Unionfs: ->open cleanup and fixes

Cleanup the code from repeated references the same dentry/mnt.
In __open_dir get lower_mnt from parent if can't find it from child.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>

diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index cd5c3048a39ed9778136f5781ec35f39f80157d1..71cacfe9f9282176d67a9e4e4f7a7b8de812d494 100644 (file)
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -438,31 +438,36 @@ out:
 }
 
 /* unionfs_open helper function: open a directory */
-static int __open_dir(struct inode *inode, struct file *file)
+static int __open_dir(struct inode *inode, struct file *file,
+                     struct dentry *parent)
 {
        struct dentry *lower_dentry;
        struct file *lower_file;
        int bindex, bstart, bend;
-       struct vfsmount *mnt;
+       struct vfsmount *lower_mnt;
+       struct dentry *dentry = file->f_path.dentry;
 
-       bstart = fbstart(file) = dbstart(file->f_path.dentry);
-       bend = fbend(file) = dbend(file->f_path.dentry);
+       bstart = fbstart(file) = dbstart(dentry);
+       bend = fbend(file) = dbend(dentry);
 
        for (bindex = bstart; bindex <= bend; bindex++) {
                lower_dentry =
-                       unionfs_lower_dentry_idx(file->f_path.dentry, bindex);
+                       unionfs_lower_dentry_idx(dentry, bindex);
                if (!lower_dentry)
                        continue;
 
                dget(lower_dentry);
-               unionfs_mntget(file->f_path.dentry, bindex);
-               mnt = unionfs_lower_mnt_idx(file->f_path.dentry, bindex);
-               lower_file = dentry_open(lower_dentry, mnt, file->f_flags,
+               lower_mnt = unionfs_mntget(dentry, bindex);
+               if (!lower_mnt)
+                       lower_mnt = unionfs_mntget(parent, bindex);
+               lower_file = dentry_open(lower_dentry, lower_mnt, file->f_flags,
                                         current_cred());
                if (IS_ERR(lower_file))
                        return PTR_ERR(lower_file);
 
                unionfs_set_lower_file_idx(file, bindex, lower_file);
+               if (!unionfs_lower_mnt_idx(dentry, bindex))
+                       unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
 
                /*
                 * The branchget goes after the open, because otherwise
@@ -482,18 +487,20 @@ static int __open_file(struct inode *inode, struct file *file,
        struct file *lower_file;
        int lower_flags;
        int bindex, bstart, bend;
+       struct dentry *dentry = file->f_path.dentry;
+       struct vfsmount *lower_mnt;
 
-       lower_dentry = unionfs_lower_dentry(file->f_path.dentry);
+       lower_dentry = unionfs_lower_dentry(dentry);
        lower_flags = file->f_flags;
 
-       bstart = fbstart(file) = dbstart(file->f_path.dentry);
-       bend = fbend(file) = dbend(file->f_path.dentry);
+       bstart = fbstart(file) = dbstart(dentry);
+       bend = fbend(file) = dbend(dentry);
 
        /*
         * check for the permission for lower file.  If the error is
         * COPYUP_ERR, copyup the file.
         */
-       if (lower_dentry->d_inode && is_robranch(file->f_path.dentry)) {
+       if (lower_dentry->d_inode && is_robranch(dentry)) {
                /*
                 * if the open will change the file, copy it up otherwise
                 * defer it.
@@ -528,11 +535,9 @@ static int __open_file(struct inode *inode, struct file *file,
         * dentry_open will decrement mnt refcnt if err.
         * otherwise fput() will do an mntput() for us upon file close.
         */
-       unionfs_mntget(file->f_path.dentry, bstart);
-       lower_file =
-               dentry_open(lower_dentry,
-                           unionfs_lower_mnt_idx(file->f_path.dentry, bstart),
-                           lower_flags, current_cred());
+       lower_mnt = unionfs_mntget(dentry, bstart);
+       lower_file = dentry_open(lower_dentry, lower_mnt, lower_flags,
+                                current_cred());
        if (IS_ERR(lower_file))
                return PTR_ERR(lower_file);
 
@@ -601,7 +606,7 @@ int unionfs_open(struct inode *inode, struct file *file)
         * these lower file structs
         */
        if (S_ISDIR(inode->i_mode))
-               err = __open_dir(inode, file);  /* open a dir */
+               err = __open_dir(inode, file, parent); /* open a dir */
        else
                err = __open_file(inode, file, parent); /* open a file */