1 files changed, 374 insertions, 122 deletions

diff --git a/fs/stat.c b/fs/stat.c
index c35610845ab1..6c79661e1b96 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -1,9 +1,11 @@
+// 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>
@@ -16,48 +18,159 @@
 #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->i_ctime_sec;
+	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
- * @inode: Inode to use as the source
- * @stat: Where to fill in the attributes
+ * @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 inode *inode, struct kstat *stat)
+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 = inode->i_uid;
-	stat->gid = inode->i_gid;
+	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->i_atime;
-	stat->mtime = inode->i_mtime;
-	stat->ctime = inode->i_ctime;
+	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 (IS_NOATIME(inode))
-		stat->result_mask &= ~STATX_ATIME;
-	if (IS_AUTOMOUNT(inode))
-		stat->attributes |= STATX_ATTR_AUTOMOUNT;
+	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 (KSTAT_QUERY_FLAGS)
+ * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
  *
  * Get attributes without calling security_inode_getattr.
  *
@@ -68,17 +181,51 @@ EXPORT_SYMBOL(generic_fillattr);
 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;
-	request_mask &= STATX_ALL;
-	query_flags &= KSTAT_QUERY_FLAGS;
-	if (inode->i_op->getattr)
-		return inode->i_op->getattr(path, stat, request_mask,
-					    query_flags);
+	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);
 
-	generic_fillattr(inode, stat);
 	return 0;
 }
 EXPORT_SYMBOL(vfs_getattr_nosec);
@@ -88,7 +235,7 @@ EXPORT_SYMBOL(vfs_getattr_nosec);
  * @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 (KSTAT_QUERY_FLAGS)
+ * @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.
@@ -110,42 +257,71 @@ int vfs_getattr(const struct path *path, struct kstat *stat,
 	int retval;
 
 	retval = security_inode_getattr(path);
-	if (retval)
+	if (unlikely(retval))
 		return retval;
 	return vfs_getattr_nosec(path, stat, request_mask, query_flags);
 }
 EXPORT_SYMBOL(vfs_getattr);
 
 /**
- * vfs_statx_fd - Get the enhanced basic attributes by file descriptor
+ * 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.
- * @request_mask: STATX_xxx flags indicating what the caller wants
- * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
  *
  * 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_statx_fd(unsigned int fd, struct kstat *stat,
-		 u32 request_mask, unsigned int query_flags)
+int vfs_fstat(int fd, struct kstat *stat)
 {
-	struct fd f;
-	int error = -EBADF;
+	CLASS(fd_raw, f)(fd);
+	if (fd_empty(f))
+		return -EBADF;
+	return vfs_getattr(&fd_file(f)->f_path, stat, STATX_BASIC_STATS, 0);
+}
 
-	if (query_flags & ~KSTAT_QUERY_FLAGS)
-		return -EINVAL;
+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;
 
-	f = fdget_raw(fd);
-	if (f.file) {
-		error = vfs_getattr(&f.file->f_path, stat,
-				    request_mask, query_flags);
-		fdput(f);
+	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;
 	}
-	return error;
+
+	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);
 }
-EXPORT_SYMBOL(vfs_statx_fd);
 
 /**
  * vfs_statx - Get basic and extra attributes by filename
@@ -162,40 +338,45 @@ EXPORT_SYMBOL(vfs_statx_fd);
  *
  * 0 will be returned on success, and a -ve error code if unsuccessful.
  */
-int vfs_statx(int dfd, const char __user *filename, int flags,
+static int vfs_statx(int dfd, struct filename *filename, int flags,
 	      struct kstat *stat, u32 request_mask)
 {
 	struct path path;
-	int error = -EINVAL;
-	unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
+	unsigned int lookup_flags = statx_lookup_flags(flags);
+	int error;
 
-	if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
-		       AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
+	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
+		      AT_STATX_SYNC_TYPE))
 		return -EINVAL;
 
-	if (flags & AT_SYMLINK_NOFOLLOW)
-		lookup_flags &= ~LOOKUP_FOLLOW;
-	if (flags & AT_NO_AUTOMOUNT)
-		lookup_flags &= ~LOOKUP_AUTOMOUNT;
-	if (flags & AT_EMPTY_PATH)
-		lookup_flags |= LOOKUP_EMPTY;
-
 retry:
-	error = user_path_at(dfd, filename, lookup_flags, &path);
+	error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
 	if (error)
-		goto out;
-
-	error = vfs_getattr(&path, stat, request_mask, flags);
+		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;
 	}
-out:
 	return error;
 }
-EXPORT_SYMBOL(vfs_statx);
 
+int vfs_fstatat(int dfd, const char __user *filename,
+			      struct kstat *stat, int flags)
+{
+	int ret;
+	int statx_flags = flags | AT_NO_AUTOMOUNT;
+	struct filename *name = getname_maybe_null(filename, flags);
+
+	if (!name && dfd >= 0)
+		return vfs_fstat(dfd, stat);
+
+	ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS);
+	putname(name);
+
+	return ret;
+}
 
 #ifdef __ARCH_WANT_OLD_STAT
 
@@ -247,7 +428,7 @@ SYSCALL_DEFINE2(stat, const char __user *, filename,
 	int error;
 
 	error = vfs_stat(filename, &stat);
-	if (error)
+	if (unlikely(error))
 		return error;
 
 	return cp_old_stat(&stat, statbuf);
@@ -260,7 +441,7 @@ SYSCALL_DEFINE2(lstat, const char __user *, filename,
 	int error;
 
 	error = vfs_lstat(filename, &stat);
-	if (error)
+	if (unlikely(error))
 		return error;
 
 	return cp_old_stat(&stat, statbuf);
@@ -269,24 +450,18 @@ SYSCALL_DEFINE2(lstat, const char __user *, filename,
 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
 {
 	struct kstat stat;
-	int error = vfs_fstat(fd, &stat);
+	int error;
 
-	if (!error)
-		error = cp_old_stat(&stat, statbuf);
+	error = vfs_fstat(fd, &stat);
+	if (unlikely(error))
+		return error;
 
-	return error;
+	return cp_old_stat(&stat, statbuf);
 }
 
 #endif /* __ARCH_WANT_OLD_STAT */
 
-#if BITS_PER_LONG == 32
-#  define choose_32_64(a,b) a
-#else
-#  define choose_32_64(a,b) b
-#endif
-
-#define valid_dev(x)  choose_32_64(old_valid_dev(x),true)
-#define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)
+#ifdef __ARCH_WANT_NEW_STAT
 
 #ifndef INIT_STRUCT_STAT_PADDING
 #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
@@ -296,7 +471,9 @@ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 {
 	struct stat tmp;
 
-	if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
+	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)
@@ -304,7 +481,7 @@ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 #endif
 
 	INIT_STRUCT_STAT_PADDING(tmp);
-	tmp.st_dev = encode_dev(stat->dev);
+	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;
@@ -314,7 +491,7 @@ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 		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 = encode_dev(stat->rdev);
+	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;
@@ -333,10 +510,12 @@ SYSCALL_DEFINE2(newstat, const char __user *, filename,
 		struct stat __user *, statbuf)
 {
 	struct kstat stat;
-	int error = vfs_stat(filename, &stat);
+	int error;
 
-	if (error)
+	error = vfs_stat(filename, &stat);
+	if (unlikely(error))
 		return error;
+
 	return cp_new_stat(&stat, statbuf);
 }
 
@@ -347,7 +526,7 @@ SYSCALL_DEFINE2(newlstat, const char __user *, filename,
 	int error;
 
 	error = vfs_lstat(filename, &stat);
-	if (error)
+	if (unlikely(error))
 		return error;
 
 	return cp_new_stat(&stat, statbuf);
@@ -361,8 +540,9 @@ SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
 	int error;
 
 	error = vfs_fstatat(dfd, filename, &stat, flag);
-	if (error)
+	if (unlikely(error))
 		return error;
+
 	return cp_new_stat(&stat, statbuf);
 }
 #endif
@@ -370,54 +550,67 @@ SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
 {
 	struct kstat stat;
-	int error = vfs_fstat(fd, &stat);
+	int error;
 
-	if (!error)
-		error = cp_new_stat(&stat, statbuf);
+	error = vfs_fstat(fd, &stat);
+	if (unlikely(error))
+		return error;
 
-	return error;
+	return cp_new_stat(&stat, statbuf);
 }
+#endif
 
-SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
-		char __user *, buf, int, bufsiz)
+static int do_readlinkat(int dfd, const char __user *pathname,
+			 char __user *buf, int bufsiz)
 {
 	struct path path;
+	struct filename *name;
 	int error;
-	int empty = 0;
 	unsigned int lookup_flags = LOOKUP_EMPTY;
 
 	if (bufsiz <= 0)
 		return -EINVAL;
 
 retry:
-	error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
-	if (!error) {
-		struct inode *inode = d_backing_inode(path.dentry);
-
-		error = empty ? -ENOENT : -EINVAL;
-		/*
-		 * AFS mountpoints allow readlink(2) but are not symlinks
-		 */
-		if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
-			error = security_inode_readlink(path.dentry);
-			if (!error) {
-				touch_atime(&path);
-				error = vfs_readlink(path.dentry, buf, bufsiz);
-			}
-		}
-		path_put(&path);
-		if (retry_estale(error, lookup_flags)) {
-			lookup_flags |= LOOKUP_REVAL;
-			goto retry;
+	name = getname_flags(pathname, lookup_flags);
+	error = filename_lookup(dfd, name, lookup_flags, &path, NULL);
+	if (unlikely(error)) {
+		putname(name);
+		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);
+	putname(name);
+	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 sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
+	return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
 }
 
 
@@ -518,9 +711,11 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
 
 	memset(&tmp, 0, sizeof(tmp));
 
-	tmp.stx_mask = stat->result_mask;
+	/* STATX_CHANGE_COOKIE is kernel-only for now */
+	tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
 	tmp.stx_blksize = stat->blksize;
-	tmp.stx_attributes = stat->attributes;
+	/* 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);
@@ -541,51 +736,108 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
 	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 "" with AT_EMPTY_PATH
+ * @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 "" as the filename and setting AT_EMPTY_PATH in the flags.
+ * 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)
 {
-	struct kstat stat;
-	int error;
+	int ret;
+	struct filename *name = getname_maybe_null(filename, flags);
 
-	if (mask & STATX__RESERVED)
-		return -EINVAL;
-	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
-		return -EINVAL;
+	if (!name && dfd >= 0)
+		return do_statx_fd(dfd, flags & ~AT_NO_AUTOMOUNT, mask, buffer);
 
-	error = vfs_statx(dfd, filename, flags, &stat, mask);
-	if (error)
-		return error;
+	ret = do_statx(dfd, name, flags, mask, buffer);
+	putname(name);
 
-	return cp_statx(&stat, buffer);
+	return ret;
 }
 
-#ifdef CONFIG_COMPAT
+#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 (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
+	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 = old_encode_dev(stat->dev);
+	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;
@@ -595,7 +847,7 @@ static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
 		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);
+	tmp.st_rdev = new_encode_dev(stat->rdev);
 	if ((u64) stat->size > MAX_NON_LFS)
 		return -EOVERFLOW;
 	tmp.st_size = stat->size;
@@ -710,7 +962,7 @@ loff_t inode_get_bytes(struct inode *inode)
 	loff_t ret;
 
 	spin_lock(&inode->i_lock);
-	ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
+	ret = __inode_get_bytes(inode);
 	spin_unlock(&inode->i_lock);
 	return ret;
 }