| /* -*- 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/mutex.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 DEFINE_MUTEX(autofs4_ioctl_mutex); |
| |
| static long autofs4_root_ioctl(struct file *filp, |
| unsigned int cmd, unsigned long arg) |
| { |
| long ret; |
| struct inode *inode = filp->f_dentry->d_inode; |
| |
| mutex_lock(&autofs4_ioctl_mutex); |
| ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); |
| mutex_unlock(&autofs4_ioctl_mutex); |
| |
| 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; |
| |
| mutex_lock(&autofs4_ioctl_mutex); |
| 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)); |
| mutex_unlock(&autofs4_ioctl_mutex); |
| |
| return ret; |
| } |
| #endif |