now no need to reboot
This commit is contained in:
parent
b9d65b0bcf
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ac32a0a607
339
statsfs.c
339
statsfs.c
@ -1,20 +1,15 @@
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/dcache.h>
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#include <linux/list.h>
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#include <linux/fs_context.h>
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#include <linux/err.h>
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#include <linux/uaccess.h>
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#include <linux/hashtable.h>
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#include <linux/buffer_head.h>
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#include <linux/mm.h>
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#include <linux/pagevec.h>
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#include <linux/writeback.h>
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#include <linux/string.h>
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#include <linux/printk.h>
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#define LIBFS_MAGIC 0xA0B0C0D0
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#define LIBFS_BOOKS_MODE 01777
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@ -22,31 +17,16 @@
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#define LIBFS_SUBDIR_MODE 01777
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static struct super_block *libfs_sb;
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static struct inode *books_inode;
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static struct inode *authors_inode;
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static struct dentry *authors_dentry;
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static void libfs_evict_inode(struct inode *inode);
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static struct inode *books_inode;
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static struct inode *authors_inode;
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static struct dentry *authors_dentry;
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struct link_entry {
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struct hlist_node node;
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struct dentry *link;
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struct dentry *link;
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};
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/* запрет создания FIFO/устройств */
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static int libfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode, dev_t dev)
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{
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return -EPERM;
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}
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/* запрет симв. ссылок */
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static int libfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, const char *target)
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{
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return -EPERM;
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}
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static void libfs_evict_inode(struct inode *inode);
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static int libfs_create(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode, bool excl);
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static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
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@ -59,40 +39,45 @@ static int libfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
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static int libfs_link(struct dentry *old_dentry, struct inode *dir,
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struct dentry *new_dentry);
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static const struct super_operations libfs_sops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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.evict_inode = libfs_evict_inode,
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};
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static const struct file_operations libfs_file_ops = {
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.read_iter = generic_file_read_iter,
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.write_iter = generic_file_write_iter,
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.llseek = generic_file_llseek,
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};
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static const struct inode_operations libfs_file_iops = {
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.setattr = simple_setattr,
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.getattr = simple_getattr,
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};
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static const struct inode_operations libfs_dir_iops = {
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.lookup = simple_lookup,
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.mkdir = libfs_mkdir,
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.mknod = libfs_mknod,
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.symlink = libfs_symlink,
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.create = libfs_create,
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.unlink = libfs_unlink,
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.mkdir = libfs_mkdir,
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.rmdir = libfs_rmdir,
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.rename = libfs_rename,
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.link = libfs_link,
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.create = libfs_create,
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.mknod = NULL, /* запрещаем */
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.symlink = NULL, /* запрещаем */
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};
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static const struct super_operations statsfs_sops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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.evict_inode = libfs_evict_inode,
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};
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static struct inode *libfs_get_inode(struct super_block *sb, umode_t mode)
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{
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struct inode *inode;
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if (!S_ISREG(mode) && !S_ISDIR(mode))
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return NULL;
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pr_info("statsfs: libfs_get_inode(sb=%p, mode=%o)\n", sb, mode);
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inode = new_inode(sb);
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if (!inode)
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if (!inode) {
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pr_err("statsfs: new_inode failed for mode %o\n", mode);
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return NULL;
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}
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inode->i_ino = get_next_ino();
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inode->i_sb = sb;
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@ -101,18 +86,21 @@ static struct inode *libfs_get_inode(struct super_block *sb, umode_t mode)
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if (S_ISDIR(mode)) {
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inode->i_op = &libfs_dir_iops;
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inode->i_fop = &simple_dir_operations;
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pr_info("statsfs: created dir inode #%lu\n", inode->i_ino);
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} else {
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/* файл — просто generic_file_* */
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &libfs_file_ops;
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/* заводим список жёстких ссылок */
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inode->i_op = &libfs_file_iops;
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inode->i_fop = &libfs_file_ops;
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inode->i_private = kzalloc(sizeof(struct hlist_head), GFP_KERNEL);
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if (!inode->i_private) {
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pr_err("statsfs: kzalloc for inode #%lu failed\n", inode->i_ino);
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iput(inode);
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return NULL;
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}
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INIT_HLIST_HEAD((struct hlist_head *)inode->i_private);
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pr_info("statsfs: created file inode #%lu with private list\n", inode->i_ino);
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}
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return inode;
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}
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@ -125,30 +113,36 @@ static void cleanup_links(struct inode *victim)
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if (!S_ISREG(victim->i_mode) || !victim->i_private)
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return;
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pr_info("statsfs: cleanup_links for inode #%lu\n", victim->i_ino);
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list = (struct hlist_head *)victim->i_private;
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hlist_for_each_entry_safe(le, tmp, list, node) {
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struct dentry *link = le->link;
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struct dentry *pd;
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struct inode *parent;
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if (!link || d_unlinked(link)) {
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pr_info("statsfs: link already gone, freeing entry\n");
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hlist_del(&le->node);
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dput(link);
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kfree(le);
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continue;
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}
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{
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struct dentry *pd = dget_parent(link);
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if (pd) {
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struct inode *parent = d_inode(pd);
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if (parent) {
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inode_lock(parent);
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vfs_unlink(NULL, parent, link, NULL);
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inode_unlock(parent);
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}
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dput(pd);
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}
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pd = dget_parent(link);
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if (pd) {
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parent = d_inode(pd);
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if (WARN_ON(!parent))
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goto skip_unlink;
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inode_lock(parent);
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vfs_unlink(NULL, parent, link, NULL);
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inode_unlock(parent);
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pr_info("statsfs: unlinked %pd from parent inode #%lu\n",
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link, parent->i_ino);
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dput(pd);
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}
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skip_unlink:
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hlist_del(&le->node);
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dput(link);
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kfree(le);
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@ -158,94 +152,10 @@ static void cleanup_links(struct inode *victim)
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victim->i_private = NULL;
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}
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static bool is_protected(struct dentry *dentry)
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static bool is_protected(const struct dentry *d)
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{
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return strcmp(dentry->d_name.name, "books") == 0
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|| strcmp(dentry->d_name.name, "authors") == 0;
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}
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static int libfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct inode *victim = d_inode(dentry);
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int ret;
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if (dir == libfs_sb->s_root->d_inode && is_protected(dentry))
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return -EPERM;
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ret = simple_unlink(dir, dentry);
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if (ret == 0 && dir == books_inode)
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cleanup_links(victim);
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return ret;
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}
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static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode)
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{
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struct inode *inode;
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if (dir == libfs_sb->s_root->d_inode || dir == books_inode)
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return -EPERM;
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if (dir == authors_inode) {
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inode = libfs_get_inode(dir->i_sb, S_IFDIR | LIBFS_SUBDIR_MODE);
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if (!inode)
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return -ENOMEM;
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inode->i_uid = current_fsuid();
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d_add(dentry, inode);
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inc_nlink(dir);
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return 0;
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}
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return -EPERM;
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}
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static int libfs_rmdir(struct inode *dir, struct dentry *dentry)
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{
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if (dir == libfs_sb->s_root->d_inode && is_protected(dentry))
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return -EPERM;
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if (dir == authors_inode)
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return -EPERM;
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return simple_rmdir(dir, dentry);
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}
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static int libfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
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struct dentry *old_dentry, struct inode *new_dir,
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struct dentry *new_dentry, unsigned int flags)
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{
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if ((old_dir == libfs_sb->s_root->d_inode
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|| new_dir == libfs_sb->s_root->d_inode)
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&& (is_protected(old_dentry) || is_protected(new_dentry)))
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return -EPERM;
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if (old_dir == authors_inode || new_dir == authors_inode)
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return -EPERM;
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return simple_rename(idmap, old_dir, old_dentry, new_dir, new_dentry, flags);
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}
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static int libfs_link(struct dentry *old_dentry, struct inode *dir,
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struct dentry *new_dentry)
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{
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struct inode *target = d_inode(old_dentry);
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struct hlist_head *list;
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struct link_entry *le;
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int ret;
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if (!S_ISREG(target->i_mode))
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return -EPERM;
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if (!authors_dentry
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|| new_dentry->d_parent->d_parent != authors_dentry)
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return -EPERM;
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ret = simple_link(old_dentry, dir, new_dentry);
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if (ret)
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return ret;
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list = (struct hlist_head *)target->i_private;
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le = kmalloc(sizeof(*le), GFP_KERNEL);
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if (!le)
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return -ENOMEM;
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le->link = dget(new_dentry);
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hlist_add_head(&le->node, list);
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return 0;
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return !strcmp(d->d_name.name, "books") ||
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!strcmp(d->d_name.name, "authors");
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}
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static int libfs_create(struct mnt_idmap *idmap, struct inode *dir,
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@ -253,15 +163,113 @@ static int libfs_create(struct mnt_idmap *idmap, struct inode *dir,
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{
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struct inode *inode;
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pr_info("statsfs: CREATE %pd in dir inode #%lu mode=%o\n",
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dentry, dir->i_ino, mode);
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if (dir != books_inode)
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return -EPERM;
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inode = libfs_get_inode(dir->i_sb, S_IFREG | mode);
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if (!inode)
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return -ENOMEM;
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inode->i_uid = current_fsuid();
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inode->i_gid = current_fsgid();
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d_add(dentry, inode);
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pr_info("statsfs: added file %pd as inode #%lu\n", dentry, inode->i_ino);
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return 0;
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}
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static int libfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct inode *victim = d_inode(dentry);
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int err;
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pr_info("statsfs: UNLINK %pd from dir inode #%lu\n",
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dentry, dir->i_ino);
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if (dir == libfs_sb->s_root->d_inode && is_protected(dentry))
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return -EPERM;
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err = simple_unlink(dir, dentry);
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if (!err && dir == books_inode) {
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cleanup_links(victim);
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}
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return err;
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}
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static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
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struct dentry *dentry, umode_t mode)
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{
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struct inode *inode;
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pr_info("statsfs: MKDIR %pd in dir inode #%lu\n",
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dentry, dir->i_ino);
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if (dir == libfs_sb->s_root->d_inode || dir == books_inode)
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return -EPERM;
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if (dir != authors_inode)
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return -EPERM;
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inode = libfs_get_inode(dir->i_sb, S_IFDIR | LIBFS_SUBDIR_MODE);
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if (!inode)
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return -ENOMEM;
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inode->i_uid = current_fsuid();
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d_add(dentry, inode);
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inc_nlink(dir);
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pr_info("statsfs: created subdir %pd as inode #%lu\n", dentry, inode->i_ino);
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return 0;
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}
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static int libfs_rmdir(struct inode *dir, struct dentry *dentry)
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{
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pr_info("statsfs: RMDIR %pd in dir inode #%lu\n",
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dentry, dir->i_ino);
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if (dir == libfs_sb->s_root->d_inode && is_protected(dentry))
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return -EPERM;
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if (dir == authors_inode)
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return -EPERM;
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return simple_rmdir(dir, dentry);
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}
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static int libfs_rename(struct mnt_idmap *idmap, struct inode *odir,
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struct dentry *odent, struct inode *ndir,
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struct dentry *ndent, unsigned int flags)
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{
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pr_info("statsfs: RENAME %pd (ino#%lu) -> %pd (ino#%lu)\n",
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odent, odir->i_ino, ndent, ndir->i_ino);
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if ((odir == libfs_sb->s_root->d_inode || ndir == libfs_sb->s_root->d_inode) &&
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(is_protected(odent) || is_protected(ndent)))
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return -EPERM;
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if (odir == authors_inode || ndir == authors_inode)
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return -EPERM;
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return simple_rename(idmap, odir, odent, ndir, ndent, flags);
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}
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static int libfs_link(struct dentry *old_dentry, struct inode *dir,
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struct dentry *new_dentry)
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{
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struct inode *t = d_inode(old_dentry);
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struct link_entry *le;
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int err;
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pr_info("statsfs: LINK %pd -> %pd in dir inode #%lu\n",
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old_dentry, new_dentry, dir->i_ino);
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if (!S_ISREG(t->i_mode))
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return -EPERM;
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if (!authors_dentry ||
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new_dentry->d_parent->d_parent != authors_dentry)
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return -EPERM;
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err = simple_link(old_dentry, dir, new_dentry);
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if (err)
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return err;
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le = kmalloc(sizeof(*le), GFP_KERNEL);
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if (!le)
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return -ENOMEM;
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le->link = dget(new_dentry);
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hlist_add_head(&le->node, (struct hlist_head *)t->i_private);
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pr_info("statsfs: recorded link entry for inode #%lu\n", t->i_ino);
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return 0;
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}
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@ -269,40 +277,42 @@ static int libfs_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *root;
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libfs_sb = sb;
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sb->s_magic = LIBFS_MAGIC;
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sb->s_op = &libfs_sops;
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pr_info("statsfs: fill_super\n");
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libfs_sb = sb;
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sb->s_magic = LIBFS_MAGIC;
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sb->s_op = &statsfs_sops;
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root = libfs_get_inode(sb, S_IFDIR | 0755);
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if (!root)
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return -ENOMEM;
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root->i_op = &libfs_dir_iops;
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root->i_fop = &simple_dir_operations;
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sb->s_root = d_make_root(root);
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if (!sb->s_root)
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return -ENOMEM;
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books_inode = libfs_get_inode(sb, S_IFDIR | LIBFS_BOOKS_MODE);
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{
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struct dentry *d = d_alloc_name(sb->s_root, "books");
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d_add(d, books_inode);
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}
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books_inode = libfs_get_inode(sb, S_IFDIR | LIBFS_BOOKS_MODE);
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d_add(d_alloc_name(sb->s_root, "books"), books_inode);
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authors_inode = libfs_get_inode(sb, S_IFDIR | LIBFS_AUTHORS_MODE);
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authors_dentry = d_alloc_name(sb->s_root, "authors");
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d_add(authors_dentry, authors_inode);
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pr_info("statsfs: superblock initialized\n");
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return 0;
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}
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static struct dentry *libfs_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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static struct dentry *libfs_mount(struct file_system_type *fs,
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int flags, const char *dev, void *data)
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{
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return mount_nodev(fs_type, flags, data, libfs_fill_super);
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pr_info("statsfs: mounting\n");
|
||||
return mount_nodev(fs, flags, data, libfs_fill_super);
|
||||
}
|
||||
|
||||
static void libfs_evict_inode(struct inode *inode)
|
||||
{
|
||||
pr_info("statsfs: evict_inode inode #%lu\n", inode->i_ino);
|
||||
truncate_inode_pages_final(&inode->i_data);
|
||||
cleanup_links(inode);
|
||||
clear_inode(inode);
|
||||
@ -317,24 +327,17 @@ static struct file_system_type libfs_type = {
|
||||
|
||||
static int __init libfs_init(void)
|
||||
{
|
||||
pr_info("statsfs: module init\n");
|
||||
return register_filesystem(&libfs_type);
|
||||
}
|
||||
|
||||
static void __exit libfs_exit(void)
|
||||
{
|
||||
if (authors_dentry) {
|
||||
dput(authors_dentry);
|
||||
authors_dentry = NULL;
|
||||
}
|
||||
if (books_inode) {
|
||||
cleanup_links(books_inode);
|
||||
iput(books_inode);
|
||||
books_inode = NULL;
|
||||
}
|
||||
if (authors_inode) {
|
||||
iput(authors_inode);
|
||||
authors_inode = NULL;
|
||||
}
|
||||
pr_info("statsfs: module exit\n");
|
||||
dput(authors_dentry);
|
||||
cleanup_links(books_inode);
|
||||
iput(books_inode);
|
||||
iput(authors_inode);
|
||||
unregister_filesystem(&libfs_type);
|
||||
}
|
||||
|
||||
@ -343,4 +346,4 @@ module_exit(libfs_exit);
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_AUTHOR("you");
|
||||
MODULE_DESCRIPTION("Custom library FS with books and authors");
|
||||
MODULE_DESCRIPTION("Custom library FS with books and authors (with debug logs)");
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user