| /* |
| * linux/include/linux/jfs.h |
| * |
| * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 |
| * |
| * Copyright 1998 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. |
| * |
| * Definitions for transaction data structures for the buffer cache |
| * filesystem journaling support. |
| */ |
| |
| #ifndef _LINUX_JFS_H |
| #define _LINUX_JFS_H |
| |
| #ifndef __KERNEL__ |
| #include "jfs_compat.h" |
| #endif |
| |
| /* |
| * Debug code |
| */ |
| |
| /* #define JFS_DEBUG */ |
| |
| #ifdef JFS_DEBUG |
| extern int jfs_enable_debug; |
| |
| #define jfs_debug(n, f, a...) \ |
| do { \ |
| if ((n) <= jfs_enable_debug) { \ |
| printk (KERN_DEBUG "JFS DEBUG: (%s, %d): %s: ", \ |
| __FILE__, __LINE__, __FUNCTION__); \ |
| printk (f, ## a); \ |
| } \ |
| } while (0) |
| #else |
| #define jfs_debug(f, a...) /**/ |
| #endif |
| |
| #define JFS_MIN_JOURNAL_BLOCKS 1024 |
| |
| /* |
| * Internal structures used by the logging mechanism: |
| */ |
| |
| #define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */ |
| |
| |
| /* |
| * On-disk structures |
| */ |
| |
| /* |
| * Descriptor block types: |
| */ |
| |
| #define JFS_DESCRIPTOR_BLOCK 1 |
| #define JFS_COMMIT_BLOCK 2 |
| #define JFS_SUPERBLOCK 3 |
| |
| /* |
| * Standard header for all descriptor blocks: |
| */ |
| typedef struct journal_header_s |
| { |
| __u32 h_magic; |
| __u32 h_blocktype; |
| __u32 h_sequence; |
| } journal_header_t; |
| |
| |
| /* |
| * The block tag: used to describe a single buffer in the journal |
| */ |
| typedef struct journal_block_tag_s |
| { |
| __u32 t_blocknr; /* The on-disk block number */ |
| __u32 t_flags; /* See below */ |
| } journal_block_tag_t; |
| |
| /* Definitions for the journal tag flags word: */ |
| #define JFS_FLAG_ESCAPE 1 /* on-disk block is escaped */ |
| #define JFS_FLAG_SAME_UUID 2 /* block has same uuid as previous */ |
| #define JFS_FLAG_DELETED 4 /* block deleted by this transaction */ |
| #define JFS_FLAG_LAST_TAG 8 /* last tag in this descriptor block */ |
| |
| |
| /* |
| * The journal superblock |
| */ |
| typedef struct journal_superblock_s |
| { |
| journal_header_t s_header; |
| |
| /* Static information describing the journal */ |
| __u32 s_blocksize; /* journal device blocksize */ |
| __u32 s_maxlen; /* total blocks in journal file */ |
| __u32 s_first; /* first block of log information */ |
| |
| /* Dynamic information describing the current state of the log */ |
| __u32 s_sequence; /* first commit ID expected in log */ |
| __u32 s_start; /* blocknr of start of log */ |
| |
| } journal_superblock_t; |
| |
| #ifdef __KERNEL__ |
| |
| #include <asm/semaphone.h> |
| #include <linux/fs.h> |
| |
| |
| #define J_ASSERT(assert) \ |
| do { if (!(assert)) { \ |
| printk (KERN_CRIT \ |
| "Assertion failure in %s() at %s line %d: " \ |
| "\"%s\"\n", \ |
| __FUNCTION__, __FILE__, __LINE__, # assert); \ |
| * ((char *) 0) = 0; \ |
| } } while (0) |
| |
| |
| |
| /* The handle_t type represents a single atomic update being performed |
| * by some process. All filesystem modifications made by the process go |
| * through this handle. Recursive operations (such as quota operations) |
| * are gathered into a single update. |
| * |
| * The buffer credits field is used to account for journaled buffers |
| * being modified by the running process. To ensure that there is |
| * enough log space for all outstanding operations, we need to limit the |
| * number of outstanding buffers possible at any time. When the |
| * operation completes, any buffer credits not used are credited back to |
| * the transaction, so that at all times we know how many buffers the |
| * outstanding updates on a transaction might possibly touch. */ |
| |
| struct handle_s |
| { |
| /* Which compound transaction is this update a part of? */ |
| transaction_t * h_transaction; |
| |
| /* Number of remaining buffers we are allowed to dirty: */ |
| int h_buffer_credits; |
| |
| /* Reference count on this handle */ |
| int h_ref; |
| |
| /* Flags */ |
| unsigned int h_sync : 1; /* sync-on-close */ |
| }; |
| |
| |
| /* The transaction_t type is the guts of the journaling mechanism. It |
| * tracks a compound transaction through its various states: |
| * |
| * RUNNING: accepting new updates |
| * LOCKED: Updates still running but we don't accept new ones |
| * RUNDOWN: Updates are tidying up but have finished requesting |
| * new buffers to modify (state not used for now) |
| * FLUSH: All updates complete, but we are still writing to disk |
| * COMMIT: All data on disk, writing commit record |
| * FINISHED: We still have to keep the transaction for checkpointing. |
| * |
| * The transaction keeps track of all of the buffers modified by a |
| * running transaction, and all of the buffers committed but not yet |
| * flushed to home for finished transactions. |
| */ |
| |
| struct transaction_s |
| { |
| /* Pointer to the journal for this transaction. */ |
| journal_t * t_journal; |
| |
| /* Sequence number for this transaction */ |
| tid_t t_tid; |
| |
| /* Transaction's current state */ |
| enum { |
| T_RUNNING, |
| T_LOCKED, |
| T_RUNDOWN, |
| T_FLUSH, |
| T_COMMIT, |
| T_FINISHED |
| } t_state; |
| |
| /* Where in the log does this transaction's commit start? */ |
| unsigned long t_log_start; |
| |
| /* Doubly-linked circular list of all inodes owned by this |
| transaction */ |
| struct inode * t_ilist; |
| |
| /* Number of buffers on the t_buffers list */ |
| int t_nr_buffers; |
| |
| /* Doubly-linked circular list of all buffers reserved but not |
| yet modified by this transaction */ |
| struct buffer_head * t_reserved_list; |
| |
| /* Doubly-linked circular list of all metadata buffers owned by this |
| transaction */ |
| struct buffer_head * t_buffers; |
| |
| /* Doubly-linked circular list of all data buffers still to be |
| flushed before this transaction can be committed */ |
| struct buffer_head * t_datalist; |
| |
| /* Doubly-linked circular list of all forget buffers (superceded |
| buffers which we can un-checkpoint once this transaction |
| commits) */ |
| struct buffer_head * t_forget; |
| |
| /* Doubly-linked circular list of all buffers still to be |
| flushed before this transaction can be checkpointed */ |
| struct buffer_head * t_checkpoint_list; |
| |
| /* Doubly-linked circular list of temporary buffers currently |
| undergoing IO in the log */ |
| struct buffer_head * t_iobuf_list; |
| |
| /* Doubly-linked circular list of metadata buffers being |
| shadowed by log IO. The IO buffers on the iobuf list and the |
| shadow buffers on this list match each other one for one at |
| all times. */ |
| struct buffer_head * t_shadow_list; |
| |
| /* Doubly-linked circular list of control buffers being written |
| to the log. */ |
| struct buffer_head * t_log_list; |
| |
| /* Number of outstanding updates running on this transaction */ |
| int t_updates; |
| |
| /* Number of buffers reserved for use by all handles in this |
| * transaction handle but not yet modified. */ |
| int t_outstanding_credits; |
| |
| /* Wait queue to wait for updates to complete */ |
| struct wait_queue * t_wait; |
| |
| /* Forward and backward links for the circular list of all |
| * transactions awaiting checkpoint */ |
| transaction_t *t_cpnext, *t_cpprev; |
| |
| /* When will the transaction expire (become due for commit), in |
| * jiffies ? */ |
| unsigned long t_expires; |
| }; |
| #endif /* __KERNEL__ */ |
| |
| |
| /* The journal_t maintains all of the journaling state information for a |
| * single filesystem. It is linked to from the fs superblock structure. |
| * |
| * We use the journal_t to keep track of all outstanding transaction |
| * activity on the filesystem, and to manage the state of the log |
| * writing process. */ |
| |
| struct journal_s |
| { |
| /* General journaling state flags */ |
| unsigned long j_flags; |
| |
| /* The superblock buffer */ |
| struct buffer_head * j_sb_buffer; |
| journal_superblock_t * j_superblock; |
| |
| #ifdef __KERNEL__ |
| /* Transactions: The current running transaction... */ |
| transaction_t * j_running_transaction; |
| |
| /* ... the transaction we are pushing to disk ... */ |
| transaction_t * j_committing_transaction; |
| |
| /* ... and a linked circular list of all transactions waiting |
| * for checkpointing. */ |
| transaction_t * j_checkpoint_transactions; |
| |
| /* Wait queue for locking of the journal structure. */ |
| struct wait_queue * j_wait_lock; |
| |
| /* Wait queue for waiting for a locked transaction to start |
| committing */ |
| struct wait_queue * j_wait_transaction_locked; |
| |
| /* Wait queue for waiting for checkpointing to complete */ |
| struct wait_queue * j_wait_logspace; |
| |
| /* Wait queue for waiting for commit to complete */ |
| struct wait_queue * j_wait_done_commit; |
| |
| /* Wait queue to trigger checkpointing */ |
| struct wait_queue * j_wait_checkpoint; |
| |
| /* Wait queue to trigger commit */ |
| struct wait_queue * j_wait_commit; |
| |
| /* Semaphore for locking against concurrent checkpoints */ |
| struct semaphore j_checkpoint_sem; |
| |
| /* Journal running state: */ |
| /* The lock flag is *NEVER* touched from interrupts. */ |
| unsigned int j_locked : 1; |
| |
| /* Pointer to the current commit thread for this journal */ |
| struct task_struct * j_task; |
| |
| /* The timer used to wakeup the commit thread: */ |
| struct timer_list * j_commit_timer; |
| int j_commit_timer_active; |
| #endif |
| |
| /* Journal head: identifies the first unused block in the journal. */ |
| unsigned long j_head; |
| |
| /* Journal tail: identifies the oldest still-used block in the |
| * journal. */ |
| unsigned long j_tail; |
| |
| /* Journal free: how many free blocks are there in the journal? */ |
| unsigned long j_free; |
| |
| /* Journal start and end: the block numbers of the first usable |
| * block and one beyond the last usable block in the journal. */ |
| unsigned long j_first, j_last; |
| |
| /* Device, blocksize and starting block offset for the location |
| * where we store the journal. */ |
| kdev_t j_dev; |
| int j_blocksize; |
| unsigned int j_blk_offset; |
| |
| /* Total maximum capacity of the journal region on disk. */ |
| unsigned int j_maxlen; |
| |
| /* Optional inode where we store the journal. If present, all |
| * journal block numbers are mapped into this inode via |
| * bmap(). */ |
| struct inode * j_inode; |
| |
| /* Sequence number of the oldest transaction in the log */ |
| tid_t j_tail_sequence; |
| /* Sequence number of the next transaction to grant */ |
| tid_t j_transaction_sequence; |
| /* Sequence number of the most recently committed transaction */ |
| tid_t j_commit_sequence; |
| /* Sequence number of the most recent transaction wanting commit */ |
| tid_t j_commit_request; |
| |
| /* Journal uuid: identifies the object (filesystem, LVM volume |
| * etc) backed by this journal. This will eventually be |
| * replaced by an array of uuids, allowing us to index multiple |
| * devices within a single journal and to perform atomic updates |
| * across them. */ |
| |
| __u8 j_uuid[16]; |
| |
| /* Maximum number of metadata buffers to allow in a single |
| * compound commit transaction */ |
| int j_max_transaction_buffers; |
| |
| /* What is the maximum transaction lifetime before we begin a |
| * commit? */ |
| unsigned long j_commit_interval; |
| |
| }; |
| |
| #ifdef __KERNEL__ |
| |
| /* |
| * Journal flag definitions |
| */ |
| #define JFS_UNMOUNT 1 /* Journal thread is being destroyed */ |
| #define JFS_SYNC 2 /* Perform synchronous transaction commits */ |
| |
| /* |
| * Journaling internal variables/parameters |
| */ |
| |
| extern int journal_flush_nr_buffers; |
| |
| |
| /* |
| * Function declarations for the journaling transaction and buffer |
| * management |
| */ |
| |
| /* Filing buffers */ |
| extern void journal_unfile_buffer(struct buffer_head *); |
| extern void journal_refile_buffer(struct buffer_head *); |
| extern void journal_file_buffer(struct buffer_head *, transaction_t *, int); |
| extern void journal_clean_data_list(transaction_t *transaction); |
| |
| /* Log buffer allocation */ |
| extern struct buffer_head * journal_get_descriptor_buffer(journal_t *); |
| extern unsigned long journal_next_log_block(journal_t *); |
| |
| /* Commit management */ |
| extern void journal_commit_transaction(journal_t *); |
| |
| /* Checkpoint list management */ |
| extern void journal_remove_checkpoint(struct buffer_head *); |
| extern void journal_insert_checkpoint(struct buffer_head *, transaction_t *); |
| |
| /* Buffer IO */ |
| extern int |
| journal_write_metadata_buffer(transaction_t *transaction, |
| struct buffer_head *bh_in, |
| struct buffer_head **bh_out, |
| int blocknr); |
| |
| /* Create and destroy transactions */ |
| extern transaction_t * get_transaction (journal_t *); |
| extern void put_transaction (transaction_t *); |
| |
| /* Notify state transitions (called by the log writer thread): */ |
| extern int set_transaction_state (transaction_t *, int); |
| |
| |
| /* |
| * Transaction locking |
| * |
| * We need to lock the journal during transaction state changes so that |
| * nobody ever tries to take a handle on the running transaction while |
| * we are in the middle of moving it to the commit phase. |
| * |
| * Note that the locking is completely interrupt unsafe. We never touch |
| * journal structures from interrupts. |
| */ |
| |
| static inline void __wait_on_journal (journal_t * journal) |
| { |
| while (journal->j_locked) |
| sleep_on (&journal->j_wait_lock); |
| } |
| |
| |
| /* Journal locking. In 2.2, we assume that the kernel lock is already |
| * held. */ |
| static inline void lock_journal (journal_t * journal) |
| { |
| if (journal->j_locked) |
| __wait_on_journal(journal); |
| journal->j_locked = 1; |
| } |
| |
| static inline int try_lock_journal (journal_t * journal) |
| { |
| if (journal->j_locked) |
| return 1; |
| journal->j_locked = 1; |
| return 0; |
| } |
| |
| static inline void unlock_journal (journal_t * journal) |
| { |
| J_ASSERT (journal->j_locked); |
| journal->j_locked = 0; |
| wake_up(&journal->j_wait_lock); |
| } |
| |
| /* This function is gross, but unfortunately we need it as long as |
| * existing filesystems want to guard against races by testing |
| * bh->b_count. @@@ Remove this? We no longer abuse b_count so badly! |
| */ |
| |
| static inline int journal_is_buffer_shared(struct buffer_head *bh) |
| { |
| int count = bh->b_count; |
| J_ASSERT (count >= 1); |
| return (count > 1); |
| } |
| |
| /* Debugging code only: */ |
| |
| #define jfs_ENOSYS() \ |
| do { \ |
| printk (KERN_ERR "JFS unimplemented function " __FUNCTION__); \ |
| current->state = TASK_UNINTERRUPTIBLE; \ |
| schedule(); \ |
| } while (1) |
| |
| /* The log thread user interface: |
| * |
| * Request space in the current transaction, and force transaction commit |
| * transitions on demand. |
| */ |
| |
| extern int log_space_left (journal_t *); /* Called with journal locked */ |
| extern void log_start_commit (journal_t *, transaction_t *); |
| extern void log_wait_commit (journal_t *, tid_t); |
| extern int log_do_checkpoint (journal_t *, int); |
| |
| extern void log_wait_for_space(journal_t *, int nblocks); |
| extern void journal_drop_transaction(journal_t *, transaction_t *); |
| |
| |
| /* The journaling code user interface: |
| * |
| * Create and destroy handles |
| * Register buffer modifications against the current transaction. |
| */ |
| |
| extern handle_t *journal_start (journal_t *, int nblocks); |
| extern int journal_restart (handle_t *, int nblocks); |
| extern int journal_extend (handle_t *, int nblocks); |
| extern int journal_get_write_access (handle_t *, struct buffer_head *); |
| extern int journal_get_create_access (handle_t *, struct buffer_head *); |
| extern int journal_get_undo_access (handle_t *, struct buffer_head *); |
| extern int journal_dirty_data (handle_t *, struct buffer_head *); |
| extern int journal_dirty_metadata (handle_t *, struct buffer_head *); |
| extern void journal_release_buffer (handle_t *, struct buffer_head *); |
| extern void journal_forget (handle_t *, struct buffer_head *); |
| extern void journal_sync_buffer (struct buffer_head *); |
| extern int journal_stop (handle_t *); |
| extern int journal_flush (journal_t *); |
| |
| extern journal_t * journal_init_dev (kdev_t, int start, int len, int bsize); |
| extern journal_t * journal_init_inode (struct inode *); |
| extern int journal_create (journal_t *); |
| extern int journal_load (journal_t *); |
| extern void journal_release (journal_t *); |
| extern void journal_update_superblock (journal_t *, int); |
| #endif /* __KERNEL__ */ |
| extern int journal_recover (journal_t *); |
| |
| #endif /* _LINUX_JFS_H */ |