Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965927AbXENJhH (ORCPT ); Mon, 14 May 2007 05:37:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966227AbXENJgl (ORCPT ); Mon, 14 May 2007 05:36:41 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:48875 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966218AbXENJgh (ORCPT ); Mon, 14 May 2007 05:36:37 -0400 Date: Mon, 14 May 2007 15:13:58 +0530 From: Bharata B Rao To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Jan Blunck Subject: [RFC][PATCH 11/14] VFS whiteout handling Message-ID: <20070514094358.GM4139@in.ibm.com> Reply-To: bharata@linux.vnet.ibm.com References: <20070514093722.GB4139@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070514093722.GB4139@in.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 24607 Lines: 916 From: Jan Blunck Subject: VFS whiteout handling Introduce white-out handling in the VFS. Signed-off-by: Jan Blunck Signed-off-by: Bharata B Rao --- fs/inode.c | 17 + fs/namei.c | 476 ++++++++++++++++++++++++++++++++++++++++++++++++-- fs/readdir.c | 10 + fs/union.c | 104 ++++++++++ include/linux/fs.h | 4 include/linux/union.h | 6 6 files changed, 605 insertions(+), 12 deletions(-) --- a/fs/inode.c +++ b/fs/inode.c @@ -1421,6 +1421,21 @@ void __init inode_init(unsigned long mem INIT_HLIST_HEAD(&inode_hashtable[loop]); } +/* + * Dummy default file-operations: + * Never open a whiteout. This is always a bug. + */ +static int whiteout_no_open(struct inode *irrelevant, struct file *dontcare) +{ + printk("Attemp to open a whiteout!\n"); + WARN_ON(1); + return -ENXIO; +} + +static struct file_operations def_wht_fops = { + .open = whiteout_no_open, +}; + void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) { inode->i_mode = mode; @@ -1434,6 +1449,8 @@ void init_special_inode(struct inode *in inode->i_fop = &def_fifo_fops; else if (S_ISSOCK(mode)) inode->i_fop = &bad_sock_fops; + else if (S_ISWHT(mode)) + inode->i_fop = &def_wht_fops; else printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n", mode); --- a/fs/namei.c +++ b/fs/namei.c @@ -969,7 +969,7 @@ static fastcall int __link_path_walk(con err = -ENOENT; inode = next.dentry->d_inode; - if (!inode) + if (!inode || S_ISWHT(inode->i_mode)) goto out_dput; err = -ENOTDIR; if (!inode->i_op) @@ -1043,6 +1043,12 @@ last_component: err = -ENOENT; if (!inode) break; + if (S_ISWHT(inode->i_mode)) { + UM_DEBUG_UID("found a whiteout\n"); + break; + //if (!(nd->flags & LOOKUP_WHT)) + // break; + } if (lookup_flags & LOOKUP_DIRECTORY) { err = -ENOTDIR; if (!inode->i_op || !inode->i_op->lookup) @@ -1556,7 +1562,7 @@ static int may_delete(struct inode *dir, static inline int may_create(struct inode *dir, struct dentry *child, struct nameidata *nd) { - if (child->d_inode) + if (child->d_inode && !S_ISWHT(child->d_inode->i_mode)) return -EEXIST; if (IS_DEADDIR(dir)) return -ENOENT; @@ -1623,6 +1629,82 @@ void unlock_rename(struct dentry *p1, st } } +/* + * __vfs_unlink_whiteout - Unlink a single whiteout from the system + * @dir: parent directory + * @dentry: the whiteout itself + * + * This is for unlinking a single whiteout. Don't use vfs_unlink() because we + * don't want any notification stuff etc. but basically it is the same stuff. + */ +static int +__vfs_unlink_whiteout(struct inode *dir, struct dentry *dentry) +{ + int error = may_delete(dir, dentry, 0); + + if (error) + return error; + + if (!dir->i_op || !dir->i_op->unlink) + return -EPERM; + + DQUOT_INIT(dir); + + mutex_lock(&dentry->d_inode->i_mutex); + if (d_mountpoint(dentry)) + error = -EBUSY; + else { + error = security_inode_unlink(dir, dentry); + if (!error) + error = dir->i_op->unlink(dir, dentry); + } + mutex_unlock(&dentry->d_inode->i_mutex); + + /* We don't d_delete() NFS sillyrenamed files--they still exist. */ + if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { + d_delete(dentry); + //inode_dir_notify(dir, DN_DELETE); + } + return error; +} + +/* + * vfs_unlink_whiteout - unlink and relookup the whiteout + * + * This is what you want to call from vfs_* functions to remove a whiteout. It + * unlinks the whiteout dentry and relookups it afterwards. + */ +static int +vfs_unlink_whiteout(struct inode *dir, struct dentry **dp) +{ + struct dentry *dentry = *dp; + struct dentry *parent = dentry->d_parent; + struct qstr name; + int error; + + BUG_ON(dir != parent->d_inode); + + error = -ENOMEM; + name.name = kmalloc(dentry->d_name.len, GFP_KERNEL); + if (!name.name) + goto out; + strncpy((char *)name.name, dentry->d_name.name, dentry->d_name.len); + name.len = dentry->d_name.len; + name.hash = dentry->d_name.hash; + + error = __vfs_unlink_whiteout(dir, dentry); + if (error) + goto out_freename; + + __dput_single(dentry); + *dp = __lookup_hash_single(&name, parent, NULL); + BUG_ON(IS_ERR(*dp)); /* Hmm, very hard response here */ +out_freename: + kfree(name.name); +out: + return error; +} + int vfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) { @@ -1638,6 +1720,13 @@ int vfs_create(struct inode *dir, struct error = security_inode_create(dir, dentry, mode); if (error) return error; + + if (dentry->d_inode && S_ISWHT(dentry->d_inode->i_mode)) { + error = vfs_unlink_whiteout(dir, &dentry); + if (error) + return error; + } + DQUOT_INIT(dir); error = dir->i_op->create(dir, dentry, mode, nd); if (!error) @@ -1833,7 +1922,14 @@ do_last: } /* Negative dentry, just create the file */ - if (!path.dentry->d_inode) { + if (!path.dentry->d_inode || S_ISWHT(path.dentry->d_inode->i_mode)) { + if (path.dentry->d_parent != dir) { + UM_DEBUG_UID("found a lower layers whiteout\n"); + dput(path.dentry); + path.dentry = __lookup_hash_single(&nd->last, dir, nd); + goto do_last; + } + error = open_namei_create(nd, &path, flag, mode); if (error) goto exit; @@ -1949,6 +2045,17 @@ do_link: struct dentry *lookup_create(struct nameidata *nd, int is_dir) { struct dentry *dentry = ERR_PTR(-EEXIST); + int error; + + if (union_is_member(nd->dentry, nd->mnt)) { + error = union_relookup_topmost(nd, nd->flags & ~LOOKUP_PARENT); + if (error) { + /* FIXME: This really sucks */ + mutex_lock_nested(&nd->dentry->d_inode->i_mutex, + I_MUTEX_PARENT); + goto fail; + } + } mutex_lock_nested(&nd->dentry->d_inode->i_mutex, I_MUTEX_PARENT); /* @@ -1968,6 +2075,15 @@ struct dentry *lookup_create(struct name if (IS_ERR(dentry)) goto fail; + /* Special case - we found a whiteout */ + if (dentry->d_inode && S_ISWHT(dentry->d_inode->i_mode)) { + if (dentry->d_parent != nd->dentry) { + UM_DEBUG_UID("found a lower layers whiteout\n"); + dput(dentry); + dentry = __lookup_hash_single(&nd->last,nd->dentry,nd); + } + } + /* * Special case - lookup gave negative, but... we had foo/bar/ * From the vfs_mknod() POV we just have a negative dentry - @@ -2002,6 +2118,12 @@ int vfs_mknod(struct inode *dir, struct if (error) return error; + if (dentry->d_inode && S_ISWHT(dentry->d_inode->i_mode)) { + error = vfs_unlink_whiteout(dir, &dentry); + if (error) + return error; + } + DQUOT_INIT(dir); error = dir->i_op->mknod(dir, dentry, mode, dev); if (!error) @@ -2067,6 +2189,7 @@ asmlinkage long sys_mknod(const char __u int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) { int error = may_create(dir, dentry, NULL); + int opaque; if (error) return error; @@ -2079,10 +2202,23 @@ int vfs_mkdir(struct inode *dir, struct if (error) return error; + if (dentry->d_inode && S_ISWHT(dentry->d_inode->i_mode)) { + error = vfs_unlink_whiteout(dir, &dentry); + if (error) + return error; + opaque = 1; + } else + opaque = 0; + DQUOT_INIT(dir); error = dir->i_op->mkdir(dir, dentry, mode); - if (!error) + if (!error) { fsnotify_mkdir(dir, dentry); +#ifdef CONFIG_UNION_MOUNT + if (opaque && dentry->d_parent->d_overlaid) + dentry->d_inode->i_flags |= S_OPAQUE; +#endif + } return error; } @@ -2124,6 +2260,225 @@ asmlinkage long sys_mkdir(const char __u return sys_mkdirat(AT_FDCWD, pathname, mode); } +/* Checks on the victiom for whiteout */ +static inline int may_whiteout(struct dentry *victim, int isdir) +{ + if (!victim->d_inode || S_ISWHT(victim->d_inode->i_mode)) + return -ENOENT; + if (IS_APPEND(victim->d_inode) || IS_IMMUTABLE(victim->d_inode)) + return -EPERM; + if (isdir) { + if (!S_ISDIR(victim->d_inode->i_mode)) + return -ENOTDIR; + if (IS_ROOT(victim)) + return -EBUSY; + if (!union_dir_is_empty(victim)) + return -ENOTEMPTY; + } else if (S_ISDIR(victim->d_inode->i_mode)) + return -EISDIR; + if (victim->d_flags & DCACHE_NFSFS_RENAMED) + return -EBUSY; + return 0; +} + +/* + * We try to whiteout a dentry. dir is the parent of the whiteout. + * Whiteouts can be vfs_unlink'ed. + */ +int vfs_whiteout(struct inode *dir, struct dentry *dentry) +{ + int err; + + BUG_ON(dentry->d_parent->d_inode != dir); + + /* from may_create() */ + if (dentry->d_inode) + return -EEXIST; + if (IS_DEADDIR(dir)) + return -ENOENT; + err = permission(dir, MAY_WRITE | MAY_EXEC, NULL); + if (err) + return err; + + /* from may_delete() */ + if (IS_APPEND(dir)) + return -EPERM; + /* We don't call check_sticky() here because d_inode == NULL */ + + if (!dir->i_op || !dir->i_op->whiteout) + return -EOPNOTSUPP; + + err = dir->i_op->whiteout(dir, dentry); + /* Ignore quota and fsnotify */ + return err; +} + +/* + * do_whiteout - whiteout a dentry, either when removing or renaming + * @dentry: the dentry to whiteout + * + * This is called by the VFS when removing or renaming files on an union mount. + */ +static int do_whiteout(struct dentry *parent, struct dentry *dentry, int isdir) +{ + int err; + struct qstr name; + + UM_DEBUG_UID("parent=\"%s\", dentry=\"%s\", isdir=%d\n", + parent->d_name.name, dentry->d_name.name, isdir); + + err = may_whiteout(dentry, isdir); + if (err) + goto out; + + err = -ENOMEM; + name.name = kmalloc(dentry->d_name.len, GFP_KERNEL); + if (!name.name) + goto out; + strncpy((char *)name.name, dentry->d_name.name, dentry->d_name.len); + name.len = dentry->d_name.len; + name.hash = dentry->d_name.hash; + + /* + * TODO: Should we BUG_ON(dentry->d_parent != parent) ? + */ + if (dentry->d_parent == parent) { + if (isdir) + err = vfs_rmdir(parent->d_inode, dentry); + else + err = vfs_unlink(parent->d_inode, dentry); + dput(dentry); + if (err) + goto out_freename; + } + + /* + * Relookup the dentry to whiteout now. By this time, the dentry is + * dput'ed in vfs_rmdir or vfs_unlink and we should find a fresh + * negative dentry. + */ + dentry = __lookup_hash_single(&name, parent, NULL); + err = PTR_ERR(dentry); + if (IS_ERR(dentry)) + goto out_freename; + + err = vfs_whiteout(parent->d_inode, dentry); + __dput_single(dentry); +out_freename: + kfree(name.name); +out: + return err; +} + +static int +__hash_one_len(const char *name, int len, struct qstr *this) +{ + unsigned long hash; + unsigned int c; + + hash = init_name_hash(); + while (len--) { + c = *(const unsigned char *)name++; + if (c == '/' || c == '\0') + return -EINVAL; + hash = partial_name_hash(c, hash); + } + this->hash = end_name_hash(hash); + return 0; +} + +static int unlink_whiteouts_filldir(void *buf, const char *name, int namlen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct dentry *parent = buf; + struct dentry *dentry; + struct qstr this; + int res; + + switch (namlen) { + case 2: + if (name[1] != '.') + break; + case 1: + if (name[0] != '.') + break; + return 0; + } + + UM_DEBUG_UID("name=\"%s\", d_type=%d\n", name, d_type); + + if (d_type != DT_WHT) + return 0; + + this.name = name; + this.len = namlen; + res = __hash_one_len(name, namlen, &this); + if (res) + return res; + + dentry = __lookup_hash_single(&this, parent, NULL); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + res = __vfs_unlink_whiteout(parent->d_inode, dentry); + __dput_single(dentry); + return res; +} + +/* + * do_unlink_whiteouts - remove all whiteouts of an "empty" directory + * @dentry: the directories dentry + * + * Before removing a directory from the file system, we have to make sure + * that there are no stale whiteouts in it. Therefore we call readdir() with + * a special filldir helper to remove all the whiteouts. + * + * XXX: Don't call any security and permission checks here (If we aren't + * allowed to go here, we shouldn't be here at all). Same with i_mutex, don't + * touch it here. + */ +static int do_unlink_whiteouts(struct dentry *dentry) +{ + struct file *file; + struct vfsmount *mnt; + struct inode *inode; + int res; + + dget(dentry); + mnt = find_mnt(dentry); + + /* + * FIXME: This is bad, because we really don't want to open a new + * file in the kernel but readdir needs a file pointer + */ + file = dentry_open(dentry, mnt, O_RDWR); + if (IS_ERR(file)) { + printk(KERN_ERR "%s: dentry_open failed (%ld)\n", + __FUNCTION__, PTR_ERR(file)); + return PTR_ERR(file); + } + + inode = file->f_path.dentry->d_inode; + + res = -ENOTDIR; + if (!file->f_op || !file->f_op->readdir) + goto out_fput; + + res = -ENOENT; + if (!IS_DEADDIR(inode)) { + res = file->f_op->readdir(file, (void *)file->f_path.dentry, + unlink_whiteouts_filldir); + file_accessed(file); + } +out_fput: + fput(file); + if (unlikely(res)) + printk(KERN_ERR "%s: readdir failed (%d)\n", + __FUNCTION__, res); + return res; +} + + /* * We try to drop the dentry early: we should have * a usage count of 2 if we're the only user of this @@ -2153,8 +2508,12 @@ void dentry_unhash(struct dentry *dentry int vfs_rmdir(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 1); + int error; + if (!dentry->d_inode || S_ISWHT(dentry->d_inode->i_mode)) + return -ENOENT; + + error = may_delete(dir, dentry, 1); if (error) return error; @@ -2170,11 +2529,15 @@ int vfs_rmdir(struct inode *dir, struct else { error = security_inode_rmdir(dir, dentry); if (!error) { + error = do_unlink_whiteouts(dentry); + if (error) + goto out; error = dir->i_op->rmdir(dir, dentry); if (!error) dentry->d_inode->i_flags |= S_DEAD; } } + out: mutex_unlock(&dentry->d_inode->i_mutex); if (!error) { d_delete(dentry); @@ -2215,8 +2578,41 @@ static long do_rmdir(int dfd, const char error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto exit2; - error = vfs_rmdir(nd.dentry->d_inode, dentry); - dput(dentry); + + if (!union_is_member(nd.dentry, nd.mnt)) { + /* Not a member of union, normal removal */ + error = vfs_rmdir(nd.dentry->d_inode, dentry); + dput(dentry); + goto exit2; + } + + if (dentry->d_parent == nd.dentry) { + /* + * Topmost dentry of the union. Check if there + * is a dentry of same name in the lower layers. + * If so create a whiteout before unlinking. + * Else normal removal. + */ + if (present_in_lower(dentry, &nd)) + error = do_whiteout(nd.dentry, dentry, 1); + else { + error = vfs_rmdir(nd.dentry->d_inode, dentry); + dput(dentry); + } + } else { + /* + * Lower layer dentry of the union. Relookup + * the dentry in the top layer(which should return + * a negative dentry) create a whiteout there. + */ + dput(dentry); + dentry = __lookup_hash_single(&nd.last, nd.dentry, &nd); + error = PTR_ERR(dentry); + if (IS_ERR(dentry)) + goto exit2; + error = vfs_whiteout(nd.dentry->d_inode, dentry); + __dput_single(dentry); + } exit2: mutex_unlock(&nd.dentry->d_inode->i_mutex); exit1: @@ -2295,10 +2691,44 @@ static long do_unlinkat(int dfd, const c inode = dentry->d_inode; if (inode) atomic_inc(&inode->i_count); - error = vfs_unlink(nd.dentry->d_inode, dentry); - exit2: - dput(dentry); + + if (!union_is_member(nd.dentry, nd.mnt)) { + /* Not a member of union, normal removal */ + error = vfs_unlink(nd.dentry->d_inode, dentry); + dput(dentry); + goto exit2; + } + + /* TODO: fix this code duplication with do_rmdir() */ + if (dentry->d_parent == nd.dentry) { + /* + * Topmost dentry of the union. Check if there + * is a dentry of same name in the lower layers. + * If so create a whiteout before unlinking. + * Else normal removal. + */ + if (present_in_lower(dentry, &nd)) + error = do_whiteout(nd.dentry, dentry, 0); + else { + error = vfs_unlink(nd.dentry->d_inode, dentry); + dput(dentry); + } + } else { + /* + * Lower layer dentry of the union. Relookup + * the dentry in the top layer(which should return + * a negative dentry) create a whiteout there. + */ + dput(dentry); + dentry = __lookup_hash_single(&nd.last, nd.dentry, &nd); + error = PTR_ERR(dentry); + if (IS_ERR(dentry)) + goto exit2; + error = vfs_whiteout(nd.dentry->d_inode, dentry); + __dput_single(dentry); + } } +exit2: mutex_unlock(&nd.dentry->d_inode->i_mutex); if (inode) iput(inode); /* truncate the inode here */ @@ -2311,6 +2741,7 @@ exit: slashes: error = !dentry->d_inode ? -ENOENT : S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; + dput(dentry); goto exit2; } @@ -2344,6 +2775,12 @@ int vfs_symlink(struct inode *dir, struc if (error) return error; + if (dentry->d_inode && S_ISWHT(dentry->d_inode->i_mode)) { + error = vfs_unlink_whiteout(dir, &dentry); + if (error) + return error; + } + DQUOT_INIT(dir); error = dir->i_op->symlink(dir, dentry, oldname); if (!error) @@ -2398,7 +2835,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *inode = old_dentry->d_inode; int error; - if (!inode) + if (!inode || S_ISWHT(inode->i_mode)) return -ENOENT; error = may_create(dir, new_dentry, NULL); @@ -2674,7 +3111,7 @@ static int do_rename(int olddfd, const c goto exit3; /* source must exist */ error = -ENOENT; - if (!old_dentry->d_inode) + if (!old_dentry->d_inode || S_ISWHT(old_dentry->d_inode->i_mode)) goto exit4; /* unless the source is a directory trailing slashes give -ENOTDIR */ if (!S_ISDIR(old_dentry->d_inode->i_mode)) { @@ -2696,6 +3133,21 @@ static int do_rename(int olddfd, const c error = -ENOTEMPTY; if (new_dentry == trap) goto exit5; + error = -EXDEV; + /* renaming of directories on unions isn't implemented, yet */ + if (union_is_member(old_dentry, oldnd.mnt)) { + error = -EOPNOTSUPP; + if (S_ISDIR(old_dentry->d_inode->i_mode)) + goto exit5; + error = -EXDEV; + if (oldnd.um_flags & LAST_LOWLEVEL) + goto exit5; + } + if (union_is_member(new_dentry, newnd.mnt)) { + error = -EXDEV; + if (newnd.um_flags & LAST_LOWLEVEL) + goto exit5; + } error = vfs_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, new_dentry); --- a/fs/readdir.c +++ b/fs/readdir.c @@ -148,6 +148,11 @@ static int filldir(void * __buf, const c unsigned long d_ino; int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 2, sizeof(long)); +#ifdef CONFIG_UNION_MOUNT + if (d_type == DT_WHT) + return 0; +#endif /* CONFIG_UNION_MOUNT */ + buf->error = -EINVAL; /* only used if we fail.. */ if (reclen > buf->count) return -EINVAL; @@ -233,6 +238,11 @@ static int filldir64(void * __buf, const struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 1, sizeof(u64)); +#ifdef CONFIG_UNION_MOUNT + if (d_type == DT_WHT) + return 0; +#endif /* CONFIG_UNION_MOUNT */ + buf->error = -EINVAL; /* only used if we fail.. */ if (reclen > buf->count) return -EINVAL; --- a/fs/union.c +++ b/fs/union.c @@ -594,6 +594,9 @@ lookup_union: if (!S_ISDIR(topmost->d_inode->i_mode)) goto out; + if (IS_OPAQUE(topmost->d_inode)) + goto out; + if (!revalidate_union(topmost)) { __dput_single(topmost); topmost = NULL; @@ -664,6 +667,8 @@ lookup_union: dentry->d_topmost = topmost; last->d_overlaid = dentry; last = dentry; + if (IS_OPAQUE(last->d_inode)) + break; parent = parent->d_overlaid; } @@ -822,6 +827,8 @@ static int __lookup_union(struct dentry loop: __dput(nd.dentry); mntput(nd.mnt); + if (IS_OPAQUE(last->d_inode)) + break; parent = parent->d_overlaid; } @@ -912,6 +919,9 @@ lookup_union: if (!parent->d_overlaid || !S_ISDIR(topmost->d_inode->i_mode)) goto out; + if (IS_OPAQUE(topmost->d_inode)) + goto out; + do { struct vfsmount *mnt = find_mnt(topmost); UM_DEBUG_UID("name=\"%s\", inode=%p, device=%s\n", @@ -988,6 +998,9 @@ lookup_union: if (!parent->d_overlaid || !S_ISDIR(topmost->d_inode->i_mode)) goto out; + if (IS_OPAQUE(topmost->d_inode)) + goto out; + do { struct vfsmount *mnt = find_mnt(topmost); UM_DEBUG_UID("name=\"%s\", inode=%p, device=%s\n", @@ -1787,3 +1800,94 @@ exit_dput: dput(dentry); return err; } + +static int +filldir_dummy(void *__buf, const char *name, int namlen, loff_t offset, + u64 ino, unsigned int d_type) +{ + int *is_empty = (int *)__buf; + + switch (namlen) { + case 2: + if (name[1] != '.') + break; + case 1: + if (name[0] != '.') + break; + return 0; + } + + if (d_type == DT_WHT) + return 0; + + (*is_empty) = 0; + return 0; +} + +int +union_dir_is_empty(struct dentry *dentry) +{ + struct file *file; + struct vfsmount *mnt; + int err; + int is_empty = 1; + + BUG_ON(!S_ISDIR(dentry->d_inode->i_mode)); + + dget(dentry); + mnt = find_mnt(dentry); + + file = dentry_open(dentry, mnt, O_RDONLY); + if (IS_ERR(file)) + return 0; + + err = vfs_readdir(file, filldir_dummy, &is_empty); + UM_DEBUG("err=%d, is_empty=%d\n", err, is_empty); + + fput(file); + return is_empty; +} + +int present_in_lower(struct dentry *dentry, struct nameidata *nd) +{ + int err = 0; + struct dentry *parent = nd->dentry->d_overlaid; + struct dentry *tmp; + struct nameidata nd_tmp; + struct qstr this; + + this.name = nd->last.name; + this.len = nd->last.len; + + while (parent) { + this.hash = nd->last.hash; + nd_tmp.dentry = dget(parent); + nd_tmp.mnt = find_mnt(parent); + mutex_lock(&parent->d_inode->i_mutex); + tmp = __lookup_hash_single(&this, nd_tmp.dentry, &nd_tmp); + mutex_unlock(&parent->d_inode->i_mutex); + /* + * If there is an error in lookup, we return 0 concluding + * that this dentry is not present in lower layers. + */ + if (IS_ERR(tmp)) + goto out; + + if (tmp->d_inode) { + __dput_single(tmp); + err = 1; + goto out; + } + + __dput_single(tmp); + mntput(nd_tmp.mnt); + dput(nd_tmp.dentry); + parent = parent->d_overlaid; + } + + return err; +out: + mntput(nd_tmp.mnt); + dput(nd_tmp.dentry); + return err; +} --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -157,6 +157,7 @@ extern int dir_notify_enable; #define S_NOCMTIME 128 /* Do not update file c/mtime */ #define S_SWAPFILE 256 /* Do not truncate: swapon got its bmaps */ #define S_PRIVATE 512 /* Inode is fs-internal */ +#define S_OPAQUE 1024 /* Directory is opaque */ /* * Note that nosuid etc flags are inode-specific: setting some file-system @@ -190,6 +191,7 @@ extern int dir_notify_enable; #define IS_NOCMTIME(inode) ((inode)->i_flags & S_NOCMTIME) #define IS_SWAPFILE(inode) ((inode)->i_flags & S_SWAPFILE) #define IS_PRIVATE(inode) ((inode)->i_flags & S_PRIVATE) +#define IS_OPAQUE(inode) ((inode)->i_flags & S_OPAQUE) /* the read-only stuff doesn't really belong here, but any other place is probably as bad and I don't want to create yet another include file. */ @@ -1050,6 +1052,7 @@ extern int vfs_link(struct dentry *, str extern int vfs_rmdir(struct inode *, struct dentry *); extern int vfs_unlink(struct inode *, struct dentry *); extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *); +extern int vfs_whiteout(struct inode *, struct dentry *); /* * VFS dentry helper functions. @@ -1175,6 +1178,7 @@ struct inode_operations { int (*mkdir) (struct inode *,struct dentry *,int); int (*rmdir) (struct inode *,struct dentry *); int (*mknod) (struct inode *,struct dentry *,int,dev_t); + int (*whiteout) (struct inode *, struct dentry *); int (*rename) (struct inode *, struct dentry *, struct inode *, struct dentry *); int (*readlink) (struct dentry *, char __user *,int); --- a/include/linux/union.h +++ b/include/linux/union.h @@ -43,6 +43,10 @@ extern int union_copy_file(struct dentry extern int union_copyup(struct nameidata *, int); extern int union_relookup_topmost(struct nameidata *, int); +/* vfs whiteout support */ +extern int union_dir_is_empty(struct dentry *); +extern int present_in_lower(struct dentry *, struct nameidata *); + #else /* CONFIG_UNION_MOUNT */ #define attach_mnt_union(mnt,nd) do { /* empty */ } while (0) @@ -54,6 +58,8 @@ extern int union_relookup_topmost(struct #define union_copy_file(dentry1,mnt1,dentry2,mnt2) ({ (0); }) #define union_copyup(x,y) ({ (0); }) #define union_relookup_topmost(x,y) ({ (0); }) +#define union_dir_is_empty(x) ({ (1); }) +#define present_in_lower(x, y) ({ (0); }) #endif /* CONFIG_UNION_MOUNT */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/