X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fautofs4%2Froot.c;h=b96a3c57359d71a73b6698f8d4d1269b116ceaee;hb=e1187b3be72be59625e445b186007e6eae27fef1;hp=541b19e6fec9e71db12e60bba01eb5e15a291f42;hpb=1b1dcc1b57a49136f118a0f16367256ff9994a69;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 541b19e..b96a3c5 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -4,7 +4,7 @@ * * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved * Copyright 1999-2000 Jeremy Fitzhardinge - * Copyright 2001-2003 Ian Kent + * Copyright 2001-2006 Ian Kent * * 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 @@ -12,11 +12,11 @@ * * ------------------------------------------------------------------------- */ +#include #include #include #include #include -#include #include "autofs_i.h" static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *); @@ -25,28 +25,30 @@ 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 int autofs4_dir_open(struct inode *inode, struct file *file); -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 int autofs4_dcache_readdir(struct file *, void *, filldir_t); +static void *autofs4_follow_link(struct dentry *, struct nameidata *); -struct file_operations autofs4_root_operations = { +#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 = autofs4_root_readdir, + .readdir = dcache_readdir, + .llseek = dcache_dir_lseek, .ioctl = autofs4_root_ioctl, }; -struct file_operations autofs4_dir_operations = { +const struct file_operations autofs4_dir_operations = { .open = autofs4_dir_open, - .release = autofs4_dir_close, + .release = dcache_dir_close, .read = generic_read_dir, - .readdir = autofs4_dir_readdir, + .readdir = dcache_readdir, + .llseek = dcache_dir_lseek, }; -struct inode_operations autofs4_root_inode_operations = { +const struct inode_operations autofs4_indirect_root_inode_operations = { .lookup = autofs4_lookup, .unlink = autofs4_dir_unlink, .symlink = autofs4_dir_symlink, @@ -54,122 +56,26 @@ struct inode_operations autofs4_root_inode_operations = { .rmdir = autofs4_dir_rmdir, }; -struct inode_operations autofs4_dir_inode_operations = { +const struct inode_operations autofs4_direct_root_inode_operations = { .lookup = autofs4_lookup, .unlink = autofs4_dir_unlink, - .symlink = autofs4_dir_symlink, .mkdir = autofs4_dir_mkdir, .rmdir = autofs4_dir_rmdir, + .follow_link = autofs4_follow_link, }; -static int autofs4_root_readdir(struct file *file, void *dirent, - filldir_t filldir) -{ - struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb); - int oz_mode = autofs4_oz_mode(sbi); - - DPRINTK("called, filp->f_pos = %lld", file->f_pos); - - /* - * Don't set reghost flag if: - * 1) f_pos is larger than zero -- we've already been here. - * 2) we haven't even enabled reghosting in the 1st place. - * 3) this is the daemon doing a readdir - */ - if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled) - sbi->needs_reghost = 1; - - DPRINTK("needs_reghost = %d", sbi->needs_reghost); - - return autofs4_dcache_readdir(file, dirent, filldir); -} - -/* 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; - - spin_lock(&dcache_lock); - 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; - } - } - spin_unlock(&dcache_lock); -} - -/* - * From 2.4 kernel readdir.c - */ -static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) -{ - int i; - struct dentry *dentry = filp->f_dentry; - - i = filp->f_pos; - switch (i) { - case 0: - if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0) - break; - i++; - filp->f_pos++; - /* fallthrough */ - case 1: - if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0) - break; - i++; - filp->f_pos++; - /* fallthrough */ - default: { - struct list_head *list; - int j = i-2; - - spin_lock(&dcache_lock); - list = dentry->d_subdirs.next; - - for (;;) { - if (list == &dentry->d_subdirs) { - spin_unlock(&dcache_lock); - return 0; - } - if (!j) - break; - j--; - list = list->next; - } - - while(1) { - struct dentry *de = list_entry(list, - struct dentry, d_u.d_child); - - if (!d_unhashed(de) && de->d_inode) { - spin_unlock(&dcache_lock); - if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0) - break; - spin_lock(&dcache_lock); - } - filp->f_pos++; - list = list->next; - if (list != &dentry->d_subdirs) - continue; - spin_unlock(&dcache_lock); - break; - } - } - } - return 0; -} +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 int autofs4_dir_open(struct inode *inode, struct file *file) { - struct dentry *dentry = file->f_dentry; - struct vfsmount *mnt = file->f_vfsmnt; + struct dentry *dentry = file->f_path.dentry; struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); - int status; DPRINTK("file=%p dentry=%p %.*s", file, dentry, dentry->d_name.len, dentry->d_name.name); @@ -177,174 +83,60 @@ static int autofs4_dir_open(struct inode *inode, struct file *file) if (autofs4_oz_mode(sbi)) goto out; - if (autofs4_ispending(dentry)) { - DPRINTK("dentry busy"); - return -EBUSY; - } - - if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) { - struct nameidata nd; - int empty; - - /* In case there are stale directory dentrys from a failed mount */ - spin_lock(&dcache_lock); - empty = list_empty(&dentry->d_subdirs); + /* + * 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) && __simple_empty(dentry)) { spin_unlock(&dcache_lock); - - if (!empty) - d_invalidate(dentry); - - nd.flags = LOOKUP_DIRECTORY; - status = (dentry->d_op->d_revalidate)(dentry, &nd); - - if (!status) - return -ENOENT; - } - - if (d_mountpoint(dentry)) { - struct file *fp = NULL; - struct vfsmount *fp_mnt = mntget(mnt); - struct dentry *fp_dentry = dget(dentry); - - if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) { - dput(fp_dentry); - mntput(fp_mnt); - return -ENOENT; - } - - fp = dentry_open(fp_dentry, fp_mnt, file->f_flags); - status = PTR_ERR(fp); - if (IS_ERR(fp)) { - file->private_data = NULL; - return status; - } - file->private_data = fp; - } -out: - return 0; -} - -static int autofs4_dir_close(struct inode *inode, struct file *file) -{ - struct dentry *dentry = file->f_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; - - if (autofs4_ispending(dentry)) { - DPRINTK("dentry busy"); - return -EBUSY; + return -ENOENT; } + spin_unlock(&dcache_lock); - if (d_mountpoint(dentry)) { - struct file *fp = file->private_data; - - if (!fp) - return -ENOENT; - - filp_close(fp, current->files); - file->private_data = NULL; - } out: - return 0; + return dcache_dir_open(inode, file); } -static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir) +static int try_to_fill_dentry(struct dentry *dentry, int flags) { - struct dentry *dentry = file->f_dentry; struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); + struct autofs_info *ino = autofs4_dentry_ino(dentry); int status; - DPRINTK("file=%p dentry=%p %.*s", - file, dentry, dentry->d_name.len, dentry->d_name.name); - - if (autofs4_oz_mode(sbi)) - goto out; - - if (autofs4_ispending(dentry)) { - DPRINTK("dentry busy"); - return -EBUSY; - } - - if (d_mountpoint(dentry)) { - struct file *fp = file->private_data; - - if (!fp) - return -ENOENT; - - if (!fp->f_op || !fp->f_op->readdir) - goto out; - - status = vfs_readdir(fp, filldir, dirent); - file->f_pos = fp->f_pos; - if (status) - autofs4_copy_atime(file, fp); - return status; - } -out: - return autofs4_dcache_readdir(file, dirent, filldir); -} - -static int try_to_fill_dentry(struct dentry *dentry, - struct super_block *sb, - struct autofs_sb_info *sbi, int flags) -{ - 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("waiting for expire %p name=%.*s", - dentry, dentry->d_name.len, dentry->d_name.name); - - status = autofs4_wait(sbi, dentry, NFY_NONE); - - DPRINTK("expire done status=%d", status); - - /* - * If the directory still exists the mount request must - * continue otherwise it can't be followed at the right - * time during the walk. - */ - status = d_invalidate(dentry); - if (status != -EBUSY) - return 0; - } - 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 */ + /* + * 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); - 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; spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; spin_unlock(&dentry->d_lock); - return 1; + return status; } else if (status) { /* Return a negative dentry, but leave it "pending" */ - return 1; + return status; } /* Trigger mount for path component or follow link */ - } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) || + } else if (dentry->d_flags & DCACHE_AUTOFS_PENDING || + flags & (TRIGGER_FLAGS | TRIGGER_INTENTS) || current->link_count) { DPRINTK("waiting for mount name=%.*s", dentry->d_name.len, dentry->d_name.name); @@ -360,19 +152,96 @@ static int try_to_fill_dentry(struct dentry *dentry, spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; spin_unlock(&dentry->d_lock); - return 0; + return status; } } - /* 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); + /* Initialize expiry counter after successful mount */ + if (ino) + ino->last_used = jiffies; spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; spin_unlock(&dentry->d_lock); - return 1; + + 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 = nd->flags & (TRIGGER_FLAGS | TRIGGER_INTENTS); + if (!(lookup_type || dentry->d_flags & DCACHE_AUTOFS_PENDING)) + 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. + */ + spin_lock(&dcache_lock); + if (dentry->d_flags & DCACHE_AUTOFS_PENDING || + (!d_mountpoint(dentry) && __simple_empty(dentry))) { + spin_unlock(&dcache_lock); + + status = try_to_fill_dentry(dentry, 0); + if (status) + goto out_error; + + goto follow; + } + spin_unlock(&dcache_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); } /* @@ -381,47 +250,76 @@ static int try_to_fill_dentry(struct dentry *dentry, * yet completely filled in, and revalidate has to delay such * lookups.. */ -static int autofs4_revalidate(struct dentry * dentry, struct nameidata *nd) +static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) { - struct inode * dir = dentry->d_parent->d_inode; + 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)) { - if (!oz_mode) - status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags); + /* 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 (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT); + 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)) { + __simple_empty(dentry)) { DPRINTK("dentry=%p %.*s, emptydir", dentry, dentry->d_name.len, dentry->d_name.name); spin_unlock(&dcache_lock); - if (!oz_mode) - status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags); + + /* 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); - /* Update the usage list */ - if (!oz_mode) - autofs4_update_usage(dentry); - return 1; } -static void autofs4_dentry_release(struct dentry *de) +void autofs4_dentry_release(struct dentry *de) { struct autofs_info *inf; @@ -431,6 +329,17 @@ static void autofs4_dentry_release(struct dentry *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; @@ -439,58 +348,203 @@ static void autofs4_dentry_release(struct dentry *de) } /* For dentries of directories in the root dir */ -static struct dentry_operations autofs4_root_dentry_operations = { +static const struct dentry_operations autofs4_root_dentry_operations = { .d_revalidate = autofs4_revalidate, .d_release = autofs4_dentry_release, }; /* For other dentries */ -static struct dentry_operations autofs4_dentry_operations = { +static const struct dentry_operations autofs4_dentry_operations = { .d_revalidate = autofs4_revalidate, .d_release = autofs4_dentry_release, }; +static struct dentry *autofs4_lookup_active(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *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 *dentry; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, active); + dentry = ino->dentry; + + spin_lock(&dentry->d_lock); + + /* Already gone? */ + if (atomic_read(&dentry->d_count) == 0) + goto next; + + qstr = &dentry->d_name; + + if (dentry->d_name.hash != hash) + goto next; + if (dentry->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(dentry)) { + dget(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + return dentry; + } +next: + spin_unlock(&dentry->d_lock); + } + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + + return NULL; +} + +static struct dentry *autofs4_lookup_expiring(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *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 *dentry; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, expiring); + dentry = ino->dentry; + + spin_lock(&dentry->d_lock); + + /* Bad luck, we've already been dentry_iput */ + if (!dentry->d_inode) + goto next; + + qstr = &dentry->d_name; + + if (dentry->d_name.hash != hash) + goto next; + if (dentry->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(dentry)) { + dget(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&sbi->lookup_lock); + spin_unlock(&dcache_lock); + return dentry; + } +next: + spin_unlock(&dentry->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, *unhashed; 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);/* File name too long to exist */ + 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, process_group(current), sbi->catatonic, oz_mode); + current->pid, task_pgrp_nr(current), 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; + unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name); + if (unhashed) + dentry = unhashed; + 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; + + spin_lock(&sbi->lookup_lock); + list_add(&ino->active, &sbi->active_list); + spin_unlock(&sbi->lookup_lock); + + d_instantiate(dentry, NULL); + } 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); - } - dentry->d_fsdata = NULL; - d_add(dentry, NULL); - - if (dentry->d_op && dentry->d_op->d_revalidate) { - mutex_unlock(&dir->i_mutex); - (dentry->d_op->d_revalidate)(dentry, nd); + if (dentry->d_op && dentry->d_op->d_revalidate) + (dentry->d_op->d_revalidate)(dentry, nd); mutex_lock(&dir->i_mutex); } @@ -505,19 +559,47 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s if (sigismember (sigset, SIGKILL) || sigismember (sigset, SIGQUIT) || sigismember (sigset, SIGINT)) { + if (unhashed) + dput(unhashed); return ERR_PTR(-ERESTARTNOINTR); } } + if (!oz_mode) { + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; + spin_unlock(&dentry->d_lock); + } } /* * 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. + * 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 ( dentry->d_inode && d_unhashed(dentry) ) - return ERR_PTR(-ENOENT); + 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 (unhashed) + dput(unhashed); + + return dentry; + } + + if (unhashed) + return unhashed; return NULL; } @@ -528,6 +610,7 @@ static int autofs4_dir_symlink(struct inode *dir, { 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; @@ -538,21 +621,32 @@ static int autofs4_dir_symlink(struct inode *dir, return -EACCES; ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555); - if (ino == NULL) - return -ENOSPC; + if (!ino) + return -ENOMEM; - ino->size = strlen(symname); - ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL); + spin_lock(&sbi->lookup_lock); + if (!list_empty(&ino->active)) + list_del_init(&ino->active); + spin_unlock(&sbi->lookup_lock); - if (cp == NULL) { - kfree(ino); - return -ENOSPC; + 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); - d_instantiate(dentry, inode); + 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; @@ -561,8 +655,13 @@ static int autofs4_dir_symlink(struct inode *dir, 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; @@ -574,9 +673,9 @@ static int autofs4_dir_symlink(struct inode *dir, * 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. + * 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. @@ -587,19 +686,33 @@ 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) ) + 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; - dentry->d_inode->i_nlink = 0; + clear_nlink(dentry->d_inode); dir->i_mtime = CURRENT_TIME; - d_drop(dentry); + spin_lock(&dcache_lock); + spin_lock(&sbi->lookup_lock); + if (list_empty(&ino->expiring)) + list_add(&ino->expiring, &sbi->expiring_list); + spin_unlock(&sbi->lookup_lock); + spin_lock(&dentry->d_lock); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); return 0; } @@ -608,7 +721,11 @@ 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; @@ -617,18 +734,26 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) spin_unlock(&dcache_lock); return -ENOTEMPTY; } + spin_lock(&sbi->lookup_lock); + if (list_empty(&ino->expiring)) + list_add(&ino->expiring, &sbi->expiring_list); + spin_unlock(&sbi->lookup_lock); 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; - dentry->d_inode->i_nlink = 0; + clear_nlink(dentry->d_inode); if (dir->i_nlink) - dir->i_nlink--; + drop_nlink(dir); return 0; } @@ -637,20 +762,31 @@ 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) ) + 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 == NULL) - return -ENOSPC; + if (!ino) + return -ENOMEM; + + spin_lock(&sbi->lookup_lock); + if (!list_empty(&ino->active)) + list_del_init(&ino->active); + spin_unlock(&sbi->lookup_lock); inode = autofs4_get_inode(dir->i_sb, ino); - d_instantiate(dentry, inode); + 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; @@ -659,8 +795,12 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) 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; - dir->i_nlink++; + inc_nlink(dir); dir->i_mtime = CURRENT_TIME; return 0; @@ -673,11 +813,11 @@ static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, int rv; unsigned long ntimeout; - if ( (rv = get_user(ntimeout, p)) || - (rv = put_user(sbi->exp_timeout/HZ, p)) ) + if ((rv = get_user(ntimeout, p)) || + (rv = put_user(sbi->exp_timeout/HZ, p))) return rv; - if ( ntimeout > ULONG_MAX/HZ ) + if (ntimeout > ULONG_MAX/HZ) sbi->exp_timeout = 0; else sbi->exp_timeout = ntimeout * HZ; @@ -698,51 +838,13 @@ static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user } /* - * Tells the daemon whether we need to reghost or not. Also, clears - * the reghost_needed flag. - */ -static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p) -{ - int status; - - DPRINTK("returning %d", sbi->needs_reghost); - - status = put_user(sbi->needs_reghost, p); - if ( status ) - return status; - - sbi->needs_reghost = 0; - return 0; -} - -/* - * Enable / Disable reghosting ioctl() operation - */ -static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p) -{ - int status; - int val; - - status = get_user(val, p); - - DPRINTK("reghost = %d", val); - - if (status) - return status; - - /* turn on/off reghosting, with the val */ - sbi->reghost_enabled = val; - return 0; -} - -/* * 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) == 0) + if (may_umount(mnt)) status = 1; DPRINTK("returning %d", status); @@ -775,13 +877,13 @@ static int autofs4_root_ioctl(struct inode *inode, struct file *filp, void __user *p = (void __user *)arg; DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", - cmd,arg,sbi,process_group(current)); + 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 ) + 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) ) + if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) return -EPERM; switch(cmd) { @@ -799,20 +901,15 @@ static int autofs4_root_ioctl(struct inode *inode, struct file *filp, case AUTOFS_IOC_SETTIMEOUT: return autofs4_get_set_timeout(sbi, p); - case AUTOFS_IOC_TOGGLEREGHOST: - return autofs4_toggle_reghost(sbi, p); - case AUTOFS_IOC_ASKREGHOST: - return autofs4_ask_reghost(sbi, p); - case AUTOFS_IOC_ASKUMOUNT: - return autofs4_ask_umount(filp->f_vfsmnt, p); + 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_vfsmnt,sbi, p); + 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_vfsmnt,sbi, p); + return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); default: return -ENOSYS;