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authorIan Kent <raven@themaw.net>2008-10-15 22:02:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 11:21:39 -0700
commit8d7b48e0bc5fa01a818eac713d4cb0763090cd0e (patch)
tree4477b2f23f8596901f38582242a40ff869fb798c /fs/autofs4/autofs_i.h
parent4b22ff13415fa30b6282c88da790c82b4c6e5127 (diff)
downloadlinux-linaro-8d7b48e0bc5fa01a818eac713d4cb0763090cd0e.tar.gz
autofs4: add miscellaneous device for ioctls
Add a miscellaneous device to the autofs4 module for routing ioctls. This provides the ability to obtain an ioctl file handle for an autofs mount point that is possibly covered by another mount. The actual problem with autofs is that it can't reconnect to existing mounts. Immediately one things of just adding the ability to remount autofs file systems would solve it, but alas, that can't work. This is because autofs direct mounts and the implementation of "on demand mount and expire" of nested mount trees have the file system mounted on top of the mount trigger dentry. To resolve this a miscellaneous device node for routing ioctl commands to these mount points has been implemented in the autofs4 kernel module and a library added to autofs. This provides the ability to open a file descriptor for these over mounted autofs mount points. Please refer to Documentation/filesystems/autofs4-mount-control.txt for a discussion of the problem, implementation alternatives considered and a description of the interface. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: build fix] Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/autofs4/autofs_i.h')
-rw-r--r--fs/autofs4/autofs_i.h35
1 files changed, 33 insertions, 2 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index fa76d18be08..e0f16da00e5 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -14,6 +14,7 @@
/* Internal header file for autofs */
#include <linux/auto_fs4.h>
+#include <linux/auto_dev-ioctl.h>
#include <linux/mutex.h>
#include <linux/list.h>
@@ -21,6 +22,9 @@
#define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
#define AUTOFS_IOC_COUNT 32
+#define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)
+#define AUTOFS_DEV_IOCTL_IOC_COUNT (AUTOFS_IOC_COUNT - 11)
+
#define AUTOFS_TYPE_TRIGGER (AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET)
#include <linux/kernel.h>
@@ -37,11 +41,27 @@
/* #define DEBUG */
#ifdef DEBUG
-#define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __func__ , ##args); } while(0)
+#define DPRINTK(fmt, args...) \
+do { \
+ printk(KERN_DEBUG "pid %d: %s: " fmt "\n", \
+ current->pid, __func__, ##args); \
+} while (0)
#else
-#define DPRINTK(fmt,args...) do {} while(0)
+#define DPRINTK(fmt, args...) do {} while (0)
#endif
+#define AUTOFS_WARN(fmt, args...) \
+do { \
+ printk(KERN_WARNING "pid %d: %s: " fmt "\n", \
+ current->pid, __func__, ##args); \
+} while (0)
+
+#define AUTOFS_ERROR(fmt, args...) \
+do { \
+ printk(KERN_ERR "pid %d: %s: " fmt "\n", \
+ current->pid, __func__, ##args); \
+} while (0)
+
/* Unified info structure. This is pointed to by both the dentry and
inode structures. Each file in the filesystem has an instance of this
structure. It holds a reference to the dentry, so dentries are never
@@ -170,6 +190,17 @@ int autofs4_expire_run(struct super_block *, struct vfsmount *,
struct autofs_packet_expire __user *);
int autofs4_expire_multi(struct super_block *, struct vfsmount *,
struct autofs_sb_info *, int __user *);
+struct dentry *autofs4_expire_direct(struct super_block *sb,
+ struct vfsmount *mnt,
+ struct autofs_sb_info *sbi, int how);
+struct dentry *autofs4_expire_indirect(struct super_block *sb,
+ struct vfsmount *mnt,
+ struct autofs_sb_info *sbi, int how);
+
+/* Device node initialization */
+
+int autofs_dev_ioctl_init(void);
+void autofs_dev_ioctl_exit(void);
/* Operations structures */