From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- fs/sysv/dir.c | 382 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 382 insertions(+) create mode 100644 fs/sysv/dir.c (limited to 'fs/sysv/dir.c') diff --git a/fs/sysv/dir.c b/fs/sysv/dir.c new file mode 100644 index 000000000..2f5ead88d --- /dev/null +++ b/fs/sysv/dir.c @@ -0,0 +1,382 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/sysv/dir.c + * + * minix/dir.c + * Copyright (C) 1991, 1992 Linus Torvalds + * + * coh/dir.c + * Copyright (C) 1993 Pascal Haible, Bruno Haible + * + * sysv/dir.c + * Copyright (C) 1993 Bruno Haible + * + * SystemV/Coherent directory handling functions + */ + +#include +#include +#include +#include "sysv.h" + +static int sysv_readdir(struct file *, struct dir_context *); + +const struct file_operations sysv_dir_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate_shared = sysv_readdir, + .fsync = generic_file_fsync, +}; + +static void dir_commit_chunk(struct page *page, loff_t pos, unsigned len) +{ + struct address_space *mapping = page->mapping; + struct inode *dir = mapping->host; + + block_write_end(NULL, mapping, pos, len, len, page, NULL); + if (pos+len > dir->i_size) { + i_size_write(dir, pos+len); + mark_inode_dirty(dir); + } + unlock_page(page); +} + +static int sysv_handle_dirsync(struct inode *dir) +{ + int err; + + err = filemap_write_and_wait(dir->i_mapping); + if (!err) + err = sync_inode_metadata(dir, 1); + return err; +} + +/* + * Calls to dir_get_page()/unmap_and_put_page() must be nested according to the + * rules documented in mm/highmem.rst. + * + * NOTE: sysv_find_entry() and sysv_dotdot() act as calls to dir_get_page() + * and must be treated accordingly for nesting purposes. + */ +static void *dir_get_page(struct inode *dir, unsigned long n, struct page **p) +{ + struct address_space *mapping = dir->i_mapping; + struct page *page = read_mapping_page(mapping, n, NULL); + if (IS_ERR(page)) + return ERR_CAST(page); + *p = page; + return kmap_local_page(page); +} + +static int sysv_readdir(struct file *file, struct dir_context *ctx) +{ + unsigned long pos = ctx->pos; + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + unsigned long npages = dir_pages(inode); + unsigned offset; + unsigned long n; + + ctx->pos = pos = (pos + SYSV_DIRSIZE-1) & ~(SYSV_DIRSIZE-1); + if (pos >= inode->i_size) + return 0; + + offset = pos & ~PAGE_MASK; + n = pos >> PAGE_SHIFT; + + for ( ; n < npages; n++, offset = 0) { + char *kaddr, *limit; + struct sysv_dir_entry *de; + struct page *page; + + kaddr = dir_get_page(inode, n, &page); + if (IS_ERR(kaddr)) + continue; + de = (struct sysv_dir_entry *)(kaddr+offset); + limit = kaddr + PAGE_SIZE - SYSV_DIRSIZE; + for ( ;(char*)de <= limit; de++, ctx->pos += sizeof(*de)) { + char *name = de->name; + + if (!de->inode) + continue; + + if (!dir_emit(ctx, name, strnlen(name,SYSV_NAMELEN), + fs16_to_cpu(SYSV_SB(sb), de->inode), + DT_UNKNOWN)) { + unmap_and_put_page(page, kaddr); + return 0; + } + } + unmap_and_put_page(page, kaddr); + } + return 0; +} + +/* compare strings: name[0..len-1] (not zero-terminated) and + * buffer[0..] (filled with zeroes up to buffer[0..maxlen-1]) + */ +static inline int namecompare(int len, int maxlen, + const char * name, const char * buffer) +{ + if (len < maxlen && buffer[len]) + return 0; + return !memcmp(name, buffer, len); +} + +/* + * sysv_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. + * + * On Success unmap_and_put_page() should be called on *res_page. + * + * sysv_find_entry() acts as a call to dir_get_page() and must be treated + * accordingly for nesting purposes. + */ +struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_page) +{ + const char * name = dentry->d_name.name; + int namelen = dentry->d_name.len; + struct inode * dir = d_inode(dentry->d_parent); + unsigned long start, n; + unsigned long npages = dir_pages(dir); + struct page *page = NULL; + struct sysv_dir_entry *de; + + *res_page = NULL; + + start = SYSV_I(dir)->i_dir_start_lookup; + if (start >= npages) + start = 0; + n = start; + + do { + char *kaddr = dir_get_page(dir, n, &page); + + if (!IS_ERR(kaddr)) { + de = (struct sysv_dir_entry *)kaddr; + kaddr += PAGE_SIZE - SYSV_DIRSIZE; + for ( ; (char *) de <= kaddr ; de++) { + if (!de->inode) + continue; + if (namecompare(namelen, SYSV_NAMELEN, + name, de->name)) + goto found; + } + unmap_and_put_page(page, kaddr); + } + + if (++n >= npages) + n = 0; + } while (n != start); + + return NULL; + +found: + SYSV_I(dir)->i_dir_start_lookup = n; + *res_page = page; + return de; +} + +int sysv_add_link(struct dentry *dentry, struct inode *inode) +{ + struct inode *dir = d_inode(dentry->d_parent); + const char * name = dentry->d_name.name; + int namelen = dentry->d_name.len; + struct page *page = NULL; + struct sysv_dir_entry * de; + unsigned long npages = dir_pages(dir); + unsigned long n; + char *kaddr; + loff_t pos; + int err; + + /* We take care of directory expansion in the same loop */ + for (n = 0; n <= npages; n++) { + kaddr = dir_get_page(dir, n, &page); + if (IS_ERR(kaddr)) + return PTR_ERR(kaddr); + de = (struct sysv_dir_entry *)kaddr; + kaddr += PAGE_SIZE - SYSV_DIRSIZE; + while ((char *)de <= kaddr) { + if (!de->inode) + goto got_it; + err = -EEXIST; + if (namecompare(namelen, SYSV_NAMELEN, name, de->name)) + goto out_page; + de++; + } + unmap_and_put_page(page, kaddr); + } + BUG(); + return -EINVAL; + +got_it: + pos = page_offset(page) + offset_in_page(de); + lock_page(page); + err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE); + if (err) + goto out_unlock; + memcpy (de->name, name, namelen); + memset (de->name + namelen, 0, SYSV_DIRSIZE - namelen - 2); + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino); + dir_commit_chunk(page, pos, SYSV_DIRSIZE); + dir->i_mtime = inode_set_ctime_current(dir); + mark_inode_dirty(dir); + err = sysv_handle_dirsync(dir); +out_page: + unmap_and_put_page(page, kaddr); + return err; +out_unlock: + unlock_page(page); + goto out_page; +} + +int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page) +{ + struct inode *inode = page->mapping->host; + loff_t pos = page_offset(page) + offset_in_page(de); + int err; + + lock_page(page); + err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE); + if (err) { + unlock_page(page); + return err; + } + de->inode = 0; + dir_commit_chunk(page, pos, SYSV_DIRSIZE); + inode->i_mtime = inode_set_ctime_current(inode); + mark_inode_dirty(inode); + return sysv_handle_dirsync(inode); +} + +int sysv_make_empty(struct inode *inode, struct inode *dir) +{ + struct page *page = grab_cache_page(inode->i_mapping, 0); + struct sysv_dir_entry * de; + char *base; + int err; + + if (!page) + return -ENOMEM; + err = sysv_prepare_chunk(page, 0, 2 * SYSV_DIRSIZE); + if (err) { + unlock_page(page); + goto fail; + } + base = kmap_local_page(page); + memset(base, 0, PAGE_SIZE); + + de = (struct sysv_dir_entry *) base; + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino); + strcpy(de->name,"."); + de++; + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), dir->i_ino); + strcpy(de->name,".."); + + kunmap_local(base); + dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE); + err = sysv_handle_dirsync(inode); +fail: + put_page(page); + return err; +} + +/* + * routine to check that the specified directory is empty (for rmdir) + */ +int sysv_empty_dir(struct inode * inode) +{ + struct super_block *sb = inode->i_sb; + struct page *page = NULL; + unsigned long i, npages = dir_pages(inode); + char *kaddr; + + for (i = 0; i < npages; i++) { + struct sysv_dir_entry *de; + + kaddr = dir_get_page(inode, i, &page); + if (IS_ERR(kaddr)) + continue; + + de = (struct sysv_dir_entry *)kaddr; + kaddr += PAGE_SIZE-SYSV_DIRSIZE; + + for ( ;(char *)de <= kaddr; de++) { + if (!de->inode) + continue; + /* check for . and .. */ + if (de->name[0] != '.') + goto not_empty; + if (!de->name[1]) { + if (de->inode == cpu_to_fs16(SYSV_SB(sb), + inode->i_ino)) + continue; + goto not_empty; + } + if (de->name[1] != '.' || de->name[2]) + goto not_empty; + } + unmap_and_put_page(page, kaddr); + } + return 1; + +not_empty: + unmap_and_put_page(page, kaddr); + return 0; +} + +/* Releases the page */ +int sysv_set_link(struct sysv_dir_entry *de, struct page *page, + struct inode *inode) +{ + struct inode *dir = page->mapping->host; + loff_t pos = page_offset(page) + offset_in_page(de); + int err; + + lock_page(page); + err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE); + if (err) { + unlock_page(page); + return err; + } + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino); + dir_commit_chunk(page, pos, SYSV_DIRSIZE); + dir->i_mtime = inode_set_ctime_current(dir); + mark_inode_dirty(dir); + return sysv_handle_dirsync(inode); +} + +/* + * Calls to dir_get_page()/unmap_and_put_page() must be nested according to the + * rules documented in mm/highmem.rst. + * + * sysv_dotdot() acts as a call to dir_get_page() and must be treated + * accordingly for nesting purposes. + */ +struct sysv_dir_entry *sysv_dotdot(struct inode *dir, struct page **p) +{ + struct sysv_dir_entry *de = dir_get_page(dir, 0, p); + + if (IS_ERR(de)) + return NULL; + /* ".." is the second directory entry */ + return de + 1; +} + +ino_t sysv_inode_by_name(struct dentry *dentry) +{ + struct page *page; + struct sysv_dir_entry *de = sysv_find_entry (dentry, &page); + ino_t res = 0; + + if (de) { + res = fs16_to_cpu(SYSV_SB(dentry->d_sb), de->inode); + unmap_and_put_page(page, de); + } + return res; +} -- cgit v1.2.3