 ` Eric Biggers
2019-04-10 1:22 ` [f2fs-dev] " Eric Biggers
2019-04-10 1:22 ` Eric Biggers
2019-04-10 1:39 ` Al Viro
2019-04-10 1:39 ` Al Viro
2019-04-10 2:58 ` Eric Biggers
2019-04-10 2:58 ` Eric Biggers
2019-04-10 3:44 ` Al Viro
2019-04-10 3:44 ` Al Viro
2019-04-10 4:04 ` Eric Biggers
2019-04-10 4:04 ` [f2fs-dev] " Eric Biggers
2019-04-10 4:04 ` Eric Biggers
2019-04-10 4:16 ` Eric Biggers
2019-04-10 4:31 ` Al Viro
2019-04-10 4:31 ` Al Viro
2019-04-10 5:04 ` Eric Biggers
2019-04-10 5:04 ` [f2fs-dev] " Eric Biggers
2019-04-10 5:04 ` Eric Biggers
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