GIT: unionfs2-2.6.27.y: Unionfs: imported fixes from korg branch's take-3 series

Erez Zadok ezk at fsl.cs.sunysb.edu
Thu Aug 12 23:16:55 EDT 2010


commit 4ec752ccda266fc332e6211504844a9cf357669d
Author: Erez_Zadok <ezk at cs.sunysb.edu>
Date:   Wed Aug 22 16:49:09 2007 -0400

    Unionfs: imported fixes from korg branch's take-3 series
    
    - removed EACCES/EROFS text from issues.txt
    - updated sioq.[hc] copyright dates to 2006 (not earlier)
    - added small XXX comment to xattr copyup code (selinux CAP_FOWNER stuff) to
      say that entire copyup code should be moved to SIOQ.
    - copyup_xattr: renamed name_list_orig -> name_list_buf
    - multi-line static inline unionfs_xattr_kfree
    - rewrote unionfs_interpose a bit cleaner (no backward goto's, better
      variable names, use small util fxn, etc.)
    - introduced CONFIG_UNION_FS_DEBUG instead of hand-editing makefile
    - unionfs_mntget/put cleanups
    - bug fix to is_robranch_idx (thanks to Patrick Aussems).  Fixed bug #571.
    - fixed a couple of important bugs in our init/release_lower_nd
    
    Signed-off-by: Erez Zadok <ezk at cs.sunysb.edu>

diff --git a/Documentation/filesystems/unionfs/issues.txt b/Documentation/filesystems/unionfs/issues.txt
index 3644fea..6101ebf 100644
--- a/Documentation/filesystems/unionfs/issues.txt
+++ b/Documentation/filesystems/unionfs/issues.txt
@@ -1,10 +1,7 @@
-KNOWN Unionfs 2.0 ISSUES:
+KNOWN Unionfs 2.1 ISSUES:
 =========================
 
-1. The NFS server returns -EACCES for read-only exports, instead of -EROFS.
-   This means we can't reliably detect a read-only NFS export.
-
-2. Unionfs should not use lookup_one_len() on the underlying f/s as it
+1. Unionfs should not use lookup_one_len() on the underlying f/s as it
    confuses NFSv4.  Currently, unionfs_lookup() passes lookup intents to the
    lower file-system, this eliminates part of the problem.  The remaining
    calls to lookup_one_len may need to be changed to pass an intent.  We are
diff --git a/fs/Kconfig b/fs/Kconfig
index 0390a16..b944140 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1013,6 +1013,12 @@ config UNION_FS_XATTR
 
 	  If unsure, say N.
 
+config UNION_FS_DEBUG
+	bool "Debug Unionfs"
+	depends on UNION_FS
+	help
+	  If you say Y here, you can turn on debugging output from Unionfs.
+
 endmenu
 
 menu "Miscellaneous filesystems"
diff --git a/fs/stack.c b/fs/stack.c
index 56fd0df..a548aac 100644
--- a/fs/stack.c
+++ b/fs/stack.c
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2003-2007 Erez Zadok
- * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
- * Copyright (c) 2003-2007 Stony Brook University
- * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ * Copyright (c) 2006-2007 Erez Zadok
+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2006-2007 Stony Brook University
+ * Copyright (c) 2006-2007 The Research Foundation of SUNY
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
diff --git a/fs/unionfs/Makefile b/fs/unionfs/Makefile
index f798b31..12ba9fa 100644
--- a/fs/unionfs/Makefile
+++ b/fs/unionfs/Makefile
@@ -10,14 +10,4 @@ unionfs-y := subr.o dentry.o file.o inode.o main.o super.o \
 
 unionfs-$(CONFIG_UNION_FS_XATTR) += xattr.o
 
-# If you want debugging output, please uncomment the following line
-# or put your options in a separate file in linux-x.y.z/fs/unionfs/local.mk
-#CONFIG_UNIONFS_DEBUG=y
-
-# Allow users to override debug options in a separate file
--include fs/unionfs/local.mk
-
-ifeq ($(CONFIG_UNIONFS_DEBUG),y)
-unionfs-y += debug.o
-EXTRA_CFLAGS += -DUNIONFS_DEBUG=1
-endif
+unionfs-$(CONFIG_UNION_FS_DEBUG) += debug.o
diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index 86b1477..23ac4c8 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -32,7 +32,7 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
 	ssize_t list_size = -1;
 	char *name_list = NULL;
 	char *attr_value = NULL;
-	char *name_list_orig = NULL;
+	char *name_list_buf = NULL;
 
 	/* query the actual size of the xattr list */
 	list_size = vfs_listxattr(old_lower_dentry, NULL, 0);
@@ -48,7 +48,7 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
 		goto out;
 	}
 
-	name_list_orig = name_list; /* save for kfree at end */
+	name_list_buf = name_list; /* save for kfree at end */
 
 	/* now get the actual xattr list of the source file */
 	list_size = vfs_listxattr(old_lower_dentry, name_list, list_size);
@@ -89,6 +89,7 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
 		 * the security of copied-up files, if Selinux is active,
 		 * then we must copy these xattrs as well.  So we need to
 		 * temporarily get FOWNER privileges.
+		 * XXX: move entire copyup code to SIOQ.
 		 */
 		if (err == -EPERM && !capable(CAP_FOWNER)) {
 			cap_raise(current->cap_effective, CAP_FOWNER);
@@ -101,7 +102,7 @@ static int copyup_xattrs(struct dentry *old_lower_dentry,
 		name_list += strlen(name_list) + 1;
 	}
 out:
-	unionfs_xattr_kfree(name_list_orig);
+	unionfs_xattr_kfree(name_list_buf);
 	unionfs_xattr_kfree(attr_value);
 	/* Ignore if xattr isn't supported */
 	if (err == -ENOTSUPP || err == -EOPNOTSUPP)
diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c
index d36f097..7fa6310 100644
--- a/fs/unionfs/lookup.c
+++ b/fs/unionfs/lookup.c
@@ -586,6 +586,8 @@ int init_lower_nd(struct nameidata *nd, unsigned int flags)
 	struct file *file;
 #endif /* ALLOC_LOWER_ND_FILE */
 
+	memset(nd, 0, sizeof(struct nameidata));
+
 	switch (flags) {
 	case LOOKUP_CREATE:
 		nd->flags = LOOKUP_CREATE;
@@ -613,9 +615,11 @@ int init_lower_nd(struct nameidata *nd, unsigned int flags)
 
 void release_lower_nd(struct nameidata *nd, int err)
 {
-	if (nd->intent.open.file)
+	if (!nd->intent.open.file)
 		return;
 	if (!err)
 		release_open_intent(nd);
+#ifdef ALLOC_LOWER_ND_FILE
 	kfree(nd->intent.open.file);
+#endif /* ALLOC_LOWER_ND_FILE */
 }
diff --git a/fs/unionfs/main.c b/fs/unionfs/main.c
index 58c2897..4faae44 100644
--- a/fs/unionfs/main.c
+++ b/fs/unionfs/main.c
@@ -20,6 +20,58 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 
+static void unionfs_fill_inode(struct dentry *dentry,
+			       struct inode *inode)
+{
+	struct inode *lower_inode;
+	struct dentry *lower_dentry;
+	int bindex, bstart, bend;
+
+	bstart = dbstart(dentry);
+	bend = dbend(dentry);
+
+	for (bindex = bstart; bindex <= bend; bindex++) {
+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+		if (!lower_dentry) {
+			unionfs_set_lower_inode_idx(inode, bindex, NULL);
+			continue;
+		}
+
+		/* Initialize the lower inode to the new lower inode. */
+		if (!lower_dentry->d_inode)
+			continue;
+
+		unionfs_set_lower_inode_idx(inode, bindex,
+					    igrab(lower_dentry->d_inode));
+	}
+
+	ibstart(inode) = dbstart(dentry);
+	ibend(inode) = dbend(dentry);
+
+	/* Use attributes from the first branch. */
+	lower_inode = unionfs_lower_inode(inode);
+
+	/* Use different set of inode ops for symlinks & directories */
+	if (S_ISLNK(lower_inode->i_mode))
+		inode->i_op = &unionfs_symlink_iops;
+	else if (S_ISDIR(lower_inode->i_mode))
+		inode->i_op = &unionfs_dir_iops;
+
+	/* Use different set of file ops for directories */
+	if (S_ISDIR(lower_inode->i_mode))
+		inode->i_fop = &unionfs_dir_fops;
+
+	/* properly initialize special inodes */
+	if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
+	    S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(lower_inode->i_mode))
+		init_special_inode(inode, lower_inode->i_mode,
+				   lower_inode->i_rdev);
+
+	/* all well, copy inode attributes */
+	unionfs_copy_attr_all(inode, lower_inode);
+	fsstack_copy_inode_size(inode, lower_inode);
+}
+
 /*
  * Connect a unionfs inode dentry/inode with several lower ones.  This is
  * the classic stackable file system "vnode interposition" action.
@@ -29,13 +81,11 @@
 struct dentry *unionfs_interpose(struct dentry *dentry, struct super_block *sb,
 				 int flag)
 {
-	struct inode *lower_inode;
-	struct dentry *lower_dentry;
 	int err = 0;
 	struct inode *inode;
 	int is_negative_dentry = 1;
 	int bindex, bstart, bend;
-	int skipped = 1;
+	int need_fill_inode = 1;
 	struct dentry *spliced = NULL;
 
 	verify_locked(dentry);
@@ -87,51 +137,9 @@ struct dentry *unionfs_interpose(struct dentry *dentry, struct super_block *sb,
 			goto skip;
 	}
 
-fill_i_info:
-	skipped = 0;
-	for (bindex = bstart; bindex <= bend; bindex++) {
-		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-		if (!lower_dentry) {
-			unionfs_set_lower_inode_idx(inode, bindex, NULL);
-			continue;
-		}
-
-		/* Initialize the lower inode to the new lower inode. */
-		if (!lower_dentry->d_inode)
-			continue;
-
-		unionfs_set_lower_inode_idx(inode, bindex,
-					    igrab(lower_dentry->d_inode));
-	}
-
-	ibstart(inode) = dbstart(dentry);
-	ibend(inode) = dbend(dentry);
-
-	/* Use attributes from the first branch. */
-	lower_inode = unionfs_lower_inode(inode);
-
-	/* Use different set of inode ops for symlinks & directories */
-	if (S_ISLNK(lower_inode->i_mode))
-		inode->i_op = &unionfs_symlink_iops;
-	else if (S_ISDIR(lower_inode->i_mode))
-		inode->i_op = &unionfs_dir_iops;
-
-	/* Use different set of file ops for directories */
-	if (S_ISDIR(lower_inode->i_mode))
-		inode->i_fop = &unionfs_dir_fops;
+	need_fill_inode = 0;
+	unionfs_fill_inode(dentry, inode);
 
-	/* properly initialize special inodes */
-	if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
-	    S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(lower_inode->i_mode))
-		init_special_inode(inode, lower_inode->i_mode,
-				   lower_inode->i_rdev);
-
-	/* all well, copy inode attributes */
-	unionfs_copy_attr_all(inode, lower_inode);
-	fsstack_copy_inode_size(inode, lower_inode);
-
-	if (spliced)
-		goto out_spliced;
 skip:
 	/* only (our) lookup wants to do a d_add */
 	switch (flag) {
@@ -156,8 +164,10 @@ skip:
 			spliced->d_fsdata = dentry->d_fsdata;
 			dentry->d_fsdata = NULL;
 			dentry = spliced;
-			if (skipped)
-				goto fill_i_info;
+			if (need_fill_inode) {
+				need_fill_inode = 0;
+				unionfs_fill_inode(dentry, inode);
+			}
 			goto out_spliced;
 		}
 		break;
diff --git a/fs/unionfs/sioq.c b/fs/unionfs/sioq.c
index ce17a8d..2a8c88e 100644
--- a/fs/unionfs/sioq.c
+++ b/fs/unionfs/sioq.c
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2003-2007 Erez Zadok
- * Copyright (c) 2003-2006 Charles P. Wright
- * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
- * Copyright (c) 2005-2006 Junjiro Okajima
- * Copyright (c) 2004-2006 David P. Quigley
- * Copyright (c) 2003-2007 Stony Brook University
- * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ * Copyright (c) 2006-2007 Erez Zadok
+ * Copyright (c) 2006      Charles P. Wright
+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2006      Junjiro Okajima
+ * Copyright (c) 2006      David P. Quigley
+ * Copyright (c) 2006-2007 Stony Brook University
+ * Copyright (c) 2006-2007 The Research Foundation of SUNY
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
diff --git a/fs/unionfs/sioq.h b/fs/unionfs/sioq.h
index 3521ed2..afb71ee 100644
--- a/fs/unionfs/sioq.h
+++ b/fs/unionfs/sioq.h
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2003-2007 Erez Zadok
- * Copyright (c) 2003-2006 Charles P. Wright
- * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
- * Copyright (c) 2005-2006 Junjiro Okajima
- * Copyright (c) 2004-2006 David P. Quigley
- * Copyright (c) 2003-2007 Stony Brook University
- * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ * Copyright (c) 2006-2007 Erez Zadok
+ * Copyright (c) 2006      Charles P. Wright
+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2006      Junjiro Okajima
+ * Copyright (c) 2006      David P. Quigley
+ * Copyright (c) 2006-2007 Stony Brook University
+ * Copyright (c) 2006-2007 The Research Foundation of SUNY
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index 1b11eab..3b555bc 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -344,7 +344,10 @@ extern struct dentry *unionfs_interpose(struct dentry *this_dentry,
 #ifdef CONFIG_UNION_FS_XATTR
 /* Extended attribute functions. */
 extern void *unionfs_xattr_alloc(size_t size, size_t limit);
-static inline void unionfs_xattr_kfree(const void *p) {kfree((p));}
+static inline void unionfs_xattr_kfree(const void *p)
+{
+	kfree(p);
+}
 extern ssize_t unionfs_getxattr(struct dentry *dentry, const char *name,
 				void *value, size_t size);
 extern int unionfs_removexattr(struct dentry *dentry, const char *name);
@@ -395,14 +398,23 @@ static inline int is_robranch_super(const struct super_block *sb, int index)
 /* Is this file on a read-only branch? */
 static inline int is_robranch_idx(const struct dentry *dentry, int index)
 {
-	int err = 0;
+	struct super_block *lower_sb;
 
 	BUG_ON(index < 0);
 
-	if ((!(branchperms(dentry->d_sb, index) & MAY_WRITE)) ||
-	    IS_RDONLY(unionfs_lower_dentry_idx(dentry, index)->d_inode))
-		err = -EROFS;
-	return err;
+	if (!(branchperms(dentry->d_sb, index) & MAY_WRITE))
+		return -EROFS;
+
+	lower_sb = unionfs_lower_super_idx(dentry->d_sb, index);
+	BUG_ON(lower_sb == NULL);
+	/*
+	 * test sb flags directly, not IS_RDONLY(lower_inode) because the
+	 * lower_dentry could be a negative.
+	 */
+	if (lower_sb->s_flags & MS_RDONLY)
+		return -EROFS;
+
+	return 0;
 }
 
 static inline int is_robranch(const struct dentry *dentry)
@@ -460,17 +472,14 @@ static inline struct vfsmount *unionfs_mntget(struct dentry *dentry,
 {
 	struct vfsmount *mnt;
 
-	BUG_ON(!dentry);
-	BUG_ON(bindex < 0);
+	BUG_ON(!dentry || bindex < 0);
 
-	mnt = unionfs_lower_mnt_idx(dentry, bindex);
-	if (mnt)
-		mnt = mntget(mnt);
-#ifdef UNIONFS_DEBUG
-	else
+	mnt = mntget(unionfs_lower_mnt_idx(dentry, bindex));
+#ifdef CONFIG_UNION_FS_DEBUG
+	if (!mnt)
 		printk(KERN_DEBUG "unionfs_mntget: mnt=%p bindex=%d\n",
 		       mnt, bindex);
-#endif /* UNIONFS_DEBUG */
+#endif /* CONFIG_UNION_FS_DEBUG */
 
 	return mnt;
 }
@@ -481,31 +490,26 @@ static inline void unionfs_mntput(struct dentry *dentry, int bindex)
 
 	if (!dentry && bindex < 0)
 		return;
-	BUG_ON(!dentry);
-	BUG_ON(bindex < 0);
+	BUG_ON(!dentry || bindex < 0);
 
 	mnt = unionfs_lower_mnt_idx(dentry, bindex);
-	if (!mnt) {
-#ifdef UNIONFS_DEBUG
-		/*
-		 * Directories can have NULL lower objects in between
-		 * start/end, but NOT if at the start/end range.  We cannot
-		 * verify that this dentry is a type=DIR, because it may
-		 * already be a negative dentry.  But if dbstart is greater
-		 * than dbend, we know that this couldn't have been a
-		 * regular file: it had to have been a directory.
-		 */
-		if (!(bindex > dbstart(dentry) && bindex < dbend(dentry)))
-			printk(KERN_WARNING
-			       "unionfs_mntput: mnt=%p bindex=%d\n",
-			       mnt, bindex);
-#endif /* UNIONFS_DEBUG */
-		return;
-	}
+#ifdef CONFIG_UNION_FS_DEBUG
+	/*
+	 * Directories can have NULL lower objects in between start/end, but
+	 * NOT if at the start/end range.  We cannot verify that this dentry
+	 * is a type=DIR, because it may already be a negative dentry.  But
+	 * if dbstart is greater than dbend, we know that this couldn't have
+	 * been a regular file: it had to have been a directory.
+	 */
+	if (!mnt && !(bindex > dbstart(dentry) && bindex < dbend(dentry)))
+		printk(KERN_WARNING
+		       "unionfs_mntput: mnt=%p bindex=%d\n",
+		       mnt, bindex);
+#endif /* CONFIG_UNION_FS_DEBUG */
 	mntput(mnt);
 }
 
-#ifdef UNIONFS_DEBUG
+#ifdef CONFIG_UNION_FS_DEBUG
 
 /* useful for tracking code reachability */
 #define UDBG printk("DBG:%s:%s:%d\n",__FILE__,__FUNCTION__,__LINE__)
@@ -541,7 +545,7 @@ extern void __show_dinode_times(const struct dentry *dentry,
 extern void __show_inode_counts(const struct inode *inode,
 			        const char *file, const char *fxn, int line);
 
-#else /* not UNIONFS_DEBUG */
+#else /* not CONFIG_UNION_FS_DEBUG */
 
 /* we leave useful hooks for these check functions throughout the code */
 #define unionfs_check_inode(i)
@@ -552,6 +556,6 @@ extern void __show_inode_counts(const struct inode *inode,
 #define show_dinode_times(d)
 #define show_inode_counts(i)
 
-#endif /* not UNIONFS_DEBUG */
+#endif /* not CONFIG_UNION_FS_DEBUG */
 
 #endif	/* not _UNION_H_ */
diff --git a/include/linux/fs_stack.h b/include/linux/fs_stack.h
index 2599c5b..28543ad 100644
--- a/include/linux/fs_stack.h
+++ b/include/linux/fs_stack.h
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2003-2007 Erez Zadok
- * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
- * Copyright (c) 2003-2007 Stony Brook University
- * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ * Copyright (c) 2006-2007 Erez Zadok
+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2006-2007 Stony Brook University
+ * Copyright (c) 2006-2007 The Research Foundation of SUNY
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as


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