512 lines
12 KiB
C
512 lines
12 KiB
C
/*
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* linux/fs/stat.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/errno.h>
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#include <linux/file.h>
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#include <linux/highuid.h>
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/pagemap.h>
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#include <asm/uaccess.h>
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#include <asm/unistd.h>
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void generic_fillattr(struct inode *inode, struct kstat *stat)
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{
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stat->dev = inode->i_sb->s_dev;
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stat->ino = inode->i_ino;
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stat->mode = inode->i_mode;
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stat->nlink = inode->i_nlink;
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stat->uid = inode->i_uid;
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stat->gid = inode->i_gid;
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stat->rdev = inode->i_rdev;
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stat->size = i_size_read(inode);
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stat->atime = inode->i_atime;
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stat->mtime = inode->i_mtime;
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stat->ctime = inode->i_ctime;
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stat->blksize = (1 << inode->i_blkbits);
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stat->blocks = inode->i_blocks;
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}
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EXPORT_SYMBOL(generic_fillattr);
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/**
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* vfs_getattr_nosec - getattr without security checks
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* @path: file to get attributes from
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* @stat: structure to return attributes in
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*
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* Get attributes without calling security_inode_getattr.
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*
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* Currently the only caller other than vfs_getattr is internal to the
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* filehandle lookup code, which uses only the inode number and returns
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* no attributes to any user. Any other code probably wants
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* vfs_getattr.
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*/
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int vfs_getattr_nosec(struct path *path, struct kstat *stat)
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{
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struct inode *inode = path->dentry->d_inode;
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if (inode->i_op->getattr)
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return inode->i_op->getattr(path->mnt, path->dentry, stat);
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generic_fillattr(inode, stat);
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return 0;
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}
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EXPORT_SYMBOL(vfs_getattr_nosec);
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int vfs_getattr(struct path *path, struct kstat *stat)
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{
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int retval;
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retval = security_inode_getattr(path->mnt, path->dentry);
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if (retval)
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return retval;
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return vfs_getattr_nosec(path, stat);
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}
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EXPORT_SYMBOL(vfs_getattr);
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int vfs_fstat(unsigned int fd, struct kstat *stat)
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{
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struct fd f = fdget_raw(fd);
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int error = -EBADF;
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if (f.file) {
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error = vfs_getattr(&f.file->f_path, stat);
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fdput(f);
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}
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return error;
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}
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EXPORT_SYMBOL(vfs_fstat);
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int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
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int flag)
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{
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struct path path;
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int error = -EINVAL;
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unsigned int lookup_flags = 0;
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if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
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AT_EMPTY_PATH)) != 0)
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goto out;
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if (!(flag & AT_SYMLINK_NOFOLLOW))
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lookup_flags |= LOOKUP_FOLLOW;
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if (flag & AT_EMPTY_PATH)
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lookup_flags |= LOOKUP_EMPTY;
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retry:
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error = user_path_at(dfd, filename, lookup_flags, &path);
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if (error)
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goto out;
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error = vfs_getattr(&path, stat);
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path_put(&path);
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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goto retry;
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}
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out:
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return error;
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}
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EXPORT_SYMBOL(vfs_fstatat);
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int vfs_stat(const char __user *name, struct kstat *stat)
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{
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return vfs_fstatat(AT_FDCWD, name, stat, 0);
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}
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EXPORT_SYMBOL(vfs_stat);
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int vfs_lstat(const char __user *name, struct kstat *stat)
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{
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return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
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}
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EXPORT_SYMBOL(vfs_lstat);
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#ifdef __ARCH_WANT_OLD_STAT
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/*
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* For backward compatibility? Maybe this should be moved
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* into arch/i386 instead?
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*/
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static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
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{
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static int warncount = 5;
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struct __old_kernel_stat tmp;
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if (warncount > 0) {
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warncount--;
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printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
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current->comm);
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} else if (warncount < 0) {
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/* it's laughable, but... */
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warncount = 0;
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}
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memset(&tmp, 0, sizeof(struct __old_kernel_stat));
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tmp.st_dev = old_encode_dev(stat->dev);
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tmp.st_ino = stat->ino;
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if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
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return -EOVERFLOW;
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tmp.st_mode = stat->mode;
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tmp.st_nlink = stat->nlink;
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if (tmp.st_nlink != stat->nlink)
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return -EOVERFLOW;
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SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
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SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
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tmp.st_rdev = old_encode_dev(stat->rdev);
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#if BITS_PER_LONG == 32
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if (stat->size > MAX_NON_LFS)
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return -EOVERFLOW;
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#endif
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tmp.st_size = stat->size;
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tmp.st_atime = stat->atime.tv_sec;
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tmp.st_mtime = stat->mtime.tv_sec;
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tmp.st_ctime = stat->ctime.tv_sec;
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return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
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}
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SYSCALL_DEFINE2(stat, const char __user *, filename,
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struct __old_kernel_stat __user *, statbuf)
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{
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struct kstat stat;
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int error;
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error = vfs_stat(filename, &stat);
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if (error)
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return error;
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return cp_old_stat(&stat, statbuf);
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}
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SYSCALL_DEFINE2(lstat, const char __user *, filename,
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struct __old_kernel_stat __user *, statbuf)
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{
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struct kstat stat;
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int error;
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error = vfs_lstat(filename, &stat);
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if (error)
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return error;
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return cp_old_stat(&stat, statbuf);
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}
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SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
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{
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struct kstat stat;
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int error = vfs_fstat(fd, &stat);
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if (!error)
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error = cp_old_stat(&stat, statbuf);
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return error;
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}
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#endif /* __ARCH_WANT_OLD_STAT */
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#if BITS_PER_LONG == 32
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# define choose_32_64(a,b) a
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#else
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# define choose_32_64(a,b) b
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#endif
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#define valid_dev(x) choose_32_64(old_valid_dev,new_valid_dev)(x)
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#define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)
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#ifndef INIT_STRUCT_STAT_PADDING
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# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
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#endif
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static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
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{
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struct stat tmp;
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if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
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return -EOVERFLOW;
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#if BITS_PER_LONG == 32
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if (stat->size > MAX_NON_LFS)
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return -EOVERFLOW;
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#endif
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INIT_STRUCT_STAT_PADDING(tmp);
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tmp.st_dev = encode_dev(stat->dev);
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tmp.st_ino = stat->ino;
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if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
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return -EOVERFLOW;
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tmp.st_mode = stat->mode;
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tmp.st_nlink = stat->nlink;
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if (tmp.st_nlink != stat->nlink)
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return -EOVERFLOW;
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SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
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SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
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tmp.st_rdev = encode_dev(stat->rdev);
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tmp.st_size = stat->size;
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tmp.st_atime = stat->atime.tv_sec;
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tmp.st_mtime = stat->mtime.tv_sec;
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tmp.st_ctime = stat->ctime.tv_sec;
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#ifdef STAT_HAVE_NSEC
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tmp.st_atime_nsec = stat->atime.tv_nsec;
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tmp.st_mtime_nsec = stat->mtime.tv_nsec;
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tmp.st_ctime_nsec = stat->ctime.tv_nsec;
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#endif
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tmp.st_blocks = stat->blocks;
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tmp.st_blksize = stat->blksize;
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return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
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}
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SYSCALL_DEFINE2(newstat, const char __user *, filename,
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struct stat __user *, statbuf)
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{
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struct kstat stat;
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int error = vfs_stat(filename, &stat);
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if (error)
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return error;
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return cp_new_stat(&stat, statbuf);
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}
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SYSCALL_DEFINE2(newlstat, const char __user *, filename,
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struct stat __user *, statbuf)
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{
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struct kstat stat;
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int error;
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error = vfs_lstat(filename, &stat);
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if (error)
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return error;
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return cp_new_stat(&stat, statbuf);
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}
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#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
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SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
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struct stat __user *, statbuf, int, flag)
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{
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struct kstat stat;
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int error;
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error = vfs_fstatat(dfd, filename, &stat, flag);
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if (error)
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return error;
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return cp_new_stat(&stat, statbuf);
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}
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#endif
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SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
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{
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struct kstat stat;
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int error = vfs_fstat(fd, &stat);
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if (!error)
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error = cp_new_stat(&stat, statbuf);
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return error;
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}
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SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
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char __user *, buf, int, bufsiz)
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{
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struct path path;
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int error;
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int empty = 0;
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unsigned int lookup_flags = LOOKUP_EMPTY;
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if (bufsiz <= 0)
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return -EINVAL;
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retry:
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error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
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if (!error) {
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struct inode *inode = path.dentry->d_inode;
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error = empty ? -ENOENT : -EINVAL;
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if (inode->i_op->readlink) {
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error = security_inode_readlink(path.dentry);
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if (!error) {
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touch_atime(&path);
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error = inode->i_op->readlink(path.dentry,
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buf, bufsiz);
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}
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}
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path_put(&path);
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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goto retry;
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}
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}
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return error;
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}
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SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
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int, bufsiz)
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{
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return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
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}
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/* ---------- LFS-64 ----------- */
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#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
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#ifndef INIT_STRUCT_STAT64_PADDING
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# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
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#endif
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static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
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{
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struct stat64 tmp;
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INIT_STRUCT_STAT64_PADDING(tmp);
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#ifdef CONFIG_MIPS
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/* mips has weird padding, so we don't get 64 bits there */
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if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
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return -EOVERFLOW;
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tmp.st_dev = new_encode_dev(stat->dev);
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tmp.st_rdev = new_encode_dev(stat->rdev);
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#else
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tmp.st_dev = huge_encode_dev(stat->dev);
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tmp.st_rdev = huge_encode_dev(stat->rdev);
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#endif
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tmp.st_ino = stat->ino;
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if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
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return -EOVERFLOW;
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#ifdef STAT64_HAS_BROKEN_ST_INO
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tmp.__st_ino = stat->ino;
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#endif
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tmp.st_mode = stat->mode;
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tmp.st_nlink = stat->nlink;
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tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
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tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
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tmp.st_atime = stat->atime.tv_sec;
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tmp.st_atime_nsec = stat->atime.tv_nsec;
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tmp.st_mtime = stat->mtime.tv_sec;
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tmp.st_mtime_nsec = stat->mtime.tv_nsec;
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tmp.st_ctime = stat->ctime.tv_sec;
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tmp.st_ctime_nsec = stat->ctime.tv_nsec;
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tmp.st_size = stat->size;
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tmp.st_blocks = stat->blocks;
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tmp.st_blksize = stat->blksize;
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return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
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}
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SYSCALL_DEFINE2(stat64, const char __user *, filename,
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struct stat64 __user *, statbuf)
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{
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struct kstat stat;
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int error = vfs_stat(filename, &stat);
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if (!error)
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error = cp_new_stat64(&stat, statbuf);
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return error;
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}
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SYSCALL_DEFINE2(lstat64, const char __user *, filename,
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struct stat64 __user *, statbuf)
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{
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struct kstat stat;
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int error = vfs_lstat(filename, &stat);
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if (!error)
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error = cp_new_stat64(&stat, statbuf);
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return error;
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}
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SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
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{
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struct kstat stat;
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int error = vfs_fstat(fd, &stat);
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if (!error)
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error = cp_new_stat64(&stat, statbuf);
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return error;
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}
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SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
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struct stat64 __user *, statbuf, int, flag)
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{
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struct kstat stat;
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int error;
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error = vfs_fstatat(dfd, filename, &stat, flag);
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if (error)
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return error;
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return cp_new_stat64(&stat, statbuf);
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}
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#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
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/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
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void __inode_add_bytes(struct inode *inode, loff_t bytes)
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{
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inode->i_blocks += bytes >> 9;
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bytes &= 511;
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inode->i_bytes += bytes;
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if (inode->i_bytes >= 512) {
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inode->i_blocks++;
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inode->i_bytes -= 512;
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}
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}
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void inode_add_bytes(struct inode *inode, loff_t bytes)
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{
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spin_lock(&inode->i_lock);
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__inode_add_bytes(inode, bytes);
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spin_unlock(&inode->i_lock);
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}
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EXPORT_SYMBOL(inode_add_bytes);
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void __inode_sub_bytes(struct inode *inode, loff_t bytes)
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{
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inode->i_blocks -= bytes >> 9;
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bytes &= 511;
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if (inode->i_bytes < bytes) {
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inode->i_blocks--;
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inode->i_bytes += 512;
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}
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inode->i_bytes -= bytes;
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}
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EXPORT_SYMBOL(__inode_sub_bytes);
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void inode_sub_bytes(struct inode *inode, loff_t bytes)
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{
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spin_lock(&inode->i_lock);
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__inode_sub_bytes(inode, bytes);
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spin_unlock(&inode->i_lock);
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}
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EXPORT_SYMBOL(inode_sub_bytes);
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loff_t inode_get_bytes(struct inode *inode)
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{
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loff_t ret;
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spin_lock(&inode->i_lock);
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ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
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spin_unlock(&inode->i_lock);
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return ret;
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}
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EXPORT_SYMBOL(inode_get_bytes);
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void inode_set_bytes(struct inode *inode, loff_t bytes)
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{
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/* Caller is here responsible for sufficient locking
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* (ie. inode->i_lock) */
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inode->i_blocks = bytes >> 9;
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inode->i_bytes = bytes & 511;
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}
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EXPORT_SYMBOL(inode_set_bytes);
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