c746ed724d
In certain emergency cases such as media failure or removal, UFS will initiate a forced unmount in order to prevent dirty buffers from accumulating against the no-longer-usable filesystem. The presence of a stacked filesystem such as nullfs or unionfs above the UFS mount will prevent this forced unmount from succeeding. This change addreses the situation by allowing stacked filesystems to be recursively unmounted on a taskqueue thread when the MNT_RECURSE flag is specified to dounmount(). This call will block until all upper mounts have been removed unless the caller specifies the MNT_DEFERRED flag to indicate the base filesystem should also be unmounted from the taskqueue. To achieve this, the recently-added vfs_pin_from_vp()/vfs_unpin() KPIs have been combined with the existing 'mnt_uppers' list used by nullfs and renamed to vfs_register_upper_from_vp()/vfs_unregister_upper(). The format of the mnt_uppers list has also been changed to accommodate filesystems such as unionfs in which a given mount may be stacked atop more than one lower mount. Additionally, management of lower FS reclaim/unlink notifications has been split into a separate list managed by a separate set of KPIs, as registration of an upper FS no longer implies interest in these notifications. Reviewed by: kib, mckusick Tested by: pho Differential Revision: https://reviews.freebsd.org/D31016
157 lines
6.6 KiB
C
157 lines
6.6 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1994 The Regents of the University of California.
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* Copyright (c) 1994 Jan-Simon Pendry.
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* Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
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* Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
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* All rights reserved.
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*
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* This code is derived from software donated to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)union.h 8.9 (Berkeley) 12/10/94
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* $FreeBSD$
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*/
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#ifdef _KERNEL
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/* copy method of attr from lower to upper */
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typedef enum _unionfs_copymode {
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UNIONFS_TRADITIONAL = 0,
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UNIONFS_TRANSPARENT,
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UNIONFS_MASQUERADE
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} unionfs_copymode;
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/* whiteout policy of upper layer */
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typedef enum _unionfs_whitemode {
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UNIONFS_WHITE_ALWAYS = 0,
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UNIONFS_WHITE_WHENNEEDED
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} unionfs_whitemode;
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struct unionfs_mount {
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struct vnode *um_lowervp; /* VREFed once */
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struct vnode *um_uppervp; /* VREFed once */
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struct vnode *um_rootvp; /* ROOT vnode */
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struct mount_upper_node um_lower_link; /* node in lower FS list of uppers */
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struct mount_upper_node um_upper_link; /* node in upper FS list of uppers */
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unionfs_copymode um_copymode;
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unionfs_whitemode um_whitemode;
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uid_t um_uid;
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gid_t um_gid;
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u_short um_udir;
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u_short um_ufile;
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};
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/* unionfs status list */
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struct unionfs_node_status {
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LIST_ENTRY(unionfs_node_status) uns_list; /* Status list */
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pid_t uns_pid; /* current process id */
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int uns_node_flag; /* uns flag */
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int uns_lower_opencnt; /* open count of lower */
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int uns_upper_opencnt; /* open count of upper */
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int uns_lower_openmode; /* open mode of lower */
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int uns_readdir_status; /* read status of readdir */
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};
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/* union node status flags */
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#define UNS_OPENL_4_READDIR 0x01 /* open lower layer for readdir */
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/* A cache of vnode references */
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struct unionfs_node {
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struct vnode *un_lowervp; /* lower side vnode */
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struct vnode *un_uppervp; /* upper side vnode */
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struct vnode *un_dvp; /* parent unionfs vnode */
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struct vnode *un_vnode; /* Back pointer */
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LIST_HEAD(, unionfs_node_status) un_unshead;
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/* unionfs status head */
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LIST_HEAD(unionfs_node_hashhead, unionfs_node) *un_hashtbl;
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/* dir vnode hash table */
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union {
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LIST_ENTRY(unionfs_node) un_hash; /* hash list entry */
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STAILQ_ENTRY(unionfs_node) un_rele; /* deferred release list */
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};
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u_long un_hashmask; /* bit mask */
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char *un_path; /* path */
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int un_flag; /* unionfs node flag */
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};
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/*
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* unionfs node flags
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* It needs the vnode with exclusive lock, when changing the un_flag variable.
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*/
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#define UNIONFS_OPENEXTL 0x01 /* openextattr (lower) */
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#define UNIONFS_OPENEXTU 0x02 /* openextattr (upper) */
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#define MOUNTTOUNIONFSMOUNT(mp) ((struct unionfs_mount *)((mp)->mnt_data))
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#define VTOUNIONFS(vp) ((struct unionfs_node *)(vp)->v_data)
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#define UNIONFSTOV(xp) ((xp)->un_vnode)
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int unionfs_init(struct vfsconf *vfsp);
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int unionfs_uninit(struct vfsconf *vfsp);
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int unionfs_nodeget(struct mount *mp, struct vnode *uppervp, struct vnode *lowervp, struct vnode *dvp, struct vnode **vpp, struct componentname *cnp, struct thread *td);
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void unionfs_noderem(struct vnode *vp, struct thread *td);
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void unionfs_get_node_status(struct unionfs_node *unp, struct thread *td, struct unionfs_node_status **unspp);
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void unionfs_tryrem_node_status(struct unionfs_node *unp, struct unionfs_node_status *unsp);
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int unionfs_check_rmdir(struct vnode *vp, struct ucred *cred, struct thread *td);
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int unionfs_copyfile(struct unionfs_node *unp, int docopy, struct ucred *cred, struct thread *td);
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void unionfs_create_uppervattr_core(struct unionfs_mount *ump, struct vattr *lva, struct vattr *uva, struct thread *td);
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int unionfs_create_uppervattr(struct unionfs_mount *ump, struct vnode *lvp, struct vattr *uva, struct ucred *cred, struct thread *td);
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int unionfs_mkshadowdir(struct unionfs_mount *ump, struct vnode *duvp, struct unionfs_node *unp, struct componentname *cnp, struct thread *td);
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int unionfs_mkwhiteout(struct vnode *dvp, struct componentname *cnp, struct thread *td, char *path);
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int unionfs_relookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp, struct componentname *cn, struct thread *td, char *path, int pathlen, u_long nameiop);
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int unionfs_relookup_for_create(struct vnode *dvp, struct componentname *cnp, struct thread *td);
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int unionfs_relookup_for_delete(struct vnode *dvp, struct componentname *cnp, struct thread *td);
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int unionfs_relookup_for_rename(struct vnode *dvp, struct componentname *cnp, struct thread *td);
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#ifdef DIAGNOSTIC
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struct vnode *unionfs_checklowervp(struct vnode *vp, char *fil, int lno);
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struct vnode *unionfs_checkuppervp(struct vnode *vp, char *fil, int lno);
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#define UNIONFSVPTOLOWERVP(vp) unionfs_checklowervp((vp), __FILE__, __LINE__)
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#define UNIONFSVPTOUPPERVP(vp) unionfs_checkuppervp((vp), __FILE__, __LINE__)
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#else
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#define UNIONFSVPTOLOWERVP(vp) (VTOUNIONFS(vp)->un_lowervp)
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#define UNIONFSVPTOUPPERVP(vp) (VTOUNIONFS(vp)->un_uppervp)
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#endif
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extern struct vop_vector unionfs_vnodeops;
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#ifdef MALLOC_DECLARE
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MALLOC_DECLARE(M_UNIONFSNODE);
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MALLOC_DECLARE(M_UNIONFSPATH);
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#endif
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#ifdef UNIONFS_DEBUG
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#define UNIONFSDEBUG(format, args...) printf(format ,## args)
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#else
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#define UNIONFSDEBUG(format, args...)
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#endif /* UNIONFS_DEBUG */
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#endif /* _KERNEL */
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