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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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4688a066ec
According to Russell King, adfs was written to not require the big kernel lock, and all inode updates are done under adfs_dir_lock. All other metadata in adfs is read-only and does not require locking. The use of the BKL is the result of various pushdowns from the VFS operations. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
297 lines
5.6 KiB
C
297 lines
5.6 KiB
C
/*
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* linux/fs/adfs/dir.c
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*
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* Copyright (C) 1999-2000 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Common directory handling for ADFS
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*/
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#include "adfs.h"
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/*
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* For future. This should probably be per-directory.
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*/
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static DEFINE_RWLOCK(adfs_dir_lock);
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static int
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adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
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{
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struct inode *inode = filp->f_path.dentry->d_inode;
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struct super_block *sb = inode->i_sb;
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struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
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struct object_info obj;
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struct adfs_dir dir;
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int ret = 0;
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if (filp->f_pos >> 32)
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goto out;
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ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
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if (ret)
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goto out;
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switch ((unsigned long)filp->f_pos) {
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case 0:
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if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
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goto free_out;
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filp->f_pos += 1;
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case 1:
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if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
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goto free_out;
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filp->f_pos += 1;
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default:
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break;
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}
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read_lock(&adfs_dir_lock);
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ret = ops->setpos(&dir, filp->f_pos - 2);
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if (ret)
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goto unlock_out;
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while (ops->getnext(&dir, &obj) == 0) {
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if (filldir(dirent, obj.name, obj.name_len,
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filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
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goto unlock_out;
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filp->f_pos += 1;
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}
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unlock_out:
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read_unlock(&adfs_dir_lock);
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free_out:
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ops->free(&dir);
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out:
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return ret;
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}
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int
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adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
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{
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int ret = -EINVAL;
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#ifdef CONFIG_ADFS_FS_RW
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struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
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struct adfs_dir dir;
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printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
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obj->file_id, obj->parent_id);
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if (!ops->update) {
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ret = -EINVAL;
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goto out;
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}
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ret = ops->read(sb, obj->parent_id, 0, &dir);
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if (ret)
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goto out;
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write_lock(&adfs_dir_lock);
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ret = ops->update(&dir, obj);
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write_unlock(&adfs_dir_lock);
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if (wait) {
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int err = ops->sync(&dir);
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if (!ret)
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ret = err;
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}
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ops->free(&dir);
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out:
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#endif
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return ret;
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}
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static int
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adfs_match(struct qstr *name, struct object_info *obj)
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{
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int i;
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if (name->len != obj->name_len)
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return 0;
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for (i = 0; i < name->len; i++) {
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char c1, c2;
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c1 = name->name[i];
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c2 = obj->name[i];
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if (c1 >= 'A' && c1 <= 'Z')
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c1 += 'a' - 'A';
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if (c2 >= 'A' && c2 <= 'Z')
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c2 += 'a' - 'A';
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if (c1 != c2)
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return 0;
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}
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return 1;
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}
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static int
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adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
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{
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struct super_block *sb = inode->i_sb;
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struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
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struct adfs_dir dir;
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int ret;
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ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
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if (ret)
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goto out;
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if (ADFS_I(inode)->parent_id != dir.parent_id) {
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adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
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ADFS_I(inode)->parent_id, dir.parent_id);
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ret = -EIO;
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goto free_out;
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}
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obj->parent_id = inode->i_ino;
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/*
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* '.' is handled by reserved_lookup() in fs/namei.c
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*/
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if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
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/*
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* Currently unable to fill in the rest of 'obj',
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* but this is better than nothing. We need to
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* ascend one level to find it's parent.
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*/
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obj->name_len = 0;
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obj->file_id = obj->parent_id;
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goto free_out;
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}
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read_lock(&adfs_dir_lock);
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ret = ops->setpos(&dir, 0);
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if (ret)
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goto unlock_out;
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ret = -ENOENT;
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while (ops->getnext(&dir, obj) == 0) {
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if (adfs_match(name, obj)) {
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ret = 0;
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break;
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}
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}
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unlock_out:
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read_unlock(&adfs_dir_lock);
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free_out:
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ops->free(&dir);
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out:
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return ret;
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}
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const struct file_operations adfs_dir_operations = {
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.read = generic_read_dir,
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.llseek = generic_file_llseek,
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.readdir = adfs_readdir,
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.fsync = generic_file_fsync,
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};
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static int
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adfs_hash(const struct dentry *parent, const struct inode *inode,
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struct qstr *qstr)
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{
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const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
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const unsigned char *name;
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unsigned long hash;
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int i;
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if (qstr->len < name_len)
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return 0;
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/*
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* Truncate the name in place, avoids
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* having to define a compare function.
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*/
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qstr->len = i = name_len;
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name = qstr->name;
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hash = init_name_hash();
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while (i--) {
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char c;
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c = *name++;
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if (c >= 'A' && c <= 'Z')
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c += 'a' - 'A';
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hash = partial_name_hash(c, hash);
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}
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qstr->hash = end_name_hash(hash);
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return 0;
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}
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/*
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* Compare two names, taking note of the name length
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* requirements of the underlying filesystem.
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*/
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static int
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adfs_compare(const struct dentry *parent, const struct inode *pinode,
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const struct dentry *dentry, const struct inode *inode,
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unsigned int len, const char *str, const struct qstr *name)
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{
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int i;
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if (len != name->len)
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return 1;
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for (i = 0; i < name->len; i++) {
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char a, b;
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a = str[i];
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b = name->name[i];
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if (a >= 'A' && a <= 'Z')
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a += 'a' - 'A';
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if (b >= 'A' && b <= 'Z')
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b += 'a' - 'A';
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if (a != b)
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return 1;
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}
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return 0;
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}
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const struct dentry_operations adfs_dentry_operations = {
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.d_hash = adfs_hash,
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.d_compare = adfs_compare,
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};
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static struct dentry *
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adfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
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{
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struct inode *inode = NULL;
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struct object_info obj;
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int error;
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error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
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if (error == 0) {
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error = -EACCES;
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/*
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* This only returns NULL if get_empty_inode
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* fails.
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*/
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inode = adfs_iget(dir->i_sb, &obj);
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if (inode)
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error = 0;
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}
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d_add(dentry, inode);
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return ERR_PTR(error);
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}
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/*
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* directories can handle most operations...
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*/
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const struct inode_operations adfs_dir_inode_operations = {
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.lookup = adfs_lookup,
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.setattr = adfs_notify_change,
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};
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