diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /fs/nilfs2/dir.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/nilfs2/dir.c')
-rw-r--r-- | fs/nilfs2/dir.c | 679 |
1 files changed, 679 insertions, 0 deletions
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c new file mode 100644 index 000000000..decd64713 --- /dev/null +++ b/fs/nilfs2/dir.c @@ -0,0 +1,679 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * NILFS directory entry operations + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * Modified for NILFS by Amagai Yoshiji. + */ +/* + * linux/fs/ext2/dir.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/dir.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * ext2 directory handling functions + * + * Big-endian to little-endian byte-swapping/bitmaps by + * David S. Miller (davem@caip.rutgers.edu), 1995 + * + * All code that works with directory layout had been switched to pagecache + * and moved here. AV + */ + +#include <linux/pagemap.h> +#include "nilfs.h" +#include "page.h" + +static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen) +{ + unsigned int len = le16_to_cpu(dlen); + +#if (PAGE_SIZE >= 65536) + if (len == NILFS_MAX_REC_LEN) + return 1 << 16; +#endif + return len; +} + +static inline __le16 nilfs_rec_len_to_disk(unsigned int len) +{ +#if (PAGE_SIZE >= 65536) + if (len == (1 << 16)) + return cpu_to_le16(NILFS_MAX_REC_LEN); + + BUG_ON(len > (1 << 16)); +#endif + return cpu_to_le16(len); +} + +/* + * nilfs uses block-sized chunks. Arguably, sector-sized ones would be + * more robust, but we have what we have + */ +static inline unsigned int nilfs_chunk_size(struct inode *inode) +{ + return inode->i_sb->s_blocksize; +} + +static inline void nilfs_put_page(struct page *page) +{ + kunmap(page); + put_page(page); +} + +/* + * Return the offset into page `page_nr' of the last valid + * byte in that page, plus one. + */ +static unsigned int nilfs_last_byte(struct inode *inode, unsigned long page_nr) +{ + unsigned int last_byte = inode->i_size; + + last_byte -= page_nr << PAGE_SHIFT; + if (last_byte > PAGE_SIZE) + last_byte = PAGE_SIZE; + return last_byte; +} + +static int nilfs_prepare_chunk(struct page *page, unsigned int from, + unsigned int to) +{ + loff_t pos = page_offset(page) + from; + + return __block_write_begin(page, pos, to - from, nilfs_get_block); +} + +static void nilfs_commit_chunk(struct page *page, + struct address_space *mapping, + unsigned int from, unsigned int to) +{ + struct inode *dir = mapping->host; + loff_t pos = page_offset(page) + from; + unsigned int len = to - from; + unsigned int nr_dirty, copied; + int err; + + nr_dirty = nilfs_page_count_clean_buffers(page, from, to); + copied = block_write_end(NULL, mapping, pos, len, len, page, NULL); + if (pos + copied > dir->i_size) + i_size_write(dir, pos + copied); + if (IS_DIRSYNC(dir)) + nilfs_set_transaction_flag(NILFS_TI_SYNC); + err = nilfs_set_file_dirty(dir, nr_dirty); + WARN_ON(err); /* do not happen */ + unlock_page(page); +} + +static bool nilfs_check_page(struct page *page) +{ + struct inode *dir = page->mapping->host; + struct super_block *sb = dir->i_sb; + unsigned int chunk_size = nilfs_chunk_size(dir); + char *kaddr = page_address(page); + unsigned int offs, rec_len; + unsigned int limit = PAGE_SIZE; + struct nilfs_dir_entry *p; + char *error; + + if ((dir->i_size >> PAGE_SHIFT) == page->index) { + limit = dir->i_size & ~PAGE_MASK; + if (limit & (chunk_size - 1)) + goto Ebadsize; + if (!limit) + goto out; + } + for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) { + p = (struct nilfs_dir_entry *)(kaddr + offs); + rec_len = nilfs_rec_len_from_disk(p->rec_len); + + if (rec_len < NILFS_DIR_REC_LEN(1)) + goto Eshort; + if (rec_len & 3) + goto Ealign; + if (rec_len < NILFS_DIR_REC_LEN(p->name_len)) + goto Enamelen; + if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) + goto Espan; + } + if (offs != limit) + goto Eend; +out: + SetPageChecked(page); + return true; + + /* Too bad, we had an error */ + +Ebadsize: + nilfs_error(sb, + "size of directory #%lu is not a multiple of chunk size", + dir->i_ino); + goto fail; +Eshort: + error = "rec_len is smaller than minimal"; + goto bad_entry; +Ealign: + error = "unaligned directory entry"; + goto bad_entry; +Enamelen: + error = "rec_len is too small for name_len"; + goto bad_entry; +Espan: + error = "directory entry across blocks"; +bad_entry: + nilfs_error(sb, + "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d", + dir->i_ino, error, (page->index << PAGE_SHIFT) + offs, + (unsigned long)le64_to_cpu(p->inode), + rec_len, p->name_len); + goto fail; +Eend: + p = (struct nilfs_dir_entry *)(kaddr + offs); + nilfs_error(sb, + "entry in directory #%lu spans the page boundary offset=%lu, inode=%lu", + dir->i_ino, (page->index << PAGE_SHIFT) + offs, + (unsigned long)le64_to_cpu(p->inode)); +fail: + SetPageError(page); + return false; +} + +static struct page *nilfs_get_page(struct inode *dir, unsigned long n) +{ + struct address_space *mapping = dir->i_mapping; + struct page *page = read_mapping_page(mapping, n, NULL); + + if (!IS_ERR(page)) { + kmap(page); + if (unlikely(!PageChecked(page))) { + if (!nilfs_check_page(page)) + goto fail; + } + } + return page; + +fail: + nilfs_put_page(page); + return ERR_PTR(-EIO); +} + +/* + * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure. + * + * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller. + */ +static int +nilfs_match(int len, const unsigned char *name, struct nilfs_dir_entry *de) +{ + if (len != de->name_len) + return 0; + if (!de->inode) + return 0; + return !memcmp(name, de->name, len); +} + +/* + * p is at least 6 bytes before the end of page + */ +static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p) +{ + return (struct nilfs_dir_entry *)((char *)p + + nilfs_rec_len_from_disk(p->rec_len)); +} + +static unsigned char +nilfs_filetype_table[NILFS_FT_MAX] = { + [NILFS_FT_UNKNOWN] = DT_UNKNOWN, + [NILFS_FT_REG_FILE] = DT_REG, + [NILFS_FT_DIR] = DT_DIR, + [NILFS_FT_CHRDEV] = DT_CHR, + [NILFS_FT_BLKDEV] = DT_BLK, + [NILFS_FT_FIFO] = DT_FIFO, + [NILFS_FT_SOCK] = DT_SOCK, + [NILFS_FT_SYMLINK] = DT_LNK, +}; + +#define S_SHIFT 12 +static unsigned char +nilfs_type_by_mode[S_IFMT >> S_SHIFT] = { + [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE, + [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR, + [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV, + [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV, + [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO, + [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK, + [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK, +}; + +static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode) +{ + umode_t mode = inode->i_mode; + + de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; +} + +static int nilfs_readdir(struct file *file, struct dir_context *ctx) +{ + loff_t pos = ctx->pos; + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + unsigned int offset = pos & ~PAGE_MASK; + unsigned long n = pos >> PAGE_SHIFT; + unsigned long npages = dir_pages(inode); + + if (pos > inode->i_size - NILFS_DIR_REC_LEN(1)) + return 0; + + for ( ; n < npages; n++, offset = 0) { + char *kaddr, *limit; + struct nilfs_dir_entry *de; + struct page *page = nilfs_get_page(inode, n); + + if (IS_ERR(page)) { + nilfs_error(sb, "bad page in #%lu", inode->i_ino); + ctx->pos += PAGE_SIZE - offset; + return -EIO; + } + kaddr = page_address(page); + de = (struct nilfs_dir_entry *)(kaddr + offset); + limit = kaddr + nilfs_last_byte(inode, n) - + NILFS_DIR_REC_LEN(1); + for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) { + if (de->rec_len == 0) { + nilfs_error(sb, "zero-length directory entry"); + nilfs_put_page(page); + return -EIO; + } + if (de->inode) { + unsigned char t; + + if (de->file_type < NILFS_FT_MAX) + t = nilfs_filetype_table[de->file_type]; + else + t = DT_UNKNOWN; + + if (!dir_emit(ctx, de->name, de->name_len, + le64_to_cpu(de->inode), t)) { + nilfs_put_page(page); + return 0; + } + } + ctx->pos += nilfs_rec_len_from_disk(de->rec_len); + } + nilfs_put_page(page); + } + return 0; +} + +/* + * nilfs_find_entry() + * + * finds an entry in the specified directory with the wanted name. It + * returns the page in which the entry was found, and the entry itself + * (as a parameter - res_dir). Page is returned mapped and unlocked. + * Entry is guaranteed to be valid. + */ +struct nilfs_dir_entry * +nilfs_find_entry(struct inode *dir, const struct qstr *qstr, + struct page **res_page) +{ + const unsigned char *name = qstr->name; + int namelen = qstr->len; + unsigned int reclen = NILFS_DIR_REC_LEN(namelen); + unsigned long start, n; + unsigned long npages = dir_pages(dir); + struct page *page = NULL; + struct nilfs_inode_info *ei = NILFS_I(dir); + struct nilfs_dir_entry *de; + + if (npages == 0) + goto out; + + /* OFFSET_CACHE */ + *res_page = NULL; + + start = ei->i_dir_start_lookup; + if (start >= npages) + start = 0; + n = start; + do { + char *kaddr; + + page = nilfs_get_page(dir, n); + if (!IS_ERR(page)) { + kaddr = page_address(page); + de = (struct nilfs_dir_entry *)kaddr; + kaddr += nilfs_last_byte(dir, n) - reclen; + while ((char *) de <= kaddr) { + if (de->rec_len == 0) { + nilfs_error(dir->i_sb, + "zero-length directory entry"); + nilfs_put_page(page); + goto out; + } + if (nilfs_match(namelen, name, de)) + goto found; + de = nilfs_next_entry(de); + } + nilfs_put_page(page); + } + if (++n >= npages) + n = 0; + /* next page is past the blocks we've got */ + if (unlikely(n > (dir->i_blocks >> (PAGE_SHIFT - 9)))) { + nilfs_error(dir->i_sb, + "dir %lu size %lld exceeds block count %llu", + dir->i_ino, dir->i_size, + (unsigned long long)dir->i_blocks); + goto out; + } + } while (n != start); +out: + return NULL; + +found: + *res_page = page; + ei->i_dir_start_lookup = n; + return de; +} + +struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p) +{ + struct page *page = nilfs_get_page(dir, 0); + struct nilfs_dir_entry *de = NULL; + + if (!IS_ERR(page)) { + de = nilfs_next_entry( + (struct nilfs_dir_entry *)page_address(page)); + *p = page; + } + return de; +} + +ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr) +{ + ino_t res = 0; + struct nilfs_dir_entry *de; + struct page *page; + + de = nilfs_find_entry(dir, qstr, &page); + if (de) { + res = le64_to_cpu(de->inode); + kunmap(page); + put_page(page); + } + return res; +} + +/* Releases the page */ +void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, + struct page *page, struct inode *inode) +{ + unsigned int from = (char *)de - (char *)page_address(page); + unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len); + struct address_space *mapping = page->mapping; + int err; + + lock_page(page); + err = nilfs_prepare_chunk(page, from, to); + BUG_ON(err); + de->inode = cpu_to_le64(inode->i_ino); + nilfs_set_de_type(de, inode); + nilfs_commit_chunk(page, mapping, from, to); + nilfs_put_page(page); + dir->i_mtime = dir->i_ctime = current_time(dir); +} + +/* + * Parent is locked. + */ +int nilfs_add_link(struct dentry *dentry, struct inode *inode) +{ + struct inode *dir = d_inode(dentry->d_parent); + const unsigned char *name = dentry->d_name.name; + int namelen = dentry->d_name.len; + unsigned int chunk_size = nilfs_chunk_size(dir); + unsigned int reclen = NILFS_DIR_REC_LEN(namelen); + unsigned short rec_len, name_len; + struct page *page = NULL; + struct nilfs_dir_entry *de; + unsigned long npages = dir_pages(dir); + unsigned long n; + char *kaddr; + unsigned int from, to; + int err; + + /* + * We take care of directory expansion in the same loop. + * This code plays outside i_size, so it locks the page + * to protect that region. + */ + for (n = 0; n <= npages; n++) { + char *dir_end; + + page = nilfs_get_page(dir, n); + err = PTR_ERR(page); + if (IS_ERR(page)) + goto out; + lock_page(page); + kaddr = page_address(page); + dir_end = kaddr + nilfs_last_byte(dir, n); + de = (struct nilfs_dir_entry *)kaddr; + kaddr += PAGE_SIZE - reclen; + while ((char *)de <= kaddr) { + if ((char *)de == dir_end) { + /* We hit i_size */ + name_len = 0; + rec_len = chunk_size; + de->rec_len = nilfs_rec_len_to_disk(chunk_size); + de->inode = 0; + goto got_it; + } + if (de->rec_len == 0) { + nilfs_error(dir->i_sb, + "zero-length directory entry"); + err = -EIO; + goto out_unlock; + } + err = -EEXIST; + if (nilfs_match(namelen, name, de)) + goto out_unlock; + name_len = NILFS_DIR_REC_LEN(de->name_len); + rec_len = nilfs_rec_len_from_disk(de->rec_len); + if (!de->inode && rec_len >= reclen) + goto got_it; + if (rec_len >= name_len + reclen) + goto got_it; + de = (struct nilfs_dir_entry *)((char *)de + rec_len); + } + unlock_page(page); + nilfs_put_page(page); + } + BUG(); + return -EINVAL; + +got_it: + from = (char *)de - (char *)page_address(page); + to = from + rec_len; + err = nilfs_prepare_chunk(page, from, to); + if (err) + goto out_unlock; + if (de->inode) { + struct nilfs_dir_entry *de1; + + de1 = (struct nilfs_dir_entry *)((char *)de + name_len); + de1->rec_len = nilfs_rec_len_to_disk(rec_len - name_len); + de->rec_len = nilfs_rec_len_to_disk(name_len); + de = de1; + } + de->name_len = namelen; + memcpy(de->name, name, namelen); + de->inode = cpu_to_le64(inode->i_ino); + nilfs_set_de_type(de, inode); + nilfs_commit_chunk(page, page->mapping, from, to); + dir->i_mtime = dir->i_ctime = current_time(dir); + nilfs_mark_inode_dirty(dir); + /* OFFSET_CACHE */ +out_put: + nilfs_put_page(page); +out: + return err; +out_unlock: + unlock_page(page); + goto out_put; +} + +/* + * nilfs_delete_entry deletes a directory entry by merging it with the + * previous entry. Page is up-to-date. Releases the page. + */ +int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = mapping->host; + char *kaddr = page_address(page); + unsigned int from, to; + struct nilfs_dir_entry *de, *pde = NULL; + int err; + + from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1); + to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len); + de = (struct nilfs_dir_entry *)(kaddr + from); + + while ((char *)de < (char *)dir) { + if (de->rec_len == 0) { + nilfs_error(inode->i_sb, + "zero-length directory entry"); + err = -EIO; + goto out; + } + pde = de; + de = nilfs_next_entry(de); + } + if (pde) + from = (char *)pde - (char *)page_address(page); + lock_page(page); + err = nilfs_prepare_chunk(page, from, to); + BUG_ON(err); + if (pde) + pde->rec_len = nilfs_rec_len_to_disk(to - from); + dir->inode = 0; + nilfs_commit_chunk(page, mapping, from, to); + inode->i_ctime = inode->i_mtime = current_time(inode); +out: + nilfs_put_page(page); + return err; +} + +/* + * Set the first fragment of directory. + */ +int nilfs_make_empty(struct inode *inode, struct inode *parent) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page = grab_cache_page(mapping, 0); + unsigned int chunk_size = nilfs_chunk_size(inode); + struct nilfs_dir_entry *de; + int err; + void *kaddr; + + if (!page) + return -ENOMEM; + + err = nilfs_prepare_chunk(page, 0, chunk_size); + if (unlikely(err)) { + unlock_page(page); + goto fail; + } + kaddr = kmap_atomic(page); + memset(kaddr, 0, chunk_size); + de = (struct nilfs_dir_entry *)kaddr; + de->name_len = 1; + de->rec_len = nilfs_rec_len_to_disk(NILFS_DIR_REC_LEN(1)); + memcpy(de->name, ".\0\0", 4); + de->inode = cpu_to_le64(inode->i_ino); + nilfs_set_de_type(de, inode); + + de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1)); + de->name_len = 2; + de->rec_len = nilfs_rec_len_to_disk(chunk_size - NILFS_DIR_REC_LEN(1)); + de->inode = cpu_to_le64(parent->i_ino); + memcpy(de->name, "..\0", 4); + nilfs_set_de_type(de, inode); + kunmap_atomic(kaddr); + nilfs_commit_chunk(page, mapping, 0, chunk_size); +fail: + put_page(page); + return err; +} + +/* + * routine to check that the specified directory is empty (for rmdir) + */ +int nilfs_empty_dir(struct inode *inode) +{ + struct page *page = NULL; + unsigned long i, npages = dir_pages(inode); + + for (i = 0; i < npages; i++) { + char *kaddr; + struct nilfs_dir_entry *de; + + page = nilfs_get_page(inode, i); + if (IS_ERR(page)) + continue; + + kaddr = page_address(page); + de = (struct nilfs_dir_entry *)kaddr; + kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1); + + while ((char *)de <= kaddr) { + if (de->rec_len == 0) { + nilfs_error(inode->i_sb, + "zero-length directory entry (kaddr=%p, de=%p)", + kaddr, de); + goto not_empty; + } + if (de->inode != 0) { + /* check for . and .. */ + if (de->name[0] != '.') + goto not_empty; + if (de->name_len > 2) + goto not_empty; + if (de->name_len < 2) { + if (de->inode != + cpu_to_le64(inode->i_ino)) + goto not_empty; + } else if (de->name[1] != '.') + goto not_empty; + } + de = nilfs_next_entry(de); + } + nilfs_put_page(page); + } + return 1; + +not_empty: + nilfs_put_page(page); + return 0; +} + +const struct file_operations nilfs_dir_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate_shared = nilfs_readdir, + .unlocked_ioctl = nilfs_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = nilfs_compat_ioctl, +#endif /* CONFIG_COMPAT */ + .fsync = nilfs_sync_file, + +}; |