215 lines
9.5 KiB
C
215 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, just don't say you wrote
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* it, 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 redistributed on the
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* understanding that the author is not responsible for the correct
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* functioning of this software in any circumstances and is not liable for
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* 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 1.2 1993/09/07 15:41:31 ws Exp $
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*/
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/*
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* This is the pc filesystem specific portion of the vnode structure. To
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* describe a file uniquely the de_dirclust, de_diroffset, and
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* de_de.deStartCluster fields are used. de_dirclust contains the cluster
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* number of the directory cluster containing the entry for a file or
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* directory. de_diroffset is the index into the cluster for the entry
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* describing a file or directory. de_de.deStartCluster is the number of
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* the first cluster of the file or directory. Now to describe the quirks
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* of the pc filesystem. - Clusters 0 and 1 are reserved. - The first
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* allocatable cluster is 2. - The root directory is of fixed size and all
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* blocks that make it up are contiguous. - Cluster 0 refers to the root
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* directory when it is found in the startcluster field of a directory
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* entry that points to another directory. - Cluster 0 implies a 0 length
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* file when found in the start cluster field of a directory entry that
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* points to a file. - You can't use the cluster number 0 to derive the
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* address of the root directory. - Multiple directory entries can point to
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* a directory. The entry in the parent directory points to a child
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* directory. Any directories in the child directory contain a ".." entry
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* that points back to the child. The child directory itself contains a
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* "." entry that points to itself. - The root directory does not contain a
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* "." or ".." entry. - Directory entries for directories are never changed
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* once they are created (except when removed). The size stays 0, and the
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* last modification time is never changed. This is because so many
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* directory entries can point to the physical clusters that make up a
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* directory. It would lead to an update nightmare. - The length field in
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* a directory entry pointing to a directory contains 0 (always). The only
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* way to find the end of a directory is to follow the cluster chain until
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* the "last cluster" marker is found. My extensions to make this house of
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* cards work. These apply only to the in memory copy of the directory
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* entry. - A reference count for each denode will be kept since dos
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* doesn't keep such things.
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*/
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/*
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* Internal pseudo-offset for (nonexistent) directory entry for the root
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* dir in the root dir
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*/
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#define MSDOSFSROOT_OFS 0x1fffffff
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/*
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* The fat cache structure. fc_fsrcn is the filesystem relative cluster
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* number that corresponds to the file relative cluster number in this
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* 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 files a "quick"
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* operation by avoiding having to scan the fat to discover the last
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* cluster of the file. The cache also helps sequential reads by
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* remembering the last cluster read from the file. This also prevents us
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* from having to rescan the fat to find the next cluster to read. This
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* cache is probably pretty worthless if a file is opened by multiple
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* 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
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* 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 entry. It is usually
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* 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 containing this entry */
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u_long de_diroffset; /* ordinal of this entry in the directory */
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long de_refcnt; /* reference count */
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struct msdosfsmount *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 to disk */
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/*
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* Shorthand macros used to reference fields in the direntry contained in
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* 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 MSDOSFS vnode operations
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*/
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int msdosfs_lookup __P((struct vnode * vp, struct nameidata * ndp, struct proc * p));
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int msdosfs_create __P((struct nameidata * ndp, struct vattr * vap, struct proc * p));
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int msdosfs_mknod __P((struct nameidata * ndp, struct vattr * vap, struct ucred * cred, struct proc * p));
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int msdosfs_open __P((struct vnode * vp, int mode, struct ucred * cred, struct proc * p));
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int msdosfs_close __P((struct vnode * vp, int fflag, struct ucred * cred, struct proc * p));
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int msdosfs_access __P((struct vnode * vp, int mode, struct ucred * cred, struct proc * p));
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int msdosfs_getattr __P((struct vnode * vp, struct vattr * vap, struct ucred * cred, struct proc * p));
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int msdosfs_setattr __P((struct vnode * vp, struct vattr * vap, struct ucred * cred, struct proc * p));
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int msdosfs_read __P((struct vnode * vp, struct uio * uio, int ioflag, struct ucred * cred));
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int msdosfs_write __P((struct vnode * vp, struct uio * uio, int ioflag, struct ucred * cred));
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int msdosfs_ioctl __P((struct vnode * vp, int command, caddr_t data, int fflag, struct ucred * cred, struct proc * p));
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int msdosfs_select __P((struct vnode * vp, int which, int fflags, struct ucred * cred, struct proc * p));
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int msdosfs_mmap __P((struct vnode * vp, int fflags, struct ucred * cred, struct proc * p));
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int msdosfs_fsync __P((struct vnode * vp, int fflags, struct ucred * cred, int waitfor, struct proc * p));
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int msdosfs_seek __P((struct vnode * vp, off_t oldoff, off_t newoff, struct ucred * cred));
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int msdosfs_remove __P((struct nameidata * ndp, struct proc * p));
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int msdosfs_link __P((struct vnode * vp, struct nameidata * ndp, struct proc * p));
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int msdosfs_rename __P((struct nameidata * fndp, struct nameidata * tdnp, struct proc * p));
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int msdosfs_mkdir __P((struct nameidata * ndp, struct vattr * vap, struct proc * p));
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int msdosfs_rmdir __P((struct nameidata * ndp, struct proc * p));
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int msdosfs_symlink __P((struct nameidata * ndp, struct vattr * vap, char *target, struct proc * p));
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int msdosfs_readdir __P((struct vnode * vp, struct uio * uio, struct ucred * cred, int *eofflagp, u_int * cookies, int ncookies));
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int msdosfs_readlink __P((struct vnode * vp, struct uio * uio, struct ucred * cred));
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int msdosfs_abortop __P((struct nameidata * ndp));
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int msdosfs_inactive __P((struct vnode * vp, struct proc * p));
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int msdosfs_reclaim __P((struct vnode * vp));
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int msdosfs_lock __P((struct vnode * vp));
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int msdosfs_unlock __P((struct vnode * vp));
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int msdosfs_bmap __P((struct vnode * vp, daddr_t bn, struct vnode ** vpp, daddr_t * bnp));
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int msdosfs_strategy __P((struct buf * bp));
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int msdosfs_print __P((struct vnode * vp));
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int msdosfs_islocked __P((struct vnode * vp));
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int msdosfs_advlock __P((struct vnode * vp, caddr_t id, int op, struct flock * fl, 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 msdosfsmount * pmp, u_long dirclust, u_long diroffset, struct direntry * direntptr, struct denode ** depp));
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#endif /* defined(KERNEL) */
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