linux/fs/jffs2/jffs2_fs_sb.h
Andres Salomon 92abc475d8 jffs2: implement mount option parsing and compression overriding
Currently jffs2 has compile-time constants (and .config options)
controlling whether or not the various compression/decompression
drivers are built in and enabled.  This is fine for embedded
systems, but it clashes with distribution kernels.  Distro kernels
tend to turn on everything; this causes OpenFirmware to fall
over, as it understands ZLIB-compressed inodes.  Booting a kernel
that has LZO compression enabled, writing to the boot partition,
and then rebooting causes OFW to fail to read the kernel from
the filesystem.  This is because LZO compression has priority
when writing new data to jffs2, if LZO is enabled.

This patch adds mount option parsing, and a single supported
option ("compr=none").  This adds the flexibility of being
able to specify which compressor overrides on a per-superblock
basis.  For now, we can simply disable compression;
additional flexibility coming soon.

v2: kill some printks, and implement show_options as suggested
by Artem Bityutskiy.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-10-19 17:22:20 +03:00

153 lines
5.2 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;
};
/* 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 */
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 */