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authorNeilBrown <neilb@suse.de>2014-08-04 17:06:29 +1000
committerAl Viro <viro@zeniv.linux.org.uk>2014-08-07 14:40:10 -0400
commitb8faf035ea9d0011b04856a8198e2e212d93346a (patch)
treefe06d46ee4a2d659f05740e331a8c823d62d5e3a /Documentation/filesystems/vfs.txt
parent7c33d5972ce382bcc506d16235f1e9b7d22cbef8 (diff)
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VFS: allow ->d_manage() to declare -EISDIR in rcu_walk mode.
In REF-walk mode, ->d_manage can return -EISDIR to indicate that the dentry is not really a mount trap (or even a mount point) and that any mounts or any DCACHE_NEED_AUTOMOUNT flag should be ignored. RCU-walk mode doesn't currently support this, so if there is a dentry with DCACHE_NEED_AUTOMOUNT set but which shouldn't be a mount-trap, lookup_fast() will always drop in REF-walk mode. With this patch, an -EISDIR from ->d_manage will always cause mounts and automounts to be ignored, both in REF-walk and RCU-walk. Bug-fixed-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Ian Kent <raven@themaw.net> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
-rw-r--r--Documentation/filesystems/vfs.txt3
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index a1d0d7a30165..61d65cc65c54 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -1053,7 +1053,8 @@ struct dentry_operations {
If the 'rcu_walk' parameter is true, then the caller is doing a
pathwalk in RCU-walk mode. Sleeping is not permitted in this mode,
and the caller can be asked to leave it and call again by returning
- -ECHILD.
+ -ECHILD. -EISDIR may also be returned to tell pathwalk to
+ ignore d_automount or any mounts.
This function is only used if DCACHE_MANAGE_TRANSIT is set on the
dentry being transited from.
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