/* -*- c -*- --------------------------------------------------------------- * * * linux/fs/autofs/root.c * * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved * Copyright 1999-2000 Jeremy Fitzhardinge * * 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 #include #include #include #include #include "autofs_i.h" static struct dentry *autofs4_dir_lookup(struct inode *,struct dentry *); 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 int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long); static struct dentry *autofs4_root_lookup(struct inode *,struct dentry *); struct file_operations autofs4_root_operations = { read: generic_read_dir, readdir: dcache_readdir, ioctl: autofs4_root_ioctl, }; struct file_operations autofs4_dir_operations = { read: generic_read_dir, readdir: dcache_readdir, }; struct inode_operations autofs4_root_inode_operations = { lookup: autofs4_root_lookup, unlink: autofs4_dir_unlink, symlink: autofs4_dir_symlink, mkdir: autofs4_dir_mkdir, rmdir: autofs4_dir_rmdir, }; struct inode_operations autofs4_dir_inode_operations = { lookup: autofs4_dir_lookup, unlink: autofs4_dir_unlink, symlink: autofs4_dir_symlink, mkdir: autofs4_dir_mkdir, rmdir: autofs4_dir_rmdir, }; /* Update usage from here to top of tree, so that scan of top-level directories will give a useful result */ static void autofs4_update_usage(struct dentry *dentry) { struct dentry *top = dentry->d_sb->s_root; for(; dentry != top; dentry = dentry->d_parent) { struct autofs_info *ino = autofs4_dentry_ino(dentry); if (ino) { update_atime(dentry->d_inode); ino->last_used = jiffies; } } } static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi) { struct autofs_info *de_info = autofs4_dentry_ino(dentry); int status = 0; /* Block on any pending expiry here; invalidate the dentry when expiration is done to trigger mount request with a new dentry */ if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) { DPRINTK(("try_to_fill_entry: waiting for expire %p name=%.*s, flags&PENDING=%s de_info=%p de_info->flags=%x\n", dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_flags & DCACHE_AUTOFS_PENDING?"t":"f", de_info, de_info?de_info->flags:0)); status = autofs4_wait(sbi, &dentry->d_name, NFY_NONE); DPRINTK(("try_to_fill_entry: expire done status=%d\n", status)); return 0; } DPRINTK(("try_to_fill_entry: dentry=%p %.*s ino=%p\n", 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 */ while(dentry->d_inode == NULL) { DPRINTK(("try_to_fill_entry: waiting for mount name=%.*s, de_info=%p de_info->flags=%x\n", dentry->d_name.len, dentry->d_name.name, de_info, de_info?de_info->flags:0)); status = autofs4_wait(sbi, &dentry->d_name, NFY_MOUNT); DPRINTK(("try_to_fill_entry: mount done status=%d\n", status)); if (status && dentry->d_inode) return 0; /* Try to get the kernel to invalidate this dentry */ /* Turn this into a real negative dentry? */ if (status == -ENOENT) { dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT; dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; return 1; } else if (status) { /* Return a negative dentry, but leave it "pending" */ return 1; } } /* If this is an unused directory that isn't a mount point, bitch at the daemon and fix it in user space */ spin_lock(&dcache_lock); if (S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { DPRINTK(("try_to_fill_entry: mounting existing dir\n")); spin_unlock(&dcache_lock); return autofs4_wait(sbi, &dentry->d_name, NFY_MOUNT) == 0; } spin_unlock(&dcache_lock); /* We don't update the usages for the autofs daemon itself, this is necessary for recursive autofs mounts */ if (!autofs4_oz_mode(sbi)) autofs4_update_usage(dentry); dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; return 1; } /* * 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_root_revalidate(struct dentry * dentry, int flags) { struct inode * dir = dentry->d_parent->d_inode; struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino; int oz_mode = autofs4_oz_mode(sbi); /* Pending dentry */ if (autofs4_ispending(dentry)) { if (autofs4_oz_mode(sbi)) return 1; else return try_to_fill_dentry(dentry, dir->i_sb, sbi); } /* Negative dentry.. invalidate if "old" */ if (dentry->d_inode == NULL) return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT); ino = autofs4_dentry_ino(dentry); /* 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(("autofs_root_revalidate: dentry=%p %.*s, emptydir\n", dentry, dentry->d_name.len, dentry->d_name.name)); spin_unlock(&dcache_lock); if (oz_mode) return 1; else return try_to_fill_dentry(dentry, dir->i_sb, sbi); } spin_unlock(&dcache_lock); /* Update the usage list */ if (!oz_mode) autofs4_update_usage(dentry); return 1; } static int autofs4_revalidate(struct dentry *dentry, int flags) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); if (!autofs4_oz_mode(sbi)) autofs4_update_usage(dentry); return 1; } static void autofs4_dentry_release(struct dentry *de) { struct autofs_info *inf; lock_kernel(); DPRINTK(("autofs4_dentry_release: releasing %p\n", de)); inf = autofs4_dentry_ino(de); de->d_fsdata = NULL; if (inf) { inf->dentry = NULL; inf->inode = NULL; autofs4_free_ino(inf); } unlock_kernel(); } /* For dentries of directories in the root dir */ static struct dentry_operations autofs4_root_dentry_operations = { d_revalidate: autofs4_root_revalidate, d_release: autofs4_dentry_release, }; /* For other dentries */ static struct dentry_operations autofs4_dentry_operations = { d_revalidate: autofs4_revalidate, d_release: autofs4_dentry_release, }; /* Lookups in non-root dirs never find anything - if it's there, it's already in the dcache */ static struct dentry *autofs4_dir_lookup(struct inode *dir, struct dentry *dentry) { #if 0 DPRINTK(("autofs_dir_lookup: ignoring lookup of %.*s/%.*s\n", dentry->d_parent->d_name.len, dentry->d_parent->d_name.name, dentry->d_name.len, dentry->d_name.name)); #endif dentry->d_fsdata = NULL; d_add(dentry, NULL); return NULL; } /* Lookups in the root directory */ static struct dentry *autofs4_root_lookup(struct inode *dir, struct dentry *dentry) { struct autofs_sb_info *sbi; int oz_mode; DPRINTK(("autofs_root_lookup: name = %.*s\n", dentry->d_name.len, dentry->d_name.name)); if (dentry->d_name.len > NAME_MAX) return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */ sbi = autofs4_sbi(dir->i_sb); oz_mode = autofs4_oz_mode(sbi); DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n", current->pid, current->pgrp, sbi->catatonic, oz_mode)); /* * Mark the dentry incomplete, but add it. This is needed so * that the VFS layer knows about the dentry, and we can count * on catching any lookups through the revalidate. * * Let all the hard work be done by the revalidate function that * needs to be able to do this anyway.. * * We need to do this before we release the directory semaphore. */ dentry->d_op = &autofs4_root_dentry_operations; if (!oz_mode) dentry->d_flags |= DCACHE_AUTOFS_PENDING; dentry->d_fsdata = NULL; d_add(dentry, NULL); if (dentry->d_op && dentry->d_op->d_revalidate) { up(&dir->i_sem); (dentry->d_op->d_revalidate)(dentry, 0); down(&dir->i_sem); } /* * If we are still pending, check if we had to handle * a signal. If so we can force a restart.. */ if (dentry->d_flags & DCACHE_AUTOFS_PENDING) { if (signal_pending(current)) return ERR_PTR(-ERESTARTNOINTR); } /* * If this dentry is unhashed, then we shouldn't honour this * lookup even if the dentry is positive. 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 ( dentry->d_inode && d_unhashed(dentry) ) return ERR_PTR(-ENOENT); 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 inode *inode; char *cp; DPRINTK(("autofs_dir_symlink: %s <- %.*s\n", 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 == NULL) return -ENOSPC; ino->size = strlen(symname); ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL); if (cp == NULL) { kfree(ino); return -ENOSPC; } strcpy(cp, symname); inode = autofs4_get_inode(dir->i_sb, ino); d_instantiate(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); ino->inode = inode; 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 since the unlink is probably the result of an expire. * We simply d_drop it, which allows the dentry lookup to remount it * if necessary. * * 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 autofs_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); /* This allows root to remove symlinks */ if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) ) return -EACCES; dput(ino->dentry); dentry->d_inode->i_size = 0; dentry->d_inode->i_nlink = 0; dir->i_mtime = CURRENT_TIME; d_drop(dentry); 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); if (!autofs4_oz_mode(sbi)) return -EACCES; spin_lock(&dcache_lock); if (!list_empty(&dentry->d_subdirs)) { spin_unlock(&dcache_lock); return -ENOTEMPTY; } list_del_init(&dentry->d_hash); spin_unlock(&dcache_lock); dput(ino->dentry); dentry->d_inode->i_size = 0; dentry->d_inode->i_nlink = 0; if (dir->i_nlink) dir->i_nlink--; 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 inode *inode; if ( !autofs4_oz_mode(sbi) ) return -EACCES; DPRINTK(("autofs_dir_mkdir: dentry %p, creating %.*s\n", dentry, dentry->d_name.len, dentry->d_name.name)); ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555); if (ino == NULL) return -ENOSPC; inode = autofs4_get_inode(dir->i_sb, ino); d_instantiate(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); ino->inode = inode; dir->i_nlink++; dir->i_mtime = CURRENT_TIME; return 0; } /* Get/set timeout ioctl() operation */ static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, unsigned long *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 *p) { return put_user(sbi->version, p); } /* Identify autofs_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(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n", cmd,arg,sbi,current->pgrp)); 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, (int *)arg); case AUTOFS_IOC_SETTIMEOUT: return autofs4_get_set_timeout(sbi,(unsigned long *)arg); /* return a single thing to expire */ case AUTOFS_IOC_EXPIRE: return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, (struct autofs_packet_expire *)arg); /* same as above, but can send multiple expires through pipe */ case AUTOFS_IOC_EXPIRE_MULTI: return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, (int *)arg); default: return -ENOSYS; } }