eea9343411
This patch will make mode_t 16-bits->32-bits, off_t 32-bits->64-bits,
ino_t 32-bits->64-bits, and nlink_t 16-bits->32-bits. As uid_t and
gid_t were already 32-bits we can drop the big_{mode,off,ino,uid,
gid,nlink}_t types from struct stat. This has huge consequences:
. lseek now has to accept a 64-bit argument and returns a 64-bit
result. Therefore we need a new lseek and return proper results
based on the used version (i.e., translate).
. some fcntl functions take and return a struct flock which holds 2
off_t fields. Like lseek, we need to distinguish between old and
new versions.
. getdents uses struct dirent which has among other fields an ino_t
and off_t field. Consequently we need a new getdents system call
and have to translate when we encounter an old call.
. truncate and ftruncate also take off_t arguments and therefore
require a new version.
To add insult to injury VFS itself uses getdents. This has as
consequence that we have 2^3 combinations of version for getdents; old
and new version of libc (new system calls), new and old version of VFS
(when booting an old image), old and new version of an FS. We can
distinguish between these cases as follows; libc will use new system
call numbers that have not yet been in use. When using a new number,
VFS knows libc is new, otherwise it's an old libc. Vice versa, libc
first tries the new number and if that fails due to ENOSYS (unknown
system call number) it knows it's dealing with an old VFS. Finally,
since we now have VFS-FS protocol versioning and by bumping the version
to 1, VFS knows an FS is old when it reports version 0 and an FS knows
VFS is old when VFS reports it's using version 0.
0 = old version, 1 = new version
libc | VFS | FS | approach
----------------------------
0 | 0 | 0 | Nothing to do
----------------------------
0 | 0 | 1 | VFS reports protocol version 0, FS falls back
| to using the old getdents function
----------------------------
0 | 1 | 0 | VFS reports protocol version 1, FS version 0.
| libc requires old getdents so there is nothing
| to do. VFS itself needs new getdents and will
| translate.
----------------------------
0 | 1 | 1 | VFS reports protocol version 1, FS version 1.
| VFS intercepts getdents results and translates
| them on the fly before returning results to libc
----------------------------
1 | 0 | 0 | libc first tries new system call number and
| then fall back to the old number. libc first
| translates the results to the new getdents before
| returning.
----------------------------
1 | 0 | 1 | VFS reports protocol version 0, so FS uses fall
| back. libc translates.
----------------------------
1 | 1 | 0 | VFS reports protocol version 1, FS version 0. VFS
| will intercept all results and translate on the
| fly.
----------------------------
1 | 1 | 1 | Nothing to do.
As VFS can distinguish between old and new system calls of (f)truncate,
lseek, and fcntl, it will translate the arguments and results if
necessary. Likewise libc falls back to using the old calls and
translating the results to the new version if necessary.
Change-Id: Id5bc819e6ef90f317dbddb21020e0a65028225ce
75 lines
2.9 KiB
C
75 lines
2.9 KiB
C
#ifndef __MFS_INODE_H__
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#define __MFS_INODE_H__
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/* Inode table. This table holds inodes that are currently in use. In some
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* cases they have been opened by an open() or creat() system call, in other
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* cases the file system itself needs the inode for one reason or another,
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* such as to search a directory for a path name.
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* The first part of the struct holds fields that are present on the
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* disk; the second part holds fields not present on the disk.
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* The disk inode part is also declared in "type.h" as 'd1_inode' for V1
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* file systems and 'd2_inode' for V2 file systems.
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*
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* Updates:
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* 2007-01-06: jfdsmit@gmail.com added i_zsearch
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*/
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#include <sys/queue.h>
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#include <minix/vfsif.h>
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#include "super.h"
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EXTERN struct inode {
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u16_t i_mode; /* file type, protection, etc. */
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u16_t i_nlinks; /* how many links to this file */
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u16_t i_uid; /* user id of the file's owner */
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u16_t i_gid; /* group number */
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i32_t i_size; /* current file size in bytes */
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u32_t i_atime; /* time of last access (V2 only) */
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u32_t i_mtime; /* when was file data last changed */
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u32_t i_ctime; /* when was inode itself changed (V2 only)*/
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u32_t i_zone[V2_NR_TZONES]; /* zone numbers for direct, ind, and dbl ind */
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/* The following items are not present on the disk. */
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dev_t i_dev; /* which device is the inode on */
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pino_t i_num; /* inode number on its (minor) device */
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int i_count; /* # times inode used; 0 means slot is free */
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unsigned int i_ndzones; /* # direct zones (Vx_NR_DZONES) */
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unsigned int i_nindirs; /* # indirect zones per indirect block */
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struct super_block *i_sp; /* pointer to super block for inode's device */
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char i_dirt; /* CLEAN or DIRTY */
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zone_t i_zsearch; /* where to start search for new zones */
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off_t i_last_dpos; /* where to start dentry search */
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char i_mountpoint; /* true if mounted on */
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char i_seek; /* set on LSEEK, cleared on READ/WRITE */
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char i_update; /* the ATIME, CTIME, and MTIME bits are here */
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LIST_ENTRY(inode) i_hash; /* hash list */
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TAILQ_ENTRY(inode) i_unused; /* free and unused list */
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} inode[NR_INODES];
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/* list of unused/free inodes */
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EXTERN TAILQ_HEAD(unused_inodes_t, inode) unused_inodes;
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/* inode hashtable */
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EXTERN LIST_HEAD(inodelist, inode) hash_inodes[INODE_HASH_SIZE];
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EXTERN unsigned int inode_cache_hit;
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EXTERN unsigned int inode_cache_miss;
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/* Field values. Note that CLEAN and DIRTY are defined in "const.h" */
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#define NO_SEEK 0 /* i_seek = NO_SEEK if last op was not SEEK */
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#define ISEEK 1 /* i_seek = ISEEK if last op was SEEK */
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#define IN_MARKCLEAN(i) i->i_dirt = IN_CLEAN
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#define IN_MARKDIRTY(i) do { if(i->i_sp->s_rd_only) { printf("%s:%d: dirty inode on rofs ", __FILE__, __LINE__); util_stacktrace(); } else { i->i_dirt = IN_DIRTY; } } while(0)
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#define IN_ISCLEAN(i) i->i_dirt == IN_CLEAN
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#define IN_ISDIRTY(i) i->i_dirt == IN_DIRTY
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#endif
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