linux-hardened/fs/jffs2/jffs2_fs_sb.h
Artem Bityutskiy 8bdc81c506 jffs2: get rid of jffs2_sync_super
Currently JFFS2 file-system maps the VFS "superblock" abstraction to the
write-buffer. Namely, it uses VFS services to synchronize the write-buffer
periodically.

The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblock using the '->write_super()' call-back. But the
problem with this thread is that it wastes power by waking up the system every
5 seconds no matter what. So we want to kill it completely and thus, we need to
make file-systems to stop using the '->write_super' VFS service, and then
remove it together with the kernel thread.

This patch switches the JFFS2 write-buffer management from
'->write_super()'/'->s_dirt' to a delayed work. Instead of setting the 's_dirt'
flag we just schedule a delayed work for synchronizing the write-buffer.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-30 21:04:52 -04:00

164 lines
5.8 KiB
C

/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#ifndef _JFFS2_FS_SB
#define _JFFS2_FS_SB
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/rwsem.h>
#define JFFS2_SB_FLAG_RO 1
#define JFFS2_SB_FLAG_SCANNING 2 /* Flash scanning is in progress */
#define JFFS2_SB_FLAG_BUILDING 4 /* File system building is in progress */
struct jffs2_inodirty;
struct jffs2_mount_opts {
bool override_compr;
unsigned int compr;
/* The size of the reserved pool. The reserved pool is the JFFS2 flash
* space which may only be used by root cannot be used by the other
* users. This is implemented simply by means of not allowing the
* latter users to write to the file system if the amount if the
* available space is less then 'rp_size'. */
unsigned int rp_size;
};
/* A struct for the overall file system control. Pointers to
jffs2_sb_info structs are named `c' in the source code.
Nee jffs_control
*/
struct jffs2_sb_info {
struct mtd_info *mtd;
uint32_t highest_ino;
uint32_t checked_ino;
unsigned int flags;
struct task_struct *gc_task; /* GC task struct */
struct completion gc_thread_start; /* GC thread start completion */
struct completion gc_thread_exit; /* GC thread exit completion port */
struct mutex alloc_sem; /* Used to protect all the following
fields, and also to protect against
out-of-order writing of nodes. And GC. */
uint32_t cleanmarker_size; /* Size of an _inline_ CLEANMARKER
(i.e. zero for OOB CLEANMARKER */
uint32_t flash_size;
uint32_t used_size;
uint32_t dirty_size;
uint32_t wasted_size;
uint32_t free_size;
uint32_t erasing_size;
uint32_t bad_size;
uint32_t sector_size;
uint32_t unchecked_size;
uint32_t nr_free_blocks;
uint32_t nr_erasing_blocks;
/* Number of free blocks there must be before we... */
uint8_t resv_blocks_write; /* ... allow a normal filesystem write */
uint8_t resv_blocks_deletion; /* ... allow a normal filesystem deletion */
uint8_t resv_blocks_gctrigger; /* ... wake up the GC thread */
uint8_t resv_blocks_gcbad; /* ... pick a block from the bad_list to GC */
uint8_t resv_blocks_gcmerge; /* ... merge pages when garbage collecting */
/* Number of 'very dirty' blocks before we trigger immediate GC */
uint8_t vdirty_blocks_gctrigger;
uint32_t nospc_dirty_size;
uint32_t nr_blocks;
struct jffs2_eraseblock *blocks; /* The whole array of blocks. Used for getting blocks
* from the offset (blocks[ofs / sector_size]) */
struct jffs2_eraseblock *nextblock; /* The block we're currently filling */
struct jffs2_eraseblock *gcblock; /* The block we're currently garbage-collecting */
struct list_head clean_list; /* Blocks 100% full of clean data */
struct list_head very_dirty_list; /* Blocks with lots of dirty space */
struct list_head dirty_list; /* Blocks with some dirty space */
struct list_head erasable_list; /* Blocks which are completely dirty, and need erasing */
struct list_head erasable_pending_wbuf_list; /* Blocks which need erasing but only after the current wbuf is flushed */
struct list_head erasing_list; /* Blocks which are currently erasing */
struct list_head erase_checking_list; /* Blocks which are being checked and marked */
struct list_head erase_pending_list; /* Blocks which need erasing now */
struct list_head erase_complete_list; /* Blocks which are erased and need the clean marker written to them */
struct list_head free_list; /* Blocks which are free and ready to be used */
struct list_head bad_list; /* Bad blocks. */
struct list_head bad_used_list; /* Bad blocks with valid data in. */
spinlock_t erase_completion_lock; /* Protect free_list and erasing_list
against erase completion handler */
wait_queue_head_t erase_wait; /* For waiting for erases to complete */
wait_queue_head_t inocache_wq;
int inocache_hashsize;
struct jffs2_inode_cache **inocache_list;
spinlock_t inocache_lock;
/* Sem to allow jffs2_garbage_collect_deletion_dirent to
drop the erase_completion_lock while it's holding a pointer
to an obsoleted node. I don't like this. Alternatives welcomed. */
struct mutex erase_free_sem;
uint32_t wbuf_pagesize; /* 0 for NOR and other flashes with no wbuf */
#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
unsigned char *wbuf_verify; /* read-back buffer for verification */
#endif
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
unsigned char *wbuf; /* Write-behind buffer for NAND flash */
uint32_t wbuf_ofs;
uint32_t wbuf_len;
struct jffs2_inodirty *wbuf_inodes;
struct rw_semaphore wbuf_sem; /* Protects the write buffer */
struct delayed_work wbuf_dwork; /* write-buffer write-out work */
int wbuf_queued; /* non-zero delayed work is queued */
spinlock_t wbuf_dwork_lock; /* protects wbuf_dwork and and wbuf_queued */
unsigned char *oobbuf;
int oobavail; /* How many bytes are available for JFFS2 in OOB */
#endif
struct jffs2_summary *summary; /* Summary information */
struct jffs2_mount_opts mount_opts;
#ifdef CONFIG_JFFS2_FS_XATTR
#define XATTRINDEX_HASHSIZE (57)
uint32_t highest_xid;
uint32_t highest_xseqno;
struct list_head xattrindex[XATTRINDEX_HASHSIZE];
struct list_head xattr_unchecked;
struct list_head xattr_dead_list;
struct jffs2_xattr_ref *xref_dead_list;
struct jffs2_xattr_ref *xref_temp;
struct rw_semaphore xattr_sem;
uint32_t xdatum_mem_usage;
uint32_t xdatum_mem_threshold;
#endif
/* OS-private pointer for getting back to master superblock info */
void *os_priv;
};
#endif /* _JFFS2_FS_SB */