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[2/4] Documentation/filesystems/vfs.txt: document how ->i_link works

Message ID 20190411231630.50177-3-ebiggers@kernel.org (mailing list archive)
State New, archived
Headers show
Series vfs: update ->get_link() related documentation | expand

Commit Message

Eric Biggers April 11, 2019, 11:16 p.m. UTC 
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 mbox series

Patch

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