Signed-off-by: Erez Zadok <ezk@xxxxxxxxxxxxx>
---
fs/unionfs/union.h | 602 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 602 insertions(+), 0 deletions(-)
create mode 100644 fs/unionfs/union.h
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
new file mode 100644
index 0000000..d324f83
--- /dev/null
+++ b/fs/unionfs/union.h
@@ -0,0 +1,602 @@
+/*
+ * 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 _UNION_H_
+#define _UNION_H_
+
+#include <linux/dcache.h>
+#include <linux/file.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/page-flags.h>
+#include <linux/pagemap.h>
+#include <linux/poll.h>
+#include <linux/security.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+#include <linux/statfs.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h>
+#include <linux/xattr.h>
+#include <linux/fs_stack.h>
+#include <linux/magic.h>
+#include <linux/log2.h>
+#include <linux/poison.h>
+#include <linux/mman.h>
+#include <linux/backing-dev.h>
+
+#include <asm/system.h>
+
+#include <linux/union_fs.h>
+
+/* the file system name */
+#define UNIONFS_NAME "unionfs"
+
+/* unionfs root inode number */
+#define UNIONFS_ROOT_INO 1
+
+/* number of times we try to get a unique temporary file name */
+#define GET_TMPNAM_MAX_RETRY 5
+
+/* maximum number of branches we support, to avoid memory blowup */
+#define UNIONFS_MAX_BRANCHES 128
+
+/* minimum time (seconds) required for time-based cache-coherency */
+#define UNIONFS_MIN_CC_TIME 3
+
+/* Operations vectors defined in specific files. */
+extern struct file_operations unionfs_main_fops;
+extern struct file_operations unionfs_dir_fops;
+extern struct inode_operations unionfs_main_iops;
+extern struct inode_operations unionfs_dir_iops;
+extern struct inode_operations unionfs_symlink_iops;
+extern struct super_operations unionfs_sops;
+extern struct dentry_operations unionfs_dops;
+extern struct address_space_operations unionfs_aops;
+
+/* How long should an entry be allowed to persist */
+#define RDCACHE_JIFFIES (5*HZ)
+
+/* file private data. */
+struct unionfs_file_info {
+ int bstart;
+ int bend;
+ atomic_t generation;
+
+ struct unionfs_dir_state *rdstate;
+ struct file **lower_files;
+ int *saved_branch_ids; /* IDs of branches when file was opened */
+};
+
+/* unionfs inode data in memory */
+struct unionfs_inode_info {
+ int bstart;
+ int bend;
+ atomic_t generation;
+ int stale;
+ /* Stuff for readdir over NFS. */
+ spinlock_t rdlock;
+ struct list_head readdircache;
+ int rdcount;
+ int hashsize;
+ int cookie;
+
+ /* The lower inodes */
+ struct inode **lower_inodes;
+
+ struct inode vfs_inode;
+};
+
+/* unionfs dentry data in memory */
+struct unionfs_dentry_info {
+ /*
+ * The semaphore is used to lock the dentry as soon as we get into a
+ * unionfs function from the VFS. Our lock ordering is that children
+ * go before their parents.
+ */
+ struct mutex lock;
+ int bstart;
+ int bend;
+ int bopaque;
+ int bcount;
+ atomic_t generation;
+ struct path *lower_paths;
+};
+
+/* These are the pointers to our various objects. */
+struct unionfs_data {
+ struct super_block *sb;
+ atomic_t open_files; /* number of open files on branch */
+ int branchperms;
+ int branch_id; /* unique branch ID at re/mount time */
+};
+
+/* unionfs super-block data in memory */
+struct unionfs_sb_info {
+ int bend;
+
+ atomic_t generation;
+
+ /*
+ * This rwsem is used to make sure that a branch management
+ * operation...
+ * 1) will not begin before all currently in-flight operations
+ * complete.
+ * 2) any new operations do not execute until the currently
+ * running branch management operation completes.
+ *
+ * The write_lock_owner records the PID of the task which grabbed
+ * the rw_sem for writing. If the same task also tries to grab the
+ * read lock, we allow it. This prevents a self-deadlock when
+ * branch-management is used on a pivot_root'ed union, because we
+ * have to ->lookup paths which belong to the same union.
+ */
+ struct rw_semaphore rwsem;
+ pid_t write_lock_owner; /* PID of rw_sem owner (write lock) */
+ int high_branch_id; /* last unique branch ID given */
+ struct unionfs_data *data;
+};
+
+/*
+ * structure for making the linked list of entries by readdir on left branch
+ * to compare with entries on right branch
+ */
+struct filldir_node {
+ struct list_head file_list; /* list for directory entries */
+ char *name; /* name entry */
+ int hash; /* name hash */
+ int namelen; /* name len since name is not 0 terminated */
+
+ /*
+ * we can check for duplicate whiteouts and files in the same branch
+ * in order to return -EIO.
+ */
+ int bindex;
+
+ /* is this a whiteout entry? */
+ int whiteout;
+
+ /* Inline name, so we don't need to separately kmalloc small ones */
+ char iname[DNAME_INLINE_LEN_MIN];
+};
+
+/* Directory hash table. */
+struct unionfs_dir_state {
+ unsigned int cookie; /* the cookie, based off of rdversion */
+ unsigned int offset; /* The entry we have returned. */
+ int bindex;
+ loff_t dirpos; /* offset within the lower level directory */
+ int size; /* How big is the hash table? */
+ int hashentries; /* How many entries have been inserted? */
+ unsigned long access;
+
+ /* This cache list is used when the inode keeps us around. */
+ struct list_head cache;
+ struct list_head list[0];
+};
+
+/* externs needed for fanout.h or sioq.h */
+extern int unionfs_get_nlinks(const struct inode *inode);
+
+/* include miscellaneous macros */
+#include "fanout.h"
+#include "sioq.h"
+
+/* externs for cache creation/deletion routines */
+extern void unionfs_destroy_filldir_cache(void);
+extern int unionfs_init_filldir_cache(void);
+extern int unionfs_init_inode_cache(void);
+extern void unionfs_destroy_inode_cache(void);
+extern int unionfs_init_dentry_cache(void);
+extern void unionfs_destroy_dentry_cache(void);
+
+/* Initialize and free readdir-specific state. */
+extern int init_rdstate(struct file *file);
+extern struct unionfs_dir_state *alloc_rdstate(struct inode *inode,
+ int bindex);
+extern struct unionfs_dir_state *find_rdstate(struct inode *inode,
+ loff_t fpos);
+extern void free_rdstate(struct unionfs_dir_state *state);
+extern int add_filldir_node(struct unionfs_dir_state *rdstate,
+ const char *name, int namelen, int bindex,
+ int whiteout);
+extern struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate,
+ const char *name, int namelen,
+ int is_whiteout);
+
+extern struct dentry **alloc_new_dentries(int objs);
+extern struct unionfs_data *alloc_new_data(int objs);
+
+/* We can only use 32-bits of offset for rdstate --- blech! */
+#define DIREOF (0xfffff)
+#define RDOFFBITS 20 /* This is the number of bits in DIREOF. */
+#define MAXRDCOOKIE (0xfff)
+/* Turn an rdstate into an offset. */
+static inline off_t rdstate2offset(struct unionfs_dir_state *buf)
+{
+ off_t tmp;
+
+ tmp = ((buf->cookie & MAXRDCOOKIE) << RDOFFBITS)
+ | (buf->offset & DIREOF);
+ return tmp;
+}
+
+/* Macros for locking a super_block. */
+enum unionfs_super_lock_class {
+ UNIONFS_SMUTEX_NORMAL,
+ UNIONFS_SMUTEX_PARENT, /* when locking on behalf of file */
+ UNIONFS_SMUTEX_CHILD, /* when locking on behalf of dentry */
+};
+static inline void unionfs_read_lock(struct super_block *sb, int subclass)
+{
+ if (UNIONFS_SB(sb)->write_lock_owner &&
+ UNIONFS_SB(sb)->write_lock_owner == current->pid)
+ return;
+ down_read_nested(&UNIONFS_SB(sb)->rwsem, subclass);
+}
+static inline void unionfs_read_unlock(struct super_block *sb)
+{
+ if (UNIONFS_SB(sb)->write_lock_owner &&
+ UNIONFS_SB(sb)->write_lock_owner == current->pid)
+ return;
+ up_read(&UNIONFS_SB(sb)->rwsem);
+}
+static inline void unionfs_write_lock(struct super_block *sb)
+{
+ down_write(&UNIONFS_SB(sb)->rwsem);
+ UNIONFS_SB(sb)->write_lock_owner = current->pid;
+}
+static inline void unionfs_write_unlock(struct super_block *sb)
+{
+ up_write(&UNIONFS_SB(sb)->rwsem);
+ UNIONFS_SB(sb)->write_lock_owner = 0;
+}
+
+static inline void unionfs_double_lock_dentry(struct dentry *d1,
+ struct dentry *d2)
+{
+ BUG_ON(d1 == d2);
+ if (d1 < d2) {
+ unionfs_lock_dentry(d1, UNIONFS_DMUTEX_PARENT);
+ unionfs_lock_dentry(d2, UNIONFS_DMUTEX_CHILD);
+ } else {
+ unionfs_lock_dentry(d2, UNIONFS_DMUTEX_PARENT);
+ unionfs_lock_dentry(d1, UNIONFS_DMUTEX_CHILD);
+ }
+}
+
+extern int new_dentry_private_data(struct dentry *dentry, int subclass);
+extern void free_dentry_private_data(struct dentry *dentry);
+extern void update_bstart(struct dentry *dentry);
+extern int init_lower_nd(struct nameidata *nd, unsigned int flags);
+extern void release_lower_nd(struct nameidata *nd, int err);
+
+/*
+ * EXTERNALS:
+ */
+
+/* replicates the directory structure up to given dentry in given branch */
+extern struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
+ const char *name, int bindex);
+extern int make_dir_opaque(struct dentry *dir, int bindex);
+
+/* partial lookup */
+extern int unionfs_partial_lookup(struct dentry *dentry);
+
+/*
+ * Pass an unionfs dentry and an index and it will try to create a whiteout
+ * in branch 'index'.
+ *
+ * On error, it will proceed to a branch to the left
+ */
+extern int create_whiteout(struct dentry *dentry, int start);
+/* copies a file from dbstart to newbindex branch */
+extern int copyup_file(struct inode *dir, struct file *file, int bstart,
+ int newbindex, loff_t size);
+extern int copyup_named_file(struct inode *dir, struct file *file,
+ char *name, int bstart, int new_bindex,
+ loff_t len);
+/* copies a dentry from dbstart to newbindex branch */
+extern int copyup_dentry(struct inode *dir, struct dentry *dentry,
+ int bstart, int new_bindex, const char *name,
+ int namelen, struct file **copyup_file, loff_t len);
+/* helper functions for post-copyup actions */
+extern void unionfs_postcopyup_setmnt(struct dentry *dentry);
+extern void unionfs_postcopyup_release(struct dentry *dentry);
+
+extern int remove_whiteouts(struct dentry *dentry,
+ struct dentry *lower_dentry, int bindex);
+
+extern int do_delete_whiteouts(struct dentry *dentry, int bindex,
+ struct unionfs_dir_state *namelist);
+
+/* Is this directory empty: 0 if it is empty, -ENOTEMPTY if not. */
+extern int check_empty(struct dentry *dentry,
+ struct unionfs_dir_state **namelist);
+/* Delete whiteouts from this directory in branch bindex. */
+extern int delete_whiteouts(struct dentry *dentry, int bindex,
+ struct unionfs_dir_state *namelist);
+
+/* Re-lookup a lower dentry. */
+extern int unionfs_refresh_lower_dentry(struct dentry *dentry, int bindex);
+
+extern void unionfs_reinterpose(struct dentry *this_dentry);
+extern struct super_block *unionfs_duplicate_super(struct super_block *sb);
+
+/* Locking functions. */
+extern int unionfs_setlk(struct file *file, int cmd, struct file_lock *fl);
+extern int unionfs_getlk(struct file *file, struct file_lock *fl);
+
+/* Common file operations. */
+extern int unionfs_file_revalidate(struct file *file, bool willwrite);
+extern int unionfs_open(struct inode *inode, struct file *file);
+extern int unionfs_file_release(struct inode *inode, struct file *file);
+extern int unionfs_flush(struct file *file, fl_owner_t id);
+extern long unionfs_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg);
+extern int unionfs_fsync(struct file *file, struct dentry *dentry,
+ int datasync);
+extern int unionfs_fasync(int fd, struct file *file, int flag);
+
+/* Inode operations */
+extern int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry);
+extern int unionfs_unlink(struct inode *dir, struct dentry *dentry);
+extern int unionfs_rmdir(struct inode *dir, struct dentry *dentry);
+
+extern bool __unionfs_d_revalidate_chain(struct dentry *dentry,
+ struct nameidata *nd, bool willwrite);
+extern bool is_newer_lower(const struct dentry *dentry);
+extern void purge_sb_data(struct super_block *sb);
+
+/* The values for unionfs_interpose's flag. */
+#define INTERPOSE_DEFAULT 0
+#define INTERPOSE_LOOKUP 1
+#define INTERPOSE_REVAL 2
+#define INTERPOSE_REVAL_NEG 3
+#define INTERPOSE_PARTIAL 4
+
+extern struct dentry *unionfs_interpose(struct dentry *this_dentry,
+ struct super_block *sb, int flag);
+
+#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);
+}
+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);
+extern ssize_t unionfs_listxattr(struct dentry *dentry, char *list,
+ size_t size);
+extern int unionfs_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags);
+#endif /* CONFIG_UNION_FS_XATTR */
+
+/* The root directory is unhashed, but isn't deleted. */
+static inline int d_deleted(struct dentry *d)
+{
+ return d_unhashed(d) && (d != d->d_sb->s_root);
+}
+
+struct dentry *unionfs_lookup_backend(struct dentry *dentry,
+ struct nameidata *nd, int lookupmode);
+
+/* unionfs_permission, check if we should bypass error to facilitate copyup */
+#define IS_COPYUP_ERR(err) ((err) == -EROFS)
+
+/* unionfs_open, check if we need to copyup the file */
+#define OPEN_WRITE_FLAGS (O_WRONLY | O_RDWR | O_APPEND)
+#define IS_WRITE_FLAG(flag) ((flag) & OPEN_WRITE_FLAGS)
+
+static inline int branchperms(const struct super_block *sb, int index)
+{
+ BUG_ON(index < 0);
+ return UNIONFS_SB(sb)->data[index].branchperms;
+}
+
+static inline int set_branchperms(struct super_block *sb, int index, int perms)
+{
+ BUG_ON(index < 0);
+ UNIONFS_SB(sb)->data[index].branchperms = perms;
+ return perms;
+}
+
+/* Is this file on a read-only branch? */
+static inline int is_robranch_super(const struct super_block *sb, int index)
+{
+ int ret;
+
+ ret = (!(branchperms(sb, index) & MAY_WRITE)) ? -EROFS : 0;
+ return ret;
+}
+
+/* Is this file on a read-only branch? */
+static inline int is_robranch_idx(const struct dentry *dentry, int index)
+{
+ struct super_block *lower_sb;
+
+ BUG_ON(index < 0);
+
+ 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)
+{
+ int index;
+
+ index = UNIONFS_D(dentry)->bstart;
+ BUG_ON(index < 0);
+
+ return is_robranch_idx(dentry, index);
+}
+
+/* What do we use for whiteouts. */
+#define UNIONFS_WHPFX ".wh."
+#define UNIONFS_WHLEN 4
+/*
+ * If a directory contains this file, then it is opaque. We start with the
+ * .wh. flag so that it is blocked by lookup.
+ */
+#define UNIONFS_DIR_OPAQUE_NAME "__dir_opaque"
+#define UNIONFS_DIR_OPAQUE UNIONFS_WHPFX UNIONFS_DIR_OPAQUE_NAME
+
+/*
+ * EXTERNALS:
+ */
+extern char *alloc_whname(const char *name, int len);
+extern int check_branch(struct nameidata *nd);
+extern int parse_branch_mode(const char *name, int *perms);
+
+/* locking helpers */
+static inline struct dentry *lock_parent(struct dentry *dentry)
+{
+ struct dentry *dir = dget(dentry->d_parent);
+ mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
+ return dir;
+}
+static inline struct dentry *lock_parent_wh(struct dentry *dentry)
+{
+ struct dentry *dir = dget(dentry->d_parent);
+
+ mutex_lock_nested(&dir->d_inode->i_mutex, UNIONFS_DMUTEX_WHITEOUT);
+ return dir;
+}
+
+static inline void unlock_dir(struct dentry *dir)
+{
+ mutex_unlock(&dir->d_inode->i_mutex);
+ dput(dir);
+}
+
+static inline struct vfsmount *unionfs_mntget(struct dentry *dentry,
+ int bindex)
+{
+ struct vfsmount *mnt;
+
+ BUG_ON(!dentry || bindex < 0);
+
+ mnt = mntget(unionfs_lower_mnt_idx(dentry, bindex));
+#ifdef CONFIG_UNION_FS_DEBUG
+ if (!mnt)
+ pr_debug("unionfs: mntget: mnt=%p bindex=%d\n",
+ mnt, bindex);
+#endif /* CONFIG_UNION_FS_DEBUG */
+
+ return mnt;
+}
+
+static inline void unionfs_mntput(struct dentry *dentry, int bindex)
+{
+ struct vfsmount *mnt;
+
+ if (!dentry && bindex < 0)
+ return;
+ BUG_ON(!dentry || bindex < 0);
+
+ mnt = unionfs_lower_mnt_idx(dentry, bindex);
+#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)))
+ pr_debug("unionfs: mntput: mnt=%p bindex=%d\n", mnt, bindex);
+#endif /* CONFIG_UNION_FS_DEBUG */
+ mntput(mnt);
+}
+
+#ifdef CONFIG_UNION_FS_DEBUG
+
+/* useful for tracking code reachability */
+#define UDBG pr_debug("DBG:%s:%s:%d\n", __FILE__, __FUNCTION__, __LINE__)
+
+#define unionfs_check_inode(i) __unionfs_check_inode((i), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define unionfs_check_dentry(d) __unionfs_check_dentry((d), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define unionfs_check_file(f) __unionfs_check_file((f), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define unionfs_check_nd(n) __unionfs_check_nd((n), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define show_branch_counts(sb) __show_branch_counts((sb), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define show_inode_times(i) __show_inode_times((i), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define show_dinode_times(d) __show_dinode_times((d), \
+ __FILE__, __FUNCTION__, __LINE__)
+#define show_inode_counts(i) __show_inode_counts((i), \
+ __FILE__, __FUNCTION__, __LINE__)
+
+extern void __unionfs_check_inode(const struct inode *inode, const char *fname,
+ const char *fxn, int line);
+extern void __unionfs_check_dentry(const struct dentry *dentry,
+ const char *fname, const char *fxn,
+ int line);
+extern void __unionfs_check_file(const struct file *file,
+ const char *fname, const char *fxn, int line);
+extern void __unionfs_check_nd(const struct nameidata *nd,
+ const char *fname, const char *fxn, int line);
+extern void __show_branch_counts(const struct super_block *sb,
+ const char *file, const char *fxn, int line);
+extern void __show_inode_times(const struct inode *inode,
+ const char *file, const char *fxn, int line);
+extern void __show_dinode_times(const struct dentry *dentry,
+ const char *file, const char *fxn, int line);
+extern void __show_inode_counts(const struct inode *inode,
+ const char *file, const char *fxn, int line);
+
+#else /* not CONFIG_UNION_FS_DEBUG */
+
+/* we leave useful hooks for these check functions throughout the code */
+#define unionfs_check_inode(i) do { } while (0)
+#define unionfs_check_dentry(d) do { } while (0)
+#define unionfs_check_file(f) do { } while (0)
+#define unionfs_check_nd(n) do { } while (0)
+#define show_branch_counts(sb) do { } while (0)
+#define show_inode_times(i) do { } while (0)
+#define show_dinode_times(d) do { } while (0)
+#define show_inode_counts(i) do { } while (0)
+
+#endif /* not CONFIG_UNION_FS_DEBUG */
+
+#endif /* not _UNION_H_ */
--
1.5.2.2
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