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linux/fs/nilfs2/nilfs.h
Ryusuke Konishi 4f6b828837 nilfs2: fix lock order reversal in nilfs_clean_segments ioctl 
This is a companion patch to ("nilfs2: fix possible circular locking
for get information ioctls").

This corrects lock order reversal between mm->mmap_sem and
nilfs->ns_segctor_sem in nilfs_clean_segments() which was detected by
lockdep check:

 =======================================================
 [ INFO: possible circular locking dependency detected ]
 2.6.30-rc3-nilfs-00003-g360bdc1 #7
 -------------------------------------------------------
 mmap/5294 is trying to acquire lock:
  (&nilfs->ns_segctor_sem){++++.+}, at: [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]

 but task is already holding lock:
  (&mm->mmap_sem){++++++}, at: [<c043700a>] do_page_fault+0x1d8/0x30a

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&mm->mmap_sem){++++++}:
        [<c01470a5>] __lock_acquire+0x1066/0x13b0
        [<c01474a9>] lock_acquire+0xba/0xdd
        [<c01836bc>] might_fault+0x68/0x88
        [<c023c61d>] copy_from_user+0x2a/0x111
        [<d0d120d0>] nilfs_ioctl_prepare_clean_segments+0x1d/0xf1 [nilfs2]
        [<d0d0e2aa>] nilfs_clean_segments+0x6d/0x1b9 [nilfs2]
        [<d0d11f68>] nilfs_ioctl+0x2ad/0x318 [nilfs2]
        [<c01a3be7>] vfs_ioctl+0x22/0x69
        [<c01a408e>] do_vfs_ioctl+0x460/0x499
        [<c01a4107>] sys_ioctl+0x40/0x5a
        [<c01031a4>] sysenter_do_call+0x12/0x38
        [<ffffffff>] 0xffffffff

 -> #0 (&nilfs->ns_segctor_sem){++++.+}:
        [<c0146e0b>] __lock_acquire+0xdcc/0x13b0
        [<c01474a9>] lock_acquire+0xba/0xdd
        [<c0433f1d>] down_read+0x2a/0x3e
        [<d0d0e846>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
        [<d0cfe0e5>] nilfs_page_mkwrite+0xe7/0x154 [nilfs2]
        [<c0183b0b>] __do_fault+0x165/0x376
        [<c01855cd>] handle_mm_fault+0x287/0x5d1
        [<c043712d>] do_page_fault+0x2fb/0x30a
        [<c0435462>] error_code+0x72/0x78
        [<ffffffff>] 0xffffffff

where nilfs_clean_segments() holds:

  nilfs->ns_segctor_sem -> copy_from_user()
                             --> page fault -> mm->mmap_sem

And, page fault path may hold:

  page fault -> mm->mmap_sem
         --> nilfs_page_mkwrite() -> nilfs->ns_segctor_sem

Even though nilfs_clean_segments() does not perform write access on
given user pages, it may cause deadlock because nilfs->ns_segctor_sem
is shared per device and mm->mmap_sem can be shared with other tasks.

To avoid this problem, this patch moves all calls of copy_from_user()
outside the nilfs->ns_segctor_sem lock in the ioctl.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-05-11 14:54:41 +09:00

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/*
* nilfs.h - NILFS local header file.
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Written by Koji Sato <koji@osrg.net>
* Ryusuke Konishi <ryusuke@osrg.net>
*/
#ifndef _NILFS_H
#define _NILFS_H
#include <linux/kernel.h>
#include <linux/buffer_head.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/nilfs2_fs.h>
#include "the_nilfs.h"
#include "sb.h"
#include "bmap.h"
#include "bmap_union.h"
/*
* nilfs inode data in memory
*/
struct nilfs_inode_info {
__u32 i_flags;
unsigned long i_state; /* Dynamic state flags */
struct nilfs_bmap *i_bmap;
union nilfs_bmap_union i_bmap_union;
__u64 i_xattr; /* sector_t ??? */
__u32 i_dir_start_lookup;
__u64 i_cno; /* check point number for GC inode */
struct address_space i_btnode_cache;
struct list_head i_dirty; /* List for connecting dirty files */
#ifdef CONFIG_NILFS_XATTR
/*
* Extended attributes can be read independently of the main file
* data. Taking i_sem even when reading would cause contention
* between readers of EAs and writers of regular file data, so
* instead we synchronize on xattr_sem when reading or changing
* EAs.
*/
struct rw_semaphore xattr_sem;
#endif
#ifdef CONFIG_NILFS_POSIX_ACL
struct posix_acl *i_acl;
struct posix_acl *i_default_acl;
#endif
struct buffer_head *i_bh; /* i_bh contains a new or dirty
disk inode */
struct inode vfs_inode;
};
static inline struct nilfs_inode_info *NILFS_I(const struct inode *inode)
{
return container_of(inode, struct nilfs_inode_info, vfs_inode);
}
static inline struct nilfs_inode_info *
NILFS_BMAP_I(const struct nilfs_bmap *bmap)
{
return container_of((union nilfs_bmap_union *)bmap,
struct nilfs_inode_info,
i_bmap_union);
}
static inline struct inode *NILFS_BTNC_I(struct address_space *btnc)
{
struct nilfs_inode_info *ii =
container_of(btnc, struct nilfs_inode_info, i_btnode_cache);
return &ii->vfs_inode;
}
static inline struct inode *NILFS_AS_I(struct address_space *mapping)
{
return (mapping->host) ? :
container_of(mapping, struct inode, i_data);
}
/*
* Dynamic state flags of NILFS on-memory inode (i_state)
*/
enum {
NILFS_I_NEW = 0, /* Inode is newly created */
NILFS_I_DIRTY, /* The file is dirty */
NILFS_I_QUEUED, /* inode is in dirty_files list */
NILFS_I_BUSY, /* inode is grabbed by a segment
constructor */
NILFS_I_COLLECTED, /* All dirty blocks are collected */
NILFS_I_UPDATED, /* The file has been written back */
NILFS_I_INODE_DIRTY, /* write_inode is requested */
NILFS_I_BMAP, /* has bmap and btnode_cache */
NILFS_I_GCINODE, /* inode for GC, on memory only */
NILFS_I_GCDAT, /* shadow DAT, on memory only */
};
/*
* Macros to check inode numbers
*/
#define NILFS_MDT_INO_BITS \
((unsigned int)(1 << NILFS_DAT_INO | 1 << NILFS_CPFILE_INO | \
1 << NILFS_SUFILE_INO | 1 << NILFS_IFILE_INO | \
1 << NILFS_ATIME_INO | 1 << NILFS_SKETCH_INO))
#define NILFS_SYS_INO_BITS \
((unsigned int)(1 << NILFS_ROOT_INO) | NILFS_MDT_INO_BITS)
#define NILFS_FIRST_INO(sb) (NILFS_SB(sb)->s_nilfs->ns_first_ino)
#define NILFS_MDT_INODE(sb, ino) \
((ino) < NILFS_FIRST_INO(sb) && (NILFS_MDT_INO_BITS & (1 << (ino))))
#define NILFS_VALID_INODE(sb, ino) \
((ino) >= NILFS_FIRST_INO(sb) || (NILFS_SYS_INO_BITS & (1 << (ino))))
/**
* struct nilfs_transaction_info: context information for synchronization
* @ti_magic: Magic number
* @ti_save: Backup of journal_info field of task_struct
* @ti_flags: Flags
* @ti_count: Nest level
* @ti_garbage: List of inode to be put when releasing semaphore
*/
struct nilfs_transaction_info {
u32 ti_magic;
void *ti_save;
/* This should never used. If this happens,
one of other filesystems has a bug. */
unsigned short ti_flags;
unsigned short ti_count;
struct list_head ti_garbage;
};
/* ti_magic */
#define NILFS_TI_MAGIC 0xd9e392fb
/* ti_flags */
#define NILFS_TI_DYNAMIC_ALLOC 0x0001 /* Allocated from slab */
#define NILFS_TI_SYNC 0x0002 /* Force to construct segment at the
end of transaction. */
#define NILFS_TI_GC 0x0004 /* GC context */
#define NILFS_TI_COMMIT 0x0008 /* Change happened or not */
#define NILFS_TI_WRITER 0x0010 /* Constructor context */
int nilfs_transaction_begin(struct super_block *,
struct nilfs_transaction_info *, int);
int nilfs_transaction_commit(struct super_block *);
void nilfs_transaction_abort(struct super_block *);
static inline void nilfs_set_transaction_flag(unsigned int flag)
{
struct nilfs_transaction_info *ti = current->journal_info;
ti->ti_flags |= flag;
}
static inline int nilfs_test_transaction_flag(unsigned int flag)
{
struct nilfs_transaction_info *ti = current->journal_info;
if (ti == NULL || ti->ti_magic != NILFS_TI_MAGIC)
return 0;
return !!(ti->ti_flags & flag);
}
static inline int nilfs_doing_gc(void)
{
return nilfs_test_transaction_flag(NILFS_TI_GC);
}
static inline int nilfs_doing_construction(void)
{
return nilfs_test_transaction_flag(NILFS_TI_WRITER);
}
static inline struct inode *nilfs_dat_inode(const struct the_nilfs *nilfs)
{
return nilfs_doing_gc() ? nilfs->ns_gc_dat : nilfs->ns_dat;
}
/*
* function prototype
*/
#ifdef CONFIG_NILFS_POSIX_ACL
#error "NILFS: not yet supported POSIX ACL"
extern int nilfs_permission(struct inode *, int, struct nameidata *);
extern int nilfs_acl_chmod(struct inode *);
extern int nilfs_init_acl(struct inode *, struct inode *);
#else
#define nilfs_permission NULL
static inline int nilfs_acl_chmod(struct inode *inode)
{
return 0;
}
static inline int nilfs_init_acl(struct inode *inode, struct inode *dir)
{
inode->i_mode &= ~current_umask();
return 0;
}
#endif
#define NILFS_ATIME_DISABLE
/* dir.c */
extern int nilfs_add_link(struct dentry *, struct inode *);
extern ino_t nilfs_inode_by_name(struct inode *, struct dentry *);
extern int nilfs_make_empty(struct inode *, struct inode *);
extern struct nilfs_dir_entry *
nilfs_find_entry(struct inode *, struct dentry *, struct page **);
extern int nilfs_delete_entry(struct nilfs_dir_entry *, struct page *);
extern int nilfs_empty_dir(struct inode *);
extern struct nilfs_dir_entry *nilfs_dotdot(struct inode *, struct page **);
extern void nilfs_set_link(struct inode *, struct nilfs_dir_entry *,
struct page *, struct inode *);
/* file.c */
extern int nilfs_sync_file(struct file *, struct dentry *, int);
/* ioctl.c */
long nilfs_ioctl(struct file *, unsigned int, unsigned long);
int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *, struct nilfs_argv *,
void **);
/* inode.c */
extern struct inode *nilfs_new_inode(struct inode *, int);
extern void nilfs_free_inode(struct inode *);
extern int nilfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
extern void nilfs_set_inode_flags(struct inode *);
extern int nilfs_read_inode_common(struct inode *, struct nilfs_inode *);
extern void nilfs_write_inode_common(struct inode *, struct nilfs_inode *, int);
extern struct inode *nilfs_iget(struct super_block *, unsigned long);
extern void nilfs_update_inode(struct inode *, struct buffer_head *);
extern void nilfs_truncate(struct inode *);
extern void nilfs_delete_inode(struct inode *);
extern int nilfs_setattr(struct dentry *, struct iattr *);
extern int nilfs_load_inode_block(struct nilfs_sb_info *, struct inode *,
struct buffer_head **);
extern int nilfs_inode_dirty(struct inode *);
extern int nilfs_set_file_dirty(struct nilfs_sb_info *, struct inode *,
unsigned);
extern int nilfs_mark_inode_dirty(struct inode *);
extern void nilfs_dirty_inode(struct inode *);
/* namei.c */
extern struct dentry *nilfs_get_parent(struct dentry *);
/* super.c */
extern struct inode *nilfs_alloc_inode(struct super_block *);
extern void nilfs_destroy_inode(struct inode *);
extern void nilfs_error(struct super_block *, const char *, const char *, ...)
__attribute__ ((format (printf, 3, 4)));
extern void nilfs_warning(struct super_block *, const char *, const char *, ...)
__attribute__ ((format (printf, 3, 4)));
extern struct nilfs_super_block *
nilfs_read_super_block(struct super_block *, u64, int, struct buffer_head **);
extern int nilfs_store_magic_and_option(struct super_block *,
struct nilfs_super_block *, char *);
extern int nilfs_commit_super(struct nilfs_sb_info *, int);
extern int nilfs_attach_checkpoint(struct nilfs_sb_info *, __u64);
extern void nilfs_detach_checkpoint(struct nilfs_sb_info *);
/* gcinode.c */
int nilfs_gccache_submit_read_data(struct inode *, sector_t, sector_t, __u64,
struct buffer_head **);
int nilfs_gccache_submit_read_node(struct inode *, sector_t, __u64,
struct buffer_head **);
int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *);
int nilfs_init_gccache(struct the_nilfs *);
void nilfs_destroy_gccache(struct the_nilfs *);
void nilfs_clear_gcinode(struct inode *);
struct inode *nilfs_gc_iget(struct the_nilfs *, ino_t, __u64);
void nilfs_remove_all_gcinode(struct the_nilfs *);
/* gcdat.c */
int nilfs_init_gcdat_inode(struct the_nilfs *);
void nilfs_commit_gcdat_inode(struct the_nilfs *);
void nilfs_clear_gcdat_inode(struct the_nilfs *);
/*
* Inodes and files operations
*/
extern struct file_operations nilfs_dir_operations;
extern struct inode_operations nilfs_file_inode_operations;
extern struct file_operations nilfs_file_operations;
extern struct address_space_operations nilfs_aops;
extern struct inode_operations nilfs_dir_inode_operations;
extern struct inode_operations nilfs_special_inode_operations;
extern struct inode_operations nilfs_symlink_inode_operations;
/*
* filesystem type
*/
extern struct file_system_type nilfs_fs_type;
#endif /* _NILFS_H */
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