249 lines
9.5 KiB
C
249 lines
9.5 KiB
C
/*
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* Written by Paul Popelka (paulp@uts.amdahl.com)
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*
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* You can do anything you want with this software,
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* just don't say you wrote it,
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* and don't remove this notice.
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*
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* This software is provided "as is".
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*
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* The author supplies this software to be publicly
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* redistributed on the understanding that the author
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* is not responsible for the correct functioning of
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* this software in any circumstances and is not liable
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* for any damages caused by this software.
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*
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* October 1992
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*
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* $Id: denode.h,v 1.3 1993/08/02 23:15:12 mycroft Exp $
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*/
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/*
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* This is the pc filesystem specific portion of the
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* vnode structure.
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* To describe a file uniquely the de_dirclust, de_diroffset,
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* and de_de.deStartCluster fields are used. de_dirclust
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* contains the cluster number of the directory cluster containing
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* the entry for a file or directory. de_diroffset is the
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* index into the cluster for the entry describing a file
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* or directory. de_de.deStartCluster is the number of the
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* first cluster of the file or directory. Now to describe the
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* quirks of the pc filesystem.
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* - Clusters 0 and 1 are reserved.
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* - The first allocatable cluster is 2.
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* - The root directory is of fixed size and all blocks that
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* make it up are contiguous.
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* - Cluster 0 refers to the root directory when it is found
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* in the startcluster field of a directory entry that points
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* to another directory.
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* - Cluster 0 implies a 0 length file when found in the start
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* cluster field of a directory entry that points to a file.
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* - You can't use the cluster number 0 to derive
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* the address of the root directory.
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* - Multiple directory entries can point to a directory.
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* The entry in the parent directory points to a child
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* directory. Any directories in the child directory contain
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* a ".." entry that points back to the child. The child
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* directory itself contains a "." entry that points to
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* itself.
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* - The root directory does not contain a "." or ".." entry.
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* - Directory entries for directories are never changed once
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* they are created (except when removed). The size stays
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* 0, and the last modification time is never changed. This
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* is because so many directory entries can point to the physical
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* clusters that make up a directory. It would lead to an update
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* nightmare.
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* - The length field in a directory entry pointing to a directory
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* contains 0 (always). The only way to find the end of a directory
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* is to follow the cluster chain until the "last cluster"
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* marker is found.
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* My extensions to make this house of cards work. These apply
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* only to the in memory copy of the directory entry.
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* - A reference count for each denode will be kept since dos doesn't
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* keep such things.
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*/
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/* Internal pseudo-offset for (nonexistent) directory entry for the root dir
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* in the root dir */
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#define PCFSROOT_OFS 0x1fffffff
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/*
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* The fat cache structure.
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* fc_fsrcn is the filesystem relative cluster number
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* that corresponds to the file relative cluster number
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* in this structure (fc_frcn).
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*/
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struct fatcache {
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u_short fc_frcn; /* file relative cluster number */
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u_short fc_fsrcn; /* filesystem relative cluster number */
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};
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/*
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* The fat entry cache as it stands helps make extending
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* files a "quick" operation by avoiding having to scan
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* the fat to discover the last cluster of the file.
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* The cache also helps sequential reads by remembering
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* the last cluster read from the file. This also prevents
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* us from having to rescan the fat to find the next cluster
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* to read. This cache is probably pretty worthless if a
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* file is opened by multiple processes.
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*/
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#define FC_SIZE 2 /* number of entries in the cache */
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#define FC_LASTMAP 0 /* entry the last call to pcbmap() resolved to */
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#define FC_LASTFC 1 /* entry for the last cluster in the file */
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#define FCE_EMPTY 0xffff /* doesn't represent an actual cluster # */
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/*
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* Set a slot in the fat cache.
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*/
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#define fc_setcache(dep, slot, frcn, fsrcn) \
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(dep)->de_fc[slot].fc_frcn = frcn; \
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(dep)->de_fc[slot].fc_fsrcn = fsrcn;
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/*
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* This is the in memory variant of a dos directory
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* entry. It is usually contained within a vnode.
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*/
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struct denode {
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struct denode *de_chain[2]; /* hash chain ptrs */
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struct vnode *de_vnode; /* addr of vnode we are part of */
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struct vnode *de_devvp; /* vnode of blk dev we live on */
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u_long de_flag; /* flag bits */
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dev_t de_dev; /* device where direntry lives */
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u_long de_dirclust; /* cluster of the directory file
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* containing this entry */
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u_long de_diroffset; /* ordinal of this entry in the
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* directory */
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long de_refcnt; /* reference count */
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struct pcfsmount *de_pmp; /* addr of our mount struct */
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struct lockf *de_lockf; /* byte level lock list */
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long de_spare0; /* current lock holder */
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long de_spare1; /* lock wanter */
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struct direntry de_de; /* the actual directory entry */
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struct fatcache de_fc[FC_SIZE]; /* fat cache */
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};
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/*
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* Values for the de_flag field of the denode.
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*/
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#define DELOCKED 0x0001 /* directory entry is locked */
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#define DEWANT 0x0002 /* someone wants this de */
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#define DERENAME 0x0004 /* de is being renamed */
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#define DEUPD 0x0008 /* file has been modified */
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#define DESHLOCK 0x0010 /* file has shared lock */
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#define DEEXLOCK 0x0020 /* file has exclusive lock */
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#define DELWAIT 0x0040 /* someone waiting on file lock */
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#define DEMOD 0x0080 /* denode wants to be written back
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* to disk */
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/*
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* Shorthand macros used to reference fields in the direntry
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* contained in the denode structure.
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*/
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#define de_Name de_de.deName
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#define de_Extension de_de.deExtension
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#define de_Attributes de_de.deAttributes
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#define de_Reserved de_de.deReserved
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#define de_Time de_de.deTime
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#define de_Date de_de.deDate
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#define de_StartCluster de_de.deStartCluster
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#define de_FileSize de_de.deFileSize
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#define de_forw de_chain[0]
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#define de_back de_chain[1]
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#if defined(KERNEL)
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#define VTODE(vp) ((struct denode *)(vp)->v_data)
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#define DETOV(de) ((de)->de_vnode)
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#define DELOCK(de) delock(de)
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#define DEUNLOCK(de) deunlock(de)
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#define DEUPDAT(dep, t, waitfor) \
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if (dep->de_flag & DEUPD) \
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(void) deupdat(dep, t, waitfor);
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#define DETIMES(dep, t) \
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if (dep->de_flag & DEUPD) { \
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(dep)->de_flag |= DEMOD; \
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unix2dostime(t, (union dosdate *)&dep->de_Date, \
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(union dostime *)&dep->de_Time); \
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(dep)->de_flag &= ~DEUPD; \
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}
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/*
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* This overlays the fid sturcture (see mount.h)
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*/
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struct defid {
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u_short defid_len; /* length of structure */
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u_short defid_pad; /* force long alignment */
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u_long defid_dirclust; /* cluster this dir entry came from */
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u_long defid_dirofs; /* index of entry within the cluster */
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/* u_long defid_gen; /* generation number */
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};
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/*
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* Prototypes for PCFS vnode operations
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*/
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int pcfs_lookup __P((struct vnode *vp, struct nameidata *ndp, struct proc *p));
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int pcfs_create __P((struct nameidata *ndp, struct vattr *vap, struct proc *p));
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int pcfs_mknod __P((struct nameidata *ndp, struct vattr *vap, struct ucred *cred,
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struct proc *p));
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int pcfs_open __P((struct vnode *vp, int mode, struct ucred *cred,
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struct proc *p));
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int pcfs_close __P((struct vnode *vp, int fflag, struct ucred *cred,
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struct proc *p));
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int pcfs_access __P((struct vnode *vp, int mode, struct ucred *cred,
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struct proc *p));
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int pcfs_getattr __P((struct vnode *vp, struct vattr *vap, struct ucred *cred,
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struct proc *p));
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int pcfs_setattr __P((struct vnode *vp, struct vattr *vap, struct ucred *cred,
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struct proc *p));
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int pcfs_read __P((struct vnode *vp, struct uio *uio, int ioflag,
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struct ucred *cred));
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int pcfs_write __P((struct vnode *vp, struct uio *uio, int ioflag,
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struct ucred *cred));
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int pcfs_ioctl __P((struct vnode *vp, int command, caddr_t data, int fflag,
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struct ucred *cred, struct proc *p));
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int pcfs_select __P((struct vnode *vp, int which, int fflags, struct ucred *cred,
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struct proc *p));
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int pcfs_mmap __P((struct vnode *vp, int fflags, struct ucred *cred,
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struct proc *p));
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int pcfs_fsync __P((struct vnode *vp, int fflags, struct ucred *cred,
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int waitfor, struct proc *p));
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int pcfs_seek __P((struct vnode *vp, off_t oldoff, off_t newoff,
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struct ucred *cred));
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int pcfs_remove __P((struct nameidata *ndp, struct proc *p));
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int pcfs_link __P((struct vnode *vp, struct nameidata *ndp, struct proc *p));
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int pcfs_rename __P((struct nameidata *fndp, struct nameidata *tdnp,
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struct proc *p));
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int pcfs_mkdir __P((struct nameidata *ndp, struct vattr *vap, struct proc *p));
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int pcfs_rmdir __P((struct nameidata *ndp, struct proc *p));
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int pcfs_symlink __P((struct nameidata *ndp, struct vattr *vap, char *target,
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struct proc *p));
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int pcfs_readdir __P((struct vnode *vp, struct uio *uio, struct ucred *cred,
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int *eofflagp));
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int pcfs_readlink __P((struct vnode *vp, struct uio *uio, struct ucred *cred));
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int pcfs_abortop __P((struct nameidata *ndp));
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int pcfs_inactive __P((struct vnode *vp, struct proc *p));
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int pcfs_reclaim __P((struct vnode *vp));
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int pcfs_lock __P((struct vnode *vp));
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int pcfs_unlock __P((struct vnode *vp));
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int pcfs_bmap __P((struct vnode *vp, daddr_t bn, struct vnode **vpp,
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daddr_t *bnp));
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int pcfs_strategy __P((struct buf *bp));
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void pcfs_print __P((struct vnode *vp));
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int pcfs_islocked __P((struct vnode *vp));
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int pcfs_advlock __P((struct vnode *vp, caddr_t id, int op, struct flock *fl,
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int flags));
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/*
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* Internal service routine prototypes.
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*/
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int deget __P((struct pcfsmount *pmp, u_long dirclust, u_long diroffset,
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struct direntry *direntptr, struct denode **depp));
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#endif /* defined(KERNEL) */
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