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authorLinus Torvalds <torvalds@linux-foundation.org>2011-01-16 11:31:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-16 11:31:50 -0800
commitf8206b925fb0eba3a11839419be118b09105d7b1 (patch)
tree5d41b356a043da09c816ed80bd79d1ea8b2b47e5 /Documentation/filesystems
parent1b59be2a6cdcb5a12e18d8315c07c94a624de48f (diff)
parentf03c65993b98eeb909a4012ce7833c5857d74755 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (23 commits) sanitize vfsmount refcounting changes fix old umount_tree() breakage autofs4: Merge the remaining dentry ops tables Unexport do_add_mount() and add in follow_automount(), not ->d_automount() Allow d_manage() to be used in RCU-walk mode Remove a further kludge from __do_follow_link() autofs4: Bump version autofs4: Add v4 pseudo direct mount support autofs4: Fix wait validation autofs4: Clean up autofs4_free_ino() autofs4: Clean up dentry operations autofs4: Clean up inode operations autofs4: Remove unused code autofs4: Add d_manage() dentry operation autofs4: Add d_automount() dentry operation Remove the automount through follow_link() kludge code from pathwalk CIFS: Use d_automount() rather than abusing follow_link() NFS: Use d_automount() rather than abusing follow_link() AFS: Use d_automount() rather than abusing follow_link() Add an AT_NO_AUTOMOUNT flag to suppress terminal automount ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/Locking4
-rw-r--r--Documentation/filesystems/vfs.txt43
2 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index ef9349a4b5d..651d5237c15 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -19,6 +19,8 @@ prototypes:
void (*d_release)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
+ struct vfsmount *(*d_automount)(struct path *path);
+ int (*d_manage)(struct dentry *, bool);
locking rules:
rename_lock ->d_lock may block rcu-walk
@@ -29,6 +31,8 @@ d_delete: no yes no no
d_release: no no yes no
d_iput: no no yes no
d_dname: no no no no
+d_automount: no no yes no
+d_manage: no no yes (ref-walk) maybe
--------------------------- inode_operations ---------------------------
prototypes:
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index cae6d27c9f5..94cf97b901d 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -864,6 +864,8 @@ struct dentry_operations {
void (*d_release)(struct dentry *);
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, bool);
};
d_revalidate: called when the VFS needs to revalidate a dentry. This
@@ -930,6 +932,47 @@ struct dentry_operations {
at the end of the buffer, and returns a pointer to the first char.
dynamic_dname() helper function is provided to take care of this.
+ d_automount: called when an automount dentry is to be traversed (optional).
+ This should create a new VFS mount record and return the record to the
+ caller. The caller is supplied with a path parameter giving the
+ automount directory to describe the automount target and the parent
+ VFS mount record to provide inheritable mount parameters. NULL should
+ be returned if someone else managed to make the automount first. If
+ the vfsmount creation failed, then an error code should be returned.
+ If -EISDIR is returned, then the directory will be treated as an
+ ordinary directory and returned to pathwalk to continue walking.
+
+ If a vfsmount is returned, the caller will attempt to mount it on the
+ mountpoint and will remove the vfsmount from its expiration list in
+ the case of failure. The vfsmount should be returned with 2 refs on
+ it to prevent automatic expiration - the caller will clean up the
+ additional ref.
+
+ This function is only used if DCACHE_NEED_AUTOMOUNT is set on the
+ dentry. This is set by __d_instantiate() if S_AUTOMOUNT is set on the
+ inode being added.
+
+ d_manage: called to allow the filesystem to manage the transition from a
+ dentry (optional). This allows autofs, for example, to hold up clients
+ waiting to explore behind a 'mountpoint' whilst letting the daemon go
+ past and construct the subtree there. 0 should be returned to let the
+ calling process continue. -EISDIR can be returned to tell pathwalk to
+ use this directory as an ordinary directory and to ignore anything
+ mounted on it and not to check the automount flag. Any other error
+ code will abort pathwalk completely.
+
+ If the 'mounting_here' parameter is true, then namespace_sem is being
+ 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.
+
Example :
static char *pipefs_dname(struct dentry *dent, char *buffer, int buflen)