From: Aurélien DESBRIERES Implement ftrfs_iget() to read inodes from the on-disk inode table: - Locate inode block from s_inode_table_blk and inode number - Read raw ftrfs_inode via sb_bread() - Verify per-inode CRC32 checksum - Populate VFS inode fields (mode, uid, gid, size, timestamps) - Copy direct/indirect block pointers to ftrfs_inode_info - Assign inode_operations and file_operations based on file type - Use inode_state_read_once() for I_NEW test (kernel 7.0 API) Signed-off-by: Aurélien DESBRIERES --- fs/ftrfs/inode.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 fs/ftrfs/inode.c diff --git a/fs/ftrfs/inode.c b/fs/ftrfs/inode.c new file mode 100644 index 000000000..e1279c796 --- /dev/null +++ b/fs/ftrfs/inode.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * FTRFS — Inode operations + * Author: roastercode - Aurelien DESBRIERES + */ + +#include +#include +#include +#include +#include "ftrfs.h" + +/* + * ftrfs_iget — read inode from disk into VFS + * @sb: superblock + * @ino: inode number (1-based) + * + * Inode table starts at s_inode_table_blk. + * Each block holds FTRFS_BLOCK_SIZE / sizeof(ftrfs_inode) inodes. + */ +struct inode *ftrfs_iget(struct super_block *sb, unsigned long ino) +{ + struct ftrfs_sb_info *sbi = FTRFS_SB(sb); + struct ftrfs_inode_info *fi; + struct ftrfs_inode *raw; + struct buffer_head *bh; + struct inode *inode; + unsigned long inodes_per_block; + unsigned long block, offset; + __u32 crc; + + inode = iget_locked(sb, ino); + if (!inode) + return ERR_PTR(-ENOMEM); + + /* Already in cache */ + if (!(inode_state_read_once(inode) & I_NEW)) + return inode; + + inodes_per_block = FTRFS_BLOCK_SIZE / sizeof(struct ftrfs_inode); + block = le64_to_cpu(sbi->s_ftrfs_sb->s_inode_table_blk) + + (ino - 1) / inodes_per_block; + offset = (ino - 1) % inodes_per_block; + + bh = sb_bread(sb, block); + if (!bh) { + pr_err("ftrfs: unable to read inode block %lu\n", block); + iget_failed(inode); + return ERR_PTR(-EIO); + } + + raw = (struct ftrfs_inode *)bh->b_data + offset; + /* Verify inode CRC32 */ + crc = ftrfs_crc32(raw, offsetof(struct ftrfs_inode, i_crc32)); + if (crc != le32_to_cpu(raw->i_crc32)) { + pr_err("ftrfs: inode %lu CRC32 mismatch\n", ino); + brelse(bh); + iget_failed(inode); + return ERR_PTR(-EIO); + } + + fi = FTRFS_I(inode); + + /* Populate VFS inode */ + inode->i_mode = le16_to_cpu(raw->i_mode); + inode->i_uid = make_kuid(sb->s_user_ns, le16_to_cpu(raw->i_uid)); + inode->i_gid = make_kgid(sb->s_user_ns, le16_to_cpu(raw->i_gid)); + set_nlink(inode, le16_to_cpu(raw->i_nlink)); + inode->i_size = le64_to_cpu(raw->i_size); + inode->i_blocks = le32_to_cpu(raw->i_blocks); + + inode_set_atime(inode, + le64_to_cpu(raw->i_atime) / NSEC_PER_SEC, + le64_to_cpu(raw->i_atime) % NSEC_PER_SEC); + inode_set_mtime(inode, + le64_to_cpu(raw->i_mtime) / NSEC_PER_SEC, + le64_to_cpu(raw->i_mtime) % NSEC_PER_SEC); + inode_set_ctime(inode, + le64_to_cpu(raw->i_ctime) / NSEC_PER_SEC, + le64_to_cpu(raw->i_ctime) % NSEC_PER_SEC); + + /* Copy block pointers to in-memory inode */ + memcpy(fi->i_direct, raw->i_direct, sizeof(fi->i_direct)); + fi->i_indirect = raw->i_indirect; + fi->i_dindirect = raw->i_dindirect; + fi->i_flags = le32_to_cpu(raw->i_flags); + + /* Set ops based on file type */ + if (S_ISDIR(inode->i_mode)) { + inode->i_op = &ftrfs_dir_inode_operations; + inode->i_fop = &ftrfs_dir_operations; + } else if (S_ISREG(inode->i_mode)) { + inode->i_op = &ftrfs_file_inode_operations; + inode->i_fop = &ftrfs_file_operations; + } else { + /* Special files: use generic */ + init_special_inode(inode, inode->i_mode, 0); + } + + brelse(bh); + unlock_new_inode(inode); + return inode; +} -- 2.52.0