freebsd-skq/sys/fs/nfsclient/nfsnode.h
Rick Macklem e2eb210c09 Fix a LOR in the NFS client which could cause a deadlock.
This was reported to the mailing list freebsd-net@freebsd.org
on July 21, 2011 under the subject "LOR with nfsclient sillyrename".
The LOR occurred when nfs_inactive() called vrele(sp->s_dvp)
while holding the vnode lock on the file in s_dvp. This patch
modifies the client so that it performs the vrele(sp->s_dvp)
as a separate task to avoid the LOR. This fix was discussed
with jhb@ and kib@, who both proposed variations of it.

Tested by:	pho, jlott at averesystems.com
Submitted by:	jhb (earlier version)
Reviewed by:	kib
Approved by:	re (kib)
MFC after:	2 weeks
2011-08-02 11:28:42 +00:00

194 lines
7.3 KiB
C

/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NFSCLIENT_NFSNODE_H_
#define _NFSCLIENT_NFSNODE_H_
#include <sys/_task.h>
/*
* Silly rename structure that hangs off the nfsnode until the name
* can be removed by nfs_inactive()
*/
struct sillyrename {
struct task s_task;
struct ucred *s_cred;
struct vnode *s_dvp;
long s_namlen;
char s_name[32];
};
/*
* This structure is used to save the logical directory offset to
* NFS cookie mappings.
* The mappings are stored in a list headed
* by n_cookies, as required.
* There is one mapping for each NFS_DIRBLKSIZ bytes of directory information
* stored in increasing logical offset byte order.
*/
#define NFSNUMCOOKIES 31
struct nfsdmap {
LIST_ENTRY(nfsdmap) ndm_list;
int ndm_eocookie;
union {
nfsuint64 ndmu3_cookies[NFSNUMCOOKIES];
uint64_t ndmu4_cookies[NFSNUMCOOKIES];
} ndm_un1;
};
#define ndm_cookies ndm_un1.ndmu3_cookies
#define ndm4_cookies ndm_un1.ndmu4_cookies
struct nfs_accesscache {
u_int32_t mode; /* ACCESS mode cache */
uid_t uid; /* credentials having mode */
time_t stamp; /* mode cache timestamp */
};
/*
* The nfsnode is the nfs equivalent to ufs's inode. Any similarity
* is purely coincidental.
* There is a unique nfsnode allocated for each active file,
* each current directory, each mounted-on file, text file, and the root.
* An nfsnode is 'named' by its file handle. (nget/nfs_node.c)
* If this structure exceeds 256 bytes (it is currently 256 using 4.4BSD-Lite
* type definitions), file handles of > 32 bytes should probably be split out
* into a separate MALLOC()'d data structure. (Reduce the size of nfsfh_t by
* changing the definition in nfsproto.h of NFS_SMALLFH.)
* NB: Hopefully the current order of the fields is such that everything will
* be well aligned and, therefore, tightly packed.
*/
struct nfsnode {
struct mtx n_mtx; /* Protects all of these members */
u_quad_t n_size; /* Current size of file */
u_quad_t n_brev; /* Modify rev when cached */
u_quad_t n_lrev; /* Modify rev for lease */
struct nfsvattr n_vattr; /* Vnode attribute cache */
time_t n_attrstamp; /* Attr. cache timestamp */
struct nfs_accesscache n_accesscache[NFS_ACCESSCACHESIZE];
struct timespec n_mtime; /* Prev modify time. */
struct timespec n_ctime; /* Prev create time. */
struct timespec n_dmtime; /* Prev dir modify time. */
int n_dmtime_ticks; /* Tick of -ve cache entry */
struct nfsfh *n_fhp; /* NFS File Handle */
struct vnode *n_vnode; /* associated vnode */
struct vnode *n_dvp; /* parent vnode */
struct lockf *n_lockf; /* Locking record of file */
int n_error; /* Save write error value */
union {
struct timespec nf_atim; /* Special file times */
nfsuint64 nd_cookieverf; /* Cookie verifier (dir only) */
u_char nd4_cookieverf[NFSX_VERF];
} n_un1;
union {
struct timespec nf_mtim;
off_t nd_direof; /* Dir. EOF offset cache */
} n_un2;
union {
struct sillyrename *nf_silly; /* Ptr to silly rename struct */
LIST_HEAD(, nfsdmap) nd_cook; /* cookies */
} n_un3;
short n_fhsize; /* size in bytes, of fh */
u_int32_t n_flag; /* Flag for locking.. */
int n_directio_opens;
int n_directio_asyncwr;
u_int64_t n_change; /* old Change attribute */
struct nfsv4node *n_v4; /* extra V4 stuff */
};
#define n_atim n_un1.nf_atim
#define n_mtim n_un2.nf_mtim
#define n_sillyrename n_un3.nf_silly
#define n_cookieverf n_un1.nd_cookieverf
#define n4_cookieverf n_un1.nd4_cookieverf
#define n_direofoffset n_un2.nd_direof
#define n_cookies n_un3.nd_cook
/*
* Flags for n_flag
*/
#define NDIRCOOKIELK 0x00000001 /* Lock to serialize access to directory cookies */
#define NFSYNCWAIT 0x00000002 /* fsync waiting for all directio async
writes to drain */
#define NMODIFIED 0x00000004 /* Might have a modified buffer in bio */
#define NWRITEERR 0x00000008 /* Flag write errors so close will know */
#define NCREATED 0x00000010 /* Opened by nfs_create() */
#define NTRUNCATE 0x00000020 /* Opened by nfs_setattr() */
#define NSIZECHANGED 0x00000040 /* File size has changed: need cache inval */
#define NNONCACHE 0x00000080 /* Node marked as noncacheable */
#define NACC 0x00000100 /* Special file accessed */
#define NUPD 0x00000200 /* Special file updated */
#define NCHG 0x00000400 /* Special file times changed */
#define NDELEGMOD 0x00000800 /* Modified delegation */
#define NDELEGRECALL 0x00001000 /* Recall in progress */
#define NREMOVEINPROG 0x00002000 /* Remove in progress */
#define NREMOVEWANT 0x00004000 /* Want notification that remove is done */
#define NLOCK 0x00008000 /* Sleep lock the node */
#define NLOCKWANT 0x00010000 /* Want the sleep lock */
/*
* Convert between nfsnode pointers and vnode pointers
*/
#define VTONFS(vp) ((struct nfsnode *)(vp)->v_data)
#define NFSTOV(np) ((struct vnode *)(np)->n_vnode)
#define NFS_TIMESPEC_COMPARE(T1, T2) (((T1)->tv_sec != (T2)->tv_sec) || ((T1)->tv_nsec != (T2)->tv_nsec))
#if defined(_KERNEL)
/*
* Prototypes for NFS vnode operations
*/
int ncl_getpages(struct vop_getpages_args *);
int ncl_putpages(struct vop_putpages_args *);
int ncl_write(struct vop_write_args *);
int ncl_inactive(struct vop_inactive_args *);
int ncl_reclaim(struct vop_reclaim_args *);
/* other stuff */
int ncl_removeit(struct sillyrename *, struct vnode *);
int ncl_nget(struct mount *, u_int8_t *, int, struct nfsnode **, int);
nfsuint64 *ncl_getcookie(struct nfsnode *, off_t, int);
void ncl_invaldir(struct vnode *);
int ncl_upgrade_vnlock(struct vnode *);
void ncl_downgrade_vnlock(struct vnode *, int);
void ncl_printf(const char *, ...);
void ncl_dircookie_lock(struct nfsnode *);
void ncl_dircookie_unlock(struct nfsnode *);
#endif /* _KERNEL */
#endif /* _NFSCLIENT_NFSNODE_H_ */