mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-30 23:50:07 +00:00
9a53c3a783
When a filesystem decrements i_nlink to zero, it means that a write must be performed in order to drop the inode from the filesystem. We're shortly going to have keep filesystems from being remounted r/o between the time that this i_nlink decrement and that write occurs. So, add a little helper function to do the decrements. We'll tie into it in a bit to note when i_nlink hits zero. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
307 lines
6.2 KiB
C
307 lines
6.2 KiB
C
/*
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* linux/fs/sysv/namei.c
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*
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* minix/namei.c
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* coh/namei.c
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* Copyright (C) 1993 Pascal Haible, Bruno Haible
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*
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* sysv/namei.c
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* Copyright (C) 1993 Bruno Haible
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* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
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*/
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include "sysv.h"
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static int add_nondir(struct dentry *dentry, struct inode *inode)
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{
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int err = sysv_add_link(dentry, inode);
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if (!err) {
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d_instantiate(dentry, inode);
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return 0;
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}
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inode_dec_link_count(inode);
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iput(inode);
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return err;
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}
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static int sysv_hash(struct dentry *dentry, struct qstr *qstr)
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{
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/* Truncate the name in place, avoids having to define a compare
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function. */
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if (qstr->len > SYSV_NAMELEN) {
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qstr->len = SYSV_NAMELEN;
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qstr->hash = full_name_hash(qstr->name, qstr->len);
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}
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return 0;
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}
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struct dentry_operations sysv_dentry_operations = {
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.d_hash = sysv_hash,
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};
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static struct dentry *sysv_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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ino_t ino;
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dentry->d_op = dir->i_sb->s_root->d_op;
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if (dentry->d_name.len > SYSV_NAMELEN)
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return ERR_PTR(-ENAMETOOLONG);
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ino = sysv_inode_by_name(dentry);
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if (ino) {
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inode = iget(dir->i_sb, ino);
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if (!inode)
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return ERR_PTR(-EACCES);
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}
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d_add(dentry, inode);
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return NULL;
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}
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static int sysv_mknod(struct inode * dir, struct dentry * dentry, int mode, dev_t rdev)
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{
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struct inode * inode;
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int err;
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if (!old_valid_dev(rdev))
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return -EINVAL;
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inode = sysv_new_inode(dir, mode);
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err = PTR_ERR(inode);
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if (!IS_ERR(inode)) {
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sysv_set_inode(inode, rdev);
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mark_inode_dirty(inode);
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err = add_nondir(dentry, inode);
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}
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return err;
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}
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static int sysv_create(struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
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{
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return sysv_mknod(dir, dentry, mode, 0);
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}
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static int sysv_symlink(struct inode * dir, struct dentry * dentry,
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const char * symname)
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{
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int err = -ENAMETOOLONG;
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int l = strlen(symname)+1;
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struct inode * inode;
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if (l > dir->i_sb->s_blocksize)
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goto out;
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inode = sysv_new_inode(dir, S_IFLNK|0777);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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goto out;
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sysv_set_inode(inode, 0);
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err = page_symlink(inode, symname, l);
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if (err)
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goto out_fail;
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mark_inode_dirty(inode);
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err = add_nondir(dentry, inode);
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out:
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return err;
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out_fail:
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inode_dec_link_count(inode);
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iput(inode);
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goto out;
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}
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static int sysv_link(struct dentry * old_dentry, struct inode * dir,
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struct dentry * dentry)
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{
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struct inode *inode = old_dentry->d_inode;
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if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max)
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return -EMLINK;
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inode->i_ctime = CURRENT_TIME_SEC;
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inode_inc_link_count(inode);
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atomic_inc(&inode->i_count);
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return add_nondir(dentry, inode);
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}
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static int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode)
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{
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struct inode * inode;
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int err = -EMLINK;
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if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max)
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goto out;
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inode_inc_link_count(dir);
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inode = sysv_new_inode(dir, S_IFDIR|mode);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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goto out_dir;
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sysv_set_inode(inode, 0);
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inode_inc_link_count(inode);
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err = sysv_make_empty(inode, dir);
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if (err)
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goto out_fail;
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err = sysv_add_link(dentry, inode);
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if (err)
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goto out_fail;
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d_instantiate(dentry, inode);
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out:
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return err;
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out_fail:
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inode_dec_link_count(inode);
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inode_dec_link_count(inode);
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iput(inode);
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out_dir:
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inode_dec_link_count(dir);
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goto out;
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}
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static int sysv_unlink(struct inode * dir, struct dentry * dentry)
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{
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struct inode * inode = dentry->d_inode;
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struct page * page;
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struct sysv_dir_entry * de;
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int err = -ENOENT;
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de = sysv_find_entry(dentry, &page);
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if (!de)
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goto out;
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err = sysv_delete_entry (de, page);
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if (err)
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goto out;
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inode->i_ctime = dir->i_ctime;
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inode_dec_link_count(inode);
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out:
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return err;
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}
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static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
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{
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struct inode *inode = dentry->d_inode;
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int err = -ENOTEMPTY;
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if (sysv_empty_dir(inode)) {
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err = sysv_unlink(dir, dentry);
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if (!err) {
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inode->i_size = 0;
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inode_dec_link_count(inode);
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inode_dec_link_count(dir);
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}
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}
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return err;
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}
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/*
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* Anybody can rename anything with this: the permission checks are left to the
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* higher-level routines.
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*/
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static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
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struct inode * new_dir, struct dentry * new_dentry)
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{
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struct inode * old_inode = old_dentry->d_inode;
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struct inode * new_inode = new_dentry->d_inode;
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struct page * dir_page = NULL;
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struct sysv_dir_entry * dir_de = NULL;
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struct page * old_page;
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struct sysv_dir_entry * old_de;
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int err = -ENOENT;
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old_de = sysv_find_entry(old_dentry, &old_page);
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if (!old_de)
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goto out;
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if (S_ISDIR(old_inode->i_mode)) {
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err = -EIO;
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dir_de = sysv_dotdot(old_inode, &dir_page);
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if (!dir_de)
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goto out_old;
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}
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if (new_inode) {
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struct page * new_page;
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struct sysv_dir_entry * new_de;
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err = -ENOTEMPTY;
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if (dir_de && !sysv_empty_dir(new_inode))
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goto out_dir;
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err = -ENOENT;
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new_de = sysv_find_entry(new_dentry, &new_page);
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if (!new_de)
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goto out_dir;
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inode_inc_link_count(old_inode);
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sysv_set_link(new_de, new_page, old_inode);
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new_inode->i_ctime = CURRENT_TIME_SEC;
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if (dir_de)
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drop_nlink(new_inode);
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inode_dec_link_count(new_inode);
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} else {
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if (dir_de) {
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err = -EMLINK;
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if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max)
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goto out_dir;
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}
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inode_inc_link_count(old_inode);
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err = sysv_add_link(new_dentry, old_inode);
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if (err) {
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inode_dec_link_count(old_inode);
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goto out_dir;
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}
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if (dir_de)
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inode_inc_link_count(new_dir);
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}
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sysv_delete_entry(old_de, old_page);
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inode_dec_link_count(old_inode);
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if (dir_de) {
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sysv_set_link(dir_de, dir_page, new_dir);
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inode_dec_link_count(old_dir);
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}
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return 0;
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out_dir:
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if (dir_de) {
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kunmap(dir_page);
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page_cache_release(dir_page);
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}
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out_old:
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kunmap(old_page);
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page_cache_release(old_page);
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out:
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return err;
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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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struct inode_operations sysv_dir_inode_operations = {
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.create = sysv_create,
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.lookup = sysv_lookup,
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.link = sysv_link,
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.unlink = sysv_unlink,
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.symlink = sysv_symlink,
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.mkdir = sysv_mkdir,
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.rmdir = sysv_rmdir,
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.mknod = sysv_mknod,
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.rename = sysv_rename,
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.getattr = sysv_getattr,
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};
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