kernel-ark/fs/ext4/ext4_jbd2.h
Dmitry Monakhov 12e9b89200 ext4: Use bitops to read/modify i_flags in struct ext4_inode_info
At several places we modify EXT4_I(inode)->i_flags without holding
i_mutex (ext4_do_update_inode, ...). These modifications are racy and
we can lose updates to i_flags. So convert handling of i_flags to use
bitops which are atomic.

https://bugzilla.kernel.org/show_bug.cgi?id=15792

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2010-05-16 22:00:00 -04:00

332 lines
10 KiB
C

/*
* ext4_jbd2.h
*
* Written by Stephen C. Tweedie <sct@redhat.com>, 1999
*
* Copyright 1998--1999 Red Hat corp --- All Rights Reserved
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* Ext4-specific journaling extensions.
*/
#ifndef _EXT4_JBD2_H
#define _EXT4_JBD2_H
#include <linux/fs.h>
#include <linux/jbd2.h>
#include "ext4.h"
#define EXT4_JOURNAL(inode) (EXT4_SB((inode)->i_sb)->s_journal)
/* Define the number of blocks we need to account to a transaction to
* modify one block of data.
*
* We may have to touch one inode, one bitmap buffer, up to three
* indirection blocks, the group and superblock summaries, and the data
* block to complete the transaction.
*
* For extents-enabled fs we may have to allocate and modify up to
* 5 levels of tree + root which are stored in the inode. */
#define EXT4_SINGLEDATA_TRANS_BLOCKS(sb) \
(EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS) \
? 27U : 8U)
/* Extended attribute operations touch at most two data buffers,
* two bitmap buffers, and two group summaries, in addition to the inode
* and the superblock, which are already accounted for. */
#define EXT4_XATTR_TRANS_BLOCKS 6U
/* Define the minimum size for a transaction which modifies data. This
* needs to take into account the fact that we may end up modifying two
* quota files too (one for the group, one for the user quota). The
* superblock only gets updated once, of course, so don't bother
* counting that again for the quota updates. */
#define EXT4_DATA_TRANS_BLOCKS(sb) (EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + \
EXT4_XATTR_TRANS_BLOCKS - 2 + \
EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
/*
* Define the number of metadata blocks we need to account to modify data.
*
* This include super block, inode block, quota blocks and xattr blocks
*/
#define EXT4_META_TRANS_BLOCKS(sb) (EXT4_XATTR_TRANS_BLOCKS + \
EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
/* Delete operations potentially hit one directory's namespace plus an
* entire inode, plus arbitrary amounts of bitmap/indirection data. Be
* generous. We can grow the delete transaction later if necessary. */
#define EXT4_DELETE_TRANS_BLOCKS(sb) (2 * EXT4_DATA_TRANS_BLOCKS(sb) + 64)
/* Define an arbitrary limit for the amount of data we will anticipate
* writing to any given transaction. For unbounded transactions such as
* write(2) and truncate(2) we can write more than this, but we always
* start off at the maximum transaction size and grow the transaction
* optimistically as we go. */
#define EXT4_MAX_TRANS_DATA 64U
/* We break up a large truncate or write transaction once the handle's
* buffer credits gets this low, we need either to extend the
* transaction or to start a new one. Reserve enough space here for
* inode, bitmap, superblock, group and indirection updates for at least
* one block, plus two quota updates. Quota allocations are not
* needed. */
#define EXT4_RESERVE_TRANS_BLOCKS 12U
#define EXT4_INDEX_EXTRA_TRANS_BLOCKS 8
#ifdef CONFIG_QUOTA
/* Amount of blocks needed for quota update - we know that the structure was
* allocated so we need to update only inode+data */
#define EXT4_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 2 : 0)
/* Amount of blocks needed for quota insert/delete - we do some block writes
* but inode, sb and group updates are done only once */
#define EXT4_QUOTA_INIT_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_INIT_ALLOC*\
(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)+3+DQUOT_INIT_REWRITE) : 0)
#define EXT4_QUOTA_DEL_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_DEL_ALLOC*\
(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)+3+DQUOT_DEL_REWRITE) : 0)
#else
#define EXT4_QUOTA_TRANS_BLOCKS(sb) 0
#define EXT4_QUOTA_INIT_BLOCKS(sb) 0
#define EXT4_QUOTA_DEL_BLOCKS(sb) 0
#endif
#define EXT4_MAXQUOTAS_TRANS_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_TRANS_BLOCKS(sb))
#define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
#define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
int
ext4_mark_iloc_dirty(handle_t *handle,
struct inode *inode,
struct ext4_iloc *iloc);
/*
* On success, We end up with an outstanding reference count against
* iloc->bh. This _must_ be cleaned up later.
*/
int ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
struct ext4_iloc *iloc);
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode);
/*
* Wrapper functions with which ext4 calls into JBD.
*/
void ext4_journal_abort_handle(const char *caller, const char *err_fn,
struct buffer_head *bh, handle_t *handle, int err);
int __ext4_journal_get_undo_access(const char *where, handle_t *handle,
struct buffer_head *bh);
int __ext4_journal_get_write_access(const char *where, handle_t *handle,
struct buffer_head *bh);
int __ext4_forget(const char *where, handle_t *handle, int is_metadata,
struct inode *inode, struct buffer_head *bh,
ext4_fsblk_t blocknr);
int __ext4_journal_get_create_access(const char *where,
handle_t *handle, struct buffer_head *bh);
int __ext4_handle_dirty_metadata(const char *where, handle_t *handle,
struct inode *inode, struct buffer_head *bh);
#define ext4_journal_get_undo_access(handle, bh) \
__ext4_journal_get_undo_access(__func__, (handle), (bh))
#define ext4_journal_get_write_access(handle, bh) \
__ext4_journal_get_write_access(__func__, (handle), (bh))
#define ext4_forget(handle, is_metadata, inode, bh, block_nr) \
__ext4_forget(__func__, (handle), (is_metadata), (inode), (bh),\
(block_nr))
#define ext4_journal_get_create_access(handle, bh) \
__ext4_journal_get_create_access(__func__, (handle), (bh))
#define ext4_handle_dirty_metadata(handle, inode, bh) \
__ext4_handle_dirty_metadata(__func__, (handle), (inode), (bh))
handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks);
int __ext4_journal_stop(const char *where, handle_t *handle);
#define EXT4_NOJOURNAL_MAX_REF_COUNT ((unsigned long) 4096)
/* Note: Do not use this for NULL handles. This is only to determine if
* a properly allocated handle is using a journal or not. */
static inline int ext4_handle_valid(handle_t *handle)
{
if ((unsigned long)handle < EXT4_NOJOURNAL_MAX_REF_COUNT)
return 0;
return 1;
}
static inline void ext4_handle_sync(handle_t *handle)
{
if (ext4_handle_valid(handle))
handle->h_sync = 1;
}
static inline void ext4_handle_release_buffer(handle_t *handle,
struct buffer_head *bh)
{
if (ext4_handle_valid(handle))
jbd2_journal_release_buffer(handle, bh);
}
static inline int ext4_handle_is_aborted(handle_t *handle)
{
if (ext4_handle_valid(handle))
return is_handle_aborted(handle);
return 0;
}
static inline int ext4_handle_has_enough_credits(handle_t *handle, int needed)
{
if (ext4_handle_valid(handle) && handle->h_buffer_credits < needed)
return 0;
return 1;
}
static inline void ext4_journal_release_buffer(handle_t *handle,
struct buffer_head *bh)
{
if (ext4_handle_valid(handle))
jbd2_journal_release_buffer(handle, bh);
}
static inline handle_t *ext4_journal_start(struct inode *inode, int nblocks)
{
return ext4_journal_start_sb(inode->i_sb, nblocks);
}
#define ext4_journal_stop(handle) \
__ext4_journal_stop(__func__, (handle))
static inline handle_t *ext4_journal_current_handle(void)
{
return journal_current_handle();
}
static inline int ext4_journal_extend(handle_t *handle, int nblocks)
{
if (ext4_handle_valid(handle))
return jbd2_journal_extend(handle, nblocks);
return 0;
}
static inline int ext4_journal_restart(handle_t *handle, int nblocks)
{
if (ext4_handle_valid(handle))
return jbd2_journal_restart(handle, nblocks);
return 0;
}
static inline int ext4_journal_blocks_per_page(struct inode *inode)
{
if (EXT4_JOURNAL(inode) != NULL)
return jbd2_journal_blocks_per_page(inode);
return 0;
}
static inline int ext4_journal_force_commit(journal_t *journal)
{
if (journal)
return jbd2_journal_force_commit(journal);
return 0;
}
static inline int ext4_jbd2_file_inode(handle_t *handle, struct inode *inode)
{
if (ext4_handle_valid(handle))
return jbd2_journal_file_inode(handle, &EXT4_I(inode)->jinode);
return 0;
}
static inline void ext4_update_inode_fsync_trans(handle_t *handle,
struct inode *inode,
int datasync)
{
struct ext4_inode_info *ei = EXT4_I(inode);
if (ext4_handle_valid(handle)) {
ei->i_sync_tid = handle->h_transaction->t_tid;
if (datasync)
ei->i_datasync_tid = handle->h_transaction->t_tid;
}
}
/* super.c */
int ext4_force_commit(struct super_block *sb);
static inline int ext4_should_journal_data(struct inode *inode)
{
if (EXT4_JOURNAL(inode) == NULL)
return 0;
if (!S_ISREG(inode->i_mode))
return 1;
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
return 1;
if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
return 1;
return 0;
}
static inline int ext4_should_order_data(struct inode *inode)
{
if (EXT4_JOURNAL(inode) == NULL)
return 0;
if (!S_ISREG(inode->i_mode))
return 0;
if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
return 0;
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
return 1;
return 0;
}
static inline int ext4_should_writeback_data(struct inode *inode)
{
if (!S_ISREG(inode->i_mode))
return 0;
if (EXT4_JOURNAL(inode) == NULL)
return 1;
if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
return 0;
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
return 1;
return 0;
}
/*
* This function controls whether or not we should try to go down the
* dioread_nolock code paths, which makes it safe to avoid taking
* i_mutex for direct I/O reads. This only works for extent-based
* files, and it doesn't work for nobh or if data journaling is
* enabled, since the dioread_nolock code uses b_private to pass
* information back to the I/O completion handler, and this conflicts
* with the jbd's use of b_private.
*/
static inline int ext4_should_dioread_nolock(struct inode *inode)
{
if (!test_opt(inode->i_sb, DIOREAD_NOLOCK))
return 0;
if (test_opt(inode->i_sb, NOBH))
return 0;
if (!S_ISREG(inode->i_mode))
return 0;
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
return 0;
if (ext4_should_journal_data(inode))
return 0;
return 1;
}
#endif /* _EXT4_JBD2_H */