This adds core functions to get, read an inode. Signed-off-by: Miao Xie <miaoxie@xxxxxxxxxx> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx> --- drivers/staging/erofs/inode.c | 210 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 drivers/staging/erofs/inode.c diff --git a/drivers/staging/erofs/inode.c b/drivers/staging/erofs/inode.c new file mode 100644 index 0000000..74e65be --- /dev/null +++ b/drivers/staging/erofs/inode.c @@ -0,0 +1,210 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/drivers/staging/erofs/inode.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" + +/* no locking */ +static int read_inode(struct inode *inode, void *data) +{ + struct erofs_vnode *vi = EROFS_V(inode); + struct erofs_inode_v1 *v1 = data; + const unsigned advise = le16_to_cpu(v1->i_advise); + + vi->data_mapping_mode = __inode_data_mapping(advise); + + if (unlikely(vi->data_mapping_mode >= EROFS_INODE_LAYOUT_MAX)) { + errln("unknown data mapping mode %u of nid %llu", + vi->data_mapping_mode, vi->nid); + DBG_BUGON(1); + return -EIO; + } + + if (__inode_version(advise) == EROFS_INODE_LAYOUT_V2) { + struct erofs_inode_v2 *v2 = data; + + vi->inode_isize = sizeof(struct erofs_inode_v2); + vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount); + + vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr); + inode->i_mode = le16_to_cpu(v2->i_mode); + + i_uid_write(inode, le32_to_cpu(v2->i_uid)); + i_gid_write(inode, le32_to_cpu(v2->i_gid)); + set_nlink(inode, le32_to_cpu(v2->i_nlink)); + + /* ns timestamp */ + inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = + le64_to_cpu(v2->i_ctime); + inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = + le32_to_cpu(v2->i_ctime_nsec); + + inode->i_size = le64_to_cpu(v2->i_size); + } else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) { + struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); + + vi->inode_isize = sizeof(struct erofs_inode_v1); + vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount); + + vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr); + inode->i_mode = le16_to_cpu(v1->i_mode); + + i_uid_write(inode, le16_to_cpu(v1->i_uid)); + i_gid_write(inode, le16_to_cpu(v1->i_gid)); + set_nlink(inode, le16_to_cpu(v1->i_nlink)); + + /* use build time to derive all file time */ + inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = + sbi->build_time; + inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = + sbi->build_time_nsec; + + inode->i_size = le32_to_cpu(v1->i_size); + } else { + errln("unsupported on-disk inode version %u of nid %llu", + __inode_version(advise), vi->nid); + DBG_BUGON(1); + return -EIO; + } + + /* measure inode.i_blocks as the generic filesystem */ + inode->i_blocks = ((inode->i_size - 1) >> 9) + 1; + return 0; +} + +/* + * try_lock can be required since locking order is: + * file data(fs_inode) + * meta(bd_inode) + * but the majority of the callers is "iget", + * in that case we are pretty sure no deadlock since + * no data operations exist. However I tend to + * try_lock since it takes no much overhead and + * will success immediately. + */ +static int fill_inline_data(struct inode *inode, void *data, unsigned m_pofs) +{ + struct erofs_vnode *vi = EROFS_V(inode); + int mode = vi->data_mapping_mode; + + DBG_BUGON(mode >= EROFS_INODE_LAYOUT_MAX); + + /* should be inode inline C */ + if (mode != EROFS_INODE_LAYOUT_INLINE) + return 0; + + /* fast symlink (following ext4) */ + if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) { + char *lnk = kmalloc(inode->i_size + 1, GFP_KERNEL); + + if (unlikely(lnk == NULL)) + return -ENOMEM; + + m_pofs += vi->inode_isize + vi->xattr_isize; + BUG_ON(m_pofs + inode->i_size > PAGE_SIZE); + + /* get in-page inline data */ + memcpy(lnk, data + m_pofs, inode->i_size); + lnk[inode->i_size] = '\0'; + + inode->i_link = lnk; + set_inode_fast_symlink(inode); + } + return -EAGAIN; +} + +static int fill_inode(struct inode *inode, int isdir) +{ + struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb); + struct erofs_vnode *vi = EROFS_V(inode); + struct page *page; + void *data; + int err; + erofs_blk_t blkaddr; + unsigned ofs; + + blkaddr = erofs_blknr(iloc(sbi, vi->nid)); + ofs = erofs_blkoff(iloc(sbi, vi->nid)); + + debugln("%s, reading inode nid %llu at %u of blkaddr %u", + __func__, vi->nid, ofs, blkaddr); + + page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir); + + if (IS_ERR(page)) { + errln("failed to get inode (nid: %llu) page, err %ld", + vi->nid, PTR_ERR(page)); + return PTR_ERR(page); + } + + BUG_ON(!PageUptodate(page)); + data = page_address(page); + + err = read_inode(inode, data + ofs); + if (!err) { + /* setup the new inode */ + if (S_ISREG(inode->i_mode)) { + inode->i_fop = &generic_ro_fops; + } else if (S_ISDIR(inode->i_mode)) { + inode->i_op = + &erofs_dir_iops; + inode->i_fop = &erofs_dir_fops; + } else if (S_ISLNK(inode->i_mode)) { + /* by default, page_get_link is used for symlink */ + inode->i_op = + &page_symlink_inode_operations; + inode_nohighmem(inode); + } else { + err = -EIO; + goto out_unlock; + } + + if (is_inode_layout_compression(inode)) { + err = -ENOTSUPP; + goto out_unlock; + } + + inode->i_mapping->a_ops = &erofs_raw_access_aops; + + /* fill last page if inline data is available */ + fill_inline_data(inode, data, ofs); + } + +out_unlock: + unlock_page(page); + put_page(page); + return err; +} + +struct inode *erofs_iget(struct super_block *sb, + erofs_nid_t nid, bool isdir) +{ + struct inode *inode = iget_locked(sb, nid); + + if (unlikely(inode == NULL)) + return ERR_PTR(-ENOMEM); + + if (inode->i_state & I_NEW) { + int err; + struct erofs_vnode *vi = EROFS_V(inode); + vi->nid = nid; + + err = fill_inode(inode, isdir); + if (likely(!err)) + unlock_new_inode(inode); + else { + iget_failed(inode); + inode = ERR_PTR(err); + } + } + return inode; +} + -- 1.9.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
