ovl: convert ovl_real_fdget_path() callers to ovl_real_file_path()

Stop using struct fd to return a real file from ovl_real_fdget_path(),
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_path(), 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 63804db4a0f4fc258eb6f798a9d200f0b5f25249..a9c26a585b279f78d9252ef3c5aa85902294d375 100644 (file)
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -119,16 +119,14 @@ static bool ovl_is_real_file(const struct file *realfile,
        return file_inode(realfile) == d_inode(realpath->dentry);
 }
 
-static int ovl_real_fdget_path(const struct file *file, struct fd *real,
-                              struct path *realpath)
+static struct file *ovl_real_file_path(const struct file *file,
+                                      struct path *realpath)
 {
        struct ovl_file *of = file->private_data;
        struct file *realfile = of->realfile;
 
-       real->word = 0;
-
        if (WARN_ON_ONCE(!realpath->dentry))
-               return -EIO;
+               return ERR_PTR(-EIO);
 
        /*
         * If the realfile that we want is not where the data used to be at
@@ -143,7 +141,7 @@ static int ovl_real_fdget_path(const struct file *file, struct fd *real,
                if (!upperfile) { /* Nobody opened upperfile yet */
                        upperfile = ovl_open_realfile(file, realpath);
                        if (IS_ERR(upperfile))
-                               return PTR_ERR(upperfile);
+                               return upperfile;
 
                        /* Store the upperfile for later */
                        old = cmpxchg_release(&of->upperfile, NULL, upperfile);
@@ -157,20 +155,23 @@ static int ovl_real_fdget_path(const struct file *file, struct fd *real,
                 * been corrupting the upper layer.
                 */
                if (WARN_ON_ONCE(!ovl_is_real_file(upperfile, realpath)))
-                       return -EIO;
+                       return ERR_PTR(-EIO);
 
                realfile = upperfile;
        }
 
        /* Did the flags change since open? */
-       if (unlikely((file->f_flags ^ realfile->f_flags) & ~OVL_OPEN_FLAGS))
-               return ovl_change_flags(realfile, file->f_flags);
+       if (unlikely((file->f_flags ^ realfile->f_flags) & ~OVL_OPEN_FLAGS)) {
+               int err = ovl_change_flags(realfile, file->f_flags);
 
-       real->word = (unsigned long)realfile;
-       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)
 {
        struct dentry *dentry = file_dentry(file);
        struct path realpath;
@@ -178,20 +179,30 @@ static int ovl_real_fdget(const struct file *file, struct fd *real)
 
        if (d_is_dir(dentry)) {
                struct file *f = ovl_dir_real_file(file, false);
-               if (IS_ERR(f))
-                       return PTR_ERR(f);
-               real->word = (unsigned long)f;
-               return 0;
+
+               if (WARN_ON_ONCE(!f))
+                       return ERR_PTR(-EIO);
+               return f;
        }
 
        /* lazy lookup and verify of lowerdata */
        err = ovl_verify_lowerdata(dentry);
        if (err)
-               return err;
+               return ERR_PTR(err);
 
        ovl_path_realdata(dentry, &realpath);
 
-       return ovl_real_fdget_path(file, real, &realpath);
+       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)
@@ -458,7 +469,7 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
        struct dentry *dentry = file_dentry(file);
        enum ovl_path_type type;
        struct path upperpath;
-       struct fd real;
+       struct file *upperfile;
        const struct cred *old_cred;
        int ret;
 
@@ -472,16 +483,14 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
                return 0;
 
        ovl_path_upper(dentry, &upperpath);
-       ret = ovl_real_fdget_path(file, &real, &upperpath);
-       if (ret)
-               return ret;
+       upperfile = ovl_real_file_path(file, &upperpath);
+       if (IS_ERR(upperfile))
+               return PTR_ERR(upperfile);
 
        old_cred = ovl_override_creds(file_inode(file)->i_sb);
-       ret = vfs_fsync_range(fd_file(real), start, end, datasync);
+       ret = vfs_fsync_range(upperfile, start, end, datasync);
        ovl_revert_creds(old_cred);
 
-       fdput(real);
-
        return ret;
 }