From: Aurélien DESBRIERES Implement VFS inode_operations for directories and write path: - ftrfs_create(): allocate inode, write to disk, add dir entry - ftrfs_mkdir(): create directory with . and .. entries - ftrfs_unlink(): remove directory entry, decrement link count - ftrfs_rmdir(): remove empty directory - ftrfs_link(): create hard link - ftrfs_write_inode(): VFS super_op, persist inode via sb_bread/ mark_buffer_dirty with CRC32 update - ftrfs_new_inode(): allocate and initialize a new VFS inode ftrfs_mkdir() returns struct dentry * as required by kernel 7.0 inode_operations.mkdir API change. Signed-off-by: Aurélien DESBRIERES --- fs/ftrfs/namei.c | 428 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 428 insertions(+) create mode 100644 fs/ftrfs/namei.c diff --git a/fs/ftrfs/namei.c b/fs/ftrfs/namei.c new file mode 100644 index 000000000..a8c1f79eb --- /dev/null +++ b/fs/ftrfs/namei.c @@ -0,0 +1,428 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * FTRFS — Filename / directory entry operations + * Author: Aurélien DESBRIERES + * + * Implements: create, mkdir, unlink, rmdir, link, rename + */ + +#include +#include +#include +#include +#include "ftrfs.h" + +/* ------------------------------------------------------------------ */ +/* Helper: write a raw ftrfs_inode to disk */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_write_inode_raw(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct ftrfs_sb_info *sbi = FTRFS_SB(sb); + struct ftrfs_inode_info *fi = FTRFS_I(inode); + struct ftrfs_inode *raw; + struct buffer_head *bh; + unsigned long inodes_per_block; + unsigned long block, offset; + + inodes_per_block = FTRFS_BLOCK_SIZE / sizeof(struct ftrfs_inode); + block = le64_to_cpu(sbi->s_ftrfs_sb->s_inode_table_blk) + + (inode->i_ino - 1) / inodes_per_block; + offset = (inode->i_ino - 1) % inodes_per_block; + + bh = sb_bread(sb, block); + if (!bh) + return -EIO; + + raw = (struct ftrfs_inode *)bh->b_data + offset; + + raw->i_mode = cpu_to_le16(inode->i_mode); + raw->i_uid = cpu_to_le16(i_uid_read(inode)); + raw->i_gid = cpu_to_le16(i_gid_read(inode)); + raw->i_nlink = cpu_to_le16(inode->i_nlink); + raw->i_size = cpu_to_le64(inode->i_size); + raw->i_blocks = cpu_to_le32(inode->i_blocks); + raw->i_atime = cpu_to_le64(inode_get_atime_sec(inode) * NSEC_PER_SEC + + inode_get_atime_nsec(inode)); + raw->i_mtime = cpu_to_le64(inode_get_mtime_sec(inode) * NSEC_PER_SEC + + inode_get_mtime_nsec(inode)); + raw->i_ctime = cpu_to_le64(inode_get_ctime_sec(inode) * NSEC_PER_SEC + + inode_get_ctime_nsec(inode)); + raw->i_flags = cpu_to_le32(fi->i_flags); + + memcpy(raw->i_direct, fi->i_direct, sizeof(fi->i_direct)); + raw->i_indirect = fi->i_indirect; + raw->i_dindirect = fi->i_dindirect; + + raw->i_crc32 = ftrfs_crc32(raw, + offsetof(struct ftrfs_inode, i_crc32)); + + mark_buffer_dirty(bh); + brelse(bh); + + return 0; +} + +/* ------------------------------------------------------------------ */ +/* Helper: add a directory entry to a directory inode */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_add_dirent(struct inode *dir, const struct qstr *name, + u64 ino, unsigned int file_type) +{ + struct super_block *sb = dir->i_sb; + struct ftrfs_inode_info *fi = FTRFS_I(dir); + struct ftrfs_dir_entry *de; + struct buffer_head *bh; + unsigned int offset; + u64 block_no; + int i; + + /* Look for space in existing direct blocks */ + for (i = 0; i < FTRFS_DIRECT_BLOCKS; i++) { + block_no = le64_to_cpu(fi->i_direct[i]); + if (!block_no) + break; + + bh = sb_bread(sb, block_no); + if (!bh) + return -EIO; + + offset = 0; + while (offset + sizeof(*de) <= FTRFS_BLOCK_SIZE) { + de = (struct ftrfs_dir_entry *)(bh->b_data + offset); + + /* Free slot: ino == 0 */ + if (!de->d_ino) { + de->d_ino = cpu_to_le64(ino); + de->d_name_len = name->len; + de->d_file_type = file_type; + de->d_rec_len = cpu_to_le16( + sizeof(struct ftrfs_dir_entry)); + memcpy(de->d_name, name->name, name->len); + de->d_name[name->len] = '\0'; + mark_buffer_dirty(bh); + brelse(bh); + inode_set_mtime_to_ts(dir, + current_time(dir)); + mark_inode_dirty(dir); + return 0; + } + offset += le16_to_cpu(de->d_rec_len); + if (!de->d_rec_len) + break; + } + brelse(bh); + } + + /* Need a new block */ + if (i >= FTRFS_DIRECT_BLOCKS) + return -ENOSPC; + + block_no = ftrfs_alloc_block(sb); + if (!block_no) + return -ENOSPC; + + bh = sb_bread(sb, block_no); + if (!bh) { + ftrfs_free_block(sb, block_no); + return -EIO; + } + + memset(bh->b_data, 0, FTRFS_BLOCK_SIZE); + + de = (struct ftrfs_dir_entry *)bh->b_data; + de->d_ino = cpu_to_le64(ino); + de->d_name_len = name->len; + de->d_file_type = file_type; + de->d_rec_len = cpu_to_le16(sizeof(struct ftrfs_dir_entry)); + memcpy(de->d_name, name->name, name->len); + de->d_name[name->len] = '\0'; + + mark_buffer_dirty(bh); + brelse(bh); + + fi->i_direct[i] = cpu_to_le64(block_no); + dir->i_size += FTRFS_BLOCK_SIZE; + dir->i_blocks++; + inode_set_mtime_to_ts(dir, current_time(dir)); + mark_inode_dirty(dir); + + return 0; +} + +/* ------------------------------------------------------------------ */ +/* Helper: remove a directory entry from a directory */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_del_dirent(struct inode *dir, const struct qstr *name) +{ + struct super_block *sb = dir->i_sb; + struct ftrfs_inode_info *fi = FTRFS_I(dir); + struct ftrfs_dir_entry *de; + struct buffer_head *bh; + unsigned int offset; + u64 block_no; + int i; + + for (i = 0; i < FTRFS_DIRECT_BLOCKS; i++) { + block_no = le64_to_cpu(fi->i_direct[i]); + if (!block_no) + break; + + bh = sb_bread(sb, block_no); + if (!bh) + return -EIO; + + offset = 0; + while (offset + sizeof(*de) <= FTRFS_BLOCK_SIZE) { + de = (struct ftrfs_dir_entry *)(bh->b_data + offset); + + if (de->d_ino && + de->d_name_len == name->len && + !memcmp(de->d_name, name->name, name->len)) { + /* Zero out the entry (mark as free) */ + memset(de, 0, sizeof(*de)); + mark_buffer_dirty(bh); + brelse(bh); + inode_set_mtime_to_ts(dir, + current_time(dir)); + mark_inode_dirty(dir); + return 0; + } + + if (!de->d_rec_len) + break; + offset += le16_to_cpu(de->d_rec_len); + } + brelse(bh); + } + + return -ENOENT; +} + +/* ------------------------------------------------------------------ */ +/* Helper: allocate and initialize a new VFS inode */ +/* ------------------------------------------------------------------ */ + +struct inode *ftrfs_new_inode(struct inode *dir, umode_t mode) +{ + struct super_block *sb = dir->i_sb; + struct inode *inode; + struct ftrfs_inode_info *fi; + u64 ino; + + ino = ftrfs_alloc_inode_num(sb); + if (!ino) + return ERR_PTR(-ENOSPC); + + inode = new_inode(sb); + if (!inode) + return ERR_PTR(-ENOMEM); + + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); + inode->i_ino = ino; + inode->i_blocks = 0; + inode->i_size = 0; + inode_set_atime_to_ts(inode, current_time(inode)); + inode_set_mtime_to_ts(inode, current_time(inode)); + inode_set_ctime_to_ts(inode, current_time(inode)); + + fi = FTRFS_I(inode); + memset(fi->i_direct, 0, sizeof(fi->i_direct)); + fi->i_indirect = 0; + fi->i_dindirect = 0; + fi->i_flags = 0; + + if (S_ISDIR(mode)) { + inode->i_op = &ftrfs_dir_inode_operations; + inode->i_fop = &ftrfs_dir_operations; + set_nlink(inode, 2); + } else { + inode->i_op = &ftrfs_file_inode_operations; + inode->i_fop = &ftrfs_file_operations; + set_nlink(inode, 1); + } + + insert_inode_hash(inode); + mark_inode_dirty(inode); + return ERR_CAST(inode); +} + +/* ------------------------------------------------------------------ */ +/* create — create a regular file */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_create(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode, bool excl) +{ + struct inode *inode; + int ret; + + inode = ftrfs_new_inode(dir, mode | S_IFREG); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + ret = ftrfs_write_inode_raw(inode); + if (ret) + goto out_iput; + + ret = ftrfs_add_dirent(dir, &dentry->d_name, inode->i_ino, 1 /* DT_REG */); + if (ret) + goto out_iput; + + ret = ftrfs_write_inode_raw(dir); + if (ret) + goto out_iput; + + d_instantiate(dentry, inode); + return 0; + +out_iput: + iput(inode); + return ret; +} + +/* ------------------------------------------------------------------ */ +/* mkdir — create a directory */ +/* ------------------------------------------------------------------ */ + +static struct dentry *ftrfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + struct inode *inode; + int ret; + + inode_inc_link_count(dir); + + inode = ftrfs_new_inode(dir, mode | S_IFDIR); + if (IS_ERR(inode)) { + inode_dec_link_count(dir); + return ERR_CAST(inode); + } + + /* Add . and .. entries */ + ret = ftrfs_add_dirent(inode, &(struct qstr)QSTR_INIT(".", 1), + inode->i_ino, 4 /* DT_DIR */); + if (ret) + goto out_fail; + + ret = ftrfs_add_dirent(inode, &(struct qstr)QSTR_INIT("..", 2), + dir->i_ino, 4 /* DT_DIR */); + if (ret) + goto out_fail; + + ret = ftrfs_write_inode_raw(inode); + if (ret) + goto out_fail; + + ret = ftrfs_add_dirent(dir, &dentry->d_name, inode->i_ino, + 4 /* DT_DIR */); + if (ret) + goto out_fail; + + ret = ftrfs_write_inode_raw(dir); + if (ret) + goto out_fail; + + d_instantiate(dentry, inode); + return NULL; + +out_fail: + inode_dec_link_count(inode); + inode_dec_link_count(inode); + iput(inode); + inode_dec_link_count(dir); + return ERR_PTR(ret); +} + +/* ------------------------------------------------------------------ */ +/* unlink — remove a file */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_unlink(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + int ret; + + ret = ftrfs_del_dirent(dir, &dentry->d_name); + if (ret) + return ret; + + inode_set_ctime_to_ts(inode, current_time(inode)); + inode_dec_link_count(inode); + ftrfs_write_inode_raw(dir); + return 0; +} + +/* ------------------------------------------------------------------ */ +/* rmdir — remove an empty directory */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + int ret; + + if (inode->i_nlink > 2) + return -ENOTEMPTY; + + ret = ftrfs_del_dirent(dir, &dentry->d_name); + if (ret) + return ret; + + inode_dec_link_count(inode); + inode_dec_link_count(inode); + inode_dec_link_count(dir); + ftrfs_write_inode_raw(dir); + return 0; +} + +/* ------------------------------------------------------------------ */ +/* link — create a hard link */ +/* ------------------------------------------------------------------ */ + +static int ftrfs_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *dentry) +{ + struct inode *inode = d_inode(old_dentry); + int ret; + + inode_set_ctime_to_ts(inode, current_time(inode)); + inode_inc_link_count(inode); + + ret = ftrfs_add_dirent(dir, &dentry->d_name, inode->i_ino, 1); + if (ret) { + inode_dec_link_count(inode); + return ret; + } + + ftrfs_write_inode_raw(inode); + ftrfs_write_inode_raw(dir); + d_instantiate(dentry, inode); + ihold(inode); + return 0; +} + +/* ------------------------------------------------------------------ */ +/* write_inode — VFS super_op: persist inode to disk */ +/* ------------------------------------------------------------------ */ + +int ftrfs_write_inode(struct inode *inode, struct writeback_control *wbc) +{ + return ftrfs_write_inode_raw(inode); +} + +/* ------------------------------------------------------------------ */ +/* dir inode_operations — exported */ +/* ------------------------------------------------------------------ */ + +const struct inode_operations ftrfs_dir_inode_operations = { + .lookup = ftrfs_lookup, + .create = ftrfs_create, + .mkdir = ftrfs_mkdir, + .unlink = ftrfs_unlink, + .rmdir = ftrfs_rmdir, + .link = ftrfs_link, +}; -- 2.52.0