900 lines
22 KiB
C
900 lines
22 KiB
C
/*
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* linux/fs/ext/namei.c
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*
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* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
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*
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* from
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*
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* linux/fs/minix/namei.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/sched.h>
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#include <linux/ext_fs.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/errno.h>
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#include <asm/segment.h>
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/*
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* comment out this line if you want names > EXT_NAME_LEN chars to be
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* truncated. Else they will be disallowed.
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*/
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/* #define NO_TRUNCATE */
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/*
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* EXT_DIR_PAD defines the directory entries boundaries
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*
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* NOTE: It must be a power of 2 and must be greater or equal than 8
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* because a directory entry needs 8 bytes for its fixed part
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* (4 bytes for the inode, 2 bytes for the entry length and 2 bytes
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* for the name length)
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*/
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#define EXT_DIR_PAD 8
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/*
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*
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* EXT_DIR_MIN_SIZE is the minimal size of a directory entry
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*
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* During allocations, a directory entry is split into 2 ones
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* *ONLY* if the size of the unused part is greater than or
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* equal to EXT_DIR_MIN_SIZE
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*/
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#define EXT_DIR_MIN_SIZE 12
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/*
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* ok, we cannot use strncmp, as the name is not in our data space.
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* Thus we'll have to use ext_match. No big problem. Match also makes
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* some sanity tests.
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*
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* NOTE! unlike strncmp, ext_match returns 1 for success, 0 for failure.
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*/
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static int ext_match(int len,const char * name,struct ext_dir_entry * de)
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{
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register int same __asm__("ax");
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if (!de || !de->inode || len > EXT_NAME_LEN)
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return 0;
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/* "" means "." ---> so paths like "/usr/lib//libc.a" work */
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if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
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return 1;
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if (len < EXT_NAME_LEN && len != de->name_len)
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return 0;
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__asm__("cld\n\t"
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"repe ; cmpsb\n\t"
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"setz %%al"
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:"=a" (same)
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:"0" (0),"S" ((long) name),"D" ((long) de->name),"c" (len)
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:"cx","di","si");
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return same;
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}
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/*
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* ext_find_entry()
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*
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* finds an entry in the specified directory with the wanted name. It
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* returns the cache buffer in which the entry was found, and the entry
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* itself (as a parameter - res_dir). It does NOT read the inode of the
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* entry - you'll have to do that yourself if you want to.
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*
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* addition for the ext file system : this function returns the previous
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* and next directory entries in the parameters prev_dir and next_dir
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*/
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static struct buffer_head * ext_find_entry(struct inode * dir,
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const char * name, int namelen, struct ext_dir_entry ** res_dir,
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struct ext_dir_entry ** prev_dir, struct ext_dir_entry ** next_dir)
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{
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long offset;
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struct buffer_head * bh;
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struct ext_dir_entry * de;
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*res_dir = NULL;
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if (!dir)
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return NULL;
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#ifdef NO_TRUNCATE
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if (namelen > EXT_NAME_LEN)
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return NULL;
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#else
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if (namelen > EXT_NAME_LEN)
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namelen = EXT_NAME_LEN;
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#endif
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bh = ext_bread(dir,0,0);
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if (!bh)
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return NULL;
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if (prev_dir)
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*prev_dir = NULL;
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if (next_dir)
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*next_dir = NULL;
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offset = 0;
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de = (struct ext_dir_entry *) bh->b_data;
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while (offset < dir->i_size) {
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if ((char *)de >= BLOCK_SIZE+bh->b_data) {
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brelse(bh);
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bh = NULL;
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bh = ext_bread(dir,offset>>BLOCK_SIZE_BITS,0);
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if (!bh)
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continue;
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de = (struct ext_dir_entry *) bh->b_data;
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if (prev_dir)
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*prev_dir = NULL;
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}
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if (de->rec_len < 8 || de->rec_len % 8 != 0 ||
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de->rec_len < de->name_len + 8 ||
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(((char *) de) + de->rec_len-1 >= BLOCK_SIZE+bh->b_data)) {
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printk ("ext_find_entry: bad dir entry\n");
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printk ("dev=%d, dir=%d, offset=%d, rec_len=%d, name_len=%d\n",
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dir->i_dev, dir->i_ino, offset, de->rec_len, de->name_len);
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de = (struct ext_dir_entry *) (bh->b_data+BLOCK_SIZE);
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offset = ((offset / BLOCK_SIZE) + 1) * BLOCK_SIZE;
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continue;
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/* brelse (bh);
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return NULL; */
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}
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if (ext_match(namelen,name,de)) {
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*res_dir = de;
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if (next_dir)
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if (offset + de->rec_len < dir->i_size &&
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((char *)de) + de->rec_len < BLOCK_SIZE+bh->b_data)
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*next_dir = (struct ext_dir_entry *)
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((char *) de + de->rec_len);
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else
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*next_dir = NULL;
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return bh;
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}
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offset += de->rec_len;
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if (prev_dir)
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*prev_dir = de;
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de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
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}
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brelse(bh);
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return NULL;
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}
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int ext_lookup(struct inode * dir,const char * name, int len,
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struct inode ** result)
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{
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int ino;
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struct ext_dir_entry * de;
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struct buffer_head * bh;
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*result = NULL;
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if (!dir)
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return -ENOENT;
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if (!S_ISDIR(dir->i_mode)) {
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iput(dir);
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return -ENOENT;
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}
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if (!(bh = ext_find_entry(dir,name,len,&de,NULL,NULL))) {
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iput(dir);
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return -ENOENT;
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}
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ino = de->inode;
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brelse(bh);
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if (!(*result = iget(dir->i_sb,ino))) {
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iput(dir);
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return -EACCES;
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}
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iput(dir);
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return 0;
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}
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/*
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* ext_add_entry()
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*
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* adds a file entry to the specified directory, using the same
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* semantics as ext_find_entry(). It returns NULL if it failed.
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*
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* NOTE!! The inode part of 'de' is left at 0 - which means you
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* may not sleep between calling this and putting something into
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* the entry, as someone else might have used it while you slept.
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*/
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static struct buffer_head * ext_add_entry(struct inode * dir,
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const char * name, int namelen, struct ext_dir_entry ** res_dir)
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{
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int i;
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long offset;
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unsigned short rec_len;
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struct buffer_head * bh;
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struct ext_dir_entry * de, * de1;
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*res_dir = NULL;
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if (!dir)
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return NULL;
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#ifdef NO_TRUNCATE
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if (namelen > EXT_NAME_LEN)
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return NULL;
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#else
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if (namelen > EXT_NAME_LEN)
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namelen = EXT_NAME_LEN;
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#endif
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if (!namelen)
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return NULL;
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bh = ext_bread(dir,0,0);
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if (!bh)
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return NULL;
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rec_len = ((8 + namelen + EXT_DIR_PAD - 1) / EXT_DIR_PAD) * EXT_DIR_PAD;
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offset = 0;
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de = (struct ext_dir_entry *) bh->b_data;
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while (1) {
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if ((char *)de >= BLOCK_SIZE+bh->b_data && offset < dir->i_size) {
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#ifdef EXTFS_DEBUG
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printk ("ext_add_entry: skipping to next block\n");
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#endif
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brelse(bh);
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bh = NULL;
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bh = ext_bread(dir,offset>>BLOCK_SIZE_BITS,0);
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if (!bh)
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return NULL;
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de = (struct ext_dir_entry *) bh->b_data;
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}
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if (offset >= dir->i_size) {
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/* Check that the directory entry fits in the block */
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if (offset % BLOCK_SIZE == 0 ||
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(BLOCK_SIZE - (offset % BLOCK_SIZE)) < rec_len) {
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if ((offset % BLOCK_SIZE) != 0) {
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/* If the entry does not fit in the
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block, the remainder of the block
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becomes an unused entry */
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de->inode = 0;
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de->rec_len = BLOCK_SIZE
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- (offset & (BLOCK_SIZE - 1));
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de->name_len = 0;
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offset += de->rec_len;
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dir->i_size += de->rec_len;
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dir->i_dirt = 1;
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#if 0
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dir->i_ctime = CURRENT_TIME;
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#endif
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bh->b_dirt = 1;
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}
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brelse (bh);
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bh = NULL;
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#ifdef EXTFS_DEBUG
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printk ("ext_add_entry : creating next block\n");
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#endif
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bh = ext_bread(dir,offset>>BLOCK_SIZE_BITS,1);
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if (!bh)
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return NULL; /* Other thing to do ??? */
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de = (struct ext_dir_entry *) bh->b_data;
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}
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/* Allocate the entry */
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de->inode=0;
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de->rec_len = rec_len;
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dir->i_size += de->rec_len;
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dir->i_dirt = 1;
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#if 0
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dir->i_ctime = CURRENT_TIME;
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#endif
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}
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if (de->rec_len < 8 || de->rec_len % 4 != 0 ||
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de->rec_len < de->name_len + 8 ||
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(((char *) de) + de->rec_len-1 >= BLOCK_SIZE+bh->b_data)) {
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printk ("ext_addr_entry: bad dir entry\n");
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printk ("dev=%d, dir=%d, offset=%d, rec_len=%d, name_len=%d\n",
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dir->i_dev, dir->i_ino, offset, de->rec_len, de->name_len);
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brelse (bh);
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return NULL;
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}
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if (!de->inode && de->rec_len >= rec_len) {
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if (de->rec_len > rec_len
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&& de->rec_len - rec_len >= EXT_DIR_MIN_SIZE) {
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/* The found entry is too big : it is split
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into 2 ones :
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- the 1st one will be used to hold the name,
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- the 2nd one is unused */
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de1 = (struct ext_dir_entry *) ((char *) de + rec_len);
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de1->inode = 0;
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de1->rec_len = de->rec_len - rec_len;
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de1->name_len = 0;
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de->rec_len = rec_len;
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}
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dir->i_mtime = dir->i_ctime = CURRENT_TIME;
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de->name_len = namelen;
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for (i=0; i < namelen ; i++)
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de->name[i] = name[i];
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bh->b_dirt = 1;
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*res_dir = de;
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return bh;
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}
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offset += de->rec_len;
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de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
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}
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brelse(bh);
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return NULL;
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}
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int ext_create(struct inode * dir,const char * name, int len, int mode,
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struct inode ** result)
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{
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struct inode * inode;
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struct buffer_head * bh;
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struct ext_dir_entry * de;
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*result = NULL;
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if (!dir)
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return -ENOENT;
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inode = ext_new_inode(dir);
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if (!inode) {
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iput(dir);
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return -ENOSPC;
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}
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inode->i_op = &ext_file_inode_operations;
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inode->i_mode = mode;
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inode->i_dirt = 1;
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bh = ext_add_entry(dir,name,len,&de);
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if (!bh) {
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inode->i_nlink--;
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inode->i_dirt = 1;
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iput(inode);
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iput(dir);
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return -ENOSPC;
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}
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de->inode = inode->i_ino;
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bh->b_dirt = 1;
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brelse(bh);
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iput(dir);
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*result = inode;
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return 0;
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}
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int ext_mknod(struct inode * dir, const char * name, int len, int mode, int rdev)
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{
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struct inode * inode;
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struct buffer_head * bh;
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struct ext_dir_entry * de;
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if (!dir)
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return -ENOENT;
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bh = ext_find_entry(dir,name,len,&de,NULL,NULL);
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if (bh) {
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brelse(bh);
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iput(dir);
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return -EEXIST;
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}
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inode = ext_new_inode(dir);
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if (!inode) {
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iput(dir);
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return -ENOSPC;
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}
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inode->i_uid = current->euid;
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inode->i_mode = mode;
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inode->i_op = NULL;
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if (S_ISREG(inode->i_mode))
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inode->i_op = &ext_file_inode_operations;
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else if (S_ISDIR(inode->i_mode)) {
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inode->i_op = &ext_dir_inode_operations;
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if (dir->i_mode & S_ISGID)
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inode->i_mode |= S_ISGID;
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}
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else if (S_ISLNK(inode->i_mode))
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inode->i_op = &ext_symlink_inode_operations;
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else if (S_ISCHR(inode->i_mode))
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inode->i_op = &chrdev_inode_operations;
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else if (S_ISBLK(inode->i_mode))
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inode->i_op = &blkdev_inode_operations;
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else if (S_ISFIFO(inode->i_mode))
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init_fifo(inode);
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if (S_ISBLK(mode) || S_ISCHR(mode))
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inode->i_rdev = rdev;
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#if 0
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inode->i_mtime = inode->i_atime = CURRENT_TIME;
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#endif
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inode->i_dirt = 1;
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bh = ext_add_entry(dir,name,len,&de);
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if (!bh) {
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inode->i_nlink--;
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inode->i_dirt = 1;
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iput(inode);
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iput(dir);
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return -ENOSPC;
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}
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de->inode = inode->i_ino;
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bh->b_dirt = 1;
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brelse(bh);
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iput(dir);
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iput(inode);
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return 0;
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}
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int ext_mkdir(struct inode * dir, const char * name, int len, int mode)
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{
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struct inode * inode;
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struct buffer_head * bh, *dir_block;
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struct ext_dir_entry * de;
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bh = ext_find_entry(dir,name,len,&de,NULL,NULL);
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if (bh) {
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brelse(bh);
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iput(dir);
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return -EEXIST;
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}
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inode = ext_new_inode(dir);
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if (!inode) {
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iput(dir);
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return -ENOSPC;
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}
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inode->i_op = &ext_dir_inode_operations;
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inode->i_size = 2 * 16; /* Each entry is coded on 16 bytes for "." and ".."
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- 4 bytes for the inode number,
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- 2 bytes for the record length
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- 2 bytes for the name length
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- 8 bytes for the name */
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#if 0
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inode->i_mtime = inode->i_atime = CURRENT_TIME;
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#endif
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dir_block = ext_bread(inode,0,1);
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if (!dir_block) {
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iput(dir);
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inode->i_nlink--;
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inode->i_dirt = 1;
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iput(inode);
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return -ENOSPC;
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}
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de = (struct ext_dir_entry *) dir_block->b_data;
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de->inode=inode->i_ino;
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de->rec_len=16;
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de->name_len=1;
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strcpy(de->name,".");
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de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
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de->inode = dir->i_ino;
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de->rec_len=16;
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de->name_len=2;
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strcpy(de->name,"..");
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inode->i_nlink = 2;
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dir_block->b_dirt = 1;
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brelse(dir_block);
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inode->i_mode = S_IFDIR | (mode & 0777 & ~current->umask);
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if (dir->i_mode & S_ISGID)
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inode->i_mode |= S_ISGID;
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inode->i_dirt = 1;
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bh = ext_add_entry(dir,name,len,&de);
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if (!bh) {
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iput(dir);
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inode->i_nlink=0;
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iput(inode);
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return -ENOSPC;
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}
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de->inode = inode->i_ino;
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bh->b_dirt = 1;
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dir->i_nlink++;
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dir->i_dirt = 1;
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iput(dir);
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iput(inode);
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brelse(bh);
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return 0;
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}
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/*
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* routine to check that the specified directory is empty (for rmdir)
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*/
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static int empty_dir(struct inode * inode)
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{
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unsigned long offset;
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struct buffer_head * bh;
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struct ext_dir_entry * de, * de1;
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if (inode->i_size < 2 * 12 || !(bh = ext_bread(inode,0,0))) {
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printk("warning - bad directory on dev %04x\n",inode->i_dev);
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return 1;
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}
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de = (struct ext_dir_entry *) bh->b_data;
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de1 = (struct ext_dir_entry *) ((char *) de + de->rec_len);
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if (de->inode != inode->i_ino || !de1->inode ||
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strcmp(".",de->name) || strcmp("..",de1->name)) {
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printk("warning - bad directory on dev %04x\n",inode->i_dev);
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return 1;
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}
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offset = de->rec_len + de1->rec_len;
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de = (struct ext_dir_entry *) ((char *) de1 + de1->rec_len);
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while (offset < inode->i_size ) {
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if ((void *) de >= (void *) (bh->b_data+BLOCK_SIZE)) {
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brelse(bh);
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bh = ext_bread(inode, offset >> BLOCK_SIZE_BITS,1);
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if (!bh) {
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offset += BLOCK_SIZE;
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|
continue;
|
|
}
|
|
de = (struct ext_dir_entry *) bh->b_data;
|
|
}
|
|
if (de->rec_len < 8 || de->rec_len %4 != 0 ||
|
|
de->rec_len < de->name_len + 8) {
|
|
printk ("empty_dir: bad dir entry\n");
|
|
printk ("dev=%d, dir=%d, offset=%d, rec_len=%d, name_len=%d\n",
|
|
inode->i_dev, inode->i_ino, offset, de->rec_len, de->name_len);
|
|
brelse (bh);
|
|
return 1;
|
|
}
|
|
if (de->inode) {
|
|
brelse(bh);
|
|
return 0;
|
|
}
|
|
offset += de->rec_len;
|
|
de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
|
|
}
|
|
brelse(bh);
|
|
return 1;
|
|
}
|
|
|
|
static inline void ext_merge_entries (struct ext_dir_entry * de,
|
|
struct ext_dir_entry * pde, struct ext_dir_entry * nde)
|
|
{
|
|
if (nde && !nde->inode)
|
|
de->rec_len += nde->rec_len;
|
|
if (pde && !pde->inode)
|
|
pde->rec_len += de->rec_len;
|
|
}
|
|
|
|
int ext_rmdir(struct inode * dir, const char * name, int len)
|
|
{
|
|
int retval;
|
|
struct inode * inode;
|
|
struct buffer_head * bh;
|
|
struct ext_dir_entry * de, * pde, * nde;
|
|
|
|
inode = NULL;
|
|
bh = ext_find_entry(dir,name,len,&de,&pde,&nde);
|
|
retval = -ENOENT;
|
|
if (!bh)
|
|
goto end_rmdir;
|
|
retval = -EPERM;
|
|
if (!(inode = iget(dir->i_sb, de->inode)))
|
|
goto end_rmdir;
|
|
if ((dir->i_mode & S_ISVTX) && current->euid &&
|
|
inode->i_uid != current->euid)
|
|
goto end_rmdir;
|
|
if (inode->i_dev != dir->i_dev)
|
|
goto end_rmdir;
|
|
if (inode == dir) /* we may not delete ".", but "../dir" is ok */
|
|
goto end_rmdir;
|
|
if (!S_ISDIR(inode->i_mode)) {
|
|
retval = -ENOTDIR;
|
|
goto end_rmdir;
|
|
}
|
|
if (!empty_dir(inode)) {
|
|
retval = -ENOTEMPTY;
|
|
goto end_rmdir;
|
|
}
|
|
if (inode->i_count > 1) {
|
|
retval = -EBUSY;
|
|
goto end_rmdir;
|
|
}
|
|
if (inode->i_nlink != 2)
|
|
printk("empty directory has nlink!=2 (%d)\n",inode->i_nlink);
|
|
de->inode = 0;
|
|
de->name_len = 0;
|
|
ext_merge_entries (de, pde, nde);
|
|
bh->b_dirt = 1;
|
|
inode->i_nlink=0;
|
|
inode->i_dirt=1;
|
|
dir->i_nlink--;
|
|
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
|
dir->i_dirt=1;
|
|
retval = 0;
|
|
end_rmdir:
|
|
iput(dir);
|
|
iput(inode);
|
|
brelse(bh);
|
|
return retval;
|
|
}
|
|
|
|
int ext_unlink(struct inode * dir, const char * name, int len)
|
|
{
|
|
int retval;
|
|
struct inode * inode;
|
|
struct buffer_head * bh;
|
|
struct ext_dir_entry * de, * pde, * nde;
|
|
|
|
retval = -ENOENT;
|
|
inode = NULL;
|
|
bh = ext_find_entry(dir,name,len,&de,&pde,&nde);
|
|
if (!bh)
|
|
goto end_unlink;
|
|
if (!(inode = iget(dir->i_sb, de->inode)))
|
|
goto end_unlink;
|
|
retval = -EPERM;
|
|
if ((dir->i_mode & S_ISVTX) && !suser() &&
|
|
current->euid != inode->i_uid &&
|
|
current->euid != dir->i_uid)
|
|
goto end_unlink;
|
|
if (S_ISDIR(inode->i_mode))
|
|
goto end_unlink;
|
|
if (!inode->i_nlink) {
|
|
printk("Deleting nonexistent file (%04x:%d), %d\n",
|
|
inode->i_dev,inode->i_ino,inode->i_nlink);
|
|
inode->i_nlink=1;
|
|
}
|
|
de->inode = 0;
|
|
de->name_len = 0;
|
|
ext_merge_entries (de, pde, nde);
|
|
bh->b_dirt = 1;
|
|
inode->i_nlink--;
|
|
inode->i_dirt = 1;
|
|
inode->i_ctime = CURRENT_TIME;
|
|
dir->i_ctime = dir->i_mtime = inode->i_ctime;
|
|
dir->i_dirt = 1;
|
|
retval = 0;
|
|
end_unlink:
|
|
brelse(bh);
|
|
iput(inode);
|
|
iput(dir);
|
|
return retval;
|
|
}
|
|
|
|
int ext_symlink(struct inode * dir, const char * name, int len, const char * symname)
|
|
{
|
|
struct ext_dir_entry * de;
|
|
struct inode * inode = NULL;
|
|
struct buffer_head * bh = NULL, * name_block = NULL;
|
|
int i;
|
|
char c;
|
|
|
|
if (!(inode = ext_new_inode(dir))) {
|
|
iput(dir);
|
|
return -ENOSPC;
|
|
}
|
|
inode->i_mode = S_IFLNK | 0777;
|
|
inode->i_op = &ext_symlink_inode_operations;
|
|
name_block = ext_bread(inode,0,1);
|
|
if (!name_block) {
|
|
iput(dir);
|
|
inode->i_nlink--;
|
|
inode->i_dirt = 1;
|
|
iput(inode);
|
|
return -ENOSPC;
|
|
}
|
|
i = 0;
|
|
while (i < 1023 && (c = *(symname++)))
|
|
name_block->b_data[i++] = c;
|
|
name_block->b_data[i] = 0;
|
|
name_block->b_dirt = 1;
|
|
brelse(name_block);
|
|
inode->i_size = i;
|
|
inode->i_dirt = 1;
|
|
bh = ext_find_entry(dir,name,len,&de,NULL,NULL);
|
|
if (bh) {
|
|
inode->i_nlink--;
|
|
inode->i_dirt = 1;
|
|
iput(inode);
|
|
brelse(bh);
|
|
iput(dir);
|
|
return -EEXIST;
|
|
}
|
|
bh = ext_add_entry(dir,name,len,&de);
|
|
if (!bh) {
|
|
inode->i_nlink--;
|
|
inode->i_dirt = 1;
|
|
iput(inode);
|
|
iput(dir);
|
|
return -ENOSPC;
|
|
}
|
|
de->inode = inode->i_ino;
|
|
bh->b_dirt = 1;
|
|
brelse(bh);
|
|
iput(dir);
|
|
iput(inode);
|
|
return 0;
|
|
}
|
|
|
|
int ext_link(struct inode * oldinode, struct inode * dir, const char * name, int len)
|
|
{
|
|
struct ext_dir_entry * de;
|
|
struct buffer_head * bh;
|
|
|
|
if (S_ISDIR(oldinode->i_mode)) {
|
|
iput(oldinode);
|
|
iput(dir);
|
|
return -EPERM;
|
|
}
|
|
if (oldinode->i_nlink > 32000) {
|
|
iput(oldinode);
|
|
iput(dir);
|
|
return -EMLINK;
|
|
}
|
|
bh = ext_find_entry(dir,name,len,&de,NULL,NULL);
|
|
if (bh) {
|
|
brelse(bh);
|
|
iput(dir);
|
|
iput(oldinode);
|
|
return -EEXIST;
|
|
}
|
|
bh = ext_add_entry(dir,name,len,&de);
|
|
if (!bh) {
|
|
iput(dir);
|
|
iput(oldinode);
|
|
return -ENOSPC;
|
|
}
|
|
de->inode = oldinode->i_ino;
|
|
bh->b_dirt = 1;
|
|
brelse(bh);
|
|
iput(dir);
|
|
oldinode->i_nlink++;
|
|
oldinode->i_ctime = CURRENT_TIME;
|
|
oldinode->i_dirt = 1;
|
|
iput(oldinode);
|
|
return 0;
|
|
}
|
|
|
|
static int subdir(struct inode * new_inode, struct inode * old_inode)
|
|
{
|
|
int ino;
|
|
int result;
|
|
|
|
new_inode->i_count++;
|
|
result = 0;
|
|
for (;;) {
|
|
if (new_inode == old_inode) {
|
|
result = 1;
|
|
break;
|
|
}
|
|
if (new_inode->i_dev != old_inode->i_dev)
|
|
break;
|
|
ino = new_inode->i_ino;
|
|
if (ext_lookup(new_inode,"..",2,&new_inode))
|
|
break;
|
|
if (new_inode->i_ino == ino)
|
|
break;
|
|
}
|
|
iput(new_inode);
|
|
return result;
|
|
}
|
|
|
|
#define PARENT_INO(buffer) \
|
|
((struct ext_dir_entry *) ((char *) buffer + \
|
|
((struct ext_dir_entry *) buffer)->rec_len))->inode
|
|
|
|
#define PARENT_NAME(buffer) \
|
|
((struct ext_dir_entry *) ((char *) buffer + \
|
|
((struct ext_dir_entry *) buffer)->rec_len))->name
|
|
|
|
/*
|
|
* rename uses retrying to avoid race-conditions: at least they should be minimal.
|
|
* it tries to allocate all the blocks, then sanity-checks, and if the sanity-
|
|
* checks fail, it tries to restart itself again. Very practical - no changes
|
|
* are done until we know everything works ok.. and then all the changes can be
|
|
* done in one fell swoop when we have claimed all the buffers needed.
|
|
*
|
|
* Anybody can rename anything with this: the permission checks are left to the
|
|
* higher-level routines.
|
|
*/
|
|
static int do_ext_rename(struct inode * old_dir, const char * old_name, int old_len,
|
|
struct inode * new_dir, const char * new_name, int new_len)
|
|
{
|
|
struct inode * old_inode, * new_inode;
|
|
struct buffer_head * old_bh, * new_bh, * dir_bh;
|
|
struct ext_dir_entry * old_de, * new_de, * pde, * nde;
|
|
int retval;
|
|
|
|
goto start_up;
|
|
try_again:
|
|
brelse(old_bh);
|
|
brelse(new_bh);
|
|
brelse(dir_bh);
|
|
iput(old_inode);
|
|
iput(new_inode);
|
|
current->counter = 0;
|
|
schedule();
|
|
start_up:
|
|
old_inode = new_inode = NULL;
|
|
old_bh = new_bh = dir_bh = NULL;
|
|
old_bh = ext_find_entry(old_dir,old_name,old_len,&old_de,&pde,&nde);
|
|
retval = -ENOENT;
|
|
if (!old_bh)
|
|
goto end_rename;
|
|
old_inode = __iget(old_dir->i_sb, old_de->inode,0); /* don't cross mnt-points */
|
|
if (!old_inode)
|
|
goto end_rename;
|
|
retval = -EPERM;
|
|
if ((old_dir->i_mode & S_ISVTX) &&
|
|
current->euid != old_inode->i_uid &&
|
|
current->euid != old_dir->i_uid && !suser())
|
|
goto end_rename;
|
|
new_bh = ext_find_entry(new_dir,new_name,new_len,&new_de,NULL,NULL);
|
|
if (new_bh) {
|
|
new_inode = __iget(new_dir->i_sb, new_de->inode,0); /* don't cross mnt-points */
|
|
if (!new_inode) {
|
|
brelse(new_bh);
|
|
new_bh = NULL;
|
|
}
|
|
}
|
|
if (new_inode == old_inode) {
|
|
retval = 0;
|
|
goto end_rename;
|
|
}
|
|
if (new_inode && S_ISDIR(new_inode->i_mode)) {
|
|
retval = -EEXIST;
|
|
goto end_rename;
|
|
}
|
|
retval = -EPERM;
|
|
if (new_inode && (new_dir->i_mode & S_ISVTX) &&
|
|
current->euid != new_inode->i_uid &&
|
|
current->euid != new_dir->i_uid && !suser())
|
|
goto end_rename;
|
|
if (S_ISDIR(old_inode->i_mode)) {
|
|
retval = -EEXIST;
|
|
if (new_bh)
|
|
goto end_rename;
|
|
retval = -EACCES;
|
|
if (!permission(old_inode, MAY_WRITE))
|
|
goto end_rename;
|
|
retval = -EINVAL;
|
|
if (subdir(new_dir, old_inode))
|
|
goto end_rename;
|
|
retval = -EIO;
|
|
dir_bh = ext_bread(old_inode,0,0);
|
|
if (!dir_bh)
|
|
goto end_rename;
|
|
if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino)
|
|
goto end_rename;
|
|
}
|
|
if (!new_bh)
|
|
new_bh = ext_add_entry(new_dir,new_name,new_len,&new_de);
|
|
retval = -ENOSPC;
|
|
if (!new_bh)
|
|
goto end_rename;
|
|
/* sanity checking before doing the rename - avoid races */
|
|
if (new_inode && (new_de->inode != new_inode->i_ino))
|
|
goto try_again;
|
|
if (new_de->inode && !new_inode)
|
|
goto try_again;
|
|
if (old_de->inode != old_inode->i_ino)
|
|
goto try_again;
|
|
/* ok, that's it */
|
|
old_de->inode = 0;
|
|
old_de->name_len = 0;
|
|
new_de->inode = old_inode->i_ino;
|
|
ext_merge_entries (old_de, pde, nde);
|
|
if (new_inode) {
|
|
new_inode->i_nlink--;
|
|
new_inode->i_dirt = 1;
|
|
}
|
|
old_bh->b_dirt = 1;
|
|
new_bh->b_dirt = 1;
|
|
if (dir_bh) {
|
|
PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
|
|
dir_bh->b_dirt = 1;
|
|
old_dir->i_nlink--;
|
|
new_dir->i_nlink++;
|
|
old_dir->i_dirt = 1;
|
|
new_dir->i_dirt = 1;
|
|
}
|
|
retval = 0;
|
|
end_rename:
|
|
brelse(dir_bh);
|
|
brelse(old_bh);
|
|
brelse(new_bh);
|
|
iput(old_inode);
|
|
iput(new_inode);
|
|
iput(old_dir);
|
|
iput(new_dir);
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Ok, rename also locks out other renames, as they can change the parent of
|
|
* a directory, and we don't want any races. Other races are checked for by
|
|
* "do_rename()", which restarts if there are inconsistencies.
|
|
*
|
|
* Note that there is no race between different filesystems: it's only within
|
|
* the same device that races occur: many renames can happen at once, as long
|
|
* as they are on different partitions.
|
|
*/
|
|
int ext_rename(struct inode * old_dir, const char * old_name, int old_len,
|
|
struct inode * new_dir, const char * new_name, int new_len)
|
|
{
|
|
static struct wait_queue * wait = NULL;
|
|
static int lock = 0;
|
|
int result;
|
|
|
|
while (lock)
|
|
sleep_on(&wait);
|
|
lock = 1;
|
|
result = do_ext_rename(old_dir, old_name, old_len,
|
|
new_dir, new_name, new_len);
|
|
lock = 0;
|
|
wake_up(&wait);
|
|
return result;
|
|
}
|