ovl: convert ovl_real_fdget() callers to ovl_real_file()

Stop using struct fd to return a real file from ovl_real_fdget(),
because we no longer return a temporary file object and the callers
always get a borrowed file reference.

Rename the helper to ovl_real_file(), return a borrowed reference of
the real file that is referenced from the overlayfs file or an error.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index a9c26a5..969b458 100644 (file)
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -195,16 +195,6 @@ static struct file *ovl_real_file(const struct file *file)
        return ovl_real_file_path(file, &realpath);
 }
 
-static int ovl_real_fdget(const struct file *file, struct fd *real)
-{
-       struct file *f = ovl_real_file(file);
-
-       if (IS_ERR(f))
-               return PTR_ERR(f);
-       real->word = (unsigned long)f;
-       return 0;
-}
-
 static int ovl_open(struct inode *inode, struct file *file)
 {
        struct dentry *dentry = file_dentry(file);
@@ -253,7 +243,7 @@ static int ovl_release(struct inode *inode, struct file *file)
 static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
 {
        struct inode *inode = file_inode(file);
-       struct fd real;
+       struct file *realfile;
        const struct cred *old_cred;
        loff_t ret;
 
@@ -269,9 +259,9 @@ 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
@@ -281,17 +271,15 @@ 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);
-       fd_file(real)->f_pos = file->f_pos;
+       realfile->f_pos = file->f_pos;
 
        old_cred = ovl_override_creds(inode->i_sb);
-       ret = vfs_llseek(fd_file(real), offset, whence);
+       ret = vfs_llseek(realfile, offset, whence);
        ovl_revert_creds(old_cred);
 
-       file->f_pos = fd_file(real)->f_pos;
+       file->f_pos = realfile->f_pos;
        ovl_inode_unlock(inode);
 
-       fdput(real);
-
        return ret;
 }
 
@@ -337,8 +325,7 @@ static void ovl_file_accessed(struct file *file)
 static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
        struct file *file = iocb->ki_filp;
-       struct fd real;
-       ssize_t ret;
+       struct file *realfile;
        struct backing_file_ctx ctx = {
                .cred = ovl_creds(file_inode(file)->i_sb),
                .accessed = ovl_file_accessed,
@@ -347,22 +334,19 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
        if (!iov_iter_count(iter))
                return 0;
 
-       ret = ovl_real_fdget(file, &real);
-       if (ret)
-               return ret;
-
-       ret = backing_file_read_iter(fd_file(real), iter, iocb, iocb->ki_flags,
-                                    &ctx);
-       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;
+       struct file *realfile;
        ssize_t ret;
        int ifl = iocb->ki_flags;
        struct backing_file_ctx ctx = {
@@ -377,8 +361,9 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
        /* Update mode */
        ovl_copyattr(inode);
 
-       ret = ovl_real_fdget(file, &real);
-       if (ret)
+       realfile = ovl_real_file(file);
+       ret = PTR_ERR(realfile);
+       if (IS_ERR(realfile))
                goto out_unlock;
 
        if (!ovl_should_sync(OVL_FS(inode->i_sb)))
@@ -389,8 +374,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
         * this property in case it is set by the issuer.
         */
        ifl &= ~IOCB_DIO_CALLER_COMP;
-       ret = backing_file_write_iter(fd_file(real), iter, iocb, ifl, &ctx);
-       fdput(real);
+       ret = backing_file_write_iter(realfile, iter, iocb, ifl, &ctx);
 
 out_unlock:
        inode_unlock(inode);
@@ -402,7 +386,7 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
                               struct pipe_inode_info *pipe, size_t len,
                               unsigned int flags)
 {
-       struct fd real;
+       struct file *realfile;
        ssize_t ret;
        struct backing_file_ctx ctx = {
                .cred = ovl_creds(file_inode(in)->i_sb),
@@ -410,15 +394,14 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
        };
        struct kiocb iocb;
 
-       ret = ovl_real_fdget(in, &real);
-       if (ret)
-               return ret;
+       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(fd_file(real), &iocb, pipe, len, flags, &ctx);
+       ret = backing_file_splice_read(realfile, &iocb, pipe, len, flags, &ctx);
        *ppos = iocb.ki_pos;
-       fdput(real);
 
        return ret;
 }
@@ -426,7 +409,7 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
 /*
  * 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(fd_file(real)) 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.
@@ -434,7 +417,7 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
 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;
+       struct file *realfile;
        struct inode *inode = file_inode(out);
        ssize_t ret;
        struct backing_file_ctx ctx = {
@@ -447,16 +430,15 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
        /* Update mode */
        ovl_copyattr(inode);
 
-       ret = ovl_real_fdget(out, &real);
-       if (ret)
+       realfile = ovl_real_file(out);
+       ret = PTR_ERR(realfile);
+       if (IS_ERR(realfile))
                goto out_unlock;
 
        init_sync_kiocb(&iocb, out);
        iocb.ki_pos = *ppos;
-       ret = backing_file_splice_write(pipe, fd_file(real), &iocb, len, flags, &ctx);
+       ret = backing_file_splice_write(pipe, realfile, &iocb, len, flags, &ctx);
        *ppos = iocb.ki_pos;
-       fdput(real);
-
 
 out_unlock:
        inode_unlock(inode);
@@ -508,7 +490,7 @@ static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
 static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 {
        struct inode *inode = file_inode(file);
-       struct fd real;
+       struct file *realfile;
        const struct cred *old_cred;
        int ret;
 
@@ -519,19 +501,18 @@ 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(fd_file(real), mode, offset, len);
+       ret = vfs_fallocate(realfile, mode, offset, len);
        ovl_revert_creds(old_cred);
 
        /* Update size */
        ovl_file_modified(file);
 
-       fdput(real);
-
 out_unlock:
        inode_unlock(inode);
 
@@ -540,20 +521,18 @@ out_unlock:
 
 static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
 {
-       struct fd real;
+       struct file *realfile;
        const struct cred *old_cred;
        int ret;
 
-       ret = ovl_real_fdget(file, &real);
-       if (ret)
-               return ret;
+       realfile = ovl_real_file(file);
+       if (IS_ERR(realfile))
+               return PTR_ERR(realfile);
 
        old_cred = ovl_override_creds(file_inode(file)->i_sb);
-       ret = vfs_fadvise(fd_file(real), offset, len, advice);
+       ret = vfs_fadvise(realfile, offset, len, advice);
        ovl_revert_creds(old_cred);
 
-       fdput(real);
-
        return ret;
 }
 
@@ -568,7 +547,7 @@ 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;
+       struct file *realfile_in, *realfile_out;
        const struct cred *old_cred;
        loff_t ret;
 
@@ -581,31 +560,31 @@ 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(fd_file(real_in), pos_in,
-                                         fd_file(real_out), pos_out, len, flags);
+               ret = vfs_copy_file_range(realfile_in, pos_in,
+                                         realfile_out, pos_out, len, flags);
                break;
 
        case OVL_CLONE:
-               ret = vfs_clone_file_range(fd_file(real_in), pos_in,
-                                          fd_file(real_out), pos_out, len, flags);
+               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(fd_file(real_in), pos_in,
-                                               fd_file(real_out), pos_out, len,
+               ret = vfs_dedupe_file_range_one(realfile_in, pos_in,
+                                               realfile_out, pos_out, len,
                                                flags);
                break;
        }
@@ -614,9 +593,6 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
        /* Update size */
        ovl_file_modified(file_out);
 
-       fdput(real_in);
-       fdput(real_out);
-
 out_unlock:
        inode_unlock(inode_out);
 
@@ -660,20 +636,19 @@ 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;
+       struct file *realfile;
        const struct cred *old_cred;
-       int err;
+       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 (fd_file(real)->f_op->flush) {
+       if (realfile->f_op->flush) {
                old_cred = ovl_override_creds(file_inode(file)->i_sb);
-               err = fd_file(real)->f_op->flush(fd_file(real), id);
+               err = realfile->f_op->flush(realfile, id);
                ovl_revert_creds(old_cred);
        }
-       fdput(real);
 
        return err;
 }