From: "Theodore Ts'o" <tytso@mit.edu>
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,
linux-mtd@lists.infradead.org, Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v2 2/2] fscrypt: cache decrypted symlink target in ->i_link
Date: Wed, 17 Apr 2019 12:55:56 -0400 [thread overview]
Message-ID: <20190417165556.GI4686@mit.edu> (raw)
In-Reply-To: <20190410202115.64501-3-ebiggers@kernel.org>
On Wed, Apr 10, 2019 at 01:21:15PM -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.
> This also involves dropping out of rcu-walk mode.
>
> Make encrypted symlinks faster by caching the decrypted symlink target
> in ->i_link. The first call to fscrypt_get_symlink() sets it. Then,
> the existing VFS path lookup code uses the non-NULL ->i_link to take the
> fast path where ->get_link() isn't called, and lookups in rcu-walk mode
> remain in rcu-walk mode.
>
> Also set ->i_link immediately when a new encrypted symlink is created.
>
> To safely free the symlink target after an RCU grace period has elapsed,
> introduce a new function fscrypt_free_inode(), and make the relevant
> filesystems call it just before actually freeing the inode.
>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Looks good, applied.
- Ted
prev parent reply other threads:[~2019-04-17 16:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 20:21 [PATCH v2 0/2] fscrypt: improve encrypted symlink performance Eric Biggers
2019-04-10 20:21 ` [PATCH v2 1/2] vfs: use READ_ONCE() to access ->i_link Eric Biggers
2019-04-10 21:06 ` Al Viro
2019-04-10 23:15 ` Eric Biggers
2019-04-11 2:25 ` Al Viro
2019-04-11 17:28 ` Eric Biggers
2019-04-17 16:41 ` Theodore Ts'o
2019-04-10 20:21 ` [PATCH v2 2/2] fscrypt: cache decrypted symlink target in ->i_link Eric Biggers
2019-04-17 16:55 ` Theodore Ts'o [this message]
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