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| author | David Howells <dhowells@redhat.com> | 2011-01-14 18:46:51 +0000 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-01-15 20:07:47 -0500 |
| commit | ab90911ff90cdab59b31c045c3f0ae480d14f29d (patch) | |
| tree | 683450a66eb9dc6bf053e38d63f4740bb53a7b6e /Documentation/filesystems | |
| parent | 87556ef19926e97464e0163a7840140527ae6615 (diff) | |
| download | lwn-ab90911ff90cdab59b31c045c3f0ae480d14f29d.tar.gz lwn-ab90911ff90cdab59b31c045c3f0ae480d14f29d.zip | |
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')
| -rw-r--r-- | Documentation/filesystems/Locking | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 7 |
2 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index cbf98b989b11..39707748ed2d 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -32,7 +32,7 @@ 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 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 4682586b147a..3c4b2f1b64d0 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. |