1 files changed, 273 insertions, 342 deletions

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index c9d0c362c7ef..cbae89457234 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -9,21 +9,11 @@
 #include <linux/xattr.h>
 #include <linux/uio.h>
 #include <linux/uaccess.h>
-#include <linux/splice.h>
 #include <linux/security.h>
-#include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/backing-file.h>
 #include "overlayfs.h"
 
-struct ovl_aio_req {
-	struct kiocb iocb;
-	refcount_t ref;
-	struct kiocb *orig_iocb;
-	struct fd fd;
-};
-
-static struct kmem_cache *ovl_aio_request_cachep;
-
 static char ovl_whatisit(struct inode *inode, struct inode *realinode)
 {
 	if (realinode != ovl_inode_upper(inode))
@@ -34,17 +24,13 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode)
 		return 'm';
 }
 
-/* No atime modification nor notify on underlying */
-#define OVL_OPEN_FLAGS (O_NOATIME | FMODE_NONOTIFY)
-
 static struct file *ovl_open_realfile(const struct file *file,
 				      const struct path *realpath)
 {
 	struct inode *realinode = d_inode(realpath->dentry);
 	struct inode *inode = file_inode(file);
-	struct user_namespace *real_mnt_userns;
+	struct mnt_idmap *real_idmap;
 	struct file *realfile;
-	const struct cred *old_cred;
 	int flags = file->f_flags | OVL_OPEN_FLAGS;
 	int acc_mode = ACC_MODE(flags);
 	int err;
@@ -52,19 +38,19 @@ static struct file *ovl_open_realfile(const struct file *file,
 	if (flags & O_APPEND)
 		acc_mode |= MAY_APPEND;
 
-	old_cred = ovl_override_creds(inode->i_sb);
-	real_mnt_userns = mnt_user_ns(realpath->mnt);
-	err = inode_permission(real_mnt_userns, realinode, MAY_OPEN | acc_mode);
-	if (err) {
-		realfile = ERR_PTR(err);
-	} else {
-		if (!inode_owner_or_capable(real_mnt_userns, realinode))
-			flags &= ~O_NOATIME;
-
-		realfile = open_with_fake_path(&file->f_path, flags, realinode,
-					       current_cred());
+	with_ovl_creds(inode->i_sb) {
+		real_idmap = mnt_idmap(realpath->mnt);
+		err = inode_permission(real_idmap, realinode, MAY_OPEN | acc_mode);
+		if (err) {
+			realfile = ERR_PTR(err);
+		} else {
+			if (!inode_owner_or_capable(real_idmap, realinode))
+				flags &= ~O_NOATIME;
+
+			realfile = backing_file_open(file_user_path(file),
+						     flags, realpath, current_cred());
+		}
 	}
-	revert_creds(old_cred);
 
 	pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
 		 file, file, ovl_whatisit(inode, realinode), file->f_flags,
@@ -102,45 +88,110 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
 	return 0;
 }
 
-static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
-			       bool allow_meta)
+struct ovl_file {
+	struct file *realfile;
+	struct file *upperfile;
+};
+
+struct ovl_file *ovl_file_alloc(struct file *realfile)
 {
-	struct dentry *dentry = file_dentry(file);
-	struct path realpath;
+	struct ovl_file *of = kzalloc(sizeof(struct ovl_file), GFP_KERNEL);
 
-	real->flags = 0;
-	real->file = file->private_data;
+	if (unlikely(!of))
+		return NULL;
 
-	if (allow_meta)
-		ovl_path_real(dentry, &realpath);
-	else
-		ovl_path_realdata(dentry, &realpath);
+	of->realfile = realfile;
+	return of;
+}
+
+void ovl_file_free(struct ovl_file *of)
+{
+	fput(of->realfile);
+	if (of->upperfile)
+		fput(of->upperfile);
+	kfree(of);
+}
+
+static bool ovl_is_real_file(const struct file *realfile,
+			     const struct path *realpath)
+{
+	return file_inode(realfile) == d_inode(realpath->dentry);
+}
+
+static struct file *ovl_real_file_path(const struct file *file,
+				       const struct path *realpath)
+{
+	struct ovl_file *of = file->private_data;
+	struct file *realfile = of->realfile;
 
-	/* Has it been copied up since we'd opened it? */
-	if (unlikely(file_inode(real->file) != d_inode(realpath.dentry))) {
-		real->flags = FDPUT_FPUT;
-		real->file = ovl_open_realfile(file, &realpath);
+	if (WARN_ON_ONCE(!realpath->dentry))
+		return ERR_PTR(-EIO);
 
-		return PTR_ERR_OR_ZERO(real->file);
+	/*
+	 * If the realfile that we want is not where the data used to be at
+	 * open time, either we'd been copied up, or it's an fsync of a
+	 * metacopied file.  We need the upperfile either way, so see if it
+	 * is already opened and if it is not then open and store it.
+	 */
+	if (unlikely(!ovl_is_real_file(realfile, realpath))) {
+		struct file *upperfile = READ_ONCE(of->upperfile);
+		struct file *old;
+
+		if (!upperfile) { /* Nobody opened upperfile yet */
+			upperfile = ovl_open_realfile(file, realpath);
+			if (IS_ERR(upperfile))
+				return upperfile;
+
+			/* Store the upperfile for later */
+			old = cmpxchg_release(&of->upperfile, NULL, upperfile);
+			if (old) { /* Someone opened upperfile before us */
+				fput(upperfile);
+				upperfile = old;
+			}
+		}
+		/*
+		 * Stored file must be from the right inode, unless someone's
+		 * been corrupting the upper layer.
+		 */
+		if (WARN_ON_ONCE(!ovl_is_real_file(upperfile, realpath)))
+			return ERR_PTR(-EIO);
+
+		realfile = upperfile;
 	}
 
 	/* Did the flags change since open? */
-	if (unlikely((file->f_flags ^ real->file->f_flags) & ~OVL_OPEN_FLAGS))
-		return ovl_change_flags(real->file, file->f_flags);
+	if (unlikely((file->f_flags ^ realfile->f_flags) & ~OVL_OPEN_FLAGS)) {
+		int err = ovl_change_flags(realfile, file->f_flags);
 
-	return 0;
+		if (err)
+			return ERR_PTR(err);
+	}
+
+	return realfile;
 }
 
-static int ovl_real_fdget(const struct file *file, struct fd *real)
+static struct file *ovl_real_file(const struct file *file)
 {
-	if (d_is_dir(file_dentry(file))) {
-		real->flags = 0;
-		real->file = ovl_dir_real_file(file, false);
+	struct dentry *dentry = file_dentry(file);
+	struct path realpath;
+	int err;
 
-		return PTR_ERR_OR_ZERO(real->file);
+	if (d_is_dir(dentry)) {
+		struct file *f = ovl_dir_real_file(file, false);
+
+		if (WARN_ON_ONCE(!f))
+			return ERR_PTR(-EIO);
+		return f;
 	}
 
-	return ovl_real_fdget_meta(file, real, false);
+	/* lazy lookup and verify of lowerdata */
+	err = ovl_verify_lowerdata(dentry);
+	if (err)
+		return ERR_PTR(err);
+
+	ovl_path_realdata(dentry, &realpath);
+
+	return ovl_real_file_path(file, &realpath);
 }
 
 static int ovl_open(struct inode *inode, struct file *file)
@@ -148,8 +199,14 @@ static int ovl_open(struct inode *inode, struct file *file)
 	struct dentry *dentry = file_dentry(file);
 	struct file *realfile;
 	struct path realpath;
+	struct ovl_file *of;
 	int err;
 
+	/* lazy lookup and verify lowerdata */
+	err = ovl_verify_lowerdata(dentry);
+	if (err)
+		return err;
+
 	err = ovl_maybe_copy_up(dentry, file->f_flags);
 	if (err)
 		return err;
@@ -158,27 +215,34 @@ static int ovl_open(struct inode *inode, struct file *file)
 	file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
 	ovl_path_realdata(dentry, &realpath);
+	if (!realpath.dentry)
+		return -EIO;
+
 	realfile = ovl_open_realfile(file, &realpath);
 	if (IS_ERR(realfile))
 		return PTR_ERR(realfile);
 
-	file->private_data = realfile;
+	of = ovl_file_alloc(realfile);
+	if (!of) {
+		fput(realfile);
+		return -ENOMEM;
+	}
+
+	file->private_data = of;
 
 	return 0;
 }
 
 static int ovl_release(struct inode *inode, struct file *file)
 {
-	fput(file->private_data);
-
+	ovl_file_free(file->private_data);
 	return 0;
 }
 
 static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct inode *inode = file_inode(file);
-	struct fd real;
-	const struct cred *old_cred;
+	struct file *realfile;
 	loff_t ret;
 
 	/*
@@ -193,9 +257,9 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
 			return vfs_setpos(file, 0, 0);
 	}
 
-	ret = ovl_real_fdget(file, &real);
-	if (ret)
-		return ret;
+	realfile = ovl_real_file(file);
+	if (IS_ERR(realfile))
+		return PTR_ERR(realfile);
 
 	/*
 	 * Overlay file f_pos is the master copy that is preserved
@@ -205,23 +269,33 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
 	 * files, so we use the real file to perform seeks.
 	 */
 	ovl_inode_lock(inode);
-	real.file->f_pos = file->f_pos;
+	realfile->f_pos = file->f_pos;
 
-	old_cred = ovl_override_creds(inode->i_sb);
-	ret = vfs_llseek(real.file, offset, whence);
-	revert_creds(old_cred);
+	with_ovl_creds(inode->i_sb)
+		ret = vfs_llseek(realfile, offset, whence);
 
-	file->f_pos = real.file->f_pos;
+	file->f_pos = realfile->f_pos;
 	ovl_inode_unlock(inode);
 
-	fdput(real);
-
 	return ret;
 }
 
+static void ovl_file_modified(struct file *file)
+{
+	/* Update size/mtime */
+	ovl_copyattr(file_inode(file));
+}
+
+static void ovl_file_end_write(struct kiocb *iocb, ssize_t ret)
+{
+	ovl_file_modified(iocb->ki_filp);
+}
+
 static void ovl_file_accessed(struct file *file)
 {
 	struct inode *inode, *upperinode;
+	struct timespec64 ctime, uctime;
+	struct timespec64 mtime, umtime;
 
 	if (file->f_flags & O_NOATIME)
 		return;
@@ -232,127 +306,50 @@ static void ovl_file_accessed(struct file *file)
 	if (!upperinode)
 		return;
 
-	if ((!timespec64_equal(&inode->i_mtime, &upperinode->i_mtime) ||
-	     !timespec64_equal(&inode->i_ctime, &upperinode->i_ctime))) {
-		inode->i_mtime = upperinode->i_mtime;
-		inode->i_ctime = upperinode->i_ctime;
+	ctime = inode_get_ctime(inode);
+	uctime = inode_get_ctime(upperinode);
+	mtime = inode_get_mtime(inode);
+	umtime = inode_get_mtime(upperinode);
+	if ((!timespec64_equal(&mtime, &umtime)) ||
+	     !timespec64_equal(&ctime, &uctime)) {
+		inode_set_mtime_to_ts(inode, inode_get_mtime(upperinode));
+		inode_set_ctime_to_ts(inode, uctime);
 	}
 
 	touch_atime(&file->f_path);
 }
 
-static rwf_t ovl_iocb_to_rwf(int ifl)
-{
-	rwf_t flags = 0;
-
-	if (ifl & IOCB_NOWAIT)
-		flags |= RWF_NOWAIT;
-	if (ifl & IOCB_HIPRI)
-		flags |= RWF_HIPRI;
-	if (ifl & IOCB_DSYNC)
-		flags |= RWF_DSYNC;
-	if (ifl & IOCB_SYNC)
-		flags |= RWF_SYNC;
-
-	return flags;
-}
-
-static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
-{
-	if (refcount_dec_and_test(&aio_req->ref)) {
-		fdput(aio_req->fd);
-		kmem_cache_free(ovl_aio_request_cachep, aio_req);
-	}
-}
-
-static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
-{
-	struct kiocb *iocb = &aio_req->iocb;
-	struct kiocb *orig_iocb = aio_req->orig_iocb;
-
-	if (iocb->ki_flags & IOCB_WRITE) {
-		struct inode *inode = file_inode(orig_iocb->ki_filp);
-
-		/* Actually acquired in ovl_write_iter() */
-		__sb_writers_acquired(file_inode(iocb->ki_filp)->i_sb,
-				      SB_FREEZE_WRITE);
-		file_end_write(iocb->ki_filp);
-		ovl_copyattr(inode);
-	}
-
-	orig_iocb->ki_pos = iocb->ki_pos;
-	ovl_aio_put(aio_req);
-}
-
-static void ovl_aio_rw_complete(struct kiocb *iocb, long res)
-{
-	struct ovl_aio_req *aio_req = container_of(iocb,
-						   struct ovl_aio_req, iocb);
-	struct kiocb *orig_iocb = aio_req->orig_iocb;
-
-	ovl_aio_cleanup_handler(aio_req);
-	orig_iocb->ki_complete(orig_iocb, res);
-}
-
 static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
-	struct fd real;
-	const struct cred *old_cred;
-	ssize_t ret;
+	struct file *realfile;
+	struct backing_file_ctx ctx = {
+		.cred = ovl_creds(file_inode(file)->i_sb),
+		.accessed = ovl_file_accessed,
+	};
 
 	if (!iov_iter_count(iter))
 		return 0;
 
-	ret = ovl_real_fdget(file, &real);
-	if (ret)
-		return ret;
-
-	ret = -EINVAL;
-	if (iocb->ki_flags & IOCB_DIRECT &&
-	    !(real.file->f_mode & FMODE_CAN_ODIRECT))
-		goto out_fdput;
-
-	old_cred = ovl_override_creds(file_inode(file)->i_sb);
-	if (is_sync_kiocb(iocb)) {
-		ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,
-				    ovl_iocb_to_rwf(iocb->ki_flags));
-	} else {
-		struct ovl_aio_req *aio_req;
-
-		ret = -ENOMEM;
-		aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
-		if (!aio_req)
-			goto out;
-
-		aio_req->fd = real;
-		real.flags = 0;
-		aio_req->orig_iocb = iocb;
-		kiocb_clone(&aio_req->iocb, iocb, real.file);
-		aio_req->iocb.ki_complete = ovl_aio_rw_complete;
-		refcount_set(&aio_req->ref, 2);
-		ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter);
-		ovl_aio_put(aio_req);
-		if (ret != -EIOCBQUEUED)
-			ovl_aio_cleanup_handler(aio_req);
-	}
-out:
-	revert_creds(old_cred);
-	ovl_file_accessed(file);
-out_fdput:
-	fdput(real);
+	realfile = ovl_real_file(file);
+	if (IS_ERR(realfile))
+		return PTR_ERR(realfile);
 
-	return ret;
+	return backing_file_read_iter(realfile, iter, iocb, iocb->ki_flags,
+				      &ctx);
 }
 
 static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
-	struct fd real;
-	const struct cred *old_cred;
+	struct file *realfile;
 	ssize_t ret;
 	int ifl = iocb->ki_flags;
+	struct backing_file_ctx ctx = {
+		.cred = ovl_creds(inode->i_sb),
+		.end_write = ovl_file_end_write,
+	};
 
 	if (!iov_iter_count(iter))
 		return 0;
@@ -360,58 +357,16 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 	inode_lock(inode);
 	/* Update mode */
 	ovl_copyattr(inode);
-	ret = file_remove_privs(file);
-	if (ret)
-		goto out_unlock;
 
-	ret = ovl_real_fdget(file, &real);
-	if (ret)
+	realfile = ovl_real_file(file);
+	ret = PTR_ERR(realfile);
+	if (IS_ERR(realfile))
 		goto out_unlock;
 
-	ret = -EINVAL;
-	if (iocb->ki_flags & IOCB_DIRECT &&
-	    !(real.file->f_mode & FMODE_CAN_ODIRECT))
-		goto out_fdput;
-
 	if (!ovl_should_sync(OVL_FS(inode->i_sb)))
 		ifl &= ~(IOCB_DSYNC | IOCB_SYNC);
 
-	old_cred = ovl_override_creds(file_inode(file)->i_sb);
-	if (is_sync_kiocb(iocb)) {
-		file_start_write(real.file);
-		ret = vfs_iter_write(real.file, iter, &iocb->ki_pos,
-				     ovl_iocb_to_rwf(ifl));
-		file_end_write(real.file);
-		/* Update size */
-		ovl_copyattr(inode);
-	} else {
-		struct ovl_aio_req *aio_req;
-
-		ret = -ENOMEM;
-		aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
-		if (!aio_req)
-			goto out;
-
-		file_start_write(real.file);
-		/* Pacify lockdep, same trick as done in aio_write() */
-		__sb_writers_release(file_inode(real.file)->i_sb,
-				     SB_FREEZE_WRITE);
-		aio_req->fd = real;
-		real.flags = 0;
-		aio_req->orig_iocb = iocb;
-		kiocb_clone(&aio_req->iocb, iocb, real.file);
-		aio_req->iocb.ki_flags = ifl;
-		aio_req->iocb.ki_complete = ovl_aio_rw_complete;
-		refcount_set(&aio_req->ref, 2);
-		ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
-		ovl_aio_put(aio_req);
-		if (ret != -EIOCBQUEUED)
-			ovl_aio_cleanup_handler(aio_req);
-	}
-out:
-	revert_creds(old_cred);
-out_fdput:
-	fdput(real);
+	ret = backing_file_write_iter(realfile, iter, iocb, ifl, &ctx);
 
 out_unlock:
 	inode_unlock(inode);
@@ -419,10 +374,34 @@ out_unlock:
 	return ret;
 }
 
+static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
+			       struct pipe_inode_info *pipe, size_t len,
+			       unsigned int flags)
+{
+	struct file *realfile;
+	ssize_t ret;
+	struct backing_file_ctx ctx = {
+		.cred = ovl_creds(file_inode(in)->i_sb),
+		.accessed = ovl_file_accessed,
+	};
+	struct kiocb iocb;
+
+	realfile = ovl_real_file(in);
+	if (IS_ERR(realfile))
+		return PTR_ERR(realfile);
+
+	init_sync_kiocb(&iocb, in);
+	iocb.ki_pos = *ppos;
+	ret = backing_file_splice_read(realfile, &iocb, pipe, len, flags, &ctx);
+	*ppos = iocb.ki_pos;
+
+	return ret;
+}
+
 /*
  * Calling iter_file_splice_write() directly from overlay's f_op may deadlock
  * due to lock order inversion between pipe->mutex in iter_file_splice_write()
- * and file_start_write(real.file) in ovl_write_iter().
+ * and file_start_write(realfile) in ovl_write_iter().
  *
  * So do everything ovl_write_iter() does and call iter_file_splice_write() on
  * the real file.
@@ -430,32 +409,28 @@ out_unlock:
 static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
 				loff_t *ppos, size_t len, unsigned int flags)
 {
-	struct fd real;
-	const struct cred *old_cred;
+	struct file *realfile;
 	struct inode *inode = file_inode(out);
 	ssize_t ret;
+	struct backing_file_ctx ctx = {
+		.cred = ovl_creds(inode->i_sb),
+		.end_write = ovl_file_end_write,
+	};
+	struct kiocb iocb;
 
 	inode_lock(inode);
 	/* Update mode */
 	ovl_copyattr(inode);
-	ret = file_remove_privs(out);
-	if (ret)
-		goto out_unlock;
 
-	ret = ovl_real_fdget(out, &real);
-	if (ret)
+	realfile = ovl_real_file(out);
+	ret = PTR_ERR(realfile);
+	if (IS_ERR(realfile))
 		goto out_unlock;
 
-	old_cred = ovl_override_creds(inode->i_sb);
-	file_start_write(real.file);
-
-	ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
-
-	file_end_write(real.file);
-	/* Update size */
-	ovl_copyattr(inode);
-	revert_creds(old_cred);
-	fdput(real);
+	init_sync_kiocb(&iocb, out);
+	iocb.ki_pos = *ppos;
+	ret = backing_file_splice_write(pipe, realfile, &iocb, len, flags, &ctx);
+	*ppos = iocb.ki_pos;
 
 out_unlock:
 	inode_unlock(inode);
@@ -465,57 +440,45 @@ out_unlock:
 
 static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
-	struct fd real;
-	const struct cred *old_cred;
+	struct dentry *dentry = file_dentry(file);
+	enum ovl_path_type type;
+	struct path upperpath;
+	struct file *upperfile;
 	int ret;
 
 	ret = ovl_sync_status(OVL_FS(file_inode(file)->i_sb));
 	if (ret <= 0)
 		return ret;
 
-	ret = ovl_real_fdget_meta(file, &real, !datasync);
-	if (ret)
-		return ret;
-
 	/* Don't sync lower file for fear of receiving EROFS error */
-	if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) {
-		old_cred = ovl_override_creds(file_inode(file)->i_sb);
-		ret = vfs_fsync_range(real.file, start, end, datasync);
-		revert_creds(old_cred);
-	}
+	type = ovl_path_type(dentry);
+	if (!OVL_TYPE_UPPER(type) || (datasync && OVL_TYPE_MERGE(type)))
+		return 0;
 
-	fdput(real);
+	ovl_path_upper(dentry, &upperpath);
+	upperfile = ovl_real_file_path(file, &upperpath);
+	if (IS_ERR(upperfile))
+		return PTR_ERR(upperfile);
 
-	return ret;
+	with_ovl_creds(file_inode(file)->i_sb)
+		return vfs_fsync_range(upperfile, start, end, datasync);
 }
 
 static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
 {
-	struct file *realfile = file->private_data;
-	const struct cred *old_cred;
-	int ret;
-
-	if (!realfile->f_op->mmap)
-		return -ENODEV;
-
-	if (WARN_ON(file != vma->vm_file))
-		return -EIO;
-
-	vma_set_file(vma, realfile);
+	struct ovl_file *of = file->private_data;
+	struct backing_file_ctx ctx = {
+		.cred = ovl_creds(file_inode(file)->i_sb),
+		.accessed = ovl_file_accessed,
+	};
 
-	old_cred = ovl_override_creds(file_inode(file)->i_sb);
-	ret = call_mmap(vma->vm_file, vma);
-	revert_creds(old_cred);
-	ovl_file_accessed(file);
-
-	return ret;
+	return backing_file_mmap(of->realfile, vma, &ctx);
 }
 
 static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 {
 	struct inode *inode = file_inode(file);
-	struct fd real;
-	const struct cred *old_cred;
+	struct file *realfile;
 	int ret;
 
 	inode_lock(inode);
@@ -525,18 +488,16 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
 	if (ret)
 		goto out_unlock;
 
-	ret = ovl_real_fdget(file, &real);
-	if (ret)
+	realfile = ovl_real_file(file);
+	ret = PTR_ERR(realfile);
+	if (IS_ERR(realfile))
 		goto out_unlock;
 
-	old_cred = ovl_override_creds(file_inode(file)->i_sb);
-	ret = vfs_fallocate(real.file, mode, offset, len);
-	revert_creds(old_cred);
+	with_ovl_creds(inode->i_sb)
+		ret = vfs_fallocate(realfile, mode, offset, len);
 
 	/* Update size */
-	ovl_copyattr(inode);
-
-	fdput(real);
+	ovl_file_modified(file);
 
 out_unlock:
 	inode_unlock(inode);
@@ -546,21 +507,14 @@ out_unlock:
 
 static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
 {
-	struct fd real;
-	const struct cred *old_cred;
-	int ret;
-
-	ret = ovl_real_fdget(file, &real);
-	if (ret)
-		return ret;
-
-	old_cred = ovl_override_creds(file_inode(file)->i_sb);
-	ret = vfs_fadvise(real.file, offset, len, advice);
-	revert_creds(old_cred);
+	struct file *realfile;
 
-	fdput(real);
+	realfile = ovl_real_file(file);
+	if (IS_ERR(realfile))
+		return PTR_ERR(realfile);
 
-	return ret;
+	with_ovl_creds(file_inode(file)->i_sb)
+		return vfs_fadvise(realfile, offset, len, advice);
 }
 
 enum ovl_copyop {
@@ -574,8 +528,7 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 			    loff_t len, unsigned int flags, enum ovl_copyop op)
 {
 	struct inode *inode_out = file_inode(file_out);
-	struct fd real_in, real_out;
-	const struct cred *old_cred;
+	struct file *realfile_in, *realfile_out;
 	loff_t ret;
 
 	inode_lock(inode_out);
@@ -587,41 +540,38 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 			goto out_unlock;
 	}
 
-	ret = ovl_real_fdget(file_out, &real_out);
-	if (ret)
+	realfile_out = ovl_real_file(file_out);
+	ret = PTR_ERR(realfile_out);
+	if (IS_ERR(realfile_out))
 		goto out_unlock;
 
-	ret = ovl_real_fdget(file_in, &real_in);
-	if (ret) {
-		fdput(real_out);
+	realfile_in = ovl_real_file(file_in);
+	ret = PTR_ERR(realfile_in);
+	if (IS_ERR(realfile_in))
 		goto out_unlock;
-	}
 
-	old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
-	switch (op) {
-	case OVL_COPY:
-		ret = vfs_copy_file_range(real_in.file, pos_in,
-					  real_out.file, pos_out, len, flags);
-		break;
-
-	case OVL_CLONE:
-		ret = vfs_clone_file_range(real_in.file, pos_in,
-					   real_out.file, pos_out, len, flags);
-		break;
-
-	case OVL_DEDUPE:
-		ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
-						real_out.file, pos_out, len,
-						flags);
-		break;
+	with_ovl_creds(file_inode(file_out)->i_sb) {
+		switch (op) {
+		case OVL_COPY:
+			ret = vfs_copy_file_range(realfile_in, pos_in,
+						  realfile_out, pos_out, len, flags);
+			break;
+
+		case OVL_CLONE:
+			ret = vfs_clone_file_range(realfile_in, pos_in,
+						   realfile_out, pos_out, len, flags);
+			break;
+
+		case OVL_DEDUPE:
+			ret = vfs_dedupe_file_range_one(realfile_in, pos_in,
+							realfile_out, pos_out, len,
+							flags);
+			break;
+		}
 	}
-	revert_creds(old_cred);
 
 	/* Update size */
-	ovl_copyattr(inode_out);
-
-	fdput(real_in);
-	fdput(real_out);
+	ovl_file_modified(file_out);
 
 out_unlock:
 	inode_unlock(inode_out);
@@ -666,20 +616,17 @@ static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,
 
 static int ovl_flush(struct file *file, fl_owner_t id)
 {
-	struct fd real;
-	const struct cred *old_cred;
-	int err;
+	struct file *realfile;
+	int err = 0;
 
-	err = ovl_real_fdget(file, &real);
-	if (err)
-		return err;
+	realfile = ovl_real_file(file);
+	if (IS_ERR(realfile))
+		return PTR_ERR(realfile);
 
-	if (real.file->f_op->flush) {
-		old_cred = ovl_override_creds(file_inode(file)->i_sb);
-		err = real.file->f_op->flush(real.file, id);
-		revert_creds(old_cred);
+	if (realfile->f_op->flush) {
+		with_ovl_creds(file_inode(file)->i_sb)
+			err = realfile->f_op->flush(realfile, id);
 	}
-	fdput(real);
 
 	return err;
 }
@@ -695,25 +642,9 @@ const struct file_operations ovl_file_operations = {
 	.fallocate	= ovl_fallocate,
 	.fadvise	= ovl_fadvise,
 	.flush		= ovl_flush,
-	.splice_read    = generic_file_splice_read,
+	.splice_read    = ovl_splice_read,
 	.splice_write   = ovl_splice_write,
 
 	.copy_file_range	= ovl_copy_file_range,
 	.remap_file_range	= ovl_remap_file_range,
 };
-
-int __init ovl_aio_request_cache_init(void)
-{
-	ovl_aio_request_cachep = kmem_cache_create("ovl_aio_req",
-						   sizeof(struct ovl_aio_req),
-						   0, SLAB_HWCACHE_ALIGN, NULL);
-	if (!ovl_aio_request_cachep)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void ovl_aio_request_cache_destroy(void)
-{
-	kmem_cache_destroy(ovl_aio_request_cachep);
-}