Message-Id: <11972545401981-git-send-email-ezk@cs.sunysb.edu>
Date:	Sun,  9 Dec 2007 21:41:43 -0500
From:	Erez Zadok <ezk@...sunysb.edu>
To:	hch@...radead.org, viro@....linux.org.uk, akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	Erez Zadok <ezk@...sunysb.edu>
Subject: [PATCH 10/42] Unionfs: fanout header definitions

Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
---
 fs/unionfs/fanout.h |  355 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 355 insertions(+), 0 deletions(-)
 create mode 100644 fs/unionfs/fanout.h

diff --git a/fs/unionfs/fanout.h b/fs/unionfs/fanout.h
new file mode 100644
index 0000000..864383e
--- /dev/null
+++ b/fs/unionfs/fanout.h
@@ -0,0 +1,355 @@
+/*
+ * Copyright (c) 2003-2007 Erez Zadok
+ * Copyright (c) 2003-2006 Charles P. Wright
+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2005      Arun M. Krishnakumar
+ * Copyright (c) 2004-2006 David P. Quigley
+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
+ * Copyright (c) 2003      Puja Gupta
+ * Copyright (c) 2003      Harikesavan Krishnan
+ * Copyright (c) 2003-2007 Stony Brook University
+ * Copyright (c) 2003-2007 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
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _FANOUT_H_
+#define _FANOUT_H_
+
+/*
+ * Inode to private data
+ *
+ * Since we use containers and the struct inode is _inside_ the
+ * unionfs_inode_info structure, UNIONFS_I will always (given a non-NULL
+ * inode pointer), return a valid non-NULL pointer.
+ */
+static inline struct unionfs_inode_info *UNIONFS_I(const struct inode *inode)
+{
+	return container_of(inode, struct unionfs_inode_info, vfs_inode);
+}
+
+#define ibstart(ino) (UNIONFS_I(ino)->bstart)
+#define ibend(ino) (UNIONFS_I(ino)->bend)
+
+/* Superblock to private data */
+#define UNIONFS_SB(super) ((struct unionfs_sb_info *)(super)->s_fs_info)
+#define sbstart(sb) 0
+#define sbend(sb) (UNIONFS_SB(sb)->bend)
+#define sbmax(sb) (UNIONFS_SB(sb)->bend + 1)
+#define sbhbid(sb) (UNIONFS_SB(sb)->high_branch_id)
+
+/* File to private Data */
+#define UNIONFS_F(file) ((struct unionfs_file_info *)((file)->private_data))
+#define fbstart(file) (UNIONFS_F(file)->bstart)
+#define fbend(file) (UNIONFS_F(file)->bend)
+
+/* macros to manipulate branch IDs in stored in our superblock */
+static inline int branch_id(struct super_block *sb, int index)
+{
+	BUG_ON(!sb || index < 0);
+	return UNIONFS_SB(sb)->data[index].branch_id;
+}
+
+static inline void set_branch_id(struct super_block *sb, int index, int val)
+{
+	BUG_ON(!sb || index < 0);
+	UNIONFS_SB(sb)->data[index].branch_id = val;
+}
+
+static inline void new_branch_id(struct super_block *sb, int index)
+{
+	BUG_ON(!sb || index < 0);
+	set_branch_id(sb, index, ++UNIONFS_SB(sb)->high_branch_id);
+}
+
+/*
+ * Find new index of matching branch with an existing superblock of a known
+ * (possibly old) id.  This is needed because branches could have been
+ * added/deleted causing the branches of any open files to shift.
+ *
+ * @sb: the new superblock which may have new/different branch IDs
+ * @id: the old/existing id we're looking for
+ * Returns index of newly found branch (0 or greater), -1 otherwise.
+ */
+static inline int branch_id_to_idx(struct super_block *sb, int id)
+{
+	int i;
+	for (i = 0; i < sbmax(sb); i++) {
+		if (branch_id(sb, i) == id)
+			return i;
+	}
+	/* in the non-ODF code, this should really never happen */
+	printk(KERN_WARNING "unionfs: cannot find branch with id %d\n", id);
+	return -1;
+}
+
+/* File to lower file. */
+static inline struct file *unionfs_lower_file(const struct file *f)
+{
+	BUG_ON(!f);
+	return UNIONFS_F(f)->lower_files[fbstart(f)];
+}
+
+static inline struct file *unionfs_lower_file_idx(const struct file *f,
+						  int index)
+{
+	BUG_ON(!f || index < 0);
+	return UNIONFS_F(f)->lower_files[index];
+}
+
+static inline void unionfs_set_lower_file_idx(struct file *f, int index,
+					      struct file *val)
+{
+	BUG_ON(!f || index < 0);
+	UNIONFS_F(f)->lower_files[index] = val;
+	/* save branch ID (may be redundant?) */
+	UNIONFS_F(f)->saved_branch_ids[index] =
+		branch_id((f)->f_path.dentry->d_sb, index);
+}
+
+static inline void unionfs_set_lower_file(struct file *f, struct file *val)
+{
+	BUG_ON(!f);
+	unionfs_set_lower_file_idx((f), fbstart(f), (val));
+}
+
+/* Inode to lower inode. */
+static inline struct inode *unionfs_lower_inode(const struct inode *i)
+{
+	BUG_ON(!i);
+	return UNIONFS_I(i)->lower_inodes[ibstart(i)];
+}
+
+static inline struct inode *unionfs_lower_inode_idx(const struct inode *i,
+						    int index)
+{
+	BUG_ON(!i || index < 0);
+	return UNIONFS_I(i)->lower_inodes[index];
+}
+
+static inline void unionfs_set_lower_inode_idx(struct inode *i, int index,
+					       struct inode *val)
+{
+	BUG_ON(!i || index < 0);
+	UNIONFS_I(i)->lower_inodes[index] = val;
+}
+
+static inline void unionfs_set_lower_inode(struct inode *i, struct inode *val)
+{
+	BUG_ON(!i);
+	UNIONFS_I(i)->lower_inodes[ibstart(i)] = val;
+}
+
+/* Superblock to lower superblock. */
+static inline struct super_block *unionfs_lower_super(
+					const struct super_block *sb)
+{
+	BUG_ON(!sb);
+	return UNIONFS_SB(sb)->data[sbstart(sb)].sb;
+}
+
+static inline struct super_block *unionfs_lower_super_idx(
+					const struct super_block *sb,
+					int index)
+{
+	BUG_ON(!sb || index < 0);
+	return UNIONFS_SB(sb)->data[index].sb;
+}
+
+static inline void unionfs_set_lower_super_idx(struct super_block *sb,
+					       int index,
+					       struct super_block *val)
+{
+	BUG_ON(!sb || index < 0);
+	UNIONFS_SB(sb)->data[index].sb = val;
+}
+
+static inline void unionfs_set_lower_super(struct super_block *sb,
+					   struct super_block *val)
+{
+	BUG_ON(!sb);
+	UNIONFS_SB(sb)->data[sbstart(sb)].sb = val;
+}
+
+/* Branch count macros. */
+static inline int branch_count(const struct super_block *sb, int index)
+{
+	BUG_ON(!sb || index < 0);
+	return atomic_read(&UNIONFS_SB(sb)->data[index].open_files);
+}
+
+static inline void set_branch_count(struct super_block *sb, int index, int val)
+{
+	BUG_ON(!sb || index < 0);
+	atomic_set(&UNIONFS_SB(sb)->data[index].open_files, val);
+}
+
+static inline void branchget(struct super_block *sb, int index)
+{
+	BUG_ON(!sb || index < 0);
+	atomic_inc(&UNIONFS_SB(sb)->data[index].open_files);
+}
+
+static inline void branchput(struct super_block *sb, int index)
+{
+	BUG_ON(!sb || index < 0);
+	atomic_dec(&UNIONFS_SB(sb)->data[index].open_files);
+}
+
+/* Dentry macros */
+static inline struct unionfs_dentry_info *UNIONFS_D(const struct dentry *dent)
+{
+	BUG_ON(!dent);
+	return dent->d_fsdata;
+}
+
+static inline int dbstart(const struct dentry *dent)
+{
+	BUG_ON(!dent);
+	return UNIONFS_D(dent)->bstart;
+}
+
+static inline void set_dbstart(struct dentry *dent, int val)
+{
+	BUG_ON(!dent);
+	UNIONFS_D(dent)->bstart = val;
+}
+
+static inline int dbend(const struct dentry *dent)
+{
+	BUG_ON(!dent);
+	return UNIONFS_D(dent)->bend;
+}
+
+static inline void set_dbend(struct dentry *dent, int val)
+{
+	BUG_ON(!dent);
+	UNIONFS_D(dent)->bend = val;
+}
+
+static inline int dbopaque(const struct dentry *dent)
+{
+	BUG_ON(!dent);
+	return UNIONFS_D(dent)->bopaque;
+}
+
+static inline void set_dbopaque(struct dentry *dent, int val)
+{
+	BUG_ON(!dent);
+	UNIONFS_D(dent)->bopaque = val;
+}
+
+static inline void unionfs_set_lower_dentry_idx(struct dentry *dent, int index,
+						struct dentry *val)
+{
+	BUG_ON(!dent || index < 0);
+	UNIONFS_D(dent)->lower_paths[index].dentry = val;
+}
+
+static inline struct dentry *unionfs_lower_dentry_idx(
+				const struct dentry *dent,
+				int index)
+{
+	BUG_ON(!dent || index < 0);
+	return UNIONFS_D(dent)->lower_paths[index].dentry;
+}
+
+static inline struct dentry *unionfs_lower_dentry(const struct dentry *dent)
+{
+	BUG_ON(!dent);
+	return unionfs_lower_dentry_idx(dent, dbstart(dent));
+}
+
+static inline void unionfs_set_lower_mnt_idx(struct dentry *dent, int index,
+					     struct vfsmount *mnt)
+{
+	BUG_ON(!dent || index < 0);
+	UNIONFS_D(dent)->lower_paths[index].mnt = mnt;
+}
+
+static inline struct vfsmount *unionfs_lower_mnt_idx(
+					const struct dentry *dent,
+					int index)
+{
+	BUG_ON(!dent || index < 0);
+	return UNIONFS_D(dent)->lower_paths[index].mnt;
+}
+
+static inline struct vfsmount *unionfs_lower_mnt(const struct dentry *dent)
+{
+	BUG_ON(!dent);
+	return unionfs_lower_mnt_idx(dent, dbstart(dent));
+}
+
+/* Macros for locking a dentry. */
+static inline void unionfs_lock_dentry(struct dentry *d)
+{
+	BUG_ON(!d);
+	mutex_lock(&UNIONFS_D(d)->lock);
+}
+
+static inline void unionfs_unlock_dentry(struct dentry *d)
+{
+	BUG_ON(!d);
+	mutex_unlock(&UNIONFS_D(d)->lock);
+}
+
+static inline void verify_locked(struct dentry *d)
+{
+	BUG_ON(!d);
+	BUG_ON(!mutex_is_locked(&UNIONFS_D(d)->lock));
+}
+
+/* copy a/m/ctime from the lower branch with the newest times */
+static inline void unionfs_copy_attr_times(struct inode *upper)
+{
+	int bindex;
+	struct inode *lower;
+
+	if (!upper || ibstart(upper) < 0)
+		return;
+	for (bindex = ibstart(upper); bindex <= ibend(upper); bindex++) {
+		lower = unionfs_lower_inode_idx(upper, bindex);
+		if (!lower)
+			continue; /* not all lower dir objects may exist */
+		if (unlikely(timespec_compare(&upper->i_mtime,
+					      &lower->i_mtime) < 0))
+			upper->i_mtime = lower->i_mtime;
+		if (unlikely(timespec_compare(&upper->i_ctime,
+					      &lower->i_ctime) < 0))
+			upper->i_ctime = lower->i_ctime;
+		if (unlikely(timespec_compare(&upper->i_atime,
+					      &lower->i_atime) < 0))
+			upper->i_atime = lower->i_atime;
+	}
+}
+
+/*
+ * A unionfs/fanout version of fsstack_copy_attr_all.  Uses a
+ * unionfs_get_nlinks to properly calcluate the number of links to a file.
+ * Also, copies the max() of all a/m/ctimes for all lower inodes (which is
+ * important if the lower inode is a directory type)
+ */
+static inline void unionfs_copy_attr_all(struct inode *dest,
+					 const struct inode *src)
+{
+	dest->i_mode = src->i_mode;
+	dest->i_uid = src->i_uid;
+	dest->i_gid = src->i_gid;
+	dest->i_rdev = src->i_rdev;
+
+	unionfs_copy_attr_times(dest);
+
+	dest->i_blkbits = src->i_blkbits;
+	dest->i_flags = src->i_flags;
+
+	/*
+	 * Update the nlinks AFTER updating the above fields, because the
+	 * get_links callback may depend on them.
+	 */
+	dest->i_nlink = unionfs_get_nlinks(dest);
+}
+
+#endif	/* not _FANOUT_H */
-- 
1.5.2.2

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