From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH][RFC] make take_dentry_name_snapshot() lockless
Date: Tue, 10 Dec 2024 02:45:23 +0000 [thread overview]
Message-ID: <20241210024523.GD3387508@ZenIV> (raw)
In-Reply-To: <20241209231237.GC3387508@ZenIV>
On Mon, Dec 09, 2024 at 11:12:37PM +0000, Al Viro wrote:
>
> Actually, grepping for DNAME_INLINE_LEN brings some interesting hits:
> drivers/net/ieee802154/adf7242.c:1165: char debugfs_dir_name[DNAME_INLINE_LEN + 1];
> cargo-culted, AFAICS; would be better off with a constant of their own.
>
> fs/ext4/fast_commit.c:326: fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
> fs/ext4/fast_commit.c:452: if (dentry->d_name.len > DNAME_INLINE_LEN) {
> fs/ext4/fast_commit.c:1332: fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
> fs/ext4/fast_commit.h:113: unsigned char fcd_iname[DNAME_INLINE_LEN]; /* Dirent name string */
> Looks like that might want struct name_snapshot, along with
> {take,release}_dentry_name_snapshot().
See viro/vfs.git#work.dcache. I've thrown ext4/fast_commit conversion
into the end of that pile. NOTE: that stuff obviously needs profiling.
It does survive light testing (boot/ltp/xfstests), but review and more
testing (including serious profiling) is obviously needed.
Patches in followups...
next parent reply other threads:[~2024-12-10 2:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
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[not found] ` <CAHk-=wh4=95ainkHyi5n3nFCToNWhLcfQtziSp3jSFSQGzQUAw@mail.gmail.com>
[not found] ` <20241209211708.GA3387508@ZenIV>
[not found] ` <20241209222854.GB3387508@ZenIV>
[not found] ` <CAHk-=wjrtchauo9CO1ebkiES0X1VaZinjnHmcXQGBcZNHzyyBA@mail.gmail.com>
[not found] ` <CAHk-=wj_rCVrTiRMyD8UKkRdUpeGiheyrZcf28H6OADRkLPFkw@mail.gmail.com>
[not found] ` <20241209231237.GC3387508@ZenIV>
2024-12-10 2:45 ` Al Viro [this message]
2024-12-10 2:48 ` [PATCH 1/5] make sure that DCACHE_INLINE_LEN is a multiple of word size Al Viro
2024-12-10 2:48 ` [PATCH 2/5] dcache: back inline names with a struct-wrapped array of unsigned long Al Viro
2024-12-10 2:48 ` [PATCH 3/5] make take_dentry_name_snapshot() lockless Al Viro
2024-12-10 2:48 ` [PATCH 4/5] dissolve external_name.u into separate members Al Viro
2024-12-10 2:48 ` [PATCH 5/5] ext4 fast_commit: make use of name_snapshot primitives Al Viro
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