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authorDavid Howells <dhowells@redhat.com>2011-01-14 18:46:51 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2011-01-15 20:07:47 -0500
commitab90911ff90cdab59b31c045c3f0ae480d14f29d (patch)
tree683450a66eb9dc6bf053e38d63f4740bb53a7b6e /Documentation/filesystems/vfs.txt
parent87556ef19926e97464e0163a7840140527ae6615 (diff)
Allow d_manage() to be used in RCU-walk mode
Allow d_manage() to be called from pathwalk when it is in RCU-walk mode as well as when it is in Ref-walk mode. This permits __follow_mount_rcu() to call d_manage() directly. d_manage() needs a parameter to indicate that it is in RCU-walk mode as it isn't allowed to sleep if in that mode (but should return -ECHILD instead). autofs4_d_manage() can then be set to retain RCU-walk mode if the daemon accesses it and otherwise request dropping back to ref-walk mode. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
-rw-r--r--Documentation/filesystems/vfs.txt7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 4682586b147..3c4b2f1b64d 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -865,7 +865,7 @@ struct dentry_operations {
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
- int (*d_manage)(struct dentry *, bool);
+ int (*d_manage)(struct dentry *, bool, bool);
};
d_revalidate: called when the VFS needs to revalidate a dentry. This
@@ -960,6 +960,11 @@ struct dentry_operations {
held by the caller and the function should not initiate any mounts or
unmounts that it will then wait for.
+ 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 returing
+ -ECHILD.
+
This function is only used if DCACHE_MANAGE_TRANSIT is set on the
dentry being transited from.