| /* |
| * linux/fs/ext/namei.c |
| * |
| * (C) 1992 Remy Card (card@masi.ibp.fr) |
| * |
| * from |
| * |
| * linux/fs/minix/namei.c |
| * |
| * (C) 1991 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 <asm/segment.h> |
| |
| #include <errno.h> |
| #include <const.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) |
| { |
| register int same __asm__("ax"); |
| |
| 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 < EXT_NAME_LEN && de->name[len]) |
| return 0; */ |
| if (len < EXT_NAME_LEN && len != de->name_len) |
| return 0; |
| __asm__("cld\n\t" |
| "fs ; repe ; cmpsb\n\t" |
| "setz %%al" |
| :"=a" (same) |
| :"0" (0),"S" ((long) name),"D" ((long) de->name),"c" (len) |
| :"cx","di","si"); |
| return same; |
| } |
| |
| /* |
| * 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) |
| { |
| /* int entries; */ |
| int block /* ,i */; |
| 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 |
| /* entries = dir->i_size / (sizeof (struct ext_dir_entry)); */ |
| if (!(block = dir->i_data[0])) |
| return NULL; |
| if (!(bh = bread(dir->i_dev,block))) |
| return NULL; |
| if (prev_dir) |
| *prev_dir = NULL; |
| if (next_dir) |
| *next_dir = NULL; |
| /* i = 0; */ |
| 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; |
| if (!(block = ext_bmap(dir,offset>>BLOCK_SIZE_BITS)) || |
| !(bh = bread(dir->i_dev,block))) { |
| /* i += EXT_DIR_ENTRIES_PER_BLOCK; */ |
| /* offset += BLOCK_SIZE; */ |
| continue; |
| } |
| de = (struct ext_dir_entry *) bh->b_data; |
| if (prev_dir) |
| *prev_dir = NULL; |
| } |
| if (ext_match(namelen,name,de)) { |
| *res_dir = de; |
| if (next_dir) |
| if (offset + de->rec_len < dir->i_size) |
| *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); |
| /* i++; */ |
| } |
| 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_dev,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 block,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; |
| if (!(block = dir->i_data[0])) |
| return NULL; |
| if (!(bh = bread(dir->i_dev,block))) |
| return NULL; |
| rec_len = ((8 + namelen + EXT_DIR_PAD - 1) / EXT_DIR_PAD) * EXT_DIR_PAD; |
| /* i = 0; */ |
| 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; |
| block = ext_create_block(dir,offset>>BLOCK_SIZE_BITS); |
| if (!block) |
| return NULL; |
| if (!(bh = bread(dir->i_dev,block))) { |
| /* i += EXT_DIR_ENTRIES_PER_BLOCK; */ |
| offset += BLOCK_SIZE; |
| continue; |
| } |
| 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; |
| dir->i_ctime = CURRENT_TIME; |
| bh->b_dirt = 1; |
| } |
| brelse (bh); |
| bh = NULL; |
| block = ext_create_block (dir,offset>>BLOCK_SIZE_BITS); |
| #ifdef EXTFS_DEBUG |
| printk ("ext_add_entry : creating next block\n"); |
| #endif |
| if (!block) |
| return NULL; |
| if (!(bh = bread(dir->i_dev,block))) |
| 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 = (i+1)*sizeof(struct ext_dir_entry); */ |
| dir->i_size += de->rec_len; |
| dir->i_dirt = 1; |
| dir->i_ctime = CURRENT_TIME; |
| } |
| 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 = CURRENT_TIME; |
| de->name_len = namelen; |
| for (i=0; i < namelen ; i++) |
| de->name[i]=/*(i<namelen)?*/get_fs_byte(name+i)/*:0*/; |
| bh->b_dirt = 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->i_dev); |
| 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; |
| bh->b_dirt = 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->i_dev); |
| if (!inode) { |
| iput(dir); |
| return -ENOSPC; |
| } |
| inode->i_uid = current->euid; |
| 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; |
| else if (S_ISLNK(inode->i_mode)) |
| inode->i_op = &ext_symlink_inode_operations; |
| else if (S_ISCHR(inode->i_mode)) |
| inode->i_op = &ext_chrdev_inode_operations; |
| else if (S_ISBLK(inode->i_mode)) |
| inode->i_op = &ext_blkdev_inode_operations; |
| else if (S_ISFIFO(inode->i_mode)) { |
| inode->i_op = &ext_fifo_inode_operations; |
| inode->i_size = 0; |
| inode->i_pipe = 1; |
| PIPE_HEAD(*inode) = PIPE_TAIL(*inode) = 0; |
| PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 0; |
| } |
| if (S_ISBLK(mode) || S_ISCHR(mode)) |
| inode->i_rdev = rdev; |
| inode->i_mtime = inode->i_atime = CURRENT_TIME; |
| 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; |
| bh->b_dirt = 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->i_dev); |
| 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 */ |
| inode->i_mtime = inode->i_atime = CURRENT_TIME; |
| if (!(inode->i_data[0] = ext_new_block(inode->i_dev))) { |
| iput(dir); |
| inode->i_nlink--; |
| inode->i_dirt = 1; |
| iput(inode); |
| return -ENOSPC; |
| } |
| inode->i_dirt = 1; |
| if (!(dir_block = bread(inode->i_dev,inode->i_data[0]))) { |
| iput(dir); |
| inode->i_nlink--; |
| inode->i_dirt = 1; |
| iput(inode); |
| return -EIO; |
| } |
| 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++; */ |
| 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; |
| dir_block->b_dirt = 1; |
| brelse(dir_block); |
| inode->i_mode = I_DIRECTORY | (mode & 0777 & ~current->umask); |
| 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; |
| bh->b_dirt = 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) |
| { |
| int /* nr, */ block; |
| /* int len; */ |
| unsigned long offset; |
| struct buffer_head * bh; |
| struct ext_dir_entry * de, * de1; |
| |
| /* len = inode->i_size / sizeof (struct ext_dir_entry); */ |
| if (inode->i_size < 2 * 12 || !inode->i_data[0] || |
| !(bh=bread(inode->i_dev,inode->i_data[0]))) { |
| printk("warning - bad directory on dev %04x\n",inode->i_dev); |
| return 0; |
| } |
| 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 %04x\n",inode->i_dev); |
| return 0; |
| } |
| /* nr = 2; */ |
| 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); |
| block = ext_bmap(inode, offset >> BLOCK_SIZE_BITS); |
| if (!block) { |
| offset += BLOCK_SIZE; |
| continue; |
| } |
| if (!(bh=bread(inode->i_dev,block))) |
| return 0; |
| de = (struct ext_dir_entry *) bh->b_data; |
| } |
| 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->inode) |
| de->rec_len += nde->rec_len; |
| if (! 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_dev, 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--; |
| 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_dev, 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; |
| 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->i_dev))) { |
| iput(dir); |
| return -ENOSPC; |
| } |
| inode->i_mode = S_IFLNK | 0777; |
| inode->i_op = &ext_symlink_inode_operations; |
| if (!(inode->i_data[0] = ext_new_block(inode->i_dev))) { |
| iput(dir); |
| inode->i_nlink--; |
| inode->i_dirt = 1; |
| iput(inode); |
| return -ENOSPC; |
| } |
| inode->i_dirt = 1; |
| if (!(name_block = bread(inode->i_dev,inode->i_data[0]))) { |
| iput(dir); |
| inode->i_nlink--; |
| inode->i_dirt = 1; |
| iput(inode); |
| return -EIO; |
| } |
| i = 0; |
| while (i < 1023 && (c=get_fs_byte(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; |
| } |
| 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, struct inode * old) |
| { |
| unsigned short fs; |
| int ino; |
| int result; |
| |
| __asm__("mov %%fs,%0":"=r" (fs)); |
| __asm__("mov %0,%%fs"::"r" ((unsigned short) 0x10)); |
| new->i_count++; |
| result = 0; |
| for (;;) { |
| if (new == old) { |
| result = 1; |
| break; |
| } |
| if (new->i_dev != old->i_dev) |
| break; |
| ino = new->i_ino; |
| if (ext_lookup(new,"..",2,&new)) |
| break; |
| if (new->i_ino == ino) |
| break; |
| } |
| iput(new); |
| __asm__("mov %0,%%fs"::"r" (fs)); |
| return result; |
| } |
| |
| #define PARENT_INO(buffer) \ |
| ((struct ext_dir_entry *) ((char *) buffer + \ |
| ((struct ext_dir_entry *) buffer)->rec_len))->inode |
| /* (((struct ext_dir_entry *) (buffer))[1].inode) */ |
| |
| #define PARENT_NAME(buffer) \ |
| ((struct ext_dir_entry *) ((char *) buffer + \ |
| ((struct ext_dir_entry *) buffer)->rec_len))->name |
| /* (((struct ext_dir_entry *) (buffer))[1].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_dev, old_de->inode); |
| if (!old_inode) |
| goto end_rename; |
| 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_dev, new_de->inode); |
| if (!new_inode) { |
| brelse(new_bh); |
| new_bh = NULL; |
| } |
| } |
| if (new_inode == old_inode) { |
| retval = 0; |
| 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; |
| if (!old_inode->i_data[0]) |
| goto end_rename; |
| if (!(dir_bh = bread(old_inode->i_dev, old_inode->i_data[0]))) |
| 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; |
| ext_merge_entries (old_de, pde, nde); |
| new_de->inode = old_inode->i_ino; |
| 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 task_struct * 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; |
| } |