| /* |
| * linux/include/linux/jbd.h |
| * |
| * Written by Stephen C. Tweedie <sct@redhat.com> |
| * |
| * Copyright 1998-2000 Red Hat, Inc --- 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_JBD_H |
| #define _LINUX_JBD_H |
| |
| /* Allow this file to be included directly into e2fsprogs */ |
| #include "jfs_compat.h" |
| #define JFS_DEBUG |
| #define jfs_debug jbd_debug |
| |
| #define journal_oom_retry 1 |
| |
| /* |
| * Define JBD_PARANIOD_IOFAIL to cause a kernel BUG() if ext3 finds |
| * certain classes of error which can occur due to failed IOs. Under |
| * normal use we want ext3 to continue after such errors, because |
| * hardware _can_ fail, but for debugging purposes when running tests on |
| * known-good hardware we may want to trap these errors. |
| */ |
| #undef JBD_PARANOID_IOFAIL |
| |
| /* |
| * The default maximum commit age, in seconds. |
| */ |
| #define JBD_DEFAULT_MAX_COMMIT_AGE 5 |
| |
| #ifdef CONFIG_JBD_DEBUG |
| /* |
| * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal |
| * consistency checks. By default we don't do this unless |
| * CONFIG_JBD_DEBUG is on. |
| */ |
| #define JBD_EXPENSIVE_CHECKING |
| extern u8 journal_enable_debug; |
| |
| #define jbd_debug(n, f, a...) \ |
| do { \ |
| if ((n) <= journal_enable_debug) { \ |
| printk (KERN_DEBUG "(%s, %d): %s: ", \ |
| __FILE__, __LINE__, __FUNCTION__); \ |
| printk (f, ## a); \ |
| } \ |
| } while (0) |
| #else |
| #define jbd_debug(f, a...) /**/ |
| #endif |
| |
| static __inline__ void *jbd_alloc(size_t size, gfp_t flags) |
| { |
| return (void *)__get_free_pages(flags, get_order(size)); |
| } |
| |
| static __inline__ void jbd_free(void *ptr, size_t size) |
| { |
| free_pages((unsigned long)ptr, get_order(size)); |
| }; |
| |
| #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_V1 3 |
| #define JFS_SUPERBLOCK_V2 4 |
| #define JFS_REVOKE_BLOCK 5 |
| |
| /* |
| * Standard header for all descriptor blocks: |
| */ |
| typedef struct journal_header_s |
| { |
| __be32 h_magic; |
| __be32 h_blocktype; |
| __be32 h_sequence; |
| } journal_header_t; |
| |
| |
| /* |
| * The block tag: used to describe a single buffer in the journal |
| */ |
| typedef struct journal_block_tag_s |
| { |
| __be32 t_blocknr; /* The on-disk block number */ |
| __be32 t_flags; /* See below */ |
| } journal_block_tag_t; |
| |
| /* |
| * The revoke descriptor: used on disk to describe a series of blocks to |
| * be revoked from the log |
| */ |
| typedef struct journal_revoke_header_s |
| { |
| journal_header_t r_header; |
| __be32 r_count; /* Count of bytes used in the block */ |
| } journal_revoke_header_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. All fields are in big-endian byte order. |
| */ |
| typedef struct journal_superblock_s |
| { |
| /* 0x0000 */ |
| journal_header_t s_header; |
| |
| /* 0x000C */ |
| /* Static information describing the journal */ |
| __be32 s_blocksize; /* journal device blocksize */ |
| __be32 s_maxlen; /* total blocks in journal file */ |
| __be32 s_first; /* first block of log information */ |
| |
| /* 0x0018 */ |
| /* Dynamic information describing the current state of the log */ |
| __be32 s_sequence; /* first commit ID expected in log */ |
| __be32 s_start; /* blocknr of start of log */ |
| |
| /* 0x0020 */ |
| /* Error value, as set by journal_abort(). */ |
| __be32 s_errno; |
| |
| /* 0x0024 */ |
| /* Remaining fields are only valid in a version-2 superblock */ |
| __be32 s_feature_compat; /* compatible feature set */ |
| __be32 s_feature_incompat; /* incompatible feature set */ |
| __be32 s_feature_ro_compat; /* readonly-compatible feature set */ |
| /* 0x0030 */ |
| __u8 s_uuid[16]; /* 128-bit uuid for journal */ |
| |
| /* 0x0040 */ |
| __be32 s_nr_users; /* Nr of filesystems sharing log */ |
| |
| __be32 s_dynsuper; /* Blocknr of dynamic superblock copy*/ |
| |
| /* 0x0048 */ |
| __be32 s_max_transaction; /* Limit of journal blocks per trans.*/ |
| __be32 s_max_trans_data; /* Limit of data blocks per trans. */ |
| |
| /* 0x0050 */ |
| __u32 s_padding[44]; |
| |
| /* 0x0100 */ |
| __u8 s_users[16*48]; /* ids of all fs'es sharing the log */ |
| /* 0x0400 */ |
| } journal_superblock_t; |
| |
| #define JFS_HAS_COMPAT_FEATURE(j,mask) \ |
| ((j)->j_format_version >= 2 && \ |
| ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask)))) |
| #define JFS_HAS_RO_COMPAT_FEATURE(j,mask) \ |
| ((j)->j_format_version >= 2 && \ |
| ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask)))) |
| #define JFS_HAS_INCOMPAT_FEATURE(j,mask) \ |
| ((j)->j_format_version >= 2 && \ |
| ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask)))) |
| |
| #define JFS_FEATURE_INCOMPAT_REVOKE 0x00000001 |
| |
| /* Features known to this kernel version: */ |
| #define JFS_KNOWN_COMPAT_FEATURES 0 |
| #define JFS_KNOWN_ROCOMPAT_FEATURES 0 |
| #define JFS_KNOWN_INCOMPAT_FEATURES JFS_FEATURE_INCOMPAT_REVOKE |
| |
| |
| /* Comparison functions for transaction IDs: perform comparisons using |
| * modulo arithmetic so that they work over sequence number wraps. */ |
| |
| static __inline__ int tid_gt(tid_t x, tid_t y) |
| { |
| int difference = (x - y); |
| return (difference > 0); |
| } |
| |
| static __inline__ int tid_geq(tid_t x, tid_t y) |
| { |
| int difference = (x - y); |
| return (difference >= 0); |
| } |
| |
| extern int journal_blocks_per_page(struct inode *inode); |
| |
| /* |
| * Return the minimum number of blocks which must be free in the journal |
| * before a new transaction may be started. Must be called under j_state_lock. |
| */ |
| static __inline__ int jbd_space_needed(journal_t *journal) |
| { |
| int nblocks = journal->j_max_transaction_buffers; |
| if (journal->j_committing_transaction) |
| nblocks += journal->j_committing_transaction-> |
| t_outstanding_credits; |
| return nblocks; |
| } |
| |
| /* |
| * Definitions which augment the buffer_head layer |
| */ |
| |
| /* journaling buffer types */ |
| #define BJ_None 0 /* Not journaled */ |
| #define BJ_SyncData 1 /* Normal data: flush before commit */ |
| #define BJ_Metadata 2 /* Normal journaled metadata */ |
| #define BJ_Forget 3 /* Buffer superseded by this transaction */ |
| #define BJ_IO 4 /* Buffer is for temporary IO use */ |
| #define BJ_Shadow 5 /* Buffer contents being shadowed to the log */ |
| #define BJ_LogCtl 6 /* Buffer contains log descriptors */ |
| #define BJ_Reserved 7 /* Buffer is reserved for access by journal */ |
| #define BJ_Locked 8 /* Locked for I/O during commit */ |
| #define BJ_Types 9 |
| |
| extern int jbd_blocks_per_page(struct inode *inode); |
| |
| |
| #endif /* _LINUX_JBD_H */ |