patch-2.1.21 linux/fs/ext/namei.c
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- Lines: 904
- Date:
Thu Jan 1 02:00:00 1970
- Orig file:
v2.1.20/linux/fs/ext/namei.c
- Orig date:
Tue Oct 29 19:58:20 1996
diff -u --recursive --new-file v2.1.20/linux/fs/ext/namei.c linux/fs/ext/namei.c
@@ -1,903 +0,0 @@
-/*
- * linux/fs/ext/namei.c
- *
- * Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
- *
- * from
- *
- * linux/fs/minix/namei.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- */
-
-#include <linux/sched.h>
-#include <linux/ext_fs.h>
-#include <linux/kernel.h>
-#include <linux/string.h>
-#include <linux/stat.h>
-#include <linux/fcntl.h>
-#include <linux/errno.h>
-
-#include <asm/uaccess.h>
-
-/*
- * comment out this line if you want names > EXT_NAME_LEN chars to be
- * truncated. Else they will be disallowed.
- */
-/* #define NO_TRUNCATE */
-
-/*
- * EXT_DIR_PAD defines the directory entries boundaries
- *
- * NOTE: It must be a power of 2 and must be greater or equal than 8
- * because a directory entry needs 8 bytes for its fixed part
- * (4 bytes for the inode, 2 bytes for the entry length and 2 bytes
- * for the name length)
- */
-#define EXT_DIR_PAD 8
-
-/*
- *
- * EXT_DIR_MIN_SIZE is the minimal size of a directory entry
- *
- * During allocations, a directory entry is split into 2 ones
- * *ONLY* if the size of the unused part is greater than or
- * equal to EXT_DIR_MIN_SIZE
- */
-#define EXT_DIR_MIN_SIZE 12
-
-/*
- * ok, we cannot use strncmp, as the name is not in our data space.
- * Thus we'll have to use ext_match. No big problem. Match also makes
- * some sanity tests.
- *
- * NOTE! unlike strncmp, ext_match returns 1 for success, 0 for failure.
- */
-static int ext_match(int len,const char * name,struct ext_dir_entry * de)
-{
- if (!de || !de->inode || len > EXT_NAME_LEN)
- return 0;
- /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
- if (!len && (de->name[0]=='.') && (de->name[1]=='\0'))
- return 1;
- if (len != de->name_len)
- return 0;
- return !memcmp(name, de->name, len);
-}
-
-/*
- * ext_find_entry()
- *
- * finds an entry in the specified directory with the wanted name. It
- * returns the cache buffer in which the entry was found, and the entry
- * itself (as a parameter - res_dir). It does NOT read the inode of the
- * entry - you'll have to do that yourself if you want to.
- *
- * addition for the ext file system : this function returns the previous
- * and next directory entries in the parameters prev_dir and next_dir
- */
-static struct buffer_head * ext_find_entry(struct inode * dir,
- const char * name, int namelen, struct ext_dir_entry ** res_dir,
- struct ext_dir_entry ** prev_dir, struct ext_dir_entry ** next_dir)
-{
- long offset;
- struct buffer_head * bh;
- struct ext_dir_entry * de;
-
- *res_dir = NULL;
- if (!dir)
- return NULL;
-#ifdef NO_TRUNCATE
- if (namelen > EXT_NAME_LEN)
- return NULL;
-#else
- if (namelen > EXT_NAME_LEN)
- namelen = EXT_NAME_LEN;
-#endif
- bh = ext_bread(dir,0,0);
- if (!bh)
- return NULL;
- if (prev_dir)
- *prev_dir = NULL;
- if (next_dir)
- *next_dir = NULL;
- offset = 0;
- de = (struct ext_dir_entry *) bh->b_data;
- while (offset < dir->i_size) {
- if ((char *)de >= BLOCK_SIZE+bh->b_data) {
- brelse(bh);
- bh = NULL;
- bh = ext_bread(dir,offset>>BLOCK_SIZE_BITS,0);
- if (!bh)
- continue;
- de = (struct ext_dir_entry *) bh->b_data;
- if (prev_dir)
- *prev_dir = NULL;
- }
- if (de->rec_len < 8 || de->rec_len % 8 != 0 ||
- de->rec_len < de->name_len + 8 ||
- (((char *) de) + de->rec_len-1 >= BLOCK_SIZE+bh->b_data)) {
- printk ("ext_find_entry: bad dir entry\n");
- printk ("dev=%s, dir=%ld, offset=%ld, "
- "rec_len=%d, name_len=%d\n",
- kdevname(dir->i_dev), dir->i_ino, offset,
- de->rec_len, de->name_len);
- de = (struct ext_dir_entry *) (bh->b_data+BLOCK_SIZE);
- offset = ((offset / BLOCK_SIZE) + 1) * BLOCK_SIZE;
- continue;
-/* brelse (bh);
- return NULL; */
- }
- if (ext_match(namelen,name,de)) {
- *res_dir = de;
- if (next_dir)
- if (offset + de->rec_len < dir->i_size &&
- ((char *)de) + de->rec_len < BLOCK_SIZE+bh->b_data)
- *next_dir = (struct ext_dir_entry *)
- ((char *) de + de->rec_len);
- else
- *next_dir = NULL;
- return bh;
- }
- offset += de->rec_len;
- if (prev_dir)
- *prev_dir = de;
- de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
- }
- brelse(bh);
- return NULL;
-}
-
-int ext_lookup(struct inode * dir,const char * name, int len,
- struct inode ** result)
-{
- int ino;
- struct ext_dir_entry * de;
- struct buffer_head * bh;
-
- *result = NULL;
- if (!dir)
- return -ENOENT;
- if (!S_ISDIR(dir->i_mode)) {
- iput(dir);
- return -ENOENT;
- }
- if (!(bh = ext_find_entry(dir,name,len,&de,NULL,NULL))) {
- iput(dir);
- return -ENOENT;
- }
- ino = de->inode;
- brelse(bh);
- if (!(*result = iget(dir->i_sb,ino))) {
- iput(dir);
- return -EACCES;
- }
- iput(dir);
- return 0;
-}
-
-/*
- * ext_add_entry()
- *
- * adds a file entry to the specified directory, using the same
- * semantics as ext_find_entry(). It returns NULL if it failed.
- *
- * NOTE!! The inode part of 'de' is left at 0 - which means you
- * may not sleep between calling this and putting something into
- * the entry, as someone else might have used it while you slept.
- */
-static struct buffer_head * ext_add_entry(struct inode * dir,
- const char * name, int namelen, struct ext_dir_entry ** res_dir)
-{
- int i;
- long offset;
- unsigned short rec_len;
- struct buffer_head * bh;
- struct ext_dir_entry * de, * de1;
-
- *res_dir = NULL;
- if (!dir)
- return NULL;
-#ifdef NO_TRUNCATE
- if (namelen > EXT_NAME_LEN)
- return NULL;
-#else
- if (namelen > EXT_NAME_LEN)
- namelen = EXT_NAME_LEN;
-#endif
- if (!namelen)
- return NULL;
- bh = ext_bread(dir,0,0);
- if (!bh)
- return NULL;
- rec_len = ((8 + namelen + EXT_DIR_PAD - 1) / EXT_DIR_PAD) * EXT_DIR_PAD;
- offset = 0;
- de = (struct ext_dir_entry *) bh->b_data;
- while (1) {
- if ((char *)de >= BLOCK_SIZE+bh->b_data && offset < dir->i_size) {
-#ifdef EXTFS_DEBUG
-printk ("ext_add_entry: skipping to next block\n");
-#endif
- brelse(bh);
- bh = NULL;
- bh = ext_bread(dir,offset>>BLOCK_SIZE_BITS,0);
- if (!bh)
- return NULL;
- de = (struct ext_dir_entry *) bh->b_data;
- }
- if (offset >= dir->i_size) {
- /* Check that the directory entry fits in the block */
- if (offset % BLOCK_SIZE == 0 ||
- (BLOCK_SIZE - (offset % BLOCK_SIZE)) < rec_len) {
- if ((offset % BLOCK_SIZE) != 0) {
- /* If the entry does not fit in the
- block, the remainder of the block
- becomes an unused entry */
- de->inode = 0;
- de->rec_len = BLOCK_SIZE
- - (offset & (BLOCK_SIZE - 1));
- de->name_len = 0;
- offset += de->rec_len;
- dir->i_size += de->rec_len;
- dir->i_dirt = 1;
-#if 0
- dir->i_ctime = CURRENT_TIME;
-#endif
- mark_buffer_dirty(bh, 1);
- }
- brelse (bh);
- bh = NULL;
-#ifdef EXTFS_DEBUG
-printk ("ext_add_entry : creating next block\n");
-#endif
- bh = ext_bread(dir,offset>>BLOCK_SIZE_BITS,1);
- if (!bh)
- return NULL; /* Other thing to do ??? */
- de = (struct ext_dir_entry *) bh->b_data;
- }
- /* Allocate the entry */
- de->inode=0;
- de->rec_len = rec_len;
- dir->i_size += de->rec_len;
- dir->i_dirt = 1;
-#if 0
- dir->i_ctime = CURRENT_TIME;
-#endif
- }
- if (de->rec_len < 8 || de->rec_len % 4 != 0 ||
- de->rec_len < de->name_len + 8 ||
- (((char *) de) + de->rec_len-1 >= BLOCK_SIZE+bh->b_data)) {
- printk ("ext_addr_entry: bad dir entry\n");
- printk ("dev=%s, dir=%ld, offset=%ld, "
- "rec_len=%d, name_len=%d\n",
- kdevname(dir->i_dev), dir->i_ino, offset,
- de->rec_len, de->name_len);
- brelse (bh);
- return NULL;
- }
- if (!de->inode && de->rec_len >= rec_len) {
- if (de->rec_len > rec_len
- && de->rec_len - rec_len >= EXT_DIR_MIN_SIZE) {
- /* The found entry is too big : it is split
- into 2 ones :
- - the 1st one will be used to hold the name,
- - the 2nd one is unused */
- de1 = (struct ext_dir_entry *) ((char *) de + rec_len);
- de1->inode = 0;
- de1->rec_len = de->rec_len - rec_len;
- de1->name_len = 0;
- de->rec_len = rec_len;
- }
- dir->i_mtime = dir->i_ctime = CURRENT_TIME;
- dir->i_dirt = 1;
- de->name_len = namelen;
- for (i=0; i < namelen ; i++)
- de->name[i] = name[i];
- mark_buffer_dirty(bh, 1);
- *res_dir = de;
- return bh;
- }
- offset += de->rec_len;
- de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
- }
- brelse(bh);
- return NULL;
-}
-
-int ext_create(struct inode * dir,const char * name, int len, int mode,
- struct inode ** result)
-{
- struct inode * inode;
- struct buffer_head * bh;
- struct ext_dir_entry * de;
-
- *result = NULL;
- if (!dir)
- return -ENOENT;
- inode = ext_new_inode(dir);
- if (!inode) {
- iput(dir);
- return -ENOSPC;
- }
- inode->i_op = &ext_file_inode_operations;
- inode->i_mode = mode;
- inode->i_dirt = 1;
- 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;
- mark_buffer_dirty(bh, 1);
- brelse(bh);
- iput(dir);
- *result = inode;
- return 0;
-}
-
-int ext_mknod(struct inode * dir, const char * name, int len, int mode, int rdev)
-{
- struct inode * inode;
- struct buffer_head * bh;
- struct ext_dir_entry * de;
-
- if (!dir)
- return -ENOENT;
- bh = ext_find_entry(dir,name,len,&de,NULL,NULL);
- if (bh) {
- brelse(bh);
- iput(dir);
- return -EEXIST;
- }
- inode = ext_new_inode(dir);
- if (!inode) {
- iput(dir);
- return -ENOSPC;
- }
- inode->i_uid = current->fsuid;
- inode->i_mode = mode;
- inode->i_op = NULL;
- if (S_ISREG(inode->i_mode))
- inode->i_op = &ext_file_inode_operations;
- else if (S_ISDIR(inode->i_mode)) {
- inode->i_op = &ext_dir_inode_operations;
- if (dir->i_mode & S_ISGID)
- inode->i_mode |= S_ISGID;
- }
- else if (S_ISLNK(inode->i_mode))
- inode->i_op = &ext_symlink_inode_operations;
- else if (S_ISCHR(inode->i_mode))
- inode->i_op = &chrdev_inode_operations;
- else if (S_ISBLK(inode->i_mode))
- inode->i_op = &blkdev_inode_operations;
- else if (S_ISFIFO(inode->i_mode))
- init_fifo(inode);
- if (S_ISBLK(mode) || S_ISCHR(mode))
- inode->i_rdev = to_kdev_t(rdev);
-#if 0
- inode->i_mtime = inode->i_atime = CURRENT_TIME;
-#endif
- inode->i_dirt = 1;
- 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;
- mark_buffer_dirty(bh, 1);
- brelse(bh);
- iput(dir);
- iput(inode);
- return 0;
-}
-
-int ext_mkdir(struct inode * dir, const char * name, int len, int mode)
-{
- struct inode * inode;
- struct buffer_head * bh, *dir_block;
- struct ext_dir_entry * de;
-
- bh = ext_find_entry(dir,name,len,&de,NULL,NULL);
- if (bh) {
- brelse(bh);
- iput(dir);
- return -EEXIST;
- }
- inode = ext_new_inode(dir);
- if (!inode) {
- iput(dir);
- return -ENOSPC;
- }
- inode->i_op = &ext_dir_inode_operations;
- inode->i_size = 2 * 16; /* Each entry is coded on 16 bytes for "." and ".."
- - 4 bytes for the inode number,
- - 2 bytes for the record length
- - 2 bytes for the name length
- - 8 bytes for the name */
-#if 0
- inode->i_mtime = inode->i_atime = CURRENT_TIME;
-#endif
- dir_block = ext_bread(inode,0,1);
- if (!dir_block) {
- iput(dir);
- inode->i_nlink--;
- inode->i_dirt = 1;
- iput(inode);
- return -ENOSPC;
- }
- de = (struct ext_dir_entry *) dir_block->b_data;
- de->inode=inode->i_ino;
- de->rec_len=16;
- de->name_len=1;
- strcpy(de->name,".");
- de = (struct ext_dir_entry *) ((char *) de + de->rec_len);
- de->inode = dir->i_ino;
- de->rec_len=16;
- de->name_len=2;
- strcpy(de->name,"..");
- inode->i_nlink = 2;
- mark_buffer_dirty(dir_block, 1);
- brelse(dir_block);
- inode->i_mode = S_IFDIR | (mode & 0777 & ~current->fs->umask);
- if (dir->i_mode & S_ISGID)
- inode->i_mode |= S_ISGID;
- inode->i_dirt = 1;
- bh = ext_add_entry(dir,name,len,&de);
- if (!bh) {
- iput(dir);
- inode->i_nlink=0;
- iput(inode);
- return -ENOSPC;
- }
- de->inode = inode->i_ino;
- mark_buffer_dirty(bh, 1);
- dir->i_nlink++;
- dir->i_dirt = 1;
- iput(dir);
- iput(inode);
- brelse(bh);
- return 0;
-}
-
-/*
- * routine to check that the specified directory is empty (for rmdir)
- */
-static int empty_dir(struct inode * inode)
-{
- unsigned long offset;
- struct buffer_head * bh;
- struct ext_dir_entry * de, * de1;
-
- if (inode->i_size < 2 * 12 || !(bh = ext_bread(inode,0,0))) {
- printk("warning - bad directory on dev %s\n",
- kdevname(inode->i_dev));
- return 1;
- }
- de = (struct ext_dir_entry *) bh->b_data;
- de1 = (struct ext_dir_entry *) ((char *) de + de->rec_len);
- if (de->inode != inode->i_ino || !de1->inode ||
- strcmp(".",de->name) || strcmp("..",de1->name)) {
- printk("warning - bad directory on dev %s\n",
- kdevname(inode->i_dev));
- return 1;
- }
- offset = de->rec_len + de1->rec_len;
- de = (struct ext_dir_entry *) ((char *) de1 + de1->rec_len);
- while (offset < inode->i_size ) {
- if ((void *) de >= (void *) (bh->b_data+BLOCK_SIZE)) {
- brelse(bh);
- bh = ext_bread(inode, offset >> BLOCK_SIZE_BITS,1);
- if (!bh) {
- offset += BLOCK_SIZE;
- 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=%s, dir=%ld, offset=%ld, "
- "rec_len=%d, name_len=%d\n",
- kdevname(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) && !fsuser() &&
- current->fsuid != inode->i_uid &&
- current->fsuid != dir->i_uid)
- 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);
- mark_buffer_dirty(bh, 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) && !fsuser() &&
- current->fsuid != inode->i_uid &&
- current->fsuid != dir->i_uid)
- goto end_unlink;
- if (S_ISDIR(inode->i_mode))
- goto end_unlink;
- if (!inode->i_nlink) {
- printk("Deleting nonexistent file (%s:%ld), %d\n",
- kdevname(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);
- mark_buffer_dirty(bh, 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;
- mark_buffer_dirty(name_block, 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;
- mark_buffer_dirty(bh, 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;
- mark_buffer_dirty(bh, 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->fsuid != old_inode->i_uid &&
- current->fsuid != old_dir->i_uid && !fsuser())
- 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->fsuid != new_inode->i_uid &&
- current->fsuid != new_dir->i_uid && !fsuser())
- goto end_rename;
- if (S_ISDIR(old_inode->i_mode)) {
- retval = -EEXIST;
- if (new_bh)
- goto end_rename;
- if ((retval = permission(old_inode, MAY_WRITE)) != 0)
- 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;
- }
- mark_buffer_dirty(old_bh, 1);
- mark_buffer_dirty(new_bh, 1);
- if (dir_bh) {
- PARENT_INO(dir_bh->b_data) = new_dir->i_ino;
- mark_buffer_dirty(dir_bh, 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,
- int must_be_dir)
-{
- 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;
-}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov