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From: Al Viro <viro@zeniv.linux.org.uk>
To: James Yonan <james@openvpn.net>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] namei: implemented RENAME_NEWER flag for renameat2() conditional replace
Date: Tue, 28 Jun 2022 18:34:14 +0100	[thread overview]
Message-ID: <Yrs7lh6hG44ERoiM@ZenIV> (raw)
In-Reply-To: <20220627221107.176495-1-james@openvpn.net>

On Mon, Jun 27, 2022 at 04:11:07PM -0600, James Yonan wrote:

> 	    && d_is_positive(new_dentry)
> 	    && timespec64_compare(&d_backing_inode(old_dentry)->i_mtime,
> 				  &d_backing_inode(new_dentry)->i_mtime) <= 0)
> 		goto exit5;
> 
> It's pretty cool in a way that a new atomic file operation can even be
> implemented in just 5 lines of code, and it's thanks to the existing
> locking infrastructure around file rename/move that these operations
> become almost trivial.  Unfortunately, every fs must approve a new
> renameat2() flag, so it bloats the patch a bit.

How is it atomic and what's to stabilize ->i_mtime in that test?
Confused...

  parent reply	other threads:[~2022-06-28 17:34 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-27 22:11 [PATCH] namei: implemented RENAME_NEWER flag for renameat2() conditional replace James Yonan
2022-06-28  9:46 ` Amir Goldstein
2022-06-28 21:56   ` James Yonan
2022-06-29  5:15     ` Amir Goldstein
2022-06-30 16:18       ` James Yonan
2022-06-28 17:34 ` Al Viro [this message]
2022-06-28 18:34   ` Amir Goldstein
2022-06-28 23:19     ` James Yonan
2022-06-29  1:43       ` Dave Chinner
2022-06-29  2:07         ` NeilBrown
2022-06-29  2:35           ` Dave Chinner
2022-06-29  2:49             ` NeilBrown
2022-06-30 16:39             ` James Yonan
2022-07-01  9:23               ` [PATCH v2] namei: implemented RENAME_NEWER_MTIME " James Yonan
2022-07-01 10:34                 ` Amir Goldstein
2022-07-01 20:06                   ` James Yonan
2022-07-02  8:07                 ` Dave Chinner
2022-07-05 13:30                   ` [PATCH v3 1/2] RENAME_NEWER_MTIME is a new userspace-visible flag for renameat2(), and stands alongside existing flags including RENAME_NOREPLACE, RENAME_EXCHANGE, and RENAME_WHITEOUT James Yonan
2022-07-05 13:30                     ` [PATCH v3 2/2] selftests: added a new target renameat2 James Yonan
2022-07-05 13:30                     ` [PATCH man-pages] rename.2: document new renameat2() flag RENAME_NEWER_MTIME James Yonan
2022-07-05 14:03                   ` [RESEND PATCH v3 1/2] namei: implemented RENAME_NEWER_MTIME flag for renameat2() conditional replace James Yonan
2022-07-11 19:13                   ` [PATCH v4 " James Yonan
2022-07-11 19:13                     ` [PATCH v4 2/2] selftests: added a new target renameat2 James Yonan
2022-07-11 23:10                     ` [PATCH v4 1/2] namei: implemented RENAME_NEWER_MTIME flag for renameat2() conditional replace Dave Chinner

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