namei c (7)


/* * linux/fs/ext2/namei.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * * from * * linux/fs/minix/namei.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include <asm/segment.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/ext2_fs.h> #include <linux/fcntl.h> #include <linux/sched.h> #include <linux/stat.h> #include <linux/string.h> #include <linux/locks.h> /* * comment out this line if you want names > EXT2_NAME_LEN chars to be * truncated. Else they will be disallowed. */ /* #define NO_TRUNCATE */ /* * define how far ahead to read directories while searching them. */ #define NAMEI_RA_CHUNKS 2 #define NAMEI_RA_BLOCKS 4 #define NAMEI_RA_SIZE (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS) #define NAMEI_RA_INDEX(c,b) (((c) * NAMEI_RA_BLOCKS) + (b)) /* * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. */ static int ext2_match (int len, const char * const name, struct ext2_dir_entry * de) { if (!de || !de->inode || len > EXT2_NAME_LEN) return 0; /* * "" means "." ---> so paths like "/usr/lib//libc.a" work */ if (!len && de->name_len == 1 && (de->name[0] == '.') && (de->name[1] == '\0')) return 1; if (len != de->name_len) return 0; return !memcmp(name, de->name, len); } /* * ext2_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. */ static struct buffer_head * ext2_find_entry (struct inode * dir, const char * const name, int namelen, struct ext2_dir_entry ** res_dir) { struct super_block * sb; struct buffer_head * bh_use[NAMEI_RA_SIZE]; struct buffer_head * bh_read[NAMEI_RA_SIZE]; unsigned long offset; int block, toread, i, err; *res_dir = NULL; if (!dir) return NULL; sb = dir->i_sb; #ifdef NO_TRUNCATE if (namelen > EXT2_NAME_LEN) return NULL; #else if (namelen > EXT2_NAME_LEN) namelen = EXT2_NAME_LEN; #endif memset (bh_use, 0, sizeof (bh_use)); toread = 0; for (block = 0; block < NAMEI_RA_SIZE; ++block) { struct buffer_head * bh; if ((block << EXT2_BLOCK_SIZE_BITS (sb)) >= dir->i_size) break; bh = ext2_getblk (dir, block, 0, &err); bh_use[block] = bh; if (bh && !buffer_uptodate(bh)) bh_read[toread++] = bh; } for (block = 0, offset = 0; offset < dir->i_size; block++) { struct buffer_head * bh; struct ext2_dir_entry * de; char * dlimit; if ((block % NAMEI_RA_BLOCKS) == 0 && toread) { ll_rw_block (READ, toread, bh_read); toread = 0; } bh = bh_use[block % NAMEI_RA_SIZE]; if (!bh) { ext2_error (sb, "ext2_find_entry", "directory #%lu contains a hole at offset %lu", dir->i_ino, offset); offset += sb->s_blocksize; continue; } wait_on_buffer (bh); if (!buffer_uptodate(bh)) { /* * read error: all bets are off */ break; } de = (struct ext2_dir_entry *) bh->b_data; dlimit = bh->b_data + sb->s_blocksize; while ((char *) de < dlimit) { if (!ext2_check_dir_entry ("ext2_find_entry", dir, de, bh, offset)) goto failure; if (de->inode != 0 && ext2_match (namelen, name, de)) { for (i = 0; i < NAMEI_RA_SIZE; ++i) { if (bh_use[i] != bh) brelse (bh_use[i]); } *res_dir = de; return bh; } offset += de->rec_len; de = (struct ext2_dir_entry *) ((char *) de + de->rec_len); } brelse (bh); if (((block + NAMEI_RA_SIZE) << EXT2_BLOCK_SIZE_BITS (sb)) >= dir->i_size) bh = NULL; else bh = ext2_getblk (dir, block + NAMEI_RA_SIZE, 0, &err); bh_use[block % NAMEI_RA_SIZE] = bh; if (bh && !buffer_uptodate(bh)) bh_read[toread++] = bh; } failure: for (i = 0; i < NAMEI_RA_SIZE; ++i) brelse (bh_use[i]); return NULL; } int ext2_lookup (struct inode * dir, const char * name, int len, struct inode ** result) { unsigned long ino; struct ext2_dir_entry * de; struct buffer_head * bh; *result = NULL; if (!dir) return -ENOENT; if (!S_ISDIR(dir->i_mode)) { iput (dir); return -ENOENT; } if (dcache_lookup(dir, name, len, &ino)) { if (!ino) { iput(dir); return -ENOENT; } if (!(*result = iget (dir->i_sb, ino))) { iput (dir); return -EACCES; } iput (dir); return 0; } ino = dir->i_version; if (!(bh = ext2_find_entry (dir, name, len, &de))) { if (ino == dir->i_version) dcache_add(dir, name, len, 0); iput (dir); return -ENOENT; } ino = de->inode; dcache_add(dir, name, len, ino); brelse (bh); if (!(*result = iget (dir->i_sb, ino))) { iput (dir); return -EACCES; } iput (dir); return 0; } /* * ext2_add_entry() * * adds a file entry to the specified directory, using the same * semantics as ext2_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 * ext2_add_entry (struct inode * dir, const char * name, int namelen, struct ext2_dir_entry ** res_dir, int *err) { unsigned long offset; unsigned short rec_len; struct buffer_head * bh; struct ext2_dir_entry * de, * de1; struct super_block * sb; *err = -EINVAL; *res_dir = NULL; if (!dir) return NULL; sb = dir->i_sb; #ifdef NO_TRUNCATE if (namelen > EXT2_NAME_LEN) return NULL; #else if (namelen > EXT2_NAME_LEN) namelen = EXT2_NAME_LEN; #endif if (!namelen) return NULL; /* * Is this a busy deleted directory? Can't create new files if so */ if (dir->i_size == 0) { *err = -ENOENT; return NULL; } bh = ext2_bread (dir, 0, 0, err); if (!bh) return NULL; rec_len = EXT2_DIR_REC_LEN(namelen); offset = 0; de = (struct ext2_dir_entry *) bh->b_data; *err = -ENOSPC; while (1) { if ((char *)de >= sb->s_blocksize + bh->b_data) { brelse (bh); bh = NULL; bh = ext2_bread (dir, offset >> EXT2_BLOCK_SIZE_BITS(sb), 1, err); if (!bh) return NULL; if (dir->i_size <= offset) { if (dir->i_size == 0) { *err = -ENOENT; return NULL; } ext2_debug ("creating next block\n"); de = (struct ext2_dir_entry *) bh->b_data; de->inode = 0; de->rec_len = sb->s_blocksize; dir->i_size = offset + sb->s_blocksize; dir->i_dirt = 1; } else { ext2_debug ("skipping to next block\n"); de = (struct ext2_dir_entry *) bh->b_data; } } if (!ext2_check_dir_entry ("ext2_add_entry", dir, de, bh, offset)) { *err = -ENOENT; brelse (bh); return NULL; } if (de->inode != 0 && ext2_match (namelen, name, de)) { *err = -EEXIST; brelse (bh); return NULL; } if ((de->inode == 0 && de->rec_len >= rec_len) || (de->rec_len >= EXT2_DIR_REC_LEN(de->name_len) + rec_len)) { offset += de->rec_len; if (de->inode) { de1 = (struct ext2_dir_entry *) ((char *) de + EXT2_DIR_REC_LEN(de->name_len)); de1->rec_len = de->rec_len - EXT2_DIR_REC_LEN(de->name_len); de->rec_len = EXT2_DIR_REC_LEN(de->name_len); de = de1; } de->inode = 0; de->name_len = namelen; memcpy (de->name, name, namelen); /* * XXX shouldn't update any times until successful * completion of syscall, but too many callers depend * on this. * * XXX similarly, too many callers depend on * ext2_new_inode() setting the times, but error * recovery deletes the inode, so the worst that can * happen is that the times are slightly out of date * and/or different from the directory change time. */ dir->i_mtime = dir->i_ctime = CURRENT_TIME; dir->i_dirt = 1; dir->i_version = ++event; mark_buffer_dirty(bh, 1); *res_dir = de; *err = 0; return bh; } offset += de->rec_len; de = (struct ext2_dir_entry *) ((char *) de + de->rec_len); } brelse (bh); return NULL; } /* * ext2_delete_entry deletes a directory entry by merging it with the * previous entry */ static int ext2_delete_entry (struct ext2_dir_entry * dir, struct buffer_head * bh) { struct ext2_dir_entry * de, * pde; int i; i = 0; pde = NULL; de = (struct ext2_dir_entry *) bh->b_data; while (i < bh->b_size) { if (!ext2_check_dir_entry ("ext2_delete_entry", NULL, de, bh, i)) return -EIO; if (de == dir) { if (pde) pde->rec_len += dir->rec_len; dir->inode = 0; return 0; } i += de->rec_len; pde = de; de = (struct ext2_dir_entry *) ((char *) de + de->rec_len); } return -ENOENT; } int ext2_create (struct inode * dir,const char * name, int len, int mode, struct inode ** result) { struct inode * inode; struct buffer_head * bh; struct ext2_dir_entry * de; int err; *result = NULL; if (!dir) return -ENOENT; inode = ext2_new_inode (dir, mode, &err); if (!inode) { iput (dir); return err; } inode->i_op = &ext2_file_inode_operations; inode->i_mode = mode; inode->i_dirt = 1; bh = ext2_add_entry (dir, name, len, &de, &err); if (!bh) { inode->i_nlink--; inode->i_dirt = 1; iput (inode); iput (dir); return err; } de->inode = inode->i_ino; dir->i_version = ++event; dcache_add(dir, de->name, de->name_len, de->inode); mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } brelse (bh); iput (dir); *result = inode; return 0; } int ext2_mknod (struct inode * dir, const char * name, int len, int mode, int rdev) { struct inode * inode; struct buffer_head * bh; struct ext2_dir_entry * de; int err; if (!dir) return -ENOENT; bh = ext2_find_entry (dir, name, len, &de); if (bh) { brelse (bh); iput (dir); return -EEXIST; } inode = ext2_new_inode (dir, mode, &err); if (!inode) { iput (dir); return err; } inode->i_uid = current->fsuid; inode->i_mode = mode; inode->i_op = NULL; if (S_ISREG(inode->i_mode)) inode->i_op = &ext2_file_inode_operations; else if (S_ISDIR(inode->i_mode)) { inode->i_op = &ext2_dir_inode_operations; if (dir->i_mode & S_ISGID) inode->i_mode |= S_ISGID; } else if (S_ISLNK(inode->i_mode)) inode->i_op = &ext2_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); inode->i_dirt = 1; bh = ext2_add_entry (dir, name, len, &de, &err); if (!bh) { inode->i_nlink--; inode->i_dirt = 1; iput (inode); iput (dir); return err; } de->inode = inode->i_ino; dir->i_version = ++event; dcache_add(dir, de->name, de->name_len, de->inode); mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } brelse (bh); iput (dir); iput (inode); return 0; } int ext2_mkdir (struct inode * dir, const char * name, int len, int mode) { struct inode * inode; struct buffer_head * bh, * dir_block; struct ext2_dir_entry * de; int err; if (!dir) return -ENOENT; bh = ext2_find_entry (dir, name, len, &de); if (bh) { brelse (bh); iput (dir); return -EEXIST; } if (dir->i_nlink >= EXT2_LINK_MAX) { iput (dir); return -EMLINK; } inode = ext2_new_inode (dir, S_IFDIR, &err); if (!inode) { iput (dir); return err; } inode->i_op = &ext2_dir_inode_operations; inode->i_size = inode->i_sb->s_blocksize; dir_block = ext2_bread (inode, 0, 1, &err); if (!dir_block) { iput (dir); inode->i_nlink--; inode->i_dirt = 1; iput (inode); return err; } inode->i_blocks = inode->i_sb->s_blocksize / 512; de = (struct ext2_dir_entry *) dir_block->b_data; de->inode = inode->i_ino; de->name_len = 1; de->rec_len = EXT2_DIR_REC_LEN(de->name_len); strcpy (de->name, "."); de = (struct ext2_dir_entry *) ((char *) de + de->rec_len); de->inode = dir->i_ino; de->rec_len = inode->i_sb->s_blocksize - EXT2_DIR_REC_LEN(1); 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 & S_IRWXUGO & ~current->fs->umask); if (dir->i_mode & S_ISGID) inode->i_mode |= S_ISGID; inode->i_dirt = 1; bh = ext2_add_entry (dir, name, len, &de, &err); if (!bh) { iput (dir); inode->i_nlink = 0; inode->i_dirt = 1; iput (inode); return err; } de->inode = inode->i_ino; dir->i_version = ++event; dcache_add(dir, de->name, de->name_len, de->inode); mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } 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 ext2_dir_entry * de, * de1; struct super_block * sb; int err; sb = inode->i_sb; if (inode->i_size < EXT2_DIR_REC_LEN(1) + EXT2_DIR_REC_LEN(2) || !(bh = ext2_bread (inode, 0, 0, &err))) { ext2_warning (inode->i_sb, "empty_dir", "bad directory (dir #%lu) - no data block", inode->i_ino); return 1; } de = (struct ext2_dir_entry *) bh->b_data; de1 = (struct ext2_dir_entry *) ((char *) de + de->rec_len); if (de->inode != inode->i_ino || !de1->inode || strcmp (".", de->name) || strcmp ("..", de1->name)) { ext2_warning (inode->i_sb, "empty_dir", "bad directory (dir #%lu) - no `.' or `..'", inode->i_ino); return 1; } offset = de->rec_len + de1->rec_len; de = (struct ext2_dir_entry *) ((char *) de1 + de1->rec_len); while (offset < inode->i_size ) { if ((void *) de >= (void *) (bh->b_data + sb->s_blocksize)) { brelse (bh); bh = ext2_bread (inode, offset >> EXT2_BLOCK_SIZE_BITS(sb), 1, &err); if (!bh) { ext2_error (sb, "empty_dir", "directory #%lu contains a hole at offset %lu", inode->i_ino, offset); offset += sb->s_blocksize; continue; } de = (struct ext2_dir_entry *) bh->b_data; } if (!ext2_check_dir_entry ("empty_dir", inode, de, bh, offset)) { brelse (bh); return 1; } if (de->inode) { brelse (bh); return 0; } offset += de->rec_len; de = (struct ext2_dir_entry *) ((char *) de + de->rec_len); } brelse (bh); return 1; } int ext2_rmdir (struct inode * dir, const char * name, int len) { int retval; struct inode * inode; struct buffer_head * bh; struct ext2_dir_entry * de; repeat: if (!dir) return -ENOENT; inode = NULL; bh = ext2_find_entry (dir, name, len, &de); retval = -ENOENT; if (!bh) goto end_rmdir; retval = -EPERM; if (!(inode = iget (dir->i_sb, de->inode))) goto end_rmdir; if (inode->i_sb->dq_op) inode->i_sb->dq_op->initialize (inode, -1); if (inode->i_dev != dir->i_dev) goto end_rmdir; if (de->inode != inode->i_ino) { iput(inode); brelse(bh); current->counter = 0; schedule(); goto repeat; } if ((dir->i_mode & S_ISVTX) && !fsuser() && current->fsuid != inode->i_uid && current->fsuid != dir->i_uid) 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; } down(&inode->i_sem); if (!empty_dir (inode)) retval = -ENOTEMPTY; else if (de->inode != inode->i_ino) retval = -ENOENT; else { if (inode->i_count > 1) { /* * Are we deleting the last instance of a busy directory? * Better clean up if so. * * Make directory empty (it will be truncated when finally * dereferenced). This also inhibits ext2_add_entry. */ inode->i_size = 0; } retval = ext2_delete_entry (de, bh); dir->i_version = ++event; } up(&inode->i_sem); if (retval) goto end_rmdir; mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } if (inode->i_nlink != 2) ext2_warning (inode->i_sb, "ext2_rmdir", "empty directory has nlink!=2 (%d)", inode->i_nlink); inode->i_version = ++event; 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; end_rmdir: iput (dir); iput (inode); brelse (bh); return retval; } int ext2_unlink (struct inode * dir, const char * name, int len) { int retval; struct inode * inode; struct buffer_head * bh; struct ext2_dir_entry * de; repeat: if (!dir) return -ENOENT; retval = -ENOENT; inode = NULL; bh = ext2_find_entry (dir, name, len, &de); if (!bh) goto end_unlink; if (!(inode = iget (dir->i_sb, de->inode))) goto end_unlink; if (inode->i_sb->dq_op) inode->i_sb->dq_op->initialize (inode, -1); retval = -EPERM; if (S_ISDIR(inode->i_mode)) goto end_unlink; if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) goto end_unlink; if (de->inode != inode->i_ino) { iput(inode); brelse(bh); current->counter = 0; schedule(); goto repeat; } if ((dir->i_mode & S_ISVTX) && !fsuser() && current->fsuid != inode->i_uid && current->fsuid != dir->i_uid) goto end_unlink; if (!inode->i_nlink) { ext2_warning (inode->i_sb, "ext2_unlink", "Deleting nonexistent file (%lu), %d", inode->i_ino, inode->i_nlink); inode->i_nlink = 1; } retval = ext2_delete_entry (de, bh); if (retval) goto end_unlink; dir->i_version = ++event; mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } dir->i_ctime = dir->i_mtime = CURRENT_TIME; dir->i_dirt = 1; inode->i_nlink--; inode->i_dirt = 1; inode->i_ctime = dir->i_ctime; retval = 0; end_unlink: brelse (bh); iput (inode); iput (dir); return retval; } int ext2_symlink (struct inode * dir, const char * name, int len, const char * symname) { struct ext2_dir_entry * de; struct inode * inode = NULL; struct buffer_head * bh = NULL, * name_block = NULL; char * link; int i, err; int l; char c; if (!(inode = ext2_new_inode (dir, S_IFLNK, &err))) { iput (dir); return err; } inode->i_mode = S_IFLNK | S_IRWXUGO; inode->i_op = &ext2_symlink_inode_operations; for (l = 0; l < inode->i_sb->s_blocksize - 1 && symname [l]; l++) ; if (l >= sizeof (inode->u.ext2_i.i_data)) { ext2_debug ("l=%d, normal symlink\n", l); name_block = ext2_bread (inode, 0, 1, &err); if (!name_block) { iput (dir); inode->i_nlink--; inode->i_dirt = 1; iput (inode); return err; } link = name_block->b_data; } else { link = (char *) inode->u.ext2_i.i_data; ext2_debug ("l=%d, fast symlink\n", l); } i = 0; while (i < inode->i_sb->s_blocksize - 1 && (c = *(symname++))) link[i++] = c; link[i] = 0; if (name_block) { mark_buffer_dirty(name_block, 1); brelse (name_block); } inode->i_size = i; inode->i_dirt = 1; bh = ext2_find_entry (dir, name, len, &de); if (bh) { inode->i_nlink--; inode->i_dirt = 1; iput (inode); brelse (bh); iput (dir); return -EEXIST; } bh = ext2_add_entry (dir, name, len, &de, &err); if (!bh) { inode->i_nlink--; inode->i_dirt = 1; iput (inode); iput (dir); return err; } de->inode = inode->i_ino; dir->i_version = ++event; dcache_add(dir, de->name, de->name_len, de->inode); mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } brelse (bh); iput (dir); iput (inode); return 0; } int ext2_link (struct inode * oldinode, struct inode * dir, const char * name, int len) { struct ext2_dir_entry * de; struct buffer_head * bh; int err; if (S_ISDIR(oldinode->i_mode)) { iput (oldinode); iput (dir); return -EPERM; } if (IS_APPEND(oldinode) || IS_IMMUTABLE(oldinode)) { iput (oldinode); iput (dir); return -EPERM; } if (oldinode->i_nlink >= EXT2_LINK_MAX) { iput (oldinode); iput (dir); return -EMLINK; } bh = ext2_find_entry (dir, name, len, &de); if (bh) { brelse (bh); iput (dir); iput (oldinode); return -EEXIST; } bh = ext2_add_entry (dir, name, len, &de, &err); if (!bh) { iput (dir); iput (oldinode); return err; } de->inode = oldinode->i_ino; dir->i_version = ++event; dcache_add(dir, de->name, de->name_len, de->inode); mark_buffer_dirty(bh, 1); if (IS_SYNC(dir)) { ll_rw_block (WRITE, 1, &bh); wait_on_buffer (bh); } 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 (ext2_lookup (new_inode, "..", 2, &new_inode)) break; if (new_inode->i_ino == ino) break; } iput (new_inode); return result; } #define PARENT_INO(buffer) \ ((struct ext2_dir_entry *) ((char *) buffer + \ ((struct ext2_dir_entry *) buffer)->rec_len))->inode #define PARENT_NAME(buffer) \ ((struct ext2_dir_entry *) ((char *) buffer + \ ((struct ext2_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_ext2_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 ext2_dir_entry * old_de, * new_de; int retval; goto start_up; try_again: if (new_bh && new_de) { ext2_delete_entry(new_de, new_bh); new_dir->i_version = ++event; } 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; new_de = NULL; old_bh = ext2_find_entry (old_dir, old_name, old_len, &old_de); 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; if (IS_APPEND(old_inode) || IS_IMMUTABLE(old_inode)) goto end_rename; new_bh = ext2_find_entry (new_dir, new_name, new_len, &new_de); if (new_bh) { new_inode = __iget (new_dir->i_sb, new_de->inode, 0); /* no mntp cross */ if (!new_inode) { brelse (new_bh); new_bh = NULL; } else { if (new_inode->i_sb->dq_op) new_inode->i_sb->dq_op->initialize (new_inode, -1); } } if (new_inode == old_inode) { retval = 0; goto end_rename; } if (new_inode && S_ISDIR(new_inode->i_mode)) { retval = -EISDIR; if (!S_ISDIR(old_inode->i_mode)) goto end_rename; retval = -EINVAL; if (subdir (new_dir, old_inode)) goto end_rename; retval = -ENOTEMPTY; if (!empty_dir (new_inode)) goto end_rename; retval = -EBUSY; if (new_inode->i_count > 1) 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 = -ENOTDIR; if (new_inode && !S_ISDIR(new_inode->i_mode)) goto end_rename; retval = -EINVAL; if (subdir (new_dir, old_inode)) goto end_rename; dir_bh = ext2_bread (old_inode, 0, 0, &retval); if (!dir_bh) goto end_rename; if (PARENT_INO(dir_bh->b_data) != old_dir->i_ino) goto end_rename; retval = -EMLINK; if (!new_inode && new_dir->i_nlink >= EXT2_LINK_MAX) goto end_rename; } if (!new_bh) new_bh = ext2_add_entry (new_dir, new_name, new_len, &new_de, &retval); if (!new_bh) goto end_rename; new_dir->i_version = ++event; /* * 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 */ new_de->inode = old_inode->i_ino; dcache_add(new_dir, new_de->name, new_de->name_len, new_de->inode); retval = ext2_delete_entry (old_de, old_bh); if (retval == -ENOENT) goto try_again; if (retval) goto end_rename; old_dir->i_version = ++event; if (new_inode) { new_inode->i_nlink--; new_inode->i_ctime = CURRENT_TIME; new_inode->i_dirt = 1; } old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME; old_dir->i_dirt = 1; if (dir_bh) { PARENT_INO(dir_bh->b_data) = new_dir->i_ino; dcache_add(old_inode, "..", 2, new_dir->i_ino); mark_buffer_dirty(dir_bh, 1); old_dir->i_nlink--; old_dir->i_dirt = 1; if (new_inode) { new_inode->i_nlink--; new_inode->i_dirt = 1; } else { new_dir->i_nlink++; new_dir->i_dirt = 1; } } mark_buffer_dirty(old_bh, 1); if (IS_SYNC(old_dir)) { ll_rw_block (WRITE, 1, &old_bh); wait_on_buffer (old_bh); } mark_buffer_dirty(new_bh, 1); if (IS_SYNC(new_dir)) { ll_rw_block (WRITE, 1, &new_bh); wait_on_buffer (new_bh); } 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. * * In the second extended file system, we use a lock flag stored in the memory * super-block. This way, we really lock other renames only if they occur * on the same file system */ int ext2_rename (struct inode * old_dir, const char * old_name, int old_len, struct inode * new_dir, const char * new_name, int new_len) { int result; while (old_dir->i_sb->u.ext2_sb.s_rename_lock) sleep_on (&old_dir->i_sb->u.ext2_sb.s_rename_wait); old_dir->i_sb->u.ext2_sb.s_rename_lock = 1; result = do_ext2_rename (old_dir, old_name, old_len, new_dir, new_name, new_len); old_dir->i_sb->u.ext2_sb.s_rename_lock = 0; wake_up (&old_dir->i_sb->u.ext2_sb.s_rename_wait); return result; }

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