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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 /fs/autofs4/root.c
parent87556ef19926e97464e0163a7840140527ae6615 (diff)
downloadop-kernel-dev-ab90911ff90cdab59b31c045c3f0ae480d14f29d.zip
op-kernel-dev-ab90911ff90cdab59b31c045c3f0ae480d14f29d.tar.gz
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 'fs/autofs4/root.c')
-rw-r--r--fs/autofs4/root.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 9194e27..dbd9551 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -36,7 +36,7 @@ static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long);
static int autofs4_dir_open(struct inode *inode, struct file *file);
static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(struct dentry *, bool, bool);
const struct file_operations autofs4_root_operations = {
.open = dcache_dir_open,
@@ -450,7 +450,7 @@ done:
return NULL;
}
-int autofs4_d_manage(struct dentry *dentry, bool mounting_here)
+int autofs4_d_manage(struct dentry *dentry, bool mounting_here, bool rcu_walk)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
@@ -464,6 +464,10 @@ int autofs4_d_manage(struct dentry *dentry, bool mounting_here)
return 0;
}
+ /* We need to sleep, so we need pathwalk to be in ref-mode */
+ if (rcu_walk)
+ return -ECHILD;
+
/* Wait for pending expires */
do_expire_wait(dentry);
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