virtio_blk: set the zone write granularitygrafted

virtblk_read_zoned_limits() reads the write granularity that the device
reports in virtio_blk_zoned_characteristics and assigns it to the
physical block size and to io_min, but never to the limit that is named
after it. queue_limits.zone_write_granularity is left at zero, so
blk_validate_zoned_limits() raises it to the logical block size:

	if (lim->zone_write_granularity < lim->logical_block_size)
		lim->zone_write_granularity = lim->logical_block_size;

A device that reports a granularity coarser than its logical block size,
which is what the field exists to express, therefore has it silently
reduced. A 512e host managed disk passed through to a guest reports a
logical block size of 512 and a write granularity of 4096, and the guest
ends up with a zone write granularity of 512.

bio_split_alignment() returns lim->zone_write_granularity if it is non-zero
and bio_split_io_at() may split a bio with as per bio_split_alignment().
This can real to the write getting rejected by the host drive, as the write
is not aligned to the physical block size.

zonefs also takes its block size from bdev_zone_write_granularity(), so it
would incorrectly use 512 on a disk that requires 4096.

sd_zbc_read_zones() sets the limit from the physical block size for the
same reason. NVMe ZNS and null_blk leave it unset, but the fallback
gives the right answer for them, as their write granularity is the
logical block size. virtio carries a separate value that may exceed it.

Set the zone write granularity from the value that the device reports.

Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices")
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://patch.msgid.link/20260918140641.2031075-2-cassel@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 968 insertions, 0 deletions

diff --git a/fs/stat.c b/fs/stat.c
new file mode 100644
index 000000000..c461c3054
--- /dev/null
+++ b/fs/stat.c
@@ -0,0 +1,968 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/stat.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/blkdev.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/highuid.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/cred.h>
+#include <linux/syscalls.h>
+#include <linux/pagemap.h>
+#include <linux/compat.h>
+#include <linux/iversion.h>
+
+#include <linux/uaccess.h>
+#include <asm/unistd.h>
+
+#include <trace/events/timestamp.h>
+
+#include "internal.h"
+#include "mount.h"
+
+/**
+ * fill_mg_cmtime - Fill in the mtime and ctime and flag ctime as QUERIED
+ * @stat: where to store the resulting values
+ * @request_mask: STATX_* values requested
+ * @inode: inode from which to grab the c/mtime
+ *
+ * Given @inode, grab the ctime and mtime out if it and store the result
+ * in @stat. When fetching the value, flag it as QUERIED (if not already)
+ * so the next write will record a distinct timestamp.
+ *
+ * NB: The QUERIED flag is tracked in the ctime, but we set it there even
+ * if only the mtime was requested, as that ensures that the next mtime
+ * change will be distinct.
+ */
+void fill_mg_cmtime(struct kstat *stat, u32 request_mask, struct inode *inode)
+{
+	atomic_t *pcn = (atomic_t *)&inode->i_ctime_nsec;
+
+	/* If neither time was requested, then don't report them */
+	if (!(request_mask & (STATX_CTIME|STATX_MTIME))) {
+		stat->result_mask &= ~(STATX_CTIME|STATX_MTIME);
+		return;
+	}
+
+	stat->mtime = inode_get_mtime(inode);
+	stat->ctime.tv_sec = inode_get_ctime_sec(inode);
+	stat->ctime.tv_nsec = (u32)atomic_read(pcn);
+	if (!(stat->ctime.tv_nsec & I_CTIME_QUERIED))
+		stat->ctime.tv_nsec = ((u32)atomic_fetch_or(I_CTIME_QUERIED, pcn));
+	stat->ctime.tv_nsec &= ~I_CTIME_QUERIED;
+	trace_fill_mg_cmtime(inode, &stat->ctime, &stat->mtime);
+}
+EXPORT_SYMBOL(fill_mg_cmtime);
+
+/**
+ * generic_fillattr - Fill in the basic attributes from the inode struct
+ * @idmap:		idmap of the mount the inode was found from
+ * @request_mask:	statx request_mask
+ * @inode:		Inode to use as the source
+ * @stat:		Where to fill in the attributes
+ *
+ * Fill in the basic attributes in the kstat structure from data that's to be
+ * found on the VFS inode structure.  This is the default if no getattr inode
+ * operation is supplied.
+ *
+ * If the inode has been found through an idmapped mount the idmap of
+ * the vfsmount must be passed through @idmap. This function will then
+ * take care to map the inode according to @idmap before filling in the
+ * uid and gid filds. On non-idmapped mounts or if permission checking is to be
+ * performed on the raw inode simply pass @nop_mnt_idmap.
+ */
+void generic_fillattr(struct mnt_idmap *idmap, u32 request_mask,
+		      struct inode *inode, struct kstat *stat)
+{
+	vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
+	vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
+
+	stat->dev = inode->i_sb->s_dev;
+	stat->ino = inode->i_ino;
+	stat->mode = inode->i_mode;
+	stat->nlink = inode->i_nlink;
+	stat->uid = vfsuid_into_kuid(vfsuid);
+	stat->gid = vfsgid_into_kgid(vfsgid);
+	stat->rdev = inode->i_rdev;
+	stat->size = i_size_read(inode);
+	stat->atime = inode_get_atime(inode);
+
+	if (is_mgtime(inode)) {
+		fill_mg_cmtime(stat, request_mask, inode);
+	} else {
+		stat->ctime = inode_get_ctime(inode);
+		stat->mtime = inode_get_mtime(inode);
+	}
+
+	stat->blksize = i_blocksize(inode);
+	stat->blocks = inode->i_blocks;
+
+	if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
+		stat->result_mask |= STATX_CHANGE_COOKIE;
+		stat->change_cookie = inode_query_iversion(inode);
+	}
+
+}
+EXPORT_SYMBOL(generic_fillattr);
+
+/**
+ * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
+ * @inode:	Inode to use as the source
+ * @stat:	Where to fill in the attribute flags
+ *
+ * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
+ * inode that are published on i_flags and enforced by the VFS.
+ */
+void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
+{
+	if (inode->i_flags & S_IMMUTABLE)
+		stat->attributes |= STATX_ATTR_IMMUTABLE;
+	if (inode->i_flags & S_APPEND)
+		stat->attributes |= STATX_ATTR_APPEND;
+	stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
+}
+EXPORT_SYMBOL(generic_fill_statx_attr);
+
+/**
+ * generic_fill_statx_atomic_writes - Fill in atomic writes statx attributes
+ * @stat:	Where to fill in the attribute flags
+ * @unit_min:	Minimum supported atomic write length in bytes
+ * @unit_max:	Maximum supported atomic write length in bytes
+ * @unit_max_opt: Optimised maximum supported atomic write length in bytes
+ *
+ * Fill in the STATX{_ATTR}_WRITE_ATOMIC flags in the kstat structure from
+ * atomic write unit_min and unit_max values.
+ */
+void generic_fill_statx_atomic_writes(struct kstat *stat,
+				      unsigned int unit_min,
+				      unsigned int unit_max,
+				      unsigned int unit_max_opt)
+{
+	/* Confirm that the request type is known */
+	stat->result_mask |= STATX_WRITE_ATOMIC;
+
+	/* Confirm that the file attribute type is known */
+	stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
+
+	if (unit_min) {
+		stat->atomic_write_unit_min = unit_min;
+		stat->atomic_write_unit_max = unit_max;
+		stat->atomic_write_unit_max_opt = unit_max_opt;
+		/* Initially only allow 1x segment */
+		stat->atomic_write_segments_max = 1;
+
+		/* Confirm atomic writes are actually supported */
+		stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
+	}
+}
+EXPORT_SYMBOL_GPL(generic_fill_statx_atomic_writes);
+
+/**
+ * vfs_getattr_nosec - getattr without security checks
+ * @path: file to get attributes from
+ * @stat: structure to return attributes in
+ * @request_mask: STATX_xxx flags indicating what the caller wants
+ * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
+ *
+ * Get attributes without calling security_inode_getattr.
+ *
+ * Currently the only caller other than vfs_getattr is internal to the
+ * filehandle lookup code, which uses only the inode number and returns no
+ * attributes to any user.  Any other code probably wants vfs_getattr.
+ */
+int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
+		      u32 request_mask, unsigned int query_flags)
+{
+	struct mnt_idmap *idmap;
+	struct inode *inode = d_backing_inode(path->dentry);
+
+	memset(stat, 0, sizeof(*stat));
+	stat->result_mask |= STATX_BASIC_STATS;
+	query_flags &= AT_STATX_SYNC_TYPE;
+
+	/* allow the fs to override these if it really wants to */
+	/* SB_NOATIME means filesystem supplies dummy atime value */
+	if (inode->i_sb->s_flags & SB_NOATIME)
+		stat->result_mask &= ~STATX_ATIME;
+
+	/*
+	 * Note: If you add another clause to set an attribute flag, please
+	 * update attributes_mask below.
+	 */
+	if (IS_AUTOMOUNT(inode))
+		stat->attributes |= STATX_ATTR_AUTOMOUNT;
+
+	if (IS_DAX(inode))
+		stat->attributes |= STATX_ATTR_DAX;
+
+	stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
+				  STATX_ATTR_DAX);
+
+	idmap = mnt_idmap(path->mnt);
+	if (inode->i_op->getattr) {
+		int ret;
+
+		ret = inode->i_op->getattr(idmap, path, stat, request_mask,
+				query_flags);
+		if (ret)
+			return ret;
+	} else {
+		generic_fillattr(idmap, request_mask, inode, stat);
+	}
+
+	/*
+	 * If this is a block device inode, override the filesystem attributes
+	 * with the block device specific parameters that need to be obtained
+	 * from the bdev backing inode.
+	 */
+	if (S_ISBLK(stat->mode))
+		bdev_statx(path, stat, request_mask);
+
+	return 0;
+}
+EXPORT_SYMBOL(vfs_getattr_nosec);
+
+/*
+ * vfs_getattr - Get the enhanced basic attributes of a file
+ * @path: The file of interest
+ * @stat: Where to return the statistics
+ * @request_mask: STATX_xxx flags indicating what the caller wants
+ * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
+ *
+ * Ask the filesystem for a file's attributes.  The caller must indicate in
+ * request_mask and query_flags to indicate what they want.
+ *
+ * If the file is remote, the filesystem can be forced to update the attributes
+ * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
+ * suppress the update by passing AT_STATX_DONT_SYNC.
+ *
+ * Bits must have been set in request_mask to indicate which attributes the
+ * caller wants retrieving.  Any such attribute not requested may be returned
+ * anyway, but the value may be approximate, and, if remote, may not have been
+ * synchronised with the server.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_getattr(const struct path *path, struct kstat *stat,
+		u32 request_mask, unsigned int query_flags)
+{
+	int retval;
+
+	retval = security_inode_getattr(path);
+	if (unlikely(retval))
+		return retval;
+	return vfs_getattr_nosec(path, stat, request_mask, query_flags);
+}
+EXPORT_SYMBOL(vfs_getattr);
+
+/**
+ * vfs_fstat - Get the basic attributes by file descriptor
+ * @fd: The file descriptor referring to the file of interest
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_getattr().  The main difference is
+ * that it uses a file descriptor to determine the file location.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_fstat(int fd, struct kstat *stat)
+{
+	CLASS(fd_raw, f)(fd);
+	if (fd_empty(f))
+		return -EBADF;
+	return vfs_getattr(&fd_file(f)->f_path, stat, STATX_BASIC_STATS, 0);
+}
+
+static int statx_lookup_flags(int flags)
+{
+	int lookup_flags = 0;
+
+	if (!(flags & AT_SYMLINK_NOFOLLOW))
+		lookup_flags |= LOOKUP_FOLLOW;
+	if (!(flags & AT_NO_AUTOMOUNT))
+		lookup_flags |= LOOKUP_AUTOMOUNT;
+
+	return lookup_flags;
+}
+
+static int vfs_statx_path(const struct path *path, int flags, struct kstat *stat,
+			  u32 request_mask)
+{
+	int error = vfs_getattr(path, stat, request_mask, flags);
+	if (error)
+		return error;
+
+	if (request_mask & STATX_MNT_ID_UNIQUE) {
+		stat->mnt_id = real_mount(path->mnt)->mnt_id_unique;
+		stat->result_mask |= STATX_MNT_ID_UNIQUE;
+	} else {
+		stat->mnt_id = real_mount(path->mnt)->mnt_id;
+		stat->result_mask |= STATX_MNT_ID;
+	}
+
+	if (path_mounted(path))
+		stat->attributes |= STATX_ATTR_MOUNT_ROOT;
+	stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
+	return 0;
+}
+
+static int vfs_statx_fd(int fd, int flags, struct kstat *stat,
+			  u32 request_mask)
+{
+	CLASS(fd_raw, f)(fd);
+	if (fd_empty(f))
+		return -EBADF;
+	return vfs_statx_path(&fd_file(f)->f_path, flags, stat, request_mask);
+}
+
+/**
+ * vfs_statx - Get basic and extra attributes by filename
+ * @dfd: A file descriptor representing the base dir for a relative filename
+ * @filename: The name of the file of interest
+ * @flags: Flags to control the query
+ * @stat: The result structure to fill in.
+ * @request_mask: STATX_xxx flags indicating what the caller wants
+ *
+ * This function is a wrapper around vfs_getattr().  The main difference is
+ * that it uses a filename and base directory to determine the file location.
+ * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
+ * at the given name from being referenced.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+static int vfs_statx(int dfd, struct filename *filename, int flags,
+	      struct kstat *stat, u32 request_mask)
+{
+	struct path path;
+	unsigned int lookup_flags = statx_lookup_flags(flags);
+	int error;
+
+	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
+		      AT_STATX_SYNC_TYPE))
+		return -EINVAL;
+
+retry:
+	error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
+	if (error)
+		return error;
+	error = vfs_statx_path(&path, flags, stat, request_mask);
+	path_put(&path);
+	if (retry_estale(error, lookup_flags)) {
+		lookup_flags |= LOOKUP_REVAL;
+		goto retry;
+	}
+	return error;
+}
+
+int vfs_fstatat(int dfd, const char __user *filename,
+			      struct kstat *stat, int flags)
+{
+	CLASS(filename_maybe_null, name)(filename, flags);
+
+	if (!name && dfd >= 0)
+		return vfs_fstat(dfd, stat);
+
+	return vfs_statx(dfd, name, flags | AT_NO_AUTOMOUNT,
+			 stat, STATX_BASIC_STATS);
+}
+
+#ifdef __ARCH_WANT_OLD_STAT
+
+/*
+ * For backward compatibility?  Maybe this should be moved
+ * into arch/i386 instead?
+ */
+static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
+{
+	static int warncount = 5;
+	struct __old_kernel_stat tmp;
+
+	if (warncount > 0) {
+		warncount--;
+		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
+			current->comm);
+	} else if (warncount < 0) {
+		/* it's laughable, but... */
+		warncount = 0;
+	}
+
+	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
+	tmp.st_dev = old_encode_dev(stat->dev);
+	tmp.st_ino = stat->ino;
+	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
+		return -EOVERFLOW;
+	tmp.st_mode = stat->mode;
+	tmp.st_nlink = stat->nlink;
+	if (tmp.st_nlink != stat->nlink)
+		return -EOVERFLOW;
+	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
+	tmp.st_rdev = old_encode_dev(stat->rdev);
+#if BITS_PER_LONG == 32
+	if (stat->size > MAX_NON_LFS)
+		return -EOVERFLOW;
+#endif
+	tmp.st_size = stat->size;
+	tmp.st_atime = stat->atime.tv_sec;
+	tmp.st_mtime = stat->mtime.tv_sec;
+	tmp.st_ctime = stat->ctime.tv_sec;
+	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
+}
+
+SYSCALL_DEFINE2(stat, const char __user *, filename,
+		struct __old_kernel_stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_stat(filename, &stat);
+	if (unlikely(error))
+		return error;
+
+	return cp_old_stat(&stat, statbuf);
+}
+
+SYSCALL_DEFINE2(lstat, const char __user *, filename,
+		struct __old_kernel_stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_lstat(filename, &stat);
+	if (unlikely(error))
+		return error;
+
+	return cp_old_stat(&stat, statbuf);
+}
+
+SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_fstat(fd, &stat);
+	if (unlikely(error))
+		return error;
+
+	return cp_old_stat(&stat, statbuf);
+}
+
+#endif /* __ARCH_WANT_OLD_STAT */
+
+#ifdef __ARCH_WANT_NEW_STAT
+
+#ifndef INIT_STRUCT_STAT_PADDING
+#  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
+#endif
+
+static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
+{
+	struct stat tmp;
+
+	if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
+		return -EOVERFLOW;
+	if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
+		return -EOVERFLOW;
+#if BITS_PER_LONG == 32
+	if (stat->size > MAX_NON_LFS)
+		return -EOVERFLOW;
+#endif
+
+	INIT_STRUCT_STAT_PADDING(tmp);
+	tmp.st_dev = new_encode_dev(stat->dev);
+	tmp.st_ino = stat->ino;
+	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
+		return -EOVERFLOW;
+	tmp.st_mode = stat->mode;
+	tmp.st_nlink = stat->nlink;
+	if (tmp.st_nlink != stat->nlink)
+		return -EOVERFLOW;
+	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
+	tmp.st_rdev = new_encode_dev(stat->rdev);
+	tmp.st_size = stat->size;
+	tmp.st_atime = stat->atime.tv_sec;
+	tmp.st_mtime = stat->mtime.tv_sec;
+	tmp.st_ctime = stat->ctime.tv_sec;
+#ifdef STAT_HAVE_NSEC
+	tmp.st_atime_nsec = stat->atime.tv_nsec;
+	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
+	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
+#endif
+	tmp.st_blocks = stat->blocks;
+	tmp.st_blksize = stat->blksize;
+	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
+}
+
+SYSCALL_DEFINE2(newstat, const char __user *, filename,
+		struct stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_stat(filename, &stat);
+	if (unlikely(error))
+		return error;
+
+	return cp_new_stat(&stat, statbuf);
+}
+
+SYSCALL_DEFINE2(newlstat, const char __user *, filename,
+		struct stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_lstat(filename, &stat);
+	if (unlikely(error))
+		return error;
+
+	return cp_new_stat(&stat, statbuf);
+}
+
+#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
+SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
+		struct stat __user *, statbuf, int, flag)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_fstatat(dfd, filename, &stat, flag);
+	if (unlikely(error))
+		return error;
+
+	return cp_new_stat(&stat, statbuf);
+}
+#endif
+
+SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_fstat(fd, &stat);
+	if (unlikely(error))
+		return error;
+
+	return cp_new_stat(&stat, statbuf);
+}
+#endif
+
+static int do_readlinkat(int dfd, const char __user *pathname,
+			 char __user *buf, int bufsiz)
+{
+	struct path path;
+	int error;
+	unsigned int lookup_flags = 0;
+
+	if (bufsiz <= 0)
+		return -EINVAL;
+
+	CLASS(filename_flags, name)(pathname, LOOKUP_EMPTY);
+retry:
+	error = filename_lookup(dfd, name, lookup_flags, &path, NULL);
+	if (unlikely(error))
+		return error;
+
+	/*
+	 * AFS mountpoints allow readlink(2) but are not symlinks
+	 */
+	if (d_is_symlink(path.dentry) ||
+	    d_backing_inode(path.dentry)->i_op->readlink) {
+		error = security_inode_readlink(path.dentry);
+		if (!error) {
+			touch_atime(&path);
+			error = vfs_readlink(path.dentry, buf, bufsiz);
+		}
+	} else {
+		error = (name->name[0] == '\0') ? -ENOENT : -EINVAL;
+	}
+	path_put(&path);
+	if (retry_estale(error, lookup_flags)) {
+		lookup_flags |= LOOKUP_REVAL;
+		goto retry;
+	}
+	return error;
+}
+
+SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
+		char __user *, buf, int, bufsiz)
+{
+	return do_readlinkat(dfd, pathname, buf, bufsiz);
+}
+
+SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
+		int, bufsiz)
+{
+	return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
+}
+
+
+/* ---------- LFS-64 ----------- */
+#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
+
+#ifndef INIT_STRUCT_STAT64_PADDING
+#  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
+#endif
+
+static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
+{
+	struct stat64 tmp;
+
+	INIT_STRUCT_STAT64_PADDING(tmp);
+#ifdef CONFIG_MIPS
+	/* mips has weird padding, so we don't get 64 bits there */
+	tmp.st_dev = new_encode_dev(stat->dev);
+	tmp.st_rdev = new_encode_dev(stat->rdev);
+#else
+	tmp.st_dev = huge_encode_dev(stat->dev);
+	tmp.st_rdev = huge_encode_dev(stat->rdev);
+#endif
+	tmp.st_ino = stat->ino;
+	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
+		return -EOVERFLOW;
+#ifdef STAT64_HAS_BROKEN_ST_INO
+	tmp.__st_ino = stat->ino;
+#endif
+	tmp.st_mode = stat->mode;
+	tmp.st_nlink = stat->nlink;
+	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
+	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
+	tmp.st_atime = stat->atime.tv_sec;
+	tmp.st_atime_nsec = stat->atime.tv_nsec;
+	tmp.st_mtime = stat->mtime.tv_sec;
+	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
+	tmp.st_ctime = stat->ctime.tv_sec;
+	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
+	tmp.st_size = stat->size;
+	tmp.st_blocks = stat->blocks;
+	tmp.st_blksize = stat->blksize;
+	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
+}
+
+SYSCALL_DEFINE2(stat64, const char __user *, filename,
+		struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int error = vfs_stat(filename, &stat);
+
+	if (!error)
+		error = cp_new_stat64(&stat, statbuf);
+
+	return error;
+}
+
+SYSCALL_DEFINE2(lstat64, const char __user *, filename,
+		struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int error = vfs_lstat(filename, &stat);
+
+	if (!error)
+		error = cp_new_stat64(&stat, statbuf);
+
+	return error;
+}
+
+SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int error = vfs_fstat(fd, &stat);
+
+	if (!error)
+		error = cp_new_stat64(&stat, statbuf);
+
+	return error;
+}
+
+SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
+		struct stat64 __user *, statbuf, int, flag)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_fstatat(dfd, filename, &stat, flag);
+	if (error)
+		return error;
+	return cp_new_stat64(&stat, statbuf);
+}
+#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
+
+static noinline_for_stack int
+cp_statx(const struct kstat *stat, struct statx __user *buffer)
+{
+	struct statx tmp;
+
+	memset(&tmp, 0, sizeof(tmp));
+
+	/* STATX_CHANGE_COOKIE is kernel-only for now */
+	tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
+	tmp.stx_blksize = stat->blksize;
+	/* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */
+	tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC;
+	tmp.stx_nlink = stat->nlink;
+	tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
+	tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
+	tmp.stx_mode = stat->mode;
+	tmp.stx_ino = stat->ino;
+	tmp.stx_size = stat->size;
+	tmp.stx_blocks = stat->blocks;
+	tmp.stx_attributes_mask = stat->attributes_mask;
+	tmp.stx_atime.tv_sec = stat->atime.tv_sec;
+	tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
+	tmp.stx_btime.tv_sec = stat->btime.tv_sec;
+	tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
+	tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
+	tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
+	tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
+	tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
+	tmp.stx_rdev_major = MAJOR(stat->rdev);
+	tmp.stx_rdev_minor = MINOR(stat->rdev);
+	tmp.stx_dev_major = MAJOR(stat->dev);
+	tmp.stx_dev_minor = MINOR(stat->dev);
+	tmp.stx_mnt_id = stat->mnt_id;
+	tmp.stx_dio_mem_align = stat->dio_mem_align;
+	tmp.stx_dio_offset_align = stat->dio_offset_align;
+	tmp.stx_dio_read_offset_align = stat->dio_read_offset_align;
+	tmp.stx_subvol = stat->subvol;
+	tmp.stx_atomic_write_unit_min = stat->atomic_write_unit_min;
+	tmp.stx_atomic_write_unit_max = stat->atomic_write_unit_max;
+	tmp.stx_atomic_write_segments_max = stat->atomic_write_segments_max;
+	tmp.stx_atomic_write_unit_max_opt = stat->atomic_write_unit_max_opt;
+
+	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
+}
+
+int do_statx(int dfd, struct filename *filename, unsigned int flags,
+	     unsigned int mask, struct statx __user *buffer)
+{
+	struct kstat stat;
+	int error;
+
+	if (mask & STATX__RESERVED)
+		return -EINVAL;
+	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
+		return -EINVAL;
+
+	/*
+	 * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
+	 * from userland.
+	 */
+	mask &= ~STATX_CHANGE_COOKIE;
+
+	error = vfs_statx(dfd, filename, flags, &stat, mask);
+	if (error)
+		return error;
+
+	return cp_statx(&stat, buffer);
+}
+
+int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
+	     struct statx __user *buffer)
+{
+	struct kstat stat;
+	int error;
+
+	if (mask & STATX__RESERVED)
+		return -EINVAL;
+	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
+		return -EINVAL;
+
+	/*
+	 * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
+	 * from userland.
+	 */
+	mask &= ~STATX_CHANGE_COOKIE;
+
+	error = vfs_statx_fd(fd, flags, &stat, mask);
+	if (error)
+		return error;
+
+	return cp_statx(&stat, buffer);
+}
+
+/**
+ * sys_statx - System call to get enhanced stats
+ * @dfd: Base directory to pathwalk from *or* fd to stat.
+ * @filename: File to stat or either NULL or "" with AT_EMPTY_PATH
+ * @flags: AT_* flags to control pathwalk.
+ * @mask: Parts of statx struct actually required.
+ * @buffer: Result buffer.
+ *
+ * Note that fstat() can be emulated by setting dfd to the fd of interest,
+ * supplying "" (or preferably NULL) as the filename and setting AT_EMPTY_PATH
+ * in the flags.
+ */
+SYSCALL_DEFINE5(statx,
+		int, dfd, const char __user *, filename, unsigned, flags,
+		unsigned int, mask,
+		struct statx __user *, buffer)
+{
+	CLASS(filename_maybe_null, name)(filename, flags);
+
+	if (!name && dfd >= 0)
+		return do_statx_fd(dfd, flags & ~AT_NO_AUTOMOUNT, mask, buffer);
+
+	return do_statx(dfd, name, flags, mask, buffer);
+}
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
+static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
+{
+	struct compat_stat tmp;
+
+	if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
+		return -EOVERFLOW;
+	if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
+		return -EOVERFLOW;
+
+	memset(&tmp, 0, sizeof(tmp));
+	tmp.st_dev = new_encode_dev(stat->dev);
+	tmp.st_ino = stat->ino;
+	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
+		return -EOVERFLOW;
+	tmp.st_mode = stat->mode;
+	tmp.st_nlink = stat->nlink;
+	if (tmp.st_nlink != stat->nlink)
+		return -EOVERFLOW;
+	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
+	tmp.st_rdev = new_encode_dev(stat->rdev);
+	if ((u64) stat->size > MAX_NON_LFS)
+		return -EOVERFLOW;
+	tmp.st_size = stat->size;
+	tmp.st_atime = stat->atime.tv_sec;
+	tmp.st_atime_nsec = stat->atime.tv_nsec;
+	tmp.st_mtime = stat->mtime.tv_sec;
+	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
+	tmp.st_ctime = stat->ctime.tv_sec;
+	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
+	tmp.st_blocks = stat->blocks;
+	tmp.st_blksize = stat->blksize;
+	return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
+}
+
+COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
+		       struct compat_stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_stat(filename, &stat);
+	if (error)
+		return error;
+	return cp_compat_stat(&stat, statbuf);
+}
+
+COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
+		       struct compat_stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_lstat(filename, &stat);
+	if (error)
+		return error;
+	return cp_compat_stat(&stat, statbuf);
+}
+
+#ifndef __ARCH_WANT_STAT64
+COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
+		       const char __user *, filename,
+		       struct compat_stat __user *, statbuf, int, flag)
+{
+	struct kstat stat;
+	int error;
+
+	error = vfs_fstatat(dfd, filename, &stat, flag);
+	if (error)
+		return error;
+	return cp_compat_stat(&stat, statbuf);
+}
+#endif
+
+COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
+		       struct compat_stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error = vfs_fstat(fd, &stat);
+
+	if (!error)
+		error = cp_compat_stat(&stat, statbuf);
+	return error;
+}
+#endif
+
+/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
+void __inode_add_bytes(struct inode *inode, loff_t bytes)
+{
+	inode->i_blocks += bytes >> 9;
+	bytes &= 511;
+	inode->i_bytes += bytes;
+	if (inode->i_bytes >= 512) {
+		inode->i_blocks++;
+		inode->i_bytes -= 512;
+	}
+}
+EXPORT_SYMBOL(__inode_add_bytes);
+
+void inode_add_bytes(struct inode *inode, loff_t bytes)
+{
+	spin_lock(&inode->i_lock);
+	__inode_add_bytes(inode, bytes);
+	spin_unlock(&inode->i_lock);
+}
+
+EXPORT_SYMBOL(inode_add_bytes);
+
+void __inode_sub_bytes(struct inode *inode, loff_t bytes)
+{
+	inode->i_blocks -= bytes >> 9;
+	bytes &= 511;
+	if (inode->i_bytes < bytes) {
+		inode->i_blocks--;
+		inode->i_bytes += 512;
+	}
+	inode->i_bytes -= bytes;
+}
+
+EXPORT_SYMBOL(__inode_sub_bytes);
+
+void inode_sub_bytes(struct inode *inode, loff_t bytes)
+{
+	spin_lock(&inode->i_lock);
+	__inode_sub_bytes(inode, bytes);
+	spin_unlock(&inode->i_lock);
+}
+
+EXPORT_SYMBOL(inode_sub_bytes);
+
+loff_t inode_get_bytes(struct inode *inode)
+{
+	loff_t ret;
+
+	spin_lock(&inode->i_lock);
+	ret = __inode_get_bytes(inode);
+	spin_unlock(&inode->i_lock);
+	return ret;
+}
+
+EXPORT_SYMBOL(inode_get_bytes);
+
+void inode_set_bytes(struct inode *inode, loff_t bytes)
+{
+	/* Caller is here responsible for sufficient locking
+	 * (ie. inode->i_lock) */
+	inode->i_blocks = bytes >> 9;
+	inode->i_bytes = bytes & 511;
+}
+
+EXPORT_SYMBOL(inode_set_bytes);