Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760989AbYAJPLK (ORCPT ); Thu, 10 Jan 2008 10:11:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759626AbYAJPCB (ORCPT ); Thu, 10 Jan 2008 10:02:01 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:57049 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758642AbYAJPAw (ORCPT ); Thu, 10 Jan 2008 10:00:52 -0500 From: Erez Zadok To: torvalds@linux-foundation.org, akpm@linux-foundation.org, hch@infradead.org, viro@ftp.linux.org.uk Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Erez Zadok Subject: [PATCH 06/29] Unionfs: main header file Date: Thu, 10 Jan 2008 09:59:25 -0500 Message-Id: <11999771911116-git-send-email-ezk@cs.sunysb.edu> X-Mailer: git-send-email 1.5.2.2 X-MailKey: Erez_Zadok In-Reply-To: <11999771882152-git-send-email-ezk@cs.sunysb.edu> References: <11999771882152-git-send-email-ezk@cs.sunysb.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 20633 Lines: 622 Signed-off-by: Erez Zadok --- 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include + +/* 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/