diff options
Diffstat (limited to 'fs/autofs4/root.c')
| -rw-r--r-- | fs/autofs4/root.c | 1011 |
1 files changed, 1011 insertions, 0 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c new file mode 100644 index 00000000..cb1bd38d --- /dev/null +++ b/fs/autofs4/root.c @@ -0,0 +1,1011 @@ +/* -*- c -*- --------------------------------------------------------------- * + * + * linux/fs/autofs/root.c + * + * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved + * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org> + * 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 + * option, any later version, incorporated herein by reference. + * + * ------------------------------------------------------------------------- */ + +#include <linux/capability.h> +#include <linux/errno.h> +#include <linux/stat.h> +#include <linux/slab.h> +#include <linux/param.h> +#include <linux/time.h> +#include <linux/compat.h> +#include <linux/smp_lock.h> + +#include "autofs_i.h" + +static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *); +static int autofs4_dir_unlink(struct inode *,struct dentry *); +static int autofs4_dir_rmdir(struct inode *,struct dentry *); +static int autofs4_dir_mkdir(struct inode *,struct dentry *,int); +static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long); +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 void *autofs4_follow_link(struct dentry *, struct nameidata *); + +#define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) +#define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE) + +const struct file_operations autofs4_root_operations = { + .open = dcache_dir_open, + .release = dcache_dir_close, + .read = generic_read_dir, + .readdir = dcache_readdir, + .llseek = dcache_dir_lseek, + .unlocked_ioctl = autofs4_root_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = autofs4_root_compat_ioctl, +#endif +}; + +const struct file_operations autofs4_dir_operations = { + .open = autofs4_dir_open, + .release = dcache_dir_close, + .read = generic_read_dir, + .readdir = dcache_readdir, + .llseek = dcache_dir_lseek, +}; + +const 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, +}; + +const struct inode_operations autofs4_direct_root_inode_operations = { + .lookup = autofs4_lookup, + .unlink = autofs4_dir_unlink, + .mkdir = autofs4_dir_mkdir, + .rmdir = autofs4_dir_rmdir, + .follow_link = autofs4_follow_link, +}; + +const struct inode_operations autofs4_dir_inode_operations = { + .lookup = autofs4_lookup, + .unlink = autofs4_dir_unlink, + .symlink = autofs4_dir_symlink, + .mkdir = autofs4_dir_mkdir, + .rmdir = autofs4_dir_rmdir, +}; + +static void autofs4_add_active(struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + if (ino) { + spin_lock(&sbi->lookup_lock); + if (!ino->active_count) { + if (list_empty(&ino->active)) + list_add(&ino->active, &sbi->active_list); + } + ino->active_count++; + spin_unlock(&sbi->lookup_lock); + } + return; +} + +static void autofs4_del_active(struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + if (ino) { + spin_lock(&sbi->lookup_lock); + ino->active_count--; + if (!ino->active_count) { + if (!list_empty(&ino->active)) + list_del_init(&ino->active); + } + spin_unlock(&sbi->lookup_lock); + } + return; +} + +static unsigned int autofs4_need_mount(unsigned int flags) +{ + unsigned int res = 0; + if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS)) + res = 1; + return res; +} + +static int autofs4_dir_open(struct inode *inode, struct file *file) +{ + struct dentry *dentry = file->f_path.dentry; + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + + DPRINTK("file=%p dentry=%p %.*s", + file, dentry, dentry->d_name.len, dentry->d_name.name); + + if (autofs4_oz_mode(sbi)) + goto out; + + /* + * An empty directory in an autofs file system is always a + * mount point. The daemon must have failed to mount this + * during lookup so it doesn't exist. This can happen, for + * example, if user space returns an incorrect status for a + * mount request. Otherwise we're doing a readdir on the + * autofs file system so just let the libfs routines handle + * it. + */ + spin_lock(&dcache_lock); + if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { + spin_unlock(&dcache_lock); + return -ENOENT; + } + spin_unlock(&dcache_lock); + +out: + return dcache_dir_open(inode, file); +} + +static int try_to_fill_dentry(struct dentry *dentry, int flags) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + int status; + + DPRINTK("dentry=%p %.*s ino=%p", + dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode); + + /* + * Wait for a pending mount, triggering one if there + * isn't one already + */ + if (dentry->d_inode == NULL) { + DPRINTK("waiting for mount name=%.*s", + dentry->d_name.len, dentry->d_name.name); + + status = autofs4_wait(sbi, dentry, NFY_MOUNT); + + DPRINTK("mount done status=%d", status); + + /* Turn this into a real negative dentry? */ + if (status == -ENOENT) { + spin_lock(&sbi->fs_lock); + ino->flags &= ~AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + return status; + } else if (status) { + /* Return a negative dentry, but leave it "pending" */ + return status; + } + /* Trigger mount for path component or follow link */ + } else if (ino->flags & AUTOFS_INF_PENDING || + autofs4_need_mount(flags)) { + DPRINTK("waiting for mount name=%.*s", + dentry->d_name.len, dentry->d_name.name); + + spin_lock(&sbi->fs_lock); + ino->flags |= AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + status = autofs4_wait(sbi, dentry, NFY_MOUNT); + + DPRINTK("mount done status=%d", status); + + if (status) { + spin_lock(&sbi->fs_lock); + ino->flags &= ~AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + return status; + } + } + + /* Initialize expiry counter after successful mount */ + ino->last_used = jiffies; + + spin_lock(&sbi->fs_lock); + ino->flags &= ~AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + + return 0; +} + +/* 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); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + 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); + /* + * For an expire of a covered direct or offset mount we need + * to break out of follow_down() at the autofs mount trigger + * (d_mounted--), so we can see the expiring flag, and manage + * the blocking and following here until the expire is completed. + */ + if (oz_mode) { + spin_lock(&sbi->fs_lock); + if (ino->flags & AUTOFS_INF_EXPIRING) { + spin_unlock(&sbi->fs_lock); + /* Follow down to our covering mount. */ + if (!follow_down(&nd->path)) + goto done; + goto follow; + } + spin_unlock(&sbi->fs_lock); + goto done; + } + + /* If an expire request is pending everyone must wait. */ + autofs4_expire_wait(dentry); + + /* We trigger a mount for almost all flags */ + lookup_type = autofs4_need_mount(nd->flags); + spin_lock(&sbi->fs_lock); + spin_lock(&dcache_lock); + if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) { + spin_unlock(&dcache_lock); + spin_unlock(&sbi->fs_lock); + goto follow; + } + + /* + * If the dentry contains directories then it is an autofs + * multi-mount with no root mount offset. So don't try to + * mount it again. + */ + if (ino->flags & AUTOFS_INF_PENDING || + (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) { + spin_unlock(&dcache_lock); + spin_unlock(&sbi->fs_lock); + + status = try_to_fill_dentry(dentry, nd->flags); + if (status) + goto out_error; + + goto follow; + } + spin_unlock(&dcache_lock); + spin_unlock(&sbi->fs_lock); +follow: + /* + * If there is no root mount it must be an autofs + * multi-mount with no root offset so we don't need + * to follow it. + */ + if (d_mountpoint(dentry)) { + if (!autofs4_follow_mount(&nd->path)) { + status = -ENOENT; + goto out_error; + } + } + +done: + return NULL; + +out_error: + path_put(&nd->path); + return ERR_PTR(status); +} + +/* + * Revalidate is called on every cache lookup. Some of those + * cache lookups may actually happen while the dentry is not + * yet completely filled in, and revalidate has to delay such + * lookups.. + */ +static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + struct inode *dir = dentry->d_parent->d_inode; + 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; + + /* Pending dentry */ + spin_lock(&sbi->fs_lock); + if (autofs4_ispending(dentry)) { + /* The daemon never causes a mount to trigger */ + spin_unlock(&sbi->fs_lock); + + if (oz_mode) + return 1; + + /* + * If the directory has gone away due to an expire + * we have been called as ->d_revalidate() and so + * we need to return false and proceed to ->lookup(). + */ + if (autofs4_expire_wait(dentry) == -EAGAIN) + return 0; + + /* + * A zero status is success otherwise we have a + * negative error code. + */ + status = try_to_fill_dentry(dentry, flags); + if (status == 0) + return 1; + + return status; + } + spin_unlock(&sbi->fs_lock); + + /* Negative dentry.. invalidate if "old" */ + if (dentry->d_inode == NULL) + return 0; + + /* Check for a non-mountpoint directory with no contents */ + spin_lock(&dcache_lock); + if (S_ISDIR(dentry->d_inode->i_mode) && + !d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { + DPRINTK("dentry=%p %.*s, emptydir", + dentry, dentry->d_name.len, dentry->d_name.name); + spin_unlock(&dcache_lock); + + /* The daemon never causes a mount to trigger */ + if (oz_mode) + return 1; + + /* + * A zero status is success otherwise we have a + * negative error code. + */ + status = try_to_fill_dentry(dentry, flags); + if (status == 0) + return 1; + + return status; + } + spin_unlock(&dcache_lock); + + return 1; +} + +void autofs4_dentry_release(struct dentry *de) +{ + struct autofs_info *inf; + + DPRINTK("releasing %p", de); + + inf = autofs4_dentry_ino(de); + de->d_fsdata = NULL; + + if (inf) { + struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); + + if (sbi) { + spin_lock(&sbi->lookup_lock); + if (!list_empty(&inf->active)) + list_del(&inf->active); + if (!list_empty(&inf->expiring)) + list_del(&inf->expiring); + spin_unlock(&sbi->lookup_lock); + } + + inf->dentry = NULL; + inf->inode = NULL; + + autofs4_free_ino(inf); + } +} + +/* For dentries of directories in the root dir */ +static const struct dentry_operations autofs4_root_dentry_operations = { + .d_revalidate = autofs4_revalidate, + .d_release = autofs4_dentry_release, +}; + +/* For other dentries */ +static const struct dentry_operations autofs4_dentry_operations = { + .d_revalidate = autofs4_revalidate, + .d_release = autofs4_dentry_release, +}; + +static struct dentry *autofs4_lookup_active(struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct dentry *parent = dentry->d_parent; + struct qstr *name = &dentry->d_name; + unsigned int len = name->len; + unsigned int hash = name->hash; + const unsigned char *str = name->name; + struct list_head *p, *head; + + spin_lock(&dcache_lock); + spin_lock(&sbi->lookup_lock); + head = &sbi->active_list; + list_for_each(p, head) { + struct autofs_info *ino; + struct dentry *active; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, active); + active = ino->dentry; + + spin_lock(&active->d_lock); + + /* Already gone? */ + if (atomic_read(&active->d_count) == 0) + goto next; + + qstr = &active->d_name; + + if (active->d_name.hash != hash) + goto next; + if (active->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(active)) { + dget(active); + spin_unlock(&active->d_lock); + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + return active; + } +next: + spin_unlock(&active->d_lock); + } + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + + return NULL; +} + +static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct dentry *parent = dentry->d_parent; + struct qstr *name = &dentry->d_name; + unsigned int len = name->len; + unsigned int hash = name->hash; + const unsigned char *str = name->name; + struct list_head *p, *head; + + spin_lock(&dcache_lock); + spin_lock(&sbi->lookup_lock); + head = &sbi->expiring_list; + list_for_each(p, head) { + struct autofs_info *ino; + struct dentry *expiring; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, expiring); + expiring = ino->dentry; + + spin_lock(&expiring->d_lock); + + /* Bad luck, we've already been dentry_iput */ + if (!expiring->d_inode) + goto next; + + qstr = &expiring->d_name; + + if (expiring->d_name.hash != hash) + goto next; + if (expiring->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(expiring)) { + dget(expiring); + spin_unlock(&expiring->d_lock); + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + return expiring; + } +next: + spin_unlock(&expiring->d_lock); + } + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + + return NULL; +} + +/* Lookups in the root directory */ +static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) +{ + struct autofs_sb_info *sbi; + struct autofs_info *ino; + struct dentry *expiring, *active; + int oz_mode; + + DPRINTK("name = %.*s", + dentry->d_name.len, dentry->d_name.name); + + /* File name too long to exist */ + if (dentry->d_name.len > NAME_MAX) + return ERR_PTR(-ENAMETOOLONG); + + sbi = autofs4_sbi(dir->i_sb); + oz_mode = autofs4_oz_mode(sbi); + + DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", + current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode); + + active = autofs4_lookup_active(dentry); + if (active) { + dentry = active; + ino = autofs4_dentry_ino(dentry); + } else { + /* + * Mark the dentry incomplete but don't hash it. We do this + * to serialize our inode creation operations (symlink and + * mkdir) which prevents deadlock during the callback to + * the daemon. Subsequent user space lookups for the same + * dentry are placed on the wait queue while the daemon + * itself is allowed passage unresticted so the create + * operation itself can then hash the dentry. Finally, + * we check for the hashed dentry and return the newly + * hashed dentry. + */ + dentry->d_op = &autofs4_root_dentry_operations; + + /* + * And we need to ensure that the same dentry is used for + * all following lookup calls until it is hashed so that + * the dentry flags are persistent throughout the request. + */ + ino = autofs4_init_ino(NULL, sbi, 0555); + if (!ino) + return ERR_PTR(-ENOMEM); + + dentry->d_fsdata = ino; + ino->dentry = dentry; + + autofs4_add_active(dentry); + + d_instantiate(dentry, NULL); + } + + if (!oz_mode) { + mutex_unlock(&dir->i_mutex); + expiring = autofs4_lookup_expiring(dentry); + 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. + */ + autofs4_expire_wait(expiring); + autofs4_del_expiring(expiring); + dput(expiring); + } + + spin_lock(&sbi->fs_lock); + ino->flags |= AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + if (dentry->d_op && dentry->d_op->d_revalidate) + (dentry->d_op->d_revalidate)(dentry, nd); + mutex_lock(&dir->i_mutex); + } + + /* + * If we are still pending, check if we had to handle + * a signal. If so we can force a restart.. + */ + if (ino->flags & AUTOFS_INF_PENDING) { + /* See if we were interrupted */ + if (signal_pending(current)) { + sigset_t *sigset = ¤t->pending.signal; + if (sigismember (sigset, SIGKILL) || + sigismember (sigset, SIGQUIT) || + sigismember (sigset, SIGINT)) { + if (active) + dput(active); + return ERR_PTR(-ERESTARTNOINTR); + } + } + if (!oz_mode) { + spin_lock(&sbi->fs_lock); + ino->flags &= ~AUTOFS_INF_PENDING; + spin_unlock(&sbi->fs_lock); + } + } + + /* + * If this dentry is unhashed, then we shouldn't honour this + * lookup. Returning ENOENT here doesn't do the right thing + * for all system calls, but it should be OK for the operations + * we permit from an autofs. + */ + if (!oz_mode && d_unhashed(dentry)) { + /* + * A user space application can (and has done in the past) + * remove and re-create this directory during the callback. + * This can leave us with an unhashed dentry, but a + * successful mount! So we need to perform another + * cached lookup in case the dentry now exists. + */ + struct dentry *parent = dentry->d_parent; + struct dentry *new = d_lookup(parent, &dentry->d_name); + if (new != NULL) + dentry = new; + else + dentry = ERR_PTR(-ENOENT); + + if (active) + dput(active); + + return dentry; + } + + if (active) + return active; + + return NULL; +} + +static int autofs4_dir_symlink(struct inode *dir, + struct dentry *dentry, + const char *symname) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; + struct inode *inode; + char *cp; + + DPRINTK("%s <- %.*s", symname, + dentry->d_name.len, dentry->d_name.name); + + if (!autofs4_oz_mode(sbi)) + return -EACCES; + + ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555); + if (!ino) + return -ENOMEM; + + autofs4_del_active(dentry); + + ino->size = strlen(symname); + cp = kmalloc(ino->size + 1, GFP_KERNEL); + if (!cp) { + if (!dentry->d_fsdata) + kfree(ino); + return -ENOMEM; + } + + strcpy(cp, symname); + + inode = autofs4_get_inode(dir->i_sb, ino); + if (!inode) { + kfree(cp); + if (!dentry->d_fsdata) + kfree(ino); + return -ENOMEM; + } + d_add(dentry, inode); + + if (dir == dir->i_sb->s_root->d_inode) + dentry->d_op = &autofs4_root_dentry_operations; + else + dentry->d_op = &autofs4_dentry_operations; + + dentry->d_fsdata = ino; + ino->dentry = dget(dentry); + atomic_inc(&ino->count); + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && dentry->d_parent != dentry) + atomic_inc(&p_ino->count); + ino->inode = inode; + + ino->u.symlink = cp; + dir->i_mtime = CURRENT_TIME; + + return 0; +} + +/* + * NOTE! + * + * Normal filesystems would do a "d_delete()" to tell the VFS dcache + * that the file no longer exists. However, doing that means that the + * VFS layer can turn the dentry into a negative dentry. We don't want + * this, because the unlink is probably the result of an expire. + * We simply d_drop it and add it to a expiring list in the super block, + * which allows the dentry lookup to check for an incomplete expire. + * + * If a process is blocked on the dentry waiting for the expire to finish, + * it will invalidate the dentry and try to mount with a new one. + * + * Also see autofs4_dir_rmdir().. + */ +static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; + + /* This allows root to remove symlinks */ + if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (atomic_dec_and_test(&ino->count)) { + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && dentry->d_parent != dentry) + atomic_dec(&p_ino->count); + } + dput(ino->dentry); + + dentry->d_inode->i_size = 0; + clear_nlink(dentry->d_inode); + + dir->i_mtime = CURRENT_TIME; + + spin_lock(&dcache_lock); + autofs4_add_expiring(dentry); + spin_lock(&dentry->d_lock); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); + + return 0; +} + +static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; + + DPRINTK("dentry %p, removing %.*s", + dentry, dentry->d_name.len, dentry->d_name.name); + + if (!autofs4_oz_mode(sbi)) + return -EACCES; + + spin_lock(&dcache_lock); + if (!list_empty(&dentry->d_subdirs)) { + spin_unlock(&dcache_lock); + return -ENOTEMPTY; + } + autofs4_add_expiring(dentry); + spin_lock(&dentry->d_lock); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); + + if (atomic_dec_and_test(&ino->count)) { + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && dentry->d_parent != dentry) + atomic_dec(&p_ino->count); + } + dput(ino->dentry); + dentry->d_inode->i_size = 0; + clear_nlink(dentry->d_inode); + + if (dir->i_nlink) + drop_nlink(dir); + + return 0; +} + +static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct autofs_info *p_ino; + struct inode *inode; + + if (!autofs4_oz_mode(sbi)) + return -EACCES; + + DPRINTK("dentry %p, creating %.*s", + dentry, dentry->d_name.len, dentry->d_name.name); + + ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555); + if (!ino) + return -ENOMEM; + + autofs4_del_active(dentry); + + inode = autofs4_get_inode(dir->i_sb, ino); + if (!inode) { + if (!dentry->d_fsdata) + kfree(ino); + return -ENOMEM; + } + d_add(dentry, inode); + + if (dir == dir->i_sb->s_root->d_inode) + dentry->d_op = &autofs4_root_dentry_operations; + else + dentry->d_op = &autofs4_dentry_operations; + + dentry->d_fsdata = ino; + ino->dentry = dget(dentry); + atomic_inc(&ino->count); + p_ino = autofs4_dentry_ino(dentry->d_parent); + if (p_ino && dentry->d_parent != dentry) + atomic_inc(&p_ino->count); + ino->inode = inode; + inc_nlink(dir); + dir->i_mtime = CURRENT_TIME; + + return 0; +} + +/* Get/set timeout ioctl() operation */ +#ifdef CONFIG_COMPAT +static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi, + compat_ulong_t __user *p) +{ + int rv; + unsigned long ntimeout; + + if ((rv = get_user(ntimeout, p)) || + (rv = put_user(sbi->exp_timeout/HZ, p))) + return rv; + + if (ntimeout > UINT_MAX/HZ) + sbi->exp_timeout = 0; + else + sbi->exp_timeout = ntimeout * HZ; + + return 0; +} +#endif + +static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, + unsigned long __user *p) +{ + int rv; + unsigned long ntimeout; + + if ((rv = get_user(ntimeout, p)) || + (rv = put_user(sbi->exp_timeout/HZ, p))) + return rv; + + if (ntimeout > ULONG_MAX/HZ) + sbi->exp_timeout = 0; + else + sbi->exp_timeout = ntimeout * HZ; + + return 0; +} + +/* Return protocol version */ +static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p) +{ + return put_user(sbi->version, p); +} + +/* Return protocol sub version */ +static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p) +{ + return put_user(sbi->sub_version, p); +} + +/* +* Tells the daemon whether it can umount the autofs mount. +*/ +static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) +{ + int status = 0; + + if (may_umount(mnt)) + status = 1; + + DPRINTK("returning %d", status); + + status = put_user(status, p); + + return status; +} + +/* Identify autofs4_dentries - this is so we can tell if there's + an extra dentry refcount or not. We only hold a refcount on the + dentry if its non-negative (ie, d_inode != NULL) +*/ +int is_autofs4_dentry(struct dentry *dentry) +{ + return dentry && dentry->d_inode && + (dentry->d_op == &autofs4_root_dentry_operations || + dentry->d_op == &autofs4_dentry_operations) && + dentry->d_fsdata != NULL; +} + +/* + * ioctl()'s on the root directory is the chief method for the daemon to + * generate kernel reactions + */ +static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); + void __user *p = (void __user *)arg; + + DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", + cmd,arg,sbi,task_pgrp_nr(current)); + + if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || + _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) + return -ENOTTY; + + if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) + return -EPERM; + + switch(cmd) { + case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ + return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0); + case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ + return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); + case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ + autofs4_catatonic_mode(sbi); + return 0; + case AUTOFS_IOC_PROTOVER: /* Get protocol version */ + return autofs4_get_protover(sbi, p); + case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ + return autofs4_get_protosubver(sbi, p); + case AUTOFS_IOC_SETTIMEOUT: + return autofs4_get_set_timeout(sbi, p); +#ifdef CONFIG_COMPAT + case AUTOFS_IOC_SETTIMEOUT32: + return autofs4_compat_get_set_timeout(sbi, p); +#endif + + case AUTOFS_IOC_ASKUMOUNT: + return autofs4_ask_umount(filp->f_path.mnt, p); + + /* return a single thing to expire */ + case AUTOFS_IOC_EXPIRE: + return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); + /* same as above, but can send multiple expires through pipe */ + case AUTOFS_IOC_EXPIRE_MULTI: + return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); + + default: + return -ENOSYS; + } +} + +static long autofs4_root_ioctl(struct file *filp, + unsigned int cmd, unsigned long arg) +{ + long ret; + struct inode *inode = filp->f_dentry->d_inode; + + lock_kernel(); + ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); + unlock_kernel(); + + return ret; +} + +#ifdef CONFIG_COMPAT +static long autofs4_root_compat_ioctl(struct file *filp, + unsigned int cmd, unsigned long arg) +{ + struct inode *inode = filp->f_path.dentry->d_inode; + int ret; + + lock_kernel(); + if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) + ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); + else + ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, + (unsigned long)compat_ptr(arg)); + unlock_kernel(); + + return ret; +} +#endif |