This adds functions for directory, mainly readdir. Signed-off-by: Miao Xie <miaoxie@xxxxxxxxxx> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx> --- drivers/staging/erofs/dir.c | 145 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) create mode 100644 drivers/staging/erofs/dir.c diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c new file mode 100644 index 0000000..be6ae3b --- /dev/null +++ b/drivers/staging/erofs/dir.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/drivers/staging/erofs/dir.c + * + * Copyright (C) 2017-2018 HUAWEI, Inc. + * http://www.huawei.com/ + * Created by Gao Xiang <gaoxiang25@xxxxxxxxxx> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of the Linux + * distribution for more details. + */ +#include "internal.h" + +static const unsigned char erofs_filetype_table[EROFS_FT_MAX] = { + [EROFS_FT_UNKNOWN] = DT_UNKNOWN, + [EROFS_FT_REG_FILE] = DT_REG, + [EROFS_FT_DIR] = DT_DIR, + [EROFS_FT_CHRDEV] = DT_CHR, + [EROFS_FT_BLKDEV] = DT_BLK, + [EROFS_FT_FIFO] = DT_FIFO, + [EROFS_FT_SOCK] = DT_SOCK, + [EROFS_FT_SYMLINK] = DT_LNK, +}; + +static int erofs_fill_dentries(struct dir_context *ctx, + void *dentry_blk, unsigned *ofs, + unsigned nameoff, unsigned maxsize) +{ + struct erofs_dirent *de = dentry_blk; + const struct erofs_dirent *end = dentry_blk + nameoff; + + de = dentry_blk + *ofs; + while (de < end) { + const char *de_name; + int de_namelen; + unsigned char d_type; +#ifdef CONFIG_EROFS_FS_DEBUG + unsigned dbg_namelen; + unsigned char dbg_namebuf[EROFS_NAME_LEN]; +#endif + + if (unlikely(de->file_type < EROFS_FT_MAX)) + d_type = erofs_filetype_table[de->file_type]; + else + d_type = DT_UNKNOWN; + + nameoff = le16_to_cpu(de->nameoff); + de_name = (char *)dentry_blk + nameoff; + + de_namelen = unlikely(de + 1 >= end) ? + /* last directory entry */ + strnlen(de_name, maxsize - nameoff) : + le16_to_cpu(de[1].nameoff) - nameoff; + + /* the corrupted directory found */ + BUG_ON(de_namelen < 0); + +#ifdef CONFIG_EROFS_FS_DEBUG + dbg_namelen = min(EROFS_NAME_LEN - 1, de_namelen); + memcpy(dbg_namebuf, de_name, dbg_namelen); + dbg_namebuf[dbg_namelen] = '\0'; + + debugln("%s, found de_name %s de_len %d d_type %d", __func__, + dbg_namebuf, de_namelen, d_type); +#endif + + if (!dir_emit(ctx, de_name, de_namelen, + le64_to_cpu(de->nid), d_type)) + /* stoped by some reason */ + return 1; + ++de; + *ofs += sizeof(struct erofs_dirent); + } + *ofs = maxsize; + return 0; +} + +static int erofs_readdir(struct file *f, struct dir_context *ctx) +{ + struct inode *dir = file_inode(f); + struct address_space *mapping = dir->i_mapping; + const size_t dirsize = i_size_read(dir); + unsigned i = ctx->pos / EROFS_BLKSIZ; + unsigned ofs = ctx->pos % EROFS_BLKSIZ; + int err = 0; + bool initial = true; + + while (ctx->pos < dirsize) { + struct page *dentry_page; + struct erofs_dirent *de; + unsigned nameoff, maxsize; + + dentry_page = read_mapping_page(mapping, i, NULL); + if (IS_ERR(dentry_page)) + continue; + + lock_page(dentry_page); + de = (struct erofs_dirent *)kmap(dentry_page); + + nameoff = le16_to_cpu(de->nameoff); + + if (unlikely(nameoff < sizeof(struct erofs_dirent) || + nameoff >= PAGE_SIZE)) { + errln("%s, invalid de[0].nameoff %u", + __func__, nameoff); + + err = -EIO; + goto skip_this; + } + + maxsize = min_t(unsigned, dirsize - ctx->pos + ofs, PAGE_SIZE); + + /* search dirents at the arbitrary position */ + if (unlikely(initial)) { + initial = false; + + ofs = roundup(ofs, sizeof(struct erofs_dirent)); + if (unlikely(ofs >= nameoff)) + goto skip_this; + } + + err = erofs_fill_dentries(ctx, de, &ofs, nameoff, maxsize); +skip_this: + kunmap(dentry_page); + + unlock_page(dentry_page); + put_page(dentry_page); + + ctx->pos = blknr_to_addr(i) + ofs; + + if (unlikely(err)) + break; + ++i; + ofs = 0; + } + return err < 0 ? err : 0; +} + +const struct file_operations erofs_dir_fops = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate = erofs_readdir, +}; + -- 1.9.1
