--- linux-2.6.27.orig/fs/autofs4/autofs_i.h
+++ linux-2.6.27/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)
+
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/time.h>
@@ -35,11 +39,27 @@
/* #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
@@ -61,6 +81,9 @@ struct autofs_info {
unsigned long last_used;
atomic_t count;
+ uid_t uid;
+ gid_t gid;
+
mode_t mode;
size_t size;
@@ -92,10 +115,6 @@ struct autofs_wait_queue {
#define AUTOFS_SBI_MAGIC 0x6d4a556d
-#define AUTOFS_TYPE_INDIRECT 0x0001
-#define AUTOFS_TYPE_DIRECT 0x0002
-#define AUTOFS_TYPE_OFFSET 0x0004
-
struct autofs_sb_info {
u32 magic;
int pipefd;
@@ -167,8 +186,21 @@ int autofs4_expire_wait(struct dentry *d
int autofs4_expire_run(struct super_block *, struct vfsmount *,
struct autofs_sb_info *,
struct autofs_packet_expire __user *);
+int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+ struct autofs_sb_info *sbi, int when);
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 */
--- linux-2.6.27.orig/fs/autofs4/expire.c
+++ linux-2.6.27/fs/autofs4/expire.c
@@ -56,12 +56,25 @@ static int autofs4_mount_busy(struct vfs
mntget(mnt);
dget(dentry);
- if (!autofs4_follow_mount(&mnt, &dentry))
+ if (!follow_down(&mnt, &dentry))
goto done;
- /* This is an autofs submount, we can't expire it */
- if (is_autofs4_dentry(dentry))
- goto done;
+ if (is_autofs4_dentry(dentry)) {
+ struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+
+ /* This is an autofs submount, we can't expire it */
+ if (autofs_type_indirect(sbi->type))
+ goto done;
+
+ /*
+ * Otherwise it's an offset mount and we need to check
+ * if we can umount its mount, if there is one.
+ */
+ if (!d_mountpoint(dentry)) {
+ status = 0;
+ goto done;
+ }
+ }
/* Update the expiry counter if fs is busy */
if (!may_umount_tree(mnt)) {
@@ -244,10 +257,10 @@ cont:
}
/* Check if we can expire a direct mount (possibly a tree) */
-static struct dentry *autofs4_expire_direct(struct super_block *sb,
- struct vfsmount *mnt,
- struct autofs_sb_info *sbi,
- int how)
+struct dentry *autofs4_expire_direct(struct super_block *sb,
+ struct vfsmount *mnt,
+ struct autofs_sb_info *sbi,
+ int how)
{
unsigned long timeout;
struct dentry *root = dget(sb->s_root);
@@ -283,10 +296,10 @@ static struct dentry *autofs4_expire_dir
* - it is unused by any user process
* - it has been unused for exp_timeout time
*/
-static struct dentry *autofs4_expire_indirect(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)
{
unsigned long timeout;
struct dentry *root = sb->s_root;
@@ -467,22 +480,16 @@ int autofs4_expire_run(struct super_bloc
return ret;
}
-/* Call repeatedly until it returns -EAGAIN, meaning there's nothing
- more to be done */
-int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
- struct autofs_sb_info *sbi, int __user *arg)
+int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+ struct autofs_sb_info *sbi, int when)
{
struct dentry *dentry;
int ret = -EAGAIN;
- int do_now = 0;
- if (arg && get_user(do_now, arg))
- return -EFAULT;
-
- if (sbi->type & AUTOFS_TYPE_DIRECT)
- dentry = autofs4_expire_direct(sb, mnt, sbi, do_now);
+ if (autofs_type_trigger(sbi->type))
+ dentry = autofs4_expire_direct(sb, mnt, sbi, when);
else
- dentry = autofs4_expire_indirect(sb, mnt, sbi, do_now);
+ dentry = autofs4_expire_indirect(sb, mnt, sbi, when);
if (dentry) {
struct autofs_info *ino = autofs4_dentry_ino(dentry);
@@ -505,3 +512,16 @@ int autofs4_expire_multi(struct super_bl
return ret;
}
+/* Call repeatedly until it returns -EAGAIN, meaning there's nothing
+ more to be done */
+int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+ struct autofs_sb_info *sbi, int __user *arg)
+{
+ int do_now = 0;
+
+ if (arg && get_user(do_now, arg))
+ return -EFAULT;
+
+ return autofs4_do_expire_multi(sb, mnt, sbi, do_now);
+}
+
--- linux-2.6.27.orig/fs/autofs4/inode.c
+++ linux-2.6.27/fs/autofs4/inode.c
@@ -53,6 +53,8 @@ struct autofs_info *autofs4_init_ino(str
atomic_set(&ino->count, 0);
}
+ ino->uid = 0;
+ ino->gid = 0;
ino->mode = mode;
ino->last_used = jiffies;
@@ -195,9 +197,9 @@ static int autofs4_show_options(struct s
seq_printf(m, ",minproto=%d", sbi->min_proto);
seq_printf(m, ",maxproto=%d", sbi->max_proto);
- if (sbi->type & AUTOFS_TYPE_OFFSET)
+ if (autofs_type_offset(sbi->type))
seq_printf(m, ",offset");
- else if (sbi->type & AUTOFS_TYPE_DIRECT)
+ else if (autofs_type_direct(sbi->type))
seq_printf(m, ",direct");
else
seq_printf(m, ",indirect");
@@ -282,13 +284,13 @@ static int parse_options(char *options,
*maxproto = option;
break;
case Opt_indirect:
- *type = AUTOFS_TYPE_INDIRECT;
+ set_autofs_type_indirect(type);
break;
case Opt_direct:
- *type = AUTOFS_TYPE_DIRECT;
+ set_autofs_type_direct(type);
break;
case Opt_offset:
- *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
+ set_autofs_type_offset(type);
break;
default:
return 1;
@@ -336,7 +338,7 @@ int autofs4_fill_super(struct super_bloc
sbi->sb = s;
sbi->version = 0;
sbi->sub_version = 0;
- sbi->type = 0;
+ set_autofs_type_indirect(&sbi->type);
sbi->min_proto = 0;
sbi->max_proto = 0;
mutex_init(&sbi->wq_mutex);
@@ -378,7 +380,7 @@ int autofs4_fill_super(struct super_bloc
}
root_inode->i_fop = &autofs4_root_operations;
- root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
+ root_inode->i_op = autofs_type_trigger(sbi->type) ?
&autofs4_direct_root_inode_operations :
&autofs4_indirect_root_inode_operations;
--- linux-2.6.27.orig/fs/autofs4/waitq.c
+++ linux-2.6.27/fs/autofs4/waitq.c
@@ -297,20 +297,14 @@ static int validate_request(struct autof
*/
if (notify == NFY_MOUNT) {
/*
- * If the dentry isn't hashed just go ahead and try the
- * mount again with a new wait (not much else we can do).
- */
- if (!d_unhashed(dentry)) {
- /*
- * But if the dentry is hashed, that means that we
- * got here through the revalidate path. Thus, we
- * need to check if the dentry has been mounted
- * while we waited on the wq_mutex. If it has,
- * simply return success.
- */
- if (d_mountpoint(dentry))
- return 0;
- }
+ * If the dentry was successfully mounted while we slept
+ * on the wait queue mutex we can return success. If it
+ * isn't mounted (doesn't have submounts for the case of
+ * a multi-mount with no mount at it's base) we can
+ * continue on and create a new request.
+ */
+ if (have_submounts(dentry))
+ return 0;
}
return 1;
@@ -337,7 +331,7 @@ int autofs4_wait(struct autofs_sb_info *
* is very similar for indirect mounts except only dentrys
* in the root of the autofs file system may be negative.
*/
- if (sbi->type & (AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET))
+ if (autofs_type_trigger(sbi->type))
return -ENOENT;
else if (!IS_ROOT(dentry->d_parent))
return -ENOENT;
@@ -348,7 +342,7 @@ int autofs4_wait(struct autofs_sb_info *
return -ENOMEM;
/* If this is a direct mount request create a dummy name */
- if (IS_ROOT(dentry) && (sbi->type & AUTOFS_TYPE_DIRECT))
+ if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
qstr.len = sprintf(name, "%p", dentry);
else {
qstr.len = autofs4_getpath(sbi, dentry, &name);
@@ -406,11 +400,11 @@ int autofs4_wait(struct autofs_sb_info *
type = autofs_ptype_expire_multi;
} else {
if (notify == NFY_MOUNT)
- type = (sbi->type & AUTOFS_TYPE_DIRECT) ?
+ type = autofs_type_trigger(sbi->type) ?
autofs_ptype_missing_direct :
autofs_ptype_missing_indirect;
else
- type = (sbi->type & AUTOFS_TYPE_DIRECT) ?
+ type = autofs_type_trigger(sbi->type) ?
autofs_ptype_expire_direct :
autofs_ptype_expire_indirect;
}
@@ -457,6 +451,40 @@ int autofs4_wait(struct autofs_sb_info *
status = wq->status;
+ /*
+ * For direct and offset mounts we need to track the requester's
+ * uid and gid in the dentry info struct. This is so it can be
+ * supplied, on request, by the misc device ioctl interface.
+ * This is needed during daemon resatart when reconnecting
+ * to existing, active, autofs mounts. The uid and gid (and
+ * related string values) may be used for macro substitution
+ * in autofs mount maps.
+ */
+ if (!status) {
+ struct autofs_info *ino;
+ struct dentry *de = NULL;
+
+ /* direct mount or browsable map */
+ ino = autofs4_dentry_ino(dentry);
+ if (!ino) {
+ /* If not lookup actual dentry used */
+ de = d_lookup(dentry->d_parent, &dentry->d_name);
+ if (de)
+ ino = autofs4_dentry_ino(de);
+ }
+
+ /* Set mount requester */
+ if (ino) {
+ spin_lock(&sbi->fs_lock);
+ ino->uid = wq->uid;
+ ino->gid = wq->gid;
+ spin_unlock(&sbi->fs_lock);
+ }
+
+ if (de)
+ dput(de);
+ }
+
/* Are we the last process to need status? */
mutex_lock(&sbi->wq_mutex);
if (!--wq->wait_ctr)
--- linux-2.6.27.orig/include/linux/auto_fs4.h
+++ linux-2.6.27/include/linux/auto_fs4.h
@@ -23,12 +23,71 @@
#define AUTOFS_MIN_PROTO_VERSION 3
#define AUTOFS_MAX_PROTO_VERSION 5
-#define AUTOFS_PROTO_SUBVERSION 0
+#define AUTOFS_PROTO_SUBVERSION 1
/* Mask for expire behaviour */
#define AUTOFS_EXP_IMMEDIATE 1
#define AUTOFS_EXP_LEAVES 2
+#define AUTOFS_TYPE_ANY 0U
+#define AUTOFS_TYPE_INDIRECT 1U
+#define AUTOFS_TYPE_DIRECT 2U
+#define AUTOFS_TYPE_OFFSET 4U
+
+static inline void set_autofs_type_indirect(unsigned int *type)
+{
+ *type = AUTOFS_TYPE_INDIRECT;
+ return;
+}
+
+static inline unsigned int autofs_type_indirect(unsigned int type)
+{
+ return (type == AUTOFS_TYPE_INDIRECT);
+}
+
+static inline void set_autofs_type_direct(unsigned int *type)
+{
+ *type = AUTOFS_TYPE_DIRECT;
+ return;
+}
+
+static inline unsigned int autofs_type_direct(unsigned int type)
+{
+ return (type == AUTOFS_TYPE_DIRECT);
+}
+
+static inline void set_autofs_type_offset(unsigned int *type)
+{
+ *type = AUTOFS_TYPE_OFFSET;
+ return;
+}
+
+static inline unsigned int autofs_type_offset(unsigned int type)
+{
+ return (type == AUTOFS_TYPE_OFFSET);
+}
+
+static inline unsigned int autofs_type_trigger(unsigned int type)
+{
+ return (type == AUTOFS_TYPE_DIRECT || type == AUTOFS_TYPE_OFFSET);
+}
+
+/*
+ * This isn't really a type as we use it to say "no type set" to
+ * indicate we want to search for "any" mount in the
+ * autofs_dev_ioctl_ismountpoint() device ioctl function.
+ */
+static inline void set_autofs_type_any(unsigned int *type)
+{
+ *type = AUTOFS_TYPE_ANY;
+ return;
+}
+
+static inline unsigned int autofs_type_any(unsigned int type)
+{
+ return (type == AUTOFS_TYPE_ANY);
+}
+
/* Daemon notification packet types */
enum autofs_notify {
NFY_NONE,
--- /dev/null
+++ linux-2.6.27/Documentation/filesystems/autofs4-mount-control.txt
@@ -0,0 +1,414 @@
+
+Miscellaneous Device control operations for the autofs4 kernel module
+====================================================================
+
+The problem
+===========
+
+There is a problem with active restarts in autofs (that is to say
+restarting autofs when there are busy mounts).
+
+During normal operation autofs uses a file descriptor opened on the
+directory that is being managed in order to be able to issue control
+operations. Using a file descriptor gives ioctl operations access to
+autofs specific information stored in the super block. The operations
+are things such as setting an autofs mount catatonic, setting the
+expire timeout and requesting expire checks. As is explained below,
+certain types of autofs triggered mounts can end up covering an autofs
+mount itself which prevents us being able to use open(2) to obtain a
+file descriptor for these operations if we don't already have one open.
+
+Currently autofs uses "umount -l" (lazy umount) to clear active mounts
+at restart. While using lazy umount works for most cases, anything that
+needs to walk back up the mount tree to construct a path, such as
+getcwd(2) and the proc file system /proc/<pid>/cwd, no longer works
+because the point from which the path is constructed has been detached
+from the mount tree.
+
+The actual problem with autofs is that it can't reconnect to existing
+mounts. Immediately one thinks 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 directly
+on top of the mount trigger directory dentry.
+
+For example, there are two types of automount maps, direct (in the kernel
+module source you will see a third type called an offset, which is just
+a direct mount in disguise) and indirect.
+
+Here is a master map with direct and indirect map entries:
+
+/- /etc/auto.direct
+/test /etc/auto.indirect
+
+and the corresponding map files:
+
+/etc/auto.direct:
+
+/automount/dparse/g6 budgie:/autofs/export1
+/automount/dparse/g1 shark:/autofs/export1
+and so on.
+
+/etc/auto.indirect:
+
+g1 shark:/autofs/export1
+g6 budgie:/autofs/export1
+and so on.
+
+For the above indirect map an autofs file system is mounted on /test and
+mounts are triggered for each sub-directory key by the inode lookup
+operation. So we see a mount of shark:/autofs/export1 on /test/g1, for
+example.
+
+The way that direct mounts are handled is by making an autofs mount on
+each full path, such as /automount/dparse/g1, and using it as a mount
+trigger. So when we walk on the path we mount shark:/autofs/export1 "on
+top of this mount point". Since these are always directories we can
+use the follow_link inode operation to trigger the mount.
+
+But, each entry in direct and indirect maps can have offsets (making
+them multi-mount map entries).
+
+For example, an indirect mount map entry could also be:
+
+g1 \
+ / shark:/autofs/export5/testing/test \
+ /s1 shark:/autofs/export/testing/test/s1 \
+ /s2 shark:/autofs/export5/testing/test/s2 \
+ /s1/ss1 shark:/autofs/export1 \
+ /s2/ss2 shark:/autofs/export2
+
+and a similarly a direct mount map entry could also be:
+
+/automount/dparse/g1 \
+ / shark:/autofs/export5/testing/test \
+ /s1 shark:/autofs/export/testing/test/s1 \
+ /s2 shark:/autofs/export5/testing/test/s2 \
+ /s1/ss1 shark:/autofs/export2 \
+ /s2/ss2 shark:/autofs/export2
+
+One of the issues with version 4 of autofs was that, when mounting an
+entry with a large number of offsets, possibly with nesting, we needed
+to mount and umount all of the offsets as a single unit. Not really a
+problem, except for people with a large number of offsets in map entries.
+This mechanism is used for the well known "hosts" map and we have seen
+cases (in 2.4) where the available number of mounts are exhausted or
+where the number of privileged ports available is exhausted.
+
+In version 5 we mount only as we go down the tree of offsets and
+similarly for expiring them which resolves the above problem. There is
+somewhat more detail to the implementation but it isn't needed for the
+sake of the problem explanation. The one important detail is that these
+offsets are implemented using the same mechanism as the direct mounts
+above and so the mount points can be covered by a mount.
+
+The current autofs implementation uses an ioctl file descriptor opened
+on the mount point for control operations. The references held by the
+descriptor are accounted for in checks made to determine if a mount is
+in use and is also used to access autofs file system information held
+in the mount super block. So the use of a file handle needs to be
+retained.
+
+
+The Solution
+============
+
+To be able to restart autofs leaving existing direct, indirect and
+offset mounts in place we need to be able to obtain a file handle
+for these potentially covered autofs mount points. Rather than just
+implement an isolated operation it was decided to re-implement the
+existing ioctl interface and add new operations to provide this
+functionality.
+
+In addition, to be able to reconstruct a mount tree that has busy mounts,
+the uid and gid of the last user that triggered the mount needs to be
+available because these can be used as macro substitution variables in
+autofs maps. They are recorded at mount request time and an operation
+has been added to retrieve them.
+
+Since we're re-implementing the control interface, a couple of other
+problems with the existing interface have been addressed. First, when
+a mount or expire operation completes a status is returned to the
+kernel by either a "send ready" or a "send fail" operation. The
+"send fail" operation of the ioctl interface could only ever send
+ENOENT so the re-implementation allows user space to send an actual
+status. Another expensive operation in user space, for those using
+very large maps, is discovering if a mount is present. Usually this
+involves scanning /proc/mounts and since it needs to be done quite
+often it can introduce significant overhead when there are many entries
+in the mount table. An operation to lookup the mount status of a mount
+point dentry (covered or not) has also been added.
+
+Current kernel development policy recommends avoiding the use of the
+ioctl mechanism in favor of systems such as Netlink. An implementation
+using this system was attempted to evaluate its suitability and it was
+found to be inadequate, in this case. The Generic Netlink system was
+used for this as raw Netlink would lead to a significant increase in
+complexity. There's no question that the Generic Netlink system is an
+elegant solution for common case ioctl functions but it's not a complete
+replacement probably because it's primary purpose in life is to be a
+message bus implementation rather than specifically an ioctl replacement.
+While it would be possible to work around this there is one concern
+that lead to the decision to not use it. This is that the autofs
+expire in the daemon has become far to complex because umount
+candidates are enumerated, almost for no other reason than to "count"
+the number of times to call the expire ioctl. This involves scanning
+the mount table which has proved to be a big overhead for users with
+large maps. The best way to improve this is try and get back to the
+way the expire was done long ago. That is, when an expire request is
+issued for a mount (file handle) we should continually call back to
+the daemon until we can't umount any more mounts, then return the
+appropriate status to the daemon. At the moment we just expire one
+mount at a time. A Generic Netlink implementation would exclude this
+possibility for future development due to the requirements of the
+message bus architecture.
+
+
+autofs4 Miscellaneous Device mount control interface
+====================================================
+
+The control interface is opening a device node, typically /dev/autofs.
+
+All the ioctls use a common structure to pass the needed parameter
+information and return operation results:
+
+struct autofs_dev_ioctl {
+ __u32 ver_major;
+ __u32 ver_minor;
+ __u32 size; /* total size of data passed in
+ * including this struct */
+ __s32 ioctlfd; /* automount command fd */
+
+ /* Command parameters */
+
+ union {
+ struct args_protover protover;
+ struct args_protosubver protosubver;
+ struct args_openmount openmount;
+ struct args_ready ready;
+ struct args_fail fail;
+ struct args_setpipefd setpipefd;
+ struct args_timeout timeout;
+ struct args_requester requester;
+ struct args_expire expire;
+ struct args_askumount askumount;
+ struct args_ismountpoint ismountpoint;
+ };
+
+ char path[0];
+};
+
+The ioctlfd field is a mount point file descriptor of an autofs mount
+point. It is returned by the open call and is used by all calls except
+the check for whether a given path is a mount point, where it may
+optionally be used to check a specific mount corresponding to a given
+mount point file descriptor, and when requesting the uid and gid of the
+last successful mount on a directory within the autofs file system.
+
+The anonymous union is used to communicate parameters and results of calls
+made as described below.
+
+The path field is used to pass a path where it is needed and the size field
+is used account for the increased structure length when translating the
+structure sent from user space.
+
+This structure can be initialized before setting specific fields by using
+the void function call init_autofs_dev_ioctl(struct autofs_dev_ioctl *).
+
+All of the ioctls perform a copy of this structure from user space to
+kernel space and return -EINVAL if the size parameter is smaller than
+the structure size itself, -ENOMEM if the kernel memory allocation fails
+or -EFAULT if the copy itself fails. Other checks include a version check
+of the compiled in user space version against the module version and a
+mismatch results in a -EINVAL return. If the size field is greater than
+the structure size then a path is assumed to be present and is checked to
+ensure it begins with a "/" and is NULL terminated, otherwise -EINVAL is
+returned. Following these checks, for all ioctl commands except
+AUTOFS_DEV_IOCTL_VERSION_CMD, AUTOFS_DEV_IOCTL_OPENMOUNT_CMD and
+AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD the ioctlfd is validated and if it is
+not a valid descriptor or doesn't correspond to an autofs mount point
+an error of -EBADF, -ENOTTY or -EINVAL (not an autofs descriptor) is
+returned.
+
+
+The ioctls
+==========
+
+An example of an implementation which uses this interface can be seen
+in autofs version 5.0.4 and later in file lib/dev-ioctl-lib.c of the
+distribution tar available for download from kernel.org in directory
+/pub/linux/daemons/autofs/v5.
+
+The device node ioctl operations implemented by this interface are:
+
+
+AUTOFS_DEV_IOCTL_VERSION
+------------------------
+
+Get the major and minor version of the autofs4 device ioctl kernel module
+implementation. It requires an initialized struct autofs_dev_ioctl as an
+input parameter and sets the version information in the passed in structure.
+It returns 0 on success or the error -EINVAL if a version mismatch is
+detected.
+
+
+AUTOFS_DEV_IOCTL_PROTOVER_CMD and AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD
+------------------------------------------------------------------
+
+Get the major and minor version of the autofs4 protocol version understood
+by loaded module. This call requires an initialized struct autofs_dev_ioctl
+with the ioctlfd field set to a valid autofs mount point descriptor
+and sets the requested version number in structure field protover.version
+and ptotosubver.sub_version respectively. These commands return 0 on
+success or one of the negative error codes if validation fails.
+
+
+AUTOFS_DEV_IOCTL_OPENMOUNT_CMD and AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD
+------------------------------------------------------------------
+
+Obtain and release a file descriptor for an autofs managed mount point
+path. The open call requires an initialized struct autofs_dev_ioctl with
+the the path field set and the size field adjusted appropriately as well
+as the openmount.devid field set to the device number of the autofs mount.
+The device number of an autofs mounted filesystem can be obtained by using
+the AUTOFS_DEV_IOCTL_ISMOUNTPOINT ioctl function by providing the path
+and autofs mount type, as described below. The close call requires an
+initialized struct autofs_dev_ioct with the ioctlfd field set to the
+descriptor obtained from the open call. The release of the file descriptor
+can also be done with close(2) so any open descriptors will also be
+closed at process exit. The close call is included in the implemented
+operations largely for completeness and to provide for a consistent
+user space implementation.
+
+
+AUTOFS_DEV_IOCTL_READY_CMD and AUTOFS_DEV_IOCTL_FAIL_CMD
+--------------------------------------------------------
+
+Return mount and expire result status from user space to the kernel.
+Both of these calls require an initialized struct autofs_dev_ioctl
+with the ioctlfd field set to the descriptor obtained from the open
+call and the ready.token or fail.token field set to the wait queue
+token number, received by user space in the foregoing mount or expire
+request. The fail.status field is set to the status to be returned when
+sending a failure notification with AUTOFS_DEV_IOCTL_FAIL_CMD.
+
+
+AUTOFS_DEV_IOCTL_SETPIPEFD_CMD
+------------------------------
+
+Set the pipe file descriptor used for kernel communication to the daemon.
+Normally this is set at mount time using an option but when reconnecting
+to a existing mount we need to use this to tell the autofs mount about
+the new kernel pipe descriptor. In order to protect mounts against
+incorrectly setting the pipe descriptor we also require that the autofs
+mount be catatonic (see next call).
+
+The call requires an initialized struct autofs_dev_ioctl with the
+ioctlfd field set to the descriptor obtained from the open call and
+the setpipefd.pipefd field set to descriptor of the pipe. On success
+the call also sets the process group id used to identify the controlling
+process (eg. the owning automount(8) daemon) to the process group of
+the caller.
+
+
+AUTOFS_DEV_IOCTL_CATATONIC_CMD
+------------------------------
+
+Make the autofs mount point catatonic. The autofs mount will no longer
+issue mount requests, the kernel communication pipe descriptor is released
+and any remaining waits in the queue released.
+
+The call requires an initialized struct autofs_dev_ioctl with the
+ioctlfd field set to the descriptor obtained from the open call.
+
+
+AUTOFS_DEV_IOCTL_TIMEOUT_CMD
+----------------------------
+
+Set the expire timeout for mounts withing an autofs mount point.
+
+The call requires an initialized struct autofs_dev_ioctl with the
+ioctlfd field set to the descriptor obtained from the open call.
+The timeout.timeout field is set to the desired timeout and this
+field is set to the value of the value of the current timeout of
+the mount upon successful completion.
+
+
+AUTOFS_DEV_IOCTL_REQUESTER_CMD
+------------------------------
+
+Return the uid and gid of the last process to successfully trigger a the
+mount on the given path dentry.
+
+The call requires an initialized struct autofs_dev_ioctl with the path
+field set to the mount point in question and the size field adjusted
+appropriately as well as the ioctlfd field set to the descriptor obtained
+from the open call. Upon return the struct fields requester.uid and
+requester.gid contain the uid and gid respectively.
+
+When reconstructing an autofs mount tree with active mounts we need to
+re-connect to mounts that may have used the original process uid and
+gid (or string variations of them) for mount lookups within the map entry.
+This call provides the ability to obtain this uid and gid so they may be
+used by user space for the mount map lookups.
+
+
+AUTOFS_DEV_IOCTL_EXPIRE_CMD
+---------------------------
+
+Issue an expire request to the kernel for an autofs mount. Typically
+this ioctl is called until no further expire candidates are found.
+
+The call requires an initialized struct autofs_dev_ioctl with the
+ioctlfd field set to the descriptor obtained from the open call. In
+addition an immediate expire, independent of the mount timeout, can be
+requested by setting the expire.how field to 1. If no expire candidates
+can be found the ioctl returns -1 with errno set to EAGAIN.
+
+This call causes the kernel module to check the mount corresponding
+to the given ioctlfd for mounts that can be expired, issues an expire
+request back to the daemon and waits for completion.
+
+AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD
+------------------------------
+
+Checks if an autofs mount point is in use.
+
+The call requires an initialized struct autofs_dev_ioctl with the
+ioctlfd field set to the descriptor obtained from the open call and
+it returns the result in the askumount.may_umount field, 1 for busy
+and 0 otherwise.
+
+
+AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
+---------------------------------
+
+Check if the given path is a mountpoint.
+
+The call requires an initialized struct autofs_dev_ioctl. There are two
+possible variations. Both use the path field set to the path of the mount
+point to check and the size field must be adjusted appropriately. One uses
+the ioctlfd field to identify a specific mount point to check while the
+other variation uses the path and optionaly the ismountpoint.in.type
+field set to an autofs mount type. The call returns 1 if this is a mount
+point and sets the ismountpoint.out.devid field to the device number of
+the mount and the ismountpoint.out.magic field to the relevant super
+block magic number (described below) or 0 if it isn't a mountpoint. In
+both cases the the device number (as returned by new_encode_dev()) is
+returned in the ismountpoint.out.devid field.
+
+If supplied with a file descriptor we're looking for a specific mount,
+not necessarily at the top of the mounted stack. In this case the path
+the descriptor corresponds to is considered a mountpoint if it is itself
+a mountpoint or contains a mount, such as a multi-mount without a root
+mount. In this case we return 1 if the descriptor corresponds to a mount
+point and and also returns the super magic of the covering mount if there
+is one or 0 if it isn't a mountpoint.
+
+If a path is supplied (and the ioctlfd field is set to -1) then the path
+is looked up and is checked to see if it is the root of a mount. If a
+type is also given we are looking for a particular autofs mount and if
+a match isn't found a fail is returned. If the the located path is the
+root of a mount 1 is returned along with the super magic of the mount
+or 0 otherwise.
+
--- linux-2.6.27.orig/fs/autofs4/Makefile
+++ linux-2.6.27/fs/autofs4/Makefile
@@ -4,4 +4,4 @@
obj-$(CONFIG_AUTOFS4_FS) += autofs4.o
-autofs4-objs := init.o inode.o root.o symlink.o waitq.o expire.o
+autofs4-objs := init.o inode.o root.o symlink.o waitq.o expire.o dev-ioctl.o
--- /dev/null
+++ linux-2.6.27/fs/autofs4/dev-ioctl.c
@@ -0,0 +1,841 @@
+/*
+ * Copyright 2008 Red Hat, Inc. All rights reserved.
+ * Copyright 2008 Ian Kent <raven@themaw.net>
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ */
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/namei.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/sched.h>
+#include <linux/compat.h>
+#include <linux/syscalls.h>
+#include <linux/smp_lock.h>
+#include <linux/magic.h>
+#include <linux/dcache.h>
+#include <linux/uaccess.h>
+
+#include "autofs_i.h"
+
+/*
+ * This module implements an interface for routing autofs ioctl control
+ * commands via a miscellaneous device file.
+ *
+ * The alternate interface is needed because we need to be able open
+ * an ioctl file descriptor on an autofs mount that may be covered by
+ * another mount. This situation arises when starting automount(8)
+ * or other user space daemon which uses direct mounts or offset
+ * mounts (used for autofs lazy mount/umount of nested mount trees),
+ * which have been left busy at at service shutdown.
+ */
+
+#define AUTOFS_DEV_IOCTL_SIZE sizeof(struct autofs_dev_ioctl)
+
+typedef int (*ioctl_fn)(struct file *,
+struct autofs_sb_info *, struct autofs_dev_ioctl *);
+
+static int check_name(const char *name)
+{
+ if (!strchr(name, '/'))
+ return -EINVAL;
+ return 0;
+}
+
+/*
+ * Check a string doesn't overrun the chunk of
+ * memory we copied from user land.
+ */
+static int invalid_str(char *str, void *end)
+{
+ while ((void *) str <= end)
+ if (!*str++)
+ return 0;
+ return -EINVAL;
+}
+
+/*
+ * Check that the user compiled against correct version of autofs
+ * misc device code.
+ *
+ * As well as checking the version compatibility this always copies
+ * the kernel interface version out.
+ */
+static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
+{
+ int err = 0;
+
+ if ((AUTOFS_DEV_IOCTL_VERSION_MAJOR != param->ver_major) ||
+ (AUTOFS_DEV_IOCTL_VERSION_MINOR < param->ver_minor)) {
+ AUTOFS_WARN("ioctl control interface version mismatch: "
+ "kernel(%u.%u), user(%u.%u), cmd(%d)",
+ AUTOFS_DEV_IOCTL_VERSION_MAJOR,
+ AUTOFS_DEV_IOCTL_VERSION_MINOR,
+ param->ver_major, param->ver_minor, cmd);
+ err = -EINVAL;
+ }
+
+ /* Fill in the kernel version. */
+ param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
+ param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
+
+ return err;
+}
+
+/*
+ * Copy parameter control struct, including a possible path allocated
+ * at the end of the struct.
+ */
+static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
+{
+ struct autofs_dev_ioctl tmp, *ads;
+
+ if (copy_from_user(&tmp, in, sizeof(tmp)))
+ return ERR_PTR(-EFAULT);
+
+ if (tmp.size < sizeof(tmp))
+ return ERR_PTR(-EINVAL);
+
+ ads = kmalloc(tmp.size, GFP_KERNEL);
+ if (!ads)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(ads, in, tmp.size)) {
+ kfree(ads);
+ return ERR_PTR(-EFAULT);
+ }
+
+ return ads;
+}
+
+static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
+{
+ kfree(param);
+ return;
+}
+
+/*
+ * Check sanity of parameter control fields and if a path is present
+ * check that it is terminated and contains at least one "/".
+ */
+static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
+{
+ int err;
+
+ if ((err = check_dev_ioctl_version(cmd, param))) {
+ AUTOFS_WARN("invalid device control module version "
+ "supplied for cmd(0x%08x)", cmd);
+ goto out;
+ }
+
+ if (param->size > sizeof(*param)) {
+ err = invalid_str(param->path,
+ (void *) ((size_t) param + param->size));
+ if (err) {
+ AUTOFS_WARN(
+ "path string terminator missing for cmd(0x%08x)",
+ cmd);
+ goto out;
+ }
+
+ err = check_name(param->path);
+ if (err) {
+ AUTOFS_WARN("invalid path supplied for cmd(0x%08x)",
+ cmd);
+ goto out;
+ }
+ }
+
+ err = 0;
+out:
+ return err;
+}
+
+/*
+ * Get the autofs super block info struct from the file opened on
+ * the autofs mount point.
+ */
+static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
+{
+ struct autofs_sb_info *sbi = NULL;
+ struct inode *inode;
+
+ if (f) {
+ inode = f->f_path.dentry->d_inode;
+ sbi = autofs4_sbi(inode->i_sb);
+ }
+ return sbi;
+}
+
+/* Return autofs module protocol version */
+static int autofs_dev_ioctl_protover(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ param->protover.version = sbi->version;
+ return 0;
+}
+
+/* Return autofs module protocol sub version */
+static int autofs_dev_ioctl_protosubver(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ param->protosubver.sub_version = sbi->sub_version;
+ return 0;
+}
+
+/*
+ * Walk down the mount stack looking for an autofs mount that
+ * has the requested device number (aka. new_encode_dev(sb->s_dev).
+ */
+static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+ struct super_block *sb;
+ dev_t s_dev;
+ unsigned int err;
+
+ err = -ENOENT;
+
+ /* Lookup the dentry name at the base of our mount point */
+ dentry = d_lookup(nd->path.dentry, &nd->last);
+ if (!dentry)
+ goto out;
+
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
+
+ /* And follow the mount stack looking for our autofs mount */
+ while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
+ inode = nd->path.dentry->d_inode;
+ if (!inode)
+ break;
+
+ sb = inode->i_sb;
+ s_dev = new_encode_dev(sb->s_dev);
+ if (devno == s_dev) {
+ if (sb->s_magic == AUTOFS_SUPER_MAGIC) {
+ err = 0;
+ break;
+ }
+ }
+ }
+out:
+ return err;
+}
+
+/*
+ * Walk down the mount stack looking for an autofs mount that
+ * has the requested mount type (ie. indirect, direct or offset).
+ */
+static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type)
+{
+ struct dentry *dentry;
+ struct autofs_info *ino;
+ unsigned int err;
+
+ err = -ENOENT;
+
+ /* Lookup the dentry name at the base of our mount point */
+ dentry = d_lookup(nd->path.dentry, &nd->last);
+ if (!dentry)
+ goto out;
+
+ dput(nd->path.dentry);
+ nd->path.dentry = dentry;
+
+ /* And follow the mount stack looking for our autofs mount */
+ while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
+ ino = autofs4_dentry_ino(nd->path.dentry);
+ if (ino && ino->sbi->type & type) {
+ err = 0;
+ break;
+ }
+ }
+out:
+ return err;
+}
+
+static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file)
+{
+ struct files_struct *files = current->files;
+ struct fdtable *fdt;
+
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ BUG_ON(fdt->fd[fd] != NULL);
+ rcu_assign_pointer(fdt->fd[fd], file);
+ FD_SET(fd, fdt->close_on_exec);
+ spin_unlock(&files->file_lock);
+}
+
+
+/*
+ * Open a file descriptor on the autofs mount point corresponding
+ * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
+ */
+static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid)
+{
+ struct file *filp;
+ struct nameidata nd;
+ int err, fd;
+
+ fd = get_unused_fd();
+ if (likely(fd >= 0)) {
+ /* Get nameidata of the parent directory */
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ /*
+ * Search down, within the parent, looking for an
+ * autofs super block that has the device number
+ * corresponding to the autofs fs we want to open.
+ */
+ err = autofs_dev_ioctl_find_super(&nd, devid);
+ if (err) {
+ path_put(&nd.path);
+ goto out;
+ }
+
+ filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY);
+ if (IS_ERR(filp)) {
+ err = PTR_ERR(filp);
+ goto out;
+ }
+
+ autofs_dev_ioctl_fd_install(fd, filp);
+ }
+
+ return fd;
+
+out:
+ put_unused_fd(fd);
+ return err;
+}
+
+/* Open a file descriptor on an autofs mount point */
+static int autofs_dev_ioctl_openmount(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ const char *path;
+ dev_t devid;
+ int err, fd;
+
+ /* param->path has already been checked */
+ if (!param->openmount.devid)
+ return -EINVAL;
+
+ param->ioctlfd = -1;
+
+ path = param->path;
+ devid = param->openmount.devid;
+
+ err = 0;
+ fd = autofs_dev_ioctl_open_mountpoint(path, devid);
+ if (unlikely(fd < 0)) {
+ err = fd;
+ goto out;
+ }
+
+ param->ioctlfd = fd;
+out:
+ return err;
+}
+
+/* Close file descriptor allocated above (user can also use close(2)). */
+static int autofs_dev_ioctl_closemount(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ return sys_close(param->ioctlfd);
+}
+
+/*
+ * Send "ready" status for an existing wait (either a mount or an expire
+ * request).
+ */
+static int autofs_dev_ioctl_ready(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ autofs_wqt_t token;
+
+ token = (autofs_wqt_t) param->ready.token;
+ return autofs4_wait_release(sbi, token, 0);
+}
+
+/*
+ * Send "fail" status for an existing wait (either a mount or an expire
+ * request).
+ */
+static int autofs_dev_ioctl_fail(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ autofs_wqt_t token;
+ int status;
+
+ token = (autofs_wqt_t) param->fail.token;
+ status = param->fail.status ? param->fail.status : -ENOENT;
+ return autofs4_wait_release(sbi, token, status);
+}
+
+/*
+ * Set the pipe fd for kernel communication to the daemon.
+ *
+ * Normally this is set at mount using an option but if we
+ * are reconnecting to a busy mount then we need to use this
+ * to tell the autofs mount about the new kernel pipe fd. In
+ * order to protect mounts against incorrectly setting the
+ * pipefd we also require that the autofs mount be catatonic.
+ *
+ * This also sets the process group id used to identify the
+ * controlling process (eg. the owning automount(8) daemon).
+ */
+static int autofs_dev_ioctl_setpipefd(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ int pipefd;
+ int err = 0;
+
+ if (param->setpipefd.pipefd == -1)
+ return -EINVAL;
+
+ pipefd = param->setpipefd.pipefd;
+
+ mutex_lock(&sbi->wq_mutex);
+ if (!sbi->catatonic) {
+ mutex_unlock(&sbi->wq_mutex);
+ return -EBUSY;
+ } else {
+ struct file *pipe = fget(pipefd);
+ if (!pipe->f_op || !pipe->f_op->write) {
+ err = -EPIPE;
+ fput(pipe);
+ goto out;
+ }
+ sbi->oz_pgrp = task_pgrp_nr(current);
+ sbi->pipefd = pipefd;
+ sbi->pipe = pipe;
+ sbi->catatonic = 0;
+ }
+out:
+ mutex_unlock(&sbi->wq_mutex);
+ return err;
+}
+
+/*
+ * Make the autofs mount point catatonic, no longer responsive to
+ * mount requests. Also closes the kernel pipe file descriptor.
+ */
+static int autofs_dev_ioctl_catatonic(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ autofs4_catatonic_mode(sbi);
+ return 0;
+}
+
+/* Set the autofs mount timeout */
+static int autofs_dev_ioctl_timeout(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ unsigned long timeout;
+
+ timeout = param->timeout.timeout;
+ param->timeout.timeout = sbi->exp_timeout / HZ;
+ sbi->exp_timeout = timeout * HZ;
+ return 0;
+}
+
+/*
+ * Return the uid and gid of the last request for the mount
+ *
+ * When reconstructing an autofs mount tree with active mounts
+ * we need to re-connect to mounts that may have used the original
+ * process uid and gid (or string variations of them) for mount
+ * lookups within the map entry.
+ */
+static int autofs_dev_ioctl_requester(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ struct autofs_info *ino;
+ struct nameidata nd;
+ const char *path;
+ dev_t devid;
+ int err = -ENOENT;
+
+ if (param->size <= sizeof(*param)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ path = param->path;
+ devid = sbi->sb->s_dev;
+
+ param->requester.uid = param->requester.gid = -1;
+
+ /* Get nameidata of the parent directory */
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ err = autofs_dev_ioctl_find_super(&nd, devid);
+ if (err)
+ goto out_release;
+
+ ino = autofs4_dentry_ino(nd.path.dentry);
+ if (ino) {
+ err = 0;
+ autofs4_expire_wait(nd.path.dentry);
+ spin_lock(&sbi->fs_lock);
+ param->requester.uid = ino->uid;
+ param->requester.gid = ino->gid;
+ spin_unlock(&sbi->fs_lock);
+ }
+
+out_release:
+ path_put(&nd.path);
+out:
+ return err;
+}
+
+/*
+ * Call repeatedly until it returns -EAGAIN, meaning there's nothing
+ * more that can be done.
+ */
+static int autofs_dev_ioctl_expire(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ struct vfsmount *mnt;
+ int how;
+
+ how = param->expire.how;
+ mnt = fp->f_path.mnt;
+
+ return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how);
+}
+
+/* Check if autofs mount point is in use */
+static int autofs_dev_ioctl_askumount(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ param->askumount.may_umount = 0;
+ if (may_umount(fp->f_path.mnt))
+ param->askumount.may_umount = 1;
+ return 0;
+}
+
+/*
+ * Check if the given path is a mountpoint.
+ *
+ * If we are supplied with the file descriptor of an autofs
+ * mount we're looking for a specific mount. In this case
+ * the path is considered a mountpoint if it is itself a
+ * mountpoint or contains a mount, such as a multi-mount
+ * without a root mount. In this case we return 1 if the
+ * path is a mount point and the super magic of the covering
+ * mount if there is one or 0 if it isn't a mountpoint.
+ *
+ * If we aren't supplied with a file descriptor then we
+ * lookup the nameidata of the path and check if it is the
+ * root of a mount. If a type is given we are looking for
+ * a particular autofs mount and if we don't find a match
+ * we return fail. If the located nameidata path is the
+ * root of a mount we return 1 along with the super magic
+ * of the mount or 0 otherwise.
+ *
+ * In both cases the the device number (as returned by
+ * new_encode_dev()) is also returned.
+ */
+static int autofs_dev_ioctl_ismountpoint(struct file *fp,
+ struct autofs_sb_info *sbi,
+ struct autofs_dev_ioctl *param)
+{
+ struct nameidata nd;
+ const char *path;
+ unsigned int type;
+ unsigned int devid, magic;
+ int err = -ENOENT;
+
+ if (param->size <= sizeof(*param)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ path = param->path;
+ type = param->ismountpoint.in.type;
+
+ param->ismountpoint.out.devid = devid = 0;
+ param->ismountpoint.out.magic = magic = 0;
+
+ if (!fp || param->ioctlfd == -1) {
+ if (autofs_type_any(type)) {
+ struct super_block *sb;
+
+ err = path_lookup(path, LOOKUP_FOLLOW, &nd);
+ if (err)
+ goto out;
+
+ sb = nd.path.dentry->d_sb;
+ devid = new_encode_dev(sb->s_dev);
+ } else {
+ struct autofs_info *ino;
+
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ err = autofs_dev_ioctl_find_sbi_type(&nd, type);
+ if (err)
+ goto out_release;
+
+ ino = autofs4_dentry_ino(nd.path.dentry);
+ devid = autofs4_get_dev(ino->sbi);
+ }
+
+ err = 0;
+ if (nd.path.dentry->d_inode &&
+ nd.path.mnt->mnt_root == nd.path.dentry) {
+ err = 1;
+ magic = nd.path.dentry->d_inode->i_sb->s_magic;
+ }
+ } else {
+ dev_t dev = autofs4_get_dev(sbi);
+
+ err = path_lookup(path, LOOKUP_PARENT, &nd);
+ if (err)
+ goto out;
+
+ err = autofs_dev_ioctl_find_super(&nd, dev);
+ if (err)
+ goto out_release;
+
+ devid = dev;
+
+ err = have_submounts(nd.path.dentry);
+
+ if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) {
+ if (follow_down(&nd.path.mnt, &nd.path.dentry)) {
+ struct inode *inode = nd.path.dentry->d_inode;
+ magic = inode->i_sb->s_magic;
+ }
+ }
+ }
+
+ param->ismountpoint.out.devid = devid;
+ param->ismountpoint.out.magic = magic;
+
+out_release:
+ path_put(&nd.path);
+out:
+ return err;
+}
+
+/*
+ * Our range of ioctl numbers isn't 0 based so we need to shift
+ * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
+ * lookup.
+ */
+#define cmd_idx(cmd) (cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
+
+static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
+{
+ static struct {
+ int cmd;
+ ioctl_fn fn;
+ } _ioctls[] = {
+ {cmd_idx(AUTOFS_DEV_IOCTL_VERSION_CMD), NULL},
+ {cmd_idx(AUTOFS_DEV_IOCTL_PROTOVER_CMD),
+ autofs_dev_ioctl_protover},
+ {cmd_idx(AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD),
+ autofs_dev_ioctl_protosubver},
+ {cmd_idx(AUTOFS_DEV_IOCTL_OPENMOUNT_CMD),
+ autofs_dev_ioctl_openmount},
+ {cmd_idx(AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD),
+ autofs_dev_ioctl_closemount},
+ {cmd_idx(AUTOFS_DEV_IOCTL_READY_CMD),
+ autofs_dev_ioctl_ready},
+ {cmd_idx(AUTOFS_DEV_IOCTL_FAIL_CMD),
+ autofs_dev_ioctl_fail},
+ {cmd_idx(AUTOFS_DEV_IOCTL_SETPIPEFD_CMD),
+ autofs_dev_ioctl_setpipefd},
+ {cmd_idx(AUTOFS_DEV_IOCTL_CATATONIC_CMD),
+ autofs_dev_ioctl_catatonic},
+ {cmd_idx(AUTOFS_DEV_IOCTL_TIMEOUT_CMD),
+ autofs_dev_ioctl_timeout},
+ {cmd_idx(AUTOFS_DEV_IOCTL_REQUESTER_CMD),
+ autofs_dev_ioctl_requester},
+ {cmd_idx(AUTOFS_DEV_IOCTL_EXPIRE_CMD),
+ autofs_dev_ioctl_expire},
+ {cmd_idx(AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD),
+ autofs_dev_ioctl_askumount},
+ {cmd_idx(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD),
+ autofs_dev_ioctl_ismountpoint}
+ };
+ unsigned int idx = cmd_idx(cmd);
+
+ return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx].fn;
+}
+
+/* ioctl dispatcher */
+static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __user *user)
+{
+ struct autofs_dev_ioctl *param;
+ struct file *fp;
+ struct autofs_sb_info *sbi;
+ unsigned int cmd_first, cmd;
+ ioctl_fn fn = NULL;
+ int err = 0;
+
+ /* only root can play with this */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
+ cmd = _IOC_NR(command);
+
+ if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
+ cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) {
+ return -ENOTTY;
+ }
+
+ /* Copy the parameters into kernel space. */
+ param = copy_dev_ioctl(user);
+ if (IS_ERR(param))
+ return PTR_ERR(param);
+
+ err = validate_dev_ioctl(command, param);
+ if (err)
+ goto out;
+
+ /* The validate routine above always sets the version */
+ if (cmd == AUTOFS_DEV_IOCTL_VERSION_CMD)
+ goto done;
+
+ fn = lookup_dev_ioctl(cmd);
+ if (!fn) {
+ AUTOFS_WARN("unknown command 0x%08x", command);
+ return -ENOTTY;
+ }
+
+ fp = NULL;
+ sbi = NULL;
+
+ /*
+ * For obvious reasons the openmount can't have a file
+ * descriptor yet. We don't take a reference to the
+ * file during close to allow for immediate release.
+ */
+ if (cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
+ cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
+ fp = fget(param->ioctlfd);
+ if (!fp) {
+ if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
+ goto cont;
+ err = -EBADF;
+ goto out;
+ }
+
+ if (!fp->f_op) {
+ err = -ENOTTY;
+ fput(fp);
+ goto out;
+ }
+
+ sbi = autofs_dev_ioctl_sbi(fp);
+ if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
+ err = -EINVAL;
+ fput(fp);
+ goto out;
+ }
+
+ /*
+ * Admin needs to be able to set the mount catatonic in
+ * order to be able to perform the re-open.
+ */
+ if (!autofs4_oz_mode(sbi) &&
+ cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
+ err = -EACCES;
+ fput(fp);
+ goto out;
+ }
+ }
+cont:
+ err = fn(fp, sbi, param);
+
+ if (fp)
+ fput(fp);
+done:
+ if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
+ err = -EFAULT;
+out:
+ free_dev_ioctl(param);
+ return err;
+}
+
+static long autofs_dev_ioctl(struct file *file, uint command, ulong u)
+{
+ int err;
+ err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
+ return (long) err;
+}
+
+#ifdef CONFIG_COMPAT
+static long autofs_dev_ioctl_compat(struct file *file, uint command, ulong u)
+{
+ return (long) autofs_dev_ioctl(file, command, (ulong) compat_ptr(u));
+}
+#else
+#define autofs_dev_ioctl_compat NULL
+#endif
+
+static const struct file_operations _dev_ioctl_fops = {
+ .unlocked_ioctl = autofs_dev_ioctl,
+ .compat_ioctl = autofs_dev_ioctl_compat,
+ .owner = THIS_MODULE,
+};
+
+static struct miscdevice _autofs_dev_ioctl_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = AUTOFS_DEVICE_NAME,
+ .fops = &_dev_ioctl_fops
+};
+
+/* Register/deregister misc character device */
+int autofs_dev_ioctl_init(void)
+{
+ int r;
+
+ r = misc_register(&_autofs_dev_ioctl_misc);
+ if (r) {
+ AUTOFS_ERROR("misc_register failed for control device");
+ return r;
+ }
+
+ return 0;
+}
+
+void autofs_dev_ioctl_exit(void)
+{
+ misc_deregister(&_autofs_dev_ioctl_misc);
+ return;
+}
+
--- linux-2.6.27.orig/fs/autofs4/init.c
+++ linux-2.6.27/fs/autofs4/init.c
@@ -29,11 +29,20 @@ static struct file_system_type autofs_fs
static int __init init_autofs4_fs(void)
{
- return register_filesystem(&autofs_fs_type);
+ int err;
+
+ err = register_filesystem(&autofs_fs_type);
+ if (err)
+ return err;
+
+ autofs_dev_ioctl_init();
+
+ return err;
}
static void __exit exit_autofs4_fs(void)
{
+ autofs_dev_ioctl_exit();
unregister_filesystem(&autofs_fs_type);
}
--- /dev/null
+++ linux-2.6.27/include/linux/auto_dev-ioctl.h
@@ -0,0 +1,229 @@
+/*
+ * Copyright 2008 Red Hat, Inc. All rights reserved.
+ * Copyright 2008 Ian Kent <raven@themaw.net>
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ */
+
+#ifndef _LINUX_AUTO_DEV_IOCTL_H
+#define _LINUX_AUTO_DEV_IOCTL_H
+
+#include <linux/auto_fs.h>
+
+#ifdef __KERNEL__
+#include <linux/string.h>
+#else
+#include <string.h>
+#endif /* __KERNEL__ */
+
+#define AUTOFS_DEVICE_NAME "autofs"
+
+#define AUTOFS_DEV_IOCTL_VERSION_MAJOR 1
+#define AUTOFS_DEV_IOCTL_VERSION_MINOR 0
+
+#define AUTOFS_DEVID_LEN 16
+
+#define AUTOFS_DEV_IOCTL_SIZE sizeof(struct autofs_dev_ioctl)
+
+/*
+ * An ioctl interface for autofs mount point control.
+ */
+
+struct args_protover {
+ __u32 version;
+};
+
+struct args_protosubver {
+ __u32 sub_version;
+};
+
+struct args_openmount {
+ __u32 devid;
+};
+
+struct args_ready {
+ __u32 token;
+};
+
+struct args_fail {
+ __u32 token;
+ __s32 status;
+};
+
+struct args_setpipefd {
+ __s32 pipefd;
+};
+
+struct args_timeout {
+ __u64 timeout;
+};
+
+struct args_requester {
+ __u32 uid;
+ __u32 gid;
+};
+
+struct args_expire {
+ __u32 how;
+};
+
+struct args_askumount {
+ __u32 may_umount;
+};
+
+struct args_ismountpoint {
+ union {
+ struct args_in {
+ __u32 type;
+ } in;
+ struct args_out {
+ __u32 devid;
+ __u32 magic;
+ } out;
+ };
+};
+
+/*
+ * All the ioctls use this structure.
+ * When sending a path size must account for the total length
+ * of the chunk of memory otherwise is is the size of the
+ * structure.
+ */
+
+struct autofs_dev_ioctl {
+ __u32 ver_major;
+ __u32 ver_minor;
+ __u32 size; /* total size of data passed in
+ * including this struct */
+ __s32 ioctlfd; /* automount command fd */
+
+ /* Command parameters */
+
+ union {
+ struct args_protover protover;
+ struct args_protosubver protosubver;
+ struct args_openmount openmount;
+ struct args_ready ready;
+ struct args_fail fail;
+ struct args_setpipefd setpipefd;
+ struct args_timeout timeout;
+ struct args_requester requester;
+ struct args_expire expire;
+ struct args_askumount askumount;
+ struct args_ismountpoint ismountpoint;
+ };
+
+ char path[0];
+};
+
+static inline void init_autofs_dev_ioctl(struct autofs_dev_ioctl *in)
+{
+ memset(in, 0, sizeof(struct autofs_dev_ioctl));
+ in->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
+ in->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
+ in->size = sizeof(struct autofs_dev_ioctl);
+ in->ioctlfd = -1;
+ return;
+}
+
+/*
+ * If you change this make sure you make the corresponding change
+ * to autofs-dev-ioctl.c:lookup_ioctl()
+ */
+enum {
+ /* Get various version info */
+ AUTOFS_DEV_IOCTL_VERSION_CMD = 0x71,
+ AUTOFS_DEV_IOCTL_PROTOVER_CMD,
+ AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD,
+
+ /* Open mount ioctl fd */
+ AUTOFS_DEV_IOCTL_OPENMOUNT_CMD,
+
+ /* Close mount ioctl fd */
+ AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD,
+
+ /* Mount/expire status returns */
+ AUTOFS_DEV_IOCTL_READY_CMD,
+ AUTOFS_DEV_IOCTL_FAIL_CMD,
+
+ /* Activate/deactivate autofs mount */
+ AUTOFS_DEV_IOCTL_SETPIPEFD_CMD,
+ AUTOFS_DEV_IOCTL_CATATONIC_CMD,
+
+ /* Expiry timeout */
+ AUTOFS_DEV_IOCTL_TIMEOUT_CMD,
+
+ /* Get mount last requesting uid and gid */
+ AUTOFS_DEV_IOCTL_REQUESTER_CMD,
+
+ /* Check for eligible expire candidates */
+ AUTOFS_DEV_IOCTL_EXPIRE_CMD,
+
+ /* Request busy status */
+ AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD,
+
+ /* Check if path is a mountpoint */
+ AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD,
+};
+
+#define AUTOFS_IOCTL 0x93
+
+#define AUTOFS_DEV_IOCTL_VERSION \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_VERSION_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_PROTOVER \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_PROTOVER_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_PROTOSUBVER \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_OPENMOUNT \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_OPENMOUNT_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_CLOSEMOUNT \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_READY \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_READY_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_FAIL \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_FAIL_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_SETPIPEFD \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_SETPIPEFD_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_CATATONIC \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_CATATONIC_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_TIMEOUT \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_TIMEOUT_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_REQUESTER \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_REQUESTER_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_EXPIRE \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_EXPIRE_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_ASKUMOUNT \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD, struct autofs_dev_ioctl)
+
+#define AUTOFS_DEV_IOCTL_ISMOUNTPOINT \
+ _IOWR(AUTOFS_IOCTL, \
+ AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD, struct autofs_dev_ioctl)
+
+#endif /* _LINUX_AUTO_DEV_IOCTL_H */
--- linux-2.6.27.orig/fs/autofs4/root.c
+++ linux-2.6.27/fs/autofs4/root.c
@@ -485,22 +485,6 @@ static struct dentry *autofs4_lookup(str
DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
- expiring = autofs4_lookup_expiring(sbi, dentry->d_parent, &dentry->d_name);
- if (expiring) {
- /*
- * If we are racing with expire the request might not
- * be quite complete but the directory has been removed
- * so it must have been successful, so just wait for it.
- */
- ino = autofs4_dentry_ino(expiring);
- autofs4_expire_wait(expiring);
- spin_lock(&sbi->lookup_lock);
- if (!list_empty(&ino->expiring))
- list_del_init(&ino->expiring);
- spin_unlock(&sbi->lookup_lock);
- dput(expiring);
- }
-
unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name);
if (unhashed)
dentry = unhashed;
@@ -538,14 +522,31 @@ static struct dentry *autofs4_lookup(str
}
if (!oz_mode) {
+ mutex_unlock(&dir->i_mutex);
+ expiring = autofs4_lookup_expiring(sbi,
+ dentry->d_parent,
+ &dentry->d_name);
+ if (expiring) {
+ /*
+ * If we are racing with expire the request might not
+ * be quite complete but the directory has been removed
+ * so it must have been successful, so just wait for it.
+ */
+ ino = autofs4_dentry_ino(expiring);
+ autofs4_expire_wait(expiring);
+ spin_lock(&sbi->lookup_lock);
+ if (!list_empty(&ino->expiring))
+ list_del_init(&ino->expiring);
+ spin_unlock(&sbi->lookup_lock);
+ dput(expiring);
+ }
+
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
- if (dentry->d_op && dentry->d_op->d_revalidate) {
- mutex_unlock(&dir->i_mutex);
+ if (dentry->d_op && dentry->d_op->d_revalidate)
(dentry->d_op->d_revalidate)(dentry, nd);
- mutex_lock(&dir->i_mutex);
- }
+ mutex_lock(&dir->i_mutex);
}
/*
--- linux-2.6.27.orig/include/linux/auto_fs.h
+++ linux-2.6.27/include/linux/auto_fs.h
@@ -17,11 +17,13 @@
#ifdef __KERNEL__
#include <linux/fs.h>
#include <linux/limits.h>
+#include <linux/types.h>
+#include <linux/ioctl.h>
+#else
#include <asm/types.h>
+#include <sys/ioctl.h>
#endif /* __KERNEL__ */
-#include <linux/ioctl.h>
-
/* This file describes autofs v3 */
#define AUTOFS_PROTO_VERSION 3