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[PATCH] autofs4: add v5 follow_link mount trigger method
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This patch adds a follow_link inode method for the root of an autofs direct
mount trigger.  It also adds the corresponding mount options and updates the
show_mount method.

Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Ian Kent authored and Linus Torvalds committed Mar 27, 2006
1 parent 051d381 commit 34ca959
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Showing 3 changed files with 103 additions and 21 deletions.
8 changes: 8 additions & 0 deletions fs/autofs4/autofs_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
* linux/fs/autofs/autofs_i.h
*
* Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
* Copyright 2005-2006 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
Expand Down Expand Up @@ -84,6 +85,10 @@ struct autofs_wait_queue {

#define AUTOFS_SBI_MAGIC 0x6d4a556d

#define AUTOFS_TYP_INDIRECT 0x0001
#define AUTOFS_TYP_DIRECT 0x0002
#define AUTOFS_TYP_OFFSET 0x0004

struct autofs_sb_info {
u32 magic;
struct dentry *root;
Expand All @@ -96,6 +101,7 @@ struct autofs_sb_info {
int min_proto;
int max_proto;
unsigned long exp_timeout;
unsigned int type;
int reghost_enabled;
int needs_reghost;
struct super_block *sb;
Expand Down Expand Up @@ -162,6 +168,8 @@ int autofs4_expire_multi(struct super_block *, struct vfsmount *,
extern struct inode_operations autofs4_symlink_inode_operations;
extern struct inode_operations autofs4_dir_inode_operations;
extern struct inode_operations autofs4_root_inode_operations;
extern struct inode_operations autofs4_indirect_root_inode_operations;
extern struct inode_operations autofs4_direct_root_inode_operations;
extern struct file_operations autofs4_dir_operations;
extern struct file_operations autofs4_root_operations;

Expand Down
52 changes: 43 additions & 9 deletions fs/autofs4/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
* linux/fs/autofs/inode.c
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
* Copyright 2005-2006 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
Expand Down Expand Up @@ -177,6 +178,13 @@ static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
seq_printf(m, ",minproto=%d", sbi->min_proto);
seq_printf(m, ",maxproto=%d", sbi->max_proto);

if (sbi->type & AUTOFS_TYP_OFFSET)
seq_printf(m, ",offset");
else if (sbi->type & AUTOFS_TYP_DIRECT)
seq_printf(m, ",direct");
else
seq_printf(m, ",indirect");

return 0;
}

Expand All @@ -186,7 +194,8 @@ static struct super_operations autofs4_sops = {
.show_options = autofs4_show_options,
};

enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
Opt_indirect, Opt_direct, Opt_offset};

static match_table_t tokens = {
{Opt_fd, "fd=%u"},
Expand All @@ -195,11 +204,15 @@ static match_table_t tokens = {
{Opt_pgrp, "pgrp=%u"},
{Opt_minproto, "minproto=%u"},
{Opt_maxproto, "maxproto=%u"},
{Opt_indirect, "indirect"},
{Opt_direct, "direct"},
{Opt_offset, "offset"},
{Opt_err, NULL}
};

static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
pid_t *pgrp, int *minproto, int *maxproto)
pid_t *pgrp, unsigned int *type,
int *minproto, int *maxproto)
{
char *p;
substring_t args[MAX_OPT_ARGS];
Expand Down Expand Up @@ -253,6 +266,15 @@ static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
return 1;
*maxproto = option;
break;
case Opt_indirect:
*type = AUTOFS_TYP_INDIRECT;
break;
case Opt_direct:
*type = AUTOFS_TYP_DIRECT;
break;
case Opt_offset:
*type = AUTOFS_TYP_DIRECT | AUTOFS_TYP_OFFSET;
break;
default:
return 1;
}
Expand All @@ -271,6 +293,11 @@ static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
return ino;
}

void autofs4_dentry_release(struct dentry *);
static struct dentry_operations autofs4_sb_dentry_operations = {
.d_release = autofs4_dentry_release,
};

int autofs4_fill_super(struct super_block *s, void *data, int silent)
{
struct inode * root_inode;
Expand All @@ -297,6 +324,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
sbi->sb = s;
sbi->version = 0;
sbi->sub_version = 0;
sbi->type = 0;
sbi->min_proto = 0;
sbi->max_proto = 0;
mutex_init(&sbi->wq_mutex);
Expand All @@ -315,27 +343,31 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
if (!ino)
goto fail_free;
root_inode = autofs4_get_inode(s, ino);
kfree(ino);
if (!root_inode)
goto fail_free;
goto fail_ino;

root_inode->i_op = &autofs4_root_inode_operations;
root_inode->i_fop = &autofs4_root_operations;
root = d_alloc_root(root_inode);
pipe = NULL;

if (!root)
goto fail_iput;
pipe = NULL;

root->d_op = &autofs4_sb_dentry_operations;
root->d_fsdata = ino;

/* Can this call block? */
if (parse_options(data, &pipefd,
&root_inode->i_uid, &root_inode->i_gid,
&sbi->oz_pgrp,
&sbi->oz_pgrp, &sbi->type,
&sbi->min_proto, &sbi->max_proto)) {
printk("autofs: called with bogus options\n");
goto fail_dput;
}

root_inode->i_fop = &autofs4_root_operations;
root_inode->i_op = sbi->type & AUTOFS_TYP_DIRECT ?
&autofs4_direct_root_inode_operations :
&autofs4_indirect_root_inode_operations;

/* Couldn't this be tested earlier? */
if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
Expand Down Expand Up @@ -391,6 +423,8 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
fail_iput:
printk("autofs: get root dentry failed\n");
iput(root_inode);
fail_ino:
kfree(ino);
fail_free:
kfree(sbi);
fail_unlock:
Expand Down
64 changes: 52 additions & 12 deletions fs/autofs4/root.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
* Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
* Copyright 2001-2003 Ian Kent <raven@themaw.net>
* Copyright 2001-2006 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
Expand All @@ -30,6 +30,7 @@ static int autofs4_dir_close(struct inode *inode, struct file *file);
static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
static void *autofs4_follow_link(struct dentry *, struct nameidata *);

struct file_operations autofs4_root_operations = {
.open = dcache_dir_open,
Expand All @@ -46,14 +47,19 @@ struct file_operations autofs4_dir_operations = {
.readdir = autofs4_dir_readdir,
};

struct inode_operations autofs4_root_inode_operations = {
struct inode_operations autofs4_indirect_root_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.symlink = autofs4_dir_symlink,
.mkdir = autofs4_dir_mkdir,
.rmdir = autofs4_dir_rmdir,
};

struct inode_operations autofs4_direct_root_inode_operations = {
.lookup = autofs4_lookup,
.follow_link = autofs4_follow_link,
};

struct inode_operations autofs4_dir_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
Expand Down Expand Up @@ -252,7 +258,7 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
*/
status = d_invalidate(dentry);
if (status != -EBUSY)
return 0;
return -ENOENT;
}

DPRINTK("dentry=%p %.*s ino=%p",
Expand All @@ -271,17 +277,17 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
DPRINTK("mount done status=%d", status);

if (status && dentry->d_inode)
return 0; /* Try to get the kernel to invalidate this dentry */
return status; /* Try to get the kernel to invalidate this dentry */

/* Turn this into a real negative dentry? */
if (status == -ENOENT) {
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
return 0;
return status;
} else if (status) {
/* Return a negative dentry, but leave it "pending" */
return 0;
return status;
}
/* Trigger mount for path component or follow link */
} else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
Expand All @@ -300,7 +306,7 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
return 0;
return status;
}
}

Expand All @@ -311,7 +317,41 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
return 1;
return status;
}

/* For autofs direct mounts the follow link triggers the mount */
static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
int oz_mode = autofs4_oz_mode(sbi);
unsigned int lookup_type;
int status;

DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
nd->flags);

/* If it's our master or we shouldn't trigger a mount we're done */
lookup_type = nd->flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY);
if (oz_mode || !lookup_type)
goto done;

status = try_to_fill_dentry(dentry, 0);
if (status)
goto out_error;

if (!autofs4_follow_mount(&nd->mnt, &nd->dentry)) {
status = -ENOENT;
goto out_error;
}

done:
return NULL;

out_error:
path_release(nd);
return ERR_PTR(status);
}

/*
Expand All @@ -326,13 +366,13 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
int oz_mode = autofs4_oz_mode(sbi);
int flags = nd ? nd->flags : 0;
int status = 1;
int status = 0;

/* Pending dentry */
if (autofs4_ispending(dentry)) {
if (!oz_mode)
status = try_to_fill_dentry(dentry, flags);
return status;
return !status;
}

/* Negative dentry.. invalidate if "old" */
Expand All @@ -349,14 +389,14 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
spin_unlock(&dcache_lock);
if (!oz_mode)
status = try_to_fill_dentry(dentry, flags);
return status;
return !status;
}
spin_unlock(&dcache_lock);

return 1;
}

static void autofs4_dentry_release(struct dentry *de)
void autofs4_dentry_release(struct dentry *de)
{
struct autofs_info *inf;

Expand Down

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