vnode EXCLUSIVE lock. This prevents threads from adding pages to the vnode while an invalidation is in progress, closing potential races. In the bioread() path, callers acquire the SHARED vnode lock - so while an invalidate was in progress, it was possible to fault in new pages onto the vnode causing the invalidation to take a while or fail. We saw these races at Yahoo! with very large files+heavy concurrent access. Forcing an upgrade to EXCLUSIVE lock before doing the invalidation closes all these races. Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
219 lines
7.5 KiB
C
219 lines
7.5 KiB
C
/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Rick Macklem at The University of Guelph.
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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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* 4. 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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* @(#)nfsnode.h 8.9 (Berkeley) 5/14/95
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* $FreeBSD$
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*/
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#ifndef _NFSCLIENT_NFSNODE_H_
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#define _NFSCLIENT_NFSNODE_H_
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#if !defined(_NFSCLIENT_NFS_H_) && !defined(_KERNEL)
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#include <nfs/nfs.h>
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#endif
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/*
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* Silly rename structure that hangs off the nfsnode until the name
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* can be removed by nfs_inactive()
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*/
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struct sillyrename {
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struct ucred *s_cred;
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struct vnode *s_dvp;
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int (*s_removeit)(struct sillyrename *sp);
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long s_namlen;
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char s_name[20];
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};
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/*
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* This structure is used to save the logical directory offset to
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* NFS cookie mappings.
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* The mappings are stored in a list headed
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* by n_cookies, as required.
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* There is one mapping for each NFS_DIRBLKSIZ bytes of directory information
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* stored in increasing logical offset byte order.
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*/
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#define NFSNUMCOOKIES 31
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struct nfsdmap {
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LIST_ENTRY(nfsdmap) ndm_list;
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int ndm_eocookie;
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union {
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nfsuint64 ndmu3_cookies[NFSNUMCOOKIES];
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uint64_t ndmu4_cookies[NFSNUMCOOKIES];
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} ndm_un1;
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};
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#define ndm_cookies ndm_un1.ndmu3_cookies
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#define ndm4_cookies ndm_un1.ndmu4_cookies
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/*
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* The nfsnode is the nfs equivalent to ufs's inode. Any similarity
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* is purely coincidental.
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* There is a unique nfsnode allocated for each active file,
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* each current directory, each mounted-on file, text file, and the root.
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* An nfsnode is 'named' by its file handle. (nget/nfs_node.c)
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* If this structure exceeds 256 bytes (it is currently 256 using 4.4BSD-Lite
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* type definitions), file handles of > 32 bytes should probably be split out
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* into a separate MALLOC()'d data structure. (Reduce the size of nfsfh_t by
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* changing the definition in nfsproto.h of NFS_SMALLFH.)
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* NB: Hopefully the current order of the fields is such that everything will
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* be well aligned and, therefore, tightly packed.
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*/
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struct nfsnode {
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LIST_ENTRY(nfsnode) n_hash; /* Hash chain */
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u_quad_t n_size; /* Current size of file */
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u_quad_t n_brev; /* Modify rev when cached */
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u_quad_t n_lrev; /* Modify rev for lease */
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struct vattr n_vattr; /* Vnode attribute cache */
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time_t n_attrstamp; /* Attr. cache timestamp */
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u_int32_t n_mode; /* ACCESS mode cache */
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uid_t n_modeuid; /* credentials having mode */
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time_t n_modestamp; /* mode cache timestamp */
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time_t n_mtime; /* Prev modify time. */
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time_t n_ctime; /* Prev create time. */
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time_t n_expiry; /* Lease expiry time */
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nfsfh_t *n_fhp; /* NFS File Handle */
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struct vnode *n_vnode; /* associated vnode */
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struct vnode *n_dvp; /* parent vnode */
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struct lockf *n_lockf; /* Locking record of file */
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int n_error; /* Save write error value */
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union {
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struct timespec nf_atim; /* Special file times */
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nfsuint64 nd_cookieverf; /* Cookie verifier (dir only) */
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u_char nd4_cookieverf[NFSX_V4VERF];
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} n_un1;
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union {
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struct timespec nf_mtim;
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off_t nd_direof; /* Dir. EOF offset cache */
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} n_un2;
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union {
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struct sillyrename *nf_silly; /* Ptr to silly rename struct */
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LIST_HEAD(, nfsdmap) nd_cook; /* cookies */
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} n_un3;
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short n_fhsize; /* size in bytes, of fh */
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short n_flag; /* Flag for locking.. */
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nfsfh_t n_fh; /* Small File Handle */
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struct lock n_rslock;
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struct nfs4_fctx n_rfc;
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struct nfs4_fctx n_wfc;
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u_char *n_name; /* leaf name, for v4 OPEN op */
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uint32_t n_namelen;
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};
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#define n_atim n_un1.nf_atim
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#define n_mtim n_un2.nf_mtim
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#define n_sillyrename n_un3.nf_silly
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#define n_cookieverf n_un1.nd_cookieverf
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#define n4_cookieverf n_un1.nd4_cookieverf
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#define n_direofoffset n_un2.nd_direof
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#define n_cookies n_un3.nd_cook
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/*
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* Flags for n_flag
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*/
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#define NMODIFIED 0x0004 /* Might have a modified buffer in bio */
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#define NWRITEERR 0x0008 /* Flag write errors so close will know */
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/* 0x20, 0x40, 0x80 free */
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#define NACC 0x0100 /* Special file accessed */
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#define NUPD 0x0200 /* Special file updated */
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#define NCHG 0x0400 /* Special file times changed */
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#define NCREATED 0x0800 /* Opened by nfs_create() */
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#define NTRUNCATE 0x1000 /* Opened by nfs_setattr() */
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#define NSIZECHANGED 0x2000 /* File size has changed: need cache inval */
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/*
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* Convert between nfsnode pointers and vnode pointers
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*/
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#define VTONFS(vp) ((struct nfsnode *)(vp)->v_data)
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#define NFSTOV(np) ((struct vnode *)(np)->n_vnode)
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/*
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* Queue head for nfsiod's
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*/
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extern TAILQ_HEAD(nfs_bufq, buf) nfs_bufq;
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extern struct proc *nfs_iodwant[NFS_MAXASYNCDAEMON];
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extern struct nfsmount *nfs_iodmount[NFS_MAXASYNCDAEMON];
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#if defined(_KERNEL)
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/*
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* nfs_rslock - Attempt to obtain lock on nfsnode
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*
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* Attempt to obtain a lock on the passed nfsnode, returning ENOLCK
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* if the lock could not be obtained due to our having to sleep. This
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* function is generally used to lock around code that modifies an
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* NFS file's size. In order to avoid deadlocks the lock
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* should not be obtained while other locks are being held.
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*/
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static __inline int
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nfs_rslock(struct nfsnode *np, struct thread *td)
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{
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return(lockmgr(&np->n_rslock,
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LK_EXCLUSIVE | LK_CANRECURSE | LK_SLEEPFAIL, NULL, td));
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}
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static __inline void
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nfs_rsunlock(struct nfsnode *np, struct thread *td)
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{
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(void)lockmgr(&np->n_rslock, LK_RELEASE, NULL, td);
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}
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extern struct vop_vector nfs_fifoops;
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extern struct vop_vector nfs_vnodeops;
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extern struct vop_vector nfs4_vnodeops;
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extern struct buf_ops buf_ops_nfs;
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extern struct buf_ops buf_ops_nfs4;
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/*
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* Prototypes for NFS vnode operations
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*/
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int nfs_getpages(struct vop_getpages_args *);
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int nfs_putpages(struct vop_putpages_args *);
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int nfs_write(struct vop_write_args *);
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int nfs_inactive(struct vop_inactive_args *);
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int nfs_reclaim(struct vop_reclaim_args *);
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/* other stuff */
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int nfs_removeit(struct sillyrename *);
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int nfs4_removeit(struct sillyrename *);
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int nfs_nget(struct mount *, nfsfh_t *, int, struct nfsnode **);
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nfsuint64 *nfs_getcookie(struct nfsnode *, off_t, int);
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uint64_t *nfs4_getcookie(struct nfsnode *, off_t, int);
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void nfs_invaldir(struct vnode *);
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void nfs4_invaldir(struct vnode *);
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#endif /* _KERNEL */
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#endif
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