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From: Eric Biggers <ebiggers@kernel.org>
To: linux-fsdevel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 2/4] Documentation/filesystems/vfs.txt: document how ->i_link works
Date: Thu, 11 Apr 2019 16:16:28 -0700	[thread overview]
Message-ID: <20190411231630.50177-3-ebiggers@kernel.org> (raw)
In-Reply-To: <20190411231630.50177-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 Documentation/filesystems/vfs.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 33120f220f86f..57fc576b1f3ea 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -463,6 +463,12 @@ otherwise noted.
 	argument.  If request can't be handled without leaving RCU mode,
 	have it return ERR_PTR(-ECHILD).
 
+	If the filesystem stores the symlink target in ->i_link, the
+	VFS may use it directly without calling ->get_link(); however,
+	->get_link() must still be provided.  ->i_link must not be
+	freed until after an RCU grace period.  Writing to ->i_link
+	post-iget() time requires a 'release' memory barrier.
+
   readlink: this is now just an override for use by readlink(2) for the
 	cases when ->get_link uses nd_jump_link() or object is not in
 	fact a symlink.  Normally filesystems should only implement
-- 
2.21.0.392.gf8f6787159e-goog


  parent reply	other threads:[~2019-04-11 23:18 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-11 23:16 [PATCH 0/4] vfs: update ->get_link() related documentation Eric Biggers
2019-04-11 23:16 ` [PATCH 1/4] Documentation/filesystems/vfs.txt: remove bogus "Last updated" date Eric Biggers
2019-04-11 23:16 ` Eric Biggers [this message]
2019-04-11 23:16 ` [PATCH 3/4] Documentation/filesystems/Locking: fix ->get_link() prototype Eric Biggers
2019-04-11 23:16 ` [PATCH 4/4] libfs: document simple_get_link() Eric Biggers
2019-04-22 18:03 ` [PATCH 0/4] vfs: update ->get_link() related documentation Eric Biggers
2019-05-01  0:25   ` Eric Biggers
2019-05-01  1:36     ` Al Viro
2019-05-01  1:49       ` Jonathan Corbet
2019-05-01  2:14         ` Al Viro
2019-05-01  2:17           ` Jonathan Corbet
2019-05-01  4:00             ` Al Viro
2019-05-01  4:15           ` Tobin C. Harding
2019-05-03 12:16             ` Jonathan Corbet

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