diff options
Diffstat (limited to 'include/linux/jbd2.h')
| -rw-r--r-- | include/linux/jbd2.h | 1407 |
1 files changed, 1407 insertions, 0 deletions
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h new file mode 100644 index 000000000..edb640ae9 --- /dev/null +++ b/include/linux/jbd2.h @@ -0,0 +1,1407 @@ +/* + * linux/include/linux/jbd2.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_JBD2_H +#define _LINUX_JBD2_H + +/* Allow this file to be included directly into e2fsprogs */ +#ifndef __KERNEL__ +#include "jfs_compat.h" +#define JBD2_DEBUG +#else + +#include <linux/types.h> +#include <linux/buffer_head.h> +#include <linux/journal-head.h> +#include <linux/stddef.h> +#include <linux/mutex.h> +#include <linux/timer.h> +#include <linux/slab.h> +#include <crypto/hash.h> +#endif + +#define journal_oom_retry 1 + +/* + * Define JBD2_PARANIOD_IOFAIL to cause a kernel BUG() if ext4 finds + * certain classes of error which can occur due to failed IOs. Under + * normal use we want ext4 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 JBD2_PARANOID_IOFAIL + +/* + * The default maximum commit age, in seconds. + */ +#define JBD2_DEFAULT_MAX_COMMIT_AGE 5 + +#ifdef CONFIG_JBD2_DEBUG +/* + * Define JBD2_EXPENSIVE_CHECKING to enable more expensive internal + * consistency checks. By default we don't do this unless + * CONFIG_JBD2_DEBUG is on. + */ +#define JBD2_EXPENSIVE_CHECKING +extern ushort jbd2_journal_enable_debug; +void __jbd2_debug(int level, const char *file, const char *func, + unsigned int line, const char *fmt, ...); + +#define jbd_debug(n, fmt, a...) \ + __jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a) +#else +#define jbd_debug(n, fmt, a...) /**/ +#endif + +extern void *jbd2_alloc(size_t size, gfp_t flags); +extern void jbd2_free(void *ptr, size_t size); + +#define JBD2_MIN_JOURNAL_BLOCKS 1024 + +#ifdef __KERNEL__ + +/** + * typedef handle_t - 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. + * + * This is an opaque datatype. + **/ +typedef struct jbd2_journal_handle handle_t; /* Atomic operation type */ + + +/** + * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem. + * + * journal_t 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. + * + * This is an opaque datatype. + **/ +typedef struct journal_s journal_t; /* Journal control structure */ +#endif + +/* + * Internal structures used by the logging mechanism: + */ + +#define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */ + +/* + * On-disk structures + */ + +/* + * Descriptor block types: + */ + +#define JBD2_DESCRIPTOR_BLOCK 1 +#define JBD2_COMMIT_BLOCK 2 +#define JBD2_SUPERBLOCK_V1 3 +#define JBD2_SUPERBLOCK_V2 4 +#define JBD2_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; + +/* + * Checksum types. + */ +#define JBD2_CRC32_CHKSUM 1 +#define JBD2_MD5_CHKSUM 2 +#define JBD2_SHA1_CHKSUM 3 +#define JBD2_CRC32C_CHKSUM 4 + +#define JBD2_CRC32_CHKSUM_SIZE 4 + +#define JBD2_CHECKSUM_BYTES (32 / sizeof(u32)) +/* + * Commit block header for storing transactional checksums: + * + * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum* + * fields are used to store a checksum of the descriptor and data blocks. + * + * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum + * field is used to store crc32c(uuid+commit_block). Each journal metadata + * block gets its own checksum, and data block checksums are stored in + * journal_block_tag (in the descriptor). The other h_chksum* fields are + * not used. + * + * If FEATURE_INCOMPAT_CSUM_V3 is set, the descriptor block uses + * journal_block_tag3_t to store a full 32-bit checksum. Everything else + * is the same as v2. + * + * Checksum v1, v2, and v3 are mutually exclusive features. + */ +struct commit_header { + __be32 h_magic; + __be32 h_blocktype; + __be32 h_sequence; + unsigned char h_chksum_type; + unsigned char h_chksum_size; + unsigned char h_padding[2]; + __be32 h_chksum[JBD2_CHECKSUM_BYTES]; + __be64 h_commit_sec; + __be32 h_commit_nsec; +}; + +/* + * The block tag: used to describe a single buffer in the journal. + * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this + * raw struct shouldn't be used for pointer math or sizeof() - use + * journal_tag_bytes(journal) instead to compute this. + */ +typedef struct journal_block_tag3_s +{ + __be32 t_blocknr; /* The on-disk block number */ + __be32 t_flags; /* See below */ + __be32 t_blocknr_high; /* most-significant high 32bits. */ + __be32 t_checksum; /* crc32c(uuid+seq+block) */ +} journal_block_tag3_t; + +typedef struct journal_block_tag_s +{ + __be32 t_blocknr; /* The on-disk block number */ + __be16 t_checksum; /* truncated crc32c(uuid+seq+block) */ + __be16 t_flags; /* See below */ + __be32 t_blocknr_high; /* most-significant high 32bits. */ +} journal_block_tag_t; + +/* Tail of descriptor block, for checksumming */ +struct jbd2_journal_block_tail { + __be32 t_checksum; /* crc32c(uuid+descr_block) */ +}; + +/* + * The revoke descriptor: used on disk to describe a series of blocks to + * be revoked from the log + */ +typedef struct jbd2_journal_revoke_header_s +{ + journal_header_t r_header; + __be32 r_count; /* Count of bytes used in the block */ +} jbd2_journal_revoke_header_t; + +/* Tail of revoke block, for checksumming */ +struct jbd2_journal_revoke_tail { + __be32 r_checksum; /* crc32c(uuid+revoke_block) */ +}; + +/* Definitions for the journal tag flags word: */ +#define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */ +#define JBD2_FLAG_SAME_UUID 2 /* block has same uuid as previous */ +#define JBD2_FLAG_DELETED 4 /* block deleted by this transaction */ +#define JBD2_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 jbd2_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 */ + __u8 s_checksum_type; /* checksum type */ + __u8 s_padding2[3]; + __u32 s_padding[42]; + __be32 s_checksum; /* crc32c(superblock) */ + +/* 0x0100 */ + __u8 s_users[16*48]; /* ids of all fs'es sharing the log */ +/* 0x0400 */ +} journal_superblock_t; + +#define JBD2_HAS_COMPAT_FEATURE(j,mask) \ + ((j)->j_format_version >= 2 && \ + ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask)))) +#define JBD2_HAS_RO_COMPAT_FEATURE(j,mask) \ + ((j)->j_format_version >= 2 && \ + ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask)))) +#define JBD2_HAS_INCOMPAT_FEATURE(j,mask) \ + ((j)->j_format_version >= 2 && \ + ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask)))) + +#define JBD2_FEATURE_COMPAT_CHECKSUM 0x00000001 + +#define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001 +#define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002 +#define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004 +#define JBD2_FEATURE_INCOMPAT_CSUM_V2 0x00000008 +#define JBD2_FEATURE_INCOMPAT_CSUM_V3 0x00000010 + +/* Features known to this kernel version: */ +#define JBD2_KNOWN_COMPAT_FEATURES JBD2_FEATURE_COMPAT_CHECKSUM +#define JBD2_KNOWN_ROCOMPAT_FEATURES 0 +#define JBD2_KNOWN_INCOMPAT_FEATURES (JBD2_FEATURE_INCOMPAT_REVOKE | \ + JBD2_FEATURE_INCOMPAT_64BIT | \ + JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \ + JBD2_FEATURE_INCOMPAT_CSUM_V2 | \ + JBD2_FEATURE_INCOMPAT_CSUM_V3) + +#ifdef __KERNEL__ + +#include <linux/fs.h> +#include <linux/sched.h> + +enum jbd_state_bits { + BH_JBD /* Has an attached ext3 journal_head */ + = BH_PrivateStart, + BH_JWrite, /* Being written to log (@@@ DEBUGGING) */ + BH_Freed, /* Has been freed (truncated) */ + BH_Revoked, /* Has been revoked from the log */ + BH_RevokeValid, /* Revoked flag is valid */ + BH_JBDDirty, /* Is dirty but journaled */ + BH_State, /* Pins most journal_head state */ + BH_JournalHead, /* Pins bh->b_private and jh->b_bh */ + BH_Shadow, /* IO on shadow buffer is running */ + BH_Verified, /* Metadata block has been verified ok */ + BH_JBDPrivateStart, /* First bit available for private use by FS */ +}; + +BUFFER_FNS(JBD, jbd) +BUFFER_FNS(JWrite, jwrite) +BUFFER_FNS(JBDDirty, jbddirty) +TAS_BUFFER_FNS(JBDDirty, jbddirty) +BUFFER_FNS(Revoked, revoked) +TAS_BUFFER_FNS(Revoked, revoked) +BUFFER_FNS(RevokeValid, revokevalid) +TAS_BUFFER_FNS(RevokeValid, revokevalid) +BUFFER_FNS(Freed, freed) +BUFFER_FNS(Shadow, shadow) +BUFFER_FNS(Verified, verified) + +#include <linux/jbd_common.h> + +#define J_ASSERT(assert) BUG_ON(!(assert)) + +#define J_ASSERT_BH(bh, expr) J_ASSERT(expr) +#define J_ASSERT_JH(jh, expr) J_ASSERT(expr) + +#if defined(JBD2_PARANOID_IOFAIL) +#define J_EXPECT(expr, why...) J_ASSERT(expr) +#define J_EXPECT_BH(bh, expr, why...) J_ASSERT_BH(bh, expr) +#define J_EXPECT_JH(jh, expr, why...) J_ASSERT_JH(jh, expr) +#else +#define __journal_expect(expr, why...) \ + ({ \ + int val = (expr); \ + if (!val) { \ + printk(KERN_ERR \ + "JBD2 unexpected failure: %s: %s;\n", \ + __func__, #expr); \ + printk(KERN_ERR why "\n"); \ + } \ + val; \ + }) +#define J_EXPECT(expr, why...) __journal_expect(expr, ## why) +#define J_EXPECT_BH(bh, expr, why...) __journal_expect(expr, ## why) +#define J_EXPECT_JH(jh, expr, why...) __journal_expect(expr, ## why) +#endif + +/* Flags in jbd_inode->i_flags */ +#define __JI_COMMIT_RUNNING 0 +/* Commit of the inode data in progress. We use this flag to protect us from + * concurrent deletion of inode. We cannot use reference to inode for this + * since we cannot afford doing last iput() on behalf of kjournald + */ +#define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING) + +/** + * struct jbd_inode is the structure linking inodes in ordered mode + * present in a transaction so that we can sync them during commit. + */ +struct jbd2_inode { + /* Which transaction does this inode belong to? Either the running + * transaction or the committing one. [j_list_lock] */ + transaction_t *i_transaction; + + /* Pointer to the running transaction modifying inode's data in case + * there is already a committing transaction touching it. [j_list_lock] */ + transaction_t *i_next_transaction; + + /* List of inodes in the i_transaction [j_list_lock] */ + struct list_head i_list; + + /* VFS inode this inode belongs to [constant during the lifetime + * of the structure] */ + struct inode *i_vfs_inode; + + /* Flags of inode [j_list_lock] */ + unsigned long i_flags; +}; + +struct jbd2_revoke_table_s; + +/** + * struct handle_s - The handle_s type is the concrete type associated with + * handle_t. + * @h_transaction: Which compound transaction is this update a part of? + * @h_buffer_credits: Number of remaining buffers we are allowed to dirty. + * @h_ref: Reference count on this handle + * @h_err: Field for caller's use to track errors through large fs operations + * @h_sync: flag for sync-on-close + * @h_jdata: flag to force data journaling + * @h_aborted: flag indicating fatal error on handle + **/ + +/* Docbook can't yet cope with the bit fields, but will leave the documentation + * in so it can be fixed later. + */ + +struct jbd2_journal_handle +{ + union { + /* Which compound transaction is this update a part of? */ + transaction_t *h_transaction; + /* Which journal handle belongs to - used iff h_reserved set */ + journal_t *h_journal; + }; + + /* Handle reserved for finishing the logical operation */ + handle_t *h_rsv_handle; + + /* Number of remaining buffers we are allowed to dirty: */ + int h_buffer_credits; + + /* Reference count on this handle */ + int h_ref; + + /* Field for caller's use to track errors through large fs */ + /* operations */ + int h_err; + + /* Flags [no locking] */ + unsigned int h_sync: 1; /* sync-on-close */ + unsigned int h_jdata: 1; /* force data journaling */ + unsigned int h_reserved: 1; /* handle with reserved credits */ + unsigned int h_aborted: 1; /* fatal error on handle */ + unsigned int h_type: 8; /* for handle statistics */ + unsigned int h_line_no: 16; /* for handle statistics */ + + unsigned long h_start_jiffies; + unsigned int h_requested_credits; + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map h_lockdep_map; +#endif +}; + + +/* + * Some stats for checkpoint phase + */ +struct transaction_chp_stats_s { + unsigned long cs_chp_time; + __u32 cs_forced_to_close; + __u32 cs_written; + __u32 cs_dropped; +}; + +/* 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. + */ + +/* + * Lock ranking: + * + * j_list_lock + * ->jbd_lock_bh_journal_head() (This is "innermost") + * + * j_state_lock + * ->jbd_lock_bh_state() + * + * jbd_lock_bh_state() + * ->j_list_lock + * + * j_state_lock + * ->t_handle_lock + * + * j_state_lock + * ->j_list_lock (journal_unmap_buffer) + * + */ + +struct transaction_s +{ + /* Pointer to the journal for this transaction. [no locking] */ + journal_t *t_journal; + + /* Sequence number for this transaction [no locking] */ + tid_t t_tid; + + /* + * Transaction's current state + * [no locking - only kjournald2 alters this] + * [j_list_lock] guards transition of a transaction into T_FINISHED + * state and subsequent call of __jbd2_journal_drop_transaction() + * FIXME: needs barriers + * KLUDGE: [use j_state_lock] + */ + enum { + T_RUNNING, + T_LOCKED, + T_FLUSH, + T_COMMIT, + T_COMMIT_DFLUSH, + T_COMMIT_JFLUSH, + T_COMMIT_CALLBACK, + T_FINISHED + } t_state; + + /* + * Where in the log does this transaction's commit start? [no locking] + */ + unsigned long t_log_start; + + /* Number of buffers on the t_buffers list [j_list_lock] */ + int t_nr_buffers; + + /* + * Doubly-linked circular list of all buffers reserved but not yet + * modified by this transaction [j_list_lock] + */ + struct journal_head *t_reserved_list; + + /* + * Doubly-linked circular list of all metadata buffers owned by this + * transaction [j_list_lock] + */ + struct journal_head *t_buffers; + + /* + * Doubly-linked circular list of all forget buffers (superseded + * buffers which we can un-checkpoint once this transaction commits) + * [j_list_lock] + */ + struct journal_head *t_forget; + + /* + * Doubly-linked circular list of all buffers still to be flushed before + * this transaction can be checkpointed. [j_list_lock] + */ + struct journal_head *t_checkpoint_list; + + /* + * Doubly-linked circular list of all buffers submitted for IO while + * checkpointing. [j_list_lock] + */ + struct journal_head *t_checkpoint_io_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. [j_list_lock] + */ + struct journal_head *t_shadow_list; + + /* + * List of inodes whose data we've modified in data=ordered mode. + * [j_list_lock] + */ + struct list_head t_inode_list; + + /* + * Protects info related to handles + */ + spinlock_t t_handle_lock; + + /* + * Longest time some handle had to wait for running transaction + */ + unsigned long t_max_wait; + + /* + * When transaction started + */ + unsigned long t_start; + + /* + * When commit was requested + */ + unsigned long t_requested; + + /* + * Checkpointing stats [j_checkpoint_sem] + */ + struct transaction_chp_stats_s t_chp_stats; + + /* + * Number of outstanding updates running on this transaction + * [t_handle_lock] + */ + atomic_t t_updates; + + /* + * Number of buffers reserved for use by all handles in this transaction + * handle but not yet modified. [t_handle_lock] + */ + atomic_t t_outstanding_credits; + + /* + * Forward and backward links for the circular list of all transactions + * awaiting checkpoint. [j_list_lock] + */ + transaction_t *t_cpnext, *t_cpprev; + + /* + * When will the transaction expire (become due for commit), in jiffies? + * [no locking] + */ + unsigned long t_expires; + + /* + * When this transaction started, in nanoseconds [no locking] + */ + ktime_t t_start_time; + + /* + * How many handles used this transaction? [t_handle_lock] + */ + atomic_t t_handle_count; + + /* + * This transaction is being forced and some process is + * waiting for it to finish. + */ + unsigned int t_synchronous_commit:1; + + /* Disk flush needs to be sent to fs partition [no locking] */ + int t_need_data_flush; + + /* + * For use by the filesystem to store fs-specific data + * structures associated with the transaction + */ + struct list_head t_private_list; +}; + +struct transaction_run_stats_s { + unsigned long rs_wait; + unsigned long rs_request_delay; + unsigned long rs_running; + unsigned long rs_locked; + unsigned long rs_flushing; + unsigned long rs_logging; + + __u32 rs_handle_count; + __u32 rs_blocks; + __u32 rs_blocks_logged; +}; + +struct transaction_stats_s { + unsigned long ts_tid; + unsigned long ts_requested; + struct transaction_run_stats_s run; +}; + +static inline unsigned long +jbd2_time_diff(unsigned long start, unsigned long end) +{ + if (end >= start) + return end - start; + + return end + (MAX_JIFFY_OFFSET - start); +} + +#define JBD2_NR_BATCH 64 + +/** + * struct journal_s - The journal_s type is the concrete type associated with + * journal_t. + * @j_flags: General journaling state flags + * @j_errno: Is there an outstanding uncleared error on the journal (from a + * prior abort)? + * @j_sb_buffer: First part of superblock buffer + * @j_superblock: Second part of superblock buffer + * @j_format_version: Version of the superblock format + * @j_state_lock: Protect the various scalars in the journal + * @j_barrier_count: Number of processes waiting to create a barrier lock + * @j_barrier: The barrier lock itself + * @j_running_transaction: The current running transaction.. + * @j_committing_transaction: the transaction we are pushing to disk + * @j_checkpoint_transactions: a linked circular list of all transactions + * waiting for checkpointing + * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction + * to start committing, or for a barrier lock to be released + * @j_wait_done_commit: Wait queue for waiting for commit to complete + * @j_wait_commit: Wait queue to trigger commit + * @j_wait_updates: Wait queue to wait for updates to complete + * @j_wait_reserved: Wait queue to wait for reserved buffer credits to drop + * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints + * @j_head: Journal head - identifies the first unused block in the journal + * @j_tail: Journal tail - identifies the oldest still-used block in the + * journal. + * @j_free: Journal free - how many free blocks are there in the journal? + * @j_first: The block number of the first usable block + * @j_last: The block number one beyond the last usable block + * @j_dev: Device where we store the journal + * @j_blocksize: blocksize for the location where we store the journal. + * @j_blk_offset: starting block offset for into the device where we store the + * journal + * @j_fs_dev: Device which holds the client fs. For internal journal this will + * be equal to j_dev + * @j_reserved_credits: Number of buffers reserved from the running transaction + * @j_maxlen: Total maximum capacity of the journal region on disk. + * @j_list_lock: Protects the buffer lists and internal buffer state. + * @j_inode: Optional inode where we store the journal. If present, all journal + * block numbers are mapped into this inode via bmap(). + * @j_tail_sequence: Sequence number of the oldest transaction in the log + * @j_transaction_sequence: Sequence number of the next transaction to grant + * @j_commit_sequence: Sequence number of the most recently committed + * transaction + * @j_commit_request: Sequence number of the most recent transaction wanting + * commit + * @j_uuid: Uuid of client object. + * @j_task: Pointer to the current commit thread for this journal + * @j_max_transaction_buffers: Maximum number of metadata buffers to allow in a + * single compound commit transaction + * @j_commit_interval: What is the maximum transaction lifetime before we begin + * a commit? + * @j_commit_timer: The timer used to wakeup the commit thread + * @j_revoke_lock: Protect the revoke table + * @j_revoke: The revoke table - maintains the list of revoked blocks in the + * current transaction. + * @j_revoke_table: alternate revoke tables for j_revoke + * @j_wbuf: array of buffer_heads for jbd2_journal_commit_transaction + * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the + * number that will fit in j_blocksize + * @j_last_sync_writer: most recent pid which did a synchronous write + * @j_history: Buffer storing the transactions statistics history + * @j_history_max: Maximum number of transactions in the statistics history + * @j_history_cur: Current number of transactions in the statistics history + * @j_history_lock: Protect the transactions statistics history + * @j_proc_entry: procfs entry for the jbd statistics directory + * @j_stats: Overall statistics + * @j_private: An opaque pointer to fs-private information. + */ + +struct journal_s +{ + /* General journaling state flags [j_state_lock] */ + unsigned long j_flags; + + /* + * Is there an outstanding uncleared error on the journal (from a prior + * abort)? [j_state_lock] + */ + int j_errno; + + /* The superblock buffer */ + struct buffer_head *j_sb_buffer; + journal_superblock_t *j_superblock; + + /* Version of the superblock format */ + int j_format_version; + + /* + * Protect the various scalars in the journal + */ + rwlock_t j_state_lock; + + /* + * Number of processes waiting to create a barrier lock [j_state_lock] + */ + int j_barrier_count; + + /* The barrier lock itself */ + struct mutex j_barrier; + + /* + * Transactions: The current running transaction... + * [j_state_lock] [caller holding open handle] + */ + transaction_t *j_running_transaction; + + /* + * the transaction we are pushing to disk + * [j_state_lock] [caller holding open handle] + */ + transaction_t *j_committing_transaction; + + /* + * ... and a linked circular list of all transactions waiting for + * checkpointing. [j_list_lock] + */ + transaction_t *j_checkpoint_transactions; + + /* + * Wait queue for waiting for a locked transaction to start committing, + * or for a barrier lock to be released + */ + wait_queue_head_t j_wait_transaction_locked; + + /* Wait queue for waiting for commit to complete */ + wait_queue_head_t j_wait_done_commit; + + /* Wait queue to trigger commit */ + wait_queue_head_t j_wait_commit; + + /* Wait queue to wait for updates to complete */ + wait_queue_head_t j_wait_updates; + + /* Wait queue to wait for reserved buffer credits to drop */ + wait_queue_head_t j_wait_reserved; + + /* Semaphore for locking against concurrent checkpoints */ + struct mutex j_checkpoint_mutex; + + /* + * List of buffer heads used by the checkpoint routine. This + * was moved from jbd2_log_do_checkpoint() to reduce stack + * usage. Access to this array is controlled by the + * j_checkpoint_mutex. [j_checkpoint_mutex] + */ + struct buffer_head *j_chkpt_bhs[JBD2_NR_BATCH]; + + /* + * Journal head: identifies the first unused block in the journal. + * [j_state_lock] + */ + unsigned long j_head; + + /* + * Journal tail: identifies the oldest still-used block in the journal. + * [j_state_lock] + */ + unsigned long j_tail; + + /* + * Journal free: how many free blocks are there in the journal? + * [j_state_lock] + */ + 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. [j_state_lock] + */ + unsigned long j_first; + unsigned long j_last; + + /* + * Device, blocksize and starting block offset for the location where we + * store the journal. + */ + struct block_device *j_dev; + int j_blocksize; + unsigned long long j_blk_offset; + char j_devname[BDEVNAME_SIZE+24]; + + /* + * Device which holds the client fs. For internal journal this will be + * equal to j_dev. + */ + struct block_device *j_fs_dev; + + /* Total maximum capacity of the journal region on disk. */ + unsigned int j_maxlen; + + /* Number of buffers reserved from the running transaction */ + atomic_t j_reserved_credits; + + /* + * Protects the buffer lists and internal buffer state. + */ + spinlock_t j_list_lock; + + /* 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 [j_state_lock] + */ + tid_t j_tail_sequence; + + /* + * Sequence number of the next transaction to grant [j_state_lock] + */ + tid_t j_transaction_sequence; + + /* + * Sequence number of the most recently committed transaction + * [j_state_lock]. + */ + tid_t j_commit_sequence; + + /* + * Sequence number of the most recent transaction wanting commit + * [j_state_lock] + */ + 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]; + + /* Pointer to the current commit thread for this journal */ + struct task_struct *j_task; + + /* + * 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; + + /* The timer used to wakeup the commit thread: */ + struct timer_list j_commit_timer; + + /* + * The revoke table: maintains the list of revoked blocks in the + * current transaction. [j_revoke_lock] + */ + spinlock_t j_revoke_lock; + struct jbd2_revoke_table_s *j_revoke; + struct jbd2_revoke_table_s *j_revoke_table[2]; + + /* + * array of bhs for jbd2_journal_commit_transaction + */ + struct buffer_head **j_wbuf; + int j_wbufsize; + + /* + * this is the pid of hte last person to run a synchronous operation + * through the journal + */ + pid_t j_last_sync_writer; + + /* + * the average amount of time in nanoseconds it takes to commit a + * transaction to disk. [j_state_lock] + */ + u64 j_average_commit_time; + + /* + * minimum and maximum times that we should wait for + * additional filesystem operations to get batched into a + * synchronous handle in microseconds + */ + u32 j_min_batch_time; + u32 j_max_batch_time; + + /* This function is called when a transaction is closed */ + void (*j_commit_callback)(journal_t *, + transaction_t *); + + /* + * Journal statistics + */ + spinlock_t j_history_lock; + struct proc_dir_entry *j_proc_entry; + struct transaction_stats_s j_stats; + + /* Failed journal commit ID */ + unsigned int j_failed_commit; + + /* + * An opaque pointer to fs-private information. ext3 puts its + * superblock pointer here + */ + void *j_private; + + /* Reference to checksum algorithm driver via cryptoapi */ + struct crypto_shash *j_chksum_driver; + + /* Precomputed journal UUID checksum for seeding other checksums */ + __u32 j_csum_seed; +}; + +/* + * Journal flag definitions + */ +#define JBD2_UNMOUNT 0x001 /* Journal thread is being destroyed */ +#define JBD2_ABORT 0x002 /* Journaling has been aborted for errors. */ +#define JBD2_ACK_ERR 0x004 /* The errno in the sb has been acked */ +#define JBD2_FLUSHED 0x008 /* The journal superblock has been flushed */ +#define JBD2_LOADED 0x010 /* The journal superblock has been loaded */ +#define JBD2_BARRIER 0x020 /* Use IDE barriers */ +#define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file + * data write error in ordered + * mode */ + +/* + * Function declarations for the journaling transaction and buffer + * management + */ + +/* Filing buffers */ +extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *); +extern void __jbd2_journal_refile_buffer(struct journal_head *); +extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *); +extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int); +extern void __journal_free_buffer(struct journal_head *bh); +extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int); +extern void __journal_clean_data_list(transaction_t *transaction); +static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh) +{ + list_add_tail(&bh->b_assoc_buffers, head); +} +static inline void jbd2_unfile_log_bh(struct buffer_head *bh) +{ + list_del_init(&bh->b_assoc_buffers); +} + +/* Log buffer allocation */ +struct buffer_head *jbd2_journal_get_descriptor_buffer(journal_t *journal); +int jbd2_journal_next_log_block(journal_t *, unsigned long long *); +int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid, + unsigned long *block); +int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block); +void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block); + +/* Commit management */ +extern void jbd2_journal_commit_transaction(journal_t *); + +/* Checkpoint list management */ +void __jbd2_journal_clean_checkpoint_list(journal_t *journal); +int __jbd2_journal_remove_checkpoint(struct journal_head *); +void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *); + + +/* + * Triggers + */ + +struct jbd2_buffer_trigger_type { + /* + * Fired a the moment data to write to the journal are known to be + * stable - so either at the moment b_frozen_data is created or just + * before a buffer is written to the journal. mapped_data is a mapped + * buffer that is the frozen data for commit. + */ + void (*t_frozen)(struct jbd2_buffer_trigger_type *type, + struct buffer_head *bh, void *mapped_data, + size_t size); + + /* + * Fired during journal abort for dirty buffers that will not be + * committed. + */ + void (*t_abort)(struct jbd2_buffer_trigger_type *type, + struct buffer_head *bh); +}; + +extern void jbd2_buffer_frozen_trigger(struct journal_head *jh, + void *mapped_data, + struct jbd2_buffer_trigger_type *triggers); +extern void jbd2_buffer_abort_trigger(struct journal_head *jh, + struct jbd2_buffer_trigger_type *triggers); + +/* Buffer IO */ +extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction, + struct journal_head *jh_in, + struct buffer_head **bh_out, + sector_t blocknr); + +/* Transaction locking */ +extern void __wait_on_journal (journal_t *); + +/* Transaction cache support */ +extern void jbd2_journal_destroy_transaction_cache(void); +extern int jbd2_journal_init_transaction_cache(void); +extern void jbd2_journal_free_transaction(transaction_t *); + +/* + * Journal 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. j_state_lock does this. + * + * Note that the locking is completely interrupt unsafe. We never touch + * journal structures from interrupts. + */ + +static inline handle_t *journal_current_handle(void) +{ + return current->journal_info; +} + +/* The journaling code user interface: + * + * Create and destroy handles + * Register buffer modifications against the current transaction. + */ + +extern handle_t *jbd2_journal_start(journal_t *, int nblocks); +extern handle_t *jbd2__journal_start(journal_t *, int blocks, int rsv_blocks, + gfp_t gfp_mask, unsigned int type, + unsigned int line_no); +extern int jbd2_journal_restart(handle_t *, int nblocks); +extern int jbd2__journal_restart(handle_t *, int nblocks, gfp_t gfp_mask); +extern int jbd2_journal_start_reserved(handle_t *handle, + unsigned int type, unsigned int line_no); +extern void jbd2_journal_free_reserved(handle_t *handle); +extern int jbd2_journal_extend (handle_t *, int nblocks); +extern int jbd2_journal_get_write_access(handle_t *, struct buffer_head *); +extern int jbd2_journal_get_create_access (handle_t *, struct buffer_head *); +extern int jbd2_journal_get_undo_access(handle_t *, struct buffer_head *); +void jbd2_journal_set_triggers(struct buffer_head *, + struct jbd2_buffer_trigger_type *type); +extern int jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *); +extern int jbd2_journal_forget (handle_t *, struct buffer_head *); +extern void journal_sync_buffer (struct buffer_head *); +extern int jbd2_journal_invalidatepage(journal_t *, + struct page *, unsigned int, unsigned int); +extern int jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t); +extern int jbd2_journal_stop(handle_t *); +extern int jbd2_journal_flush (journal_t *); +extern void jbd2_journal_lock_updates (journal_t *); +extern void jbd2_journal_unlock_updates (journal_t *); + +extern journal_t * jbd2_journal_init_dev(struct block_device *bdev, + struct block_device *fs_dev, + unsigned long long start, int len, int bsize); +extern journal_t * jbd2_journal_init_inode (struct inode *); +extern int jbd2_journal_update_format (journal_t *); +extern int jbd2_journal_check_used_features + (journal_t *, unsigned long, unsigned long, unsigned long); +extern int jbd2_journal_check_available_features + (journal_t *, unsigned long, unsigned long, unsigned long); +extern int jbd2_journal_set_features + (journal_t *, unsigned long, unsigned long, unsigned long); +extern void jbd2_journal_clear_features + (journal_t *, unsigned long, unsigned long, unsigned long); +extern int jbd2_journal_load (journal_t *journal); +extern int jbd2_journal_destroy (journal_t *); +extern int jbd2_journal_recover (journal_t *journal); +extern int jbd2_journal_wipe (journal_t *, int); +extern int jbd2_journal_skip_recovery (journal_t *); +extern void jbd2_journal_update_sb_errno(journal_t *); +extern int jbd2_journal_update_sb_log_tail (journal_t *, tid_t, + unsigned long, int); +extern void __jbd2_journal_abort_hard (journal_t *); +extern void jbd2_journal_abort (journal_t *, int); +extern int jbd2_journal_errno (journal_t *); +extern void jbd2_journal_ack_err (journal_t *); +extern int jbd2_journal_clear_err (journal_t *); +extern int jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *); +extern int jbd2_journal_force_commit(journal_t *); +extern int jbd2_journal_force_commit_nested(journal_t *); +extern int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *inode); +extern int jbd2_journal_begin_ordered_truncate(journal_t *journal, + struct jbd2_inode *inode, loff_t new_size); +extern void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode); +extern void jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode); + +/* + * journal_head management + */ +struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh); +struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh); +void jbd2_journal_put_journal_head(struct journal_head *jh); + +/* + * handle management + */ +extern struct kmem_cache *jbd2_handle_cache; + +static inline handle_t *jbd2_alloc_handle(gfp_t gfp_flags) +{ + return kmem_cache_zalloc(jbd2_handle_cache, gfp_flags); +} + +static inline void jbd2_free_handle(handle_t *handle) +{ + kmem_cache_free(jbd2_handle_cache, handle); +} + +/* + * jbd2_inode management (optional, for those file systems that want to use + * dynamically allocated jbd2_inode structures) + */ +extern struct kmem_cache *jbd2_inode_cache; + +static inline struct jbd2_inode *jbd2_alloc_inode(gfp_t gfp_flags) +{ + return kmem_cache_alloc(jbd2_inode_cache, gfp_flags); +} + +static inline void jbd2_free_inode(struct jbd2_inode *jinode) +{ + kmem_cache_free(jbd2_inode_cache, jinode); +} + +/* Primary revoke support */ +#define JOURNAL_REVOKE_DEFAULT_HASH 256 +extern int jbd2_journal_init_revoke(journal_t *, int); +extern void jbd2_journal_destroy_revoke_caches(void); +extern int jbd2_journal_init_revoke_caches(void); + +extern void jbd2_journal_destroy_revoke(journal_t *); +extern int jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *); +extern int jbd2_journal_cancel_revoke(handle_t *, struct journal_head *); +extern void jbd2_journal_write_revoke_records(journal_t *journal, + transaction_t *transaction, + struct list_head *log_bufs, + int write_op); + +/* Recovery revoke support */ +extern int jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t); +extern int jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t); +extern void jbd2_journal_clear_revoke(journal_t *); +extern void jbd2_journal_switch_revoke_table(journal_t *journal); +extern void jbd2_clear_buffer_revoked_flags(journal_t *journal); + +/* + * The log thread user interface: + * + * Request space in the current transaction, and force transaction commit + * transitions on demand. + */ + +int jbd2_log_start_commit(journal_t *journal, tid_t tid); +int __jbd2_log_start_commit(journal_t *journal, tid_t tid); +int jbd2_journal_start_commit(journal_t *journal, tid_t *tid); +int jbd2_log_wait_commit(journal_t *journal, tid_t tid); +int jbd2_complete_transaction(journal_t *journal, tid_t tid); +int jbd2_log_do_checkpoint(journal_t *journal); +int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid); + +void __jbd2_log_wait_for_space(journal_t *journal); +extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *); +extern int jbd2_cleanup_journal_tail(journal_t *); + +/* + * is_journal_abort + * + * Simple test wrapper function to test the JBD2_ABORT state flag. This + * bit, when set, indicates that we have had a fatal error somewhere, + * either inside the journaling layer or indicated to us by the client + * (eg. ext3), and that we and should not commit any further + * transactions. + */ + +static inline int is_journal_aborted(journal_t *journal) +{ + return journal->j_flags & JBD2_ABORT; +} + +static inline int is_handle_aborted(handle_t *handle) +{ + if (handle->h_aborted || !handle->h_transaction) + return 1; + return is_journal_aborted(handle->h_transaction->t_journal); +} + +static inline void jbd2_journal_abort_handle(handle_t *handle) +{ + handle->h_aborted = 1; +} + +#endif /* __KERNEL__ */ + +/* 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 jbd2_journal_blocks_per_page(struct inode *inode); +extern size_t journal_tag_bytes(journal_t *journal); + +static inline int jbd2_journal_has_csum_v2or3(journal_t *journal) +{ + if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2) || + JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V3)) + return 1; + + return 0; +} + +/* + * We reserve t_outstanding_credits >> JBD2_CONTROL_BLOCKS_SHIFT for + * transaction control blocks. + */ +#define JBD2_CONTROL_BLOCKS_SHIFT 5 + +/* + * 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 jbd2_space_needed(journal_t *journal) +{ + int nblocks = journal->j_max_transaction_buffers; + return nblocks + (nblocks >> JBD2_CONTROL_BLOCKS_SHIFT); +} + +/* + * Return number of free blocks in the log. Must be called under j_state_lock. + */ +static inline unsigned long jbd2_log_space_left(journal_t *journal) +{ + /* Allow for rounding errors */ + unsigned long free = journal->j_free - 32; + + if (journal->j_committing_transaction) { + unsigned long committing = atomic_read(&journal-> + j_committing_transaction->t_outstanding_credits); + + /* Transaction + control blocks */ + free -= committing + (committing >> JBD2_CONTROL_BLOCKS_SHIFT); + } + return free; +} + +/* + * Definitions which augment the buffer_head layer + */ + +/* journaling buffer types */ +#define BJ_None 0 /* Not journaled */ +#define BJ_Metadata 1 /* Normal journaled metadata */ +#define BJ_Forget 2 /* Buffer superseded by this transaction */ +#define BJ_Shadow 3 /* Buffer contents being shadowed to the log */ +#define BJ_Reserved 4 /* Buffer is reserved for access by journal */ +#define BJ_Types 5 + +extern int jbd_blocks_per_page(struct inode *inode); + +/* JBD uses a CRC32 checksum */ +#define JBD_MAX_CHECKSUM_SIZE 4 + +static inline u32 jbd2_chksum(journal_t *journal, u32 crc, + const void *address, unsigned int length) +{ + struct { + struct shash_desc shash; + char ctx[JBD_MAX_CHECKSUM_SIZE]; + } desc; + int err; + + BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) > + JBD_MAX_CHECKSUM_SIZE); + + desc.shash.tfm = journal->j_chksum_driver; + desc.shash.flags = 0; + *(u32 *)desc.ctx = crc; + + err = crypto_shash_update(&desc.shash, address, length); + BUG_ON(err); + + return *(u32 *)desc.ctx; +} + +/* Return most recent uncommitted transaction */ +static inline tid_t jbd2_get_latest_transaction(journal_t *journal) +{ + tid_t tid; + + read_lock(&journal->j_state_lock); + tid = journal->j_commit_request; + if (journal->j_running_transaction) + tid = journal->j_running_transaction->t_tid; + read_unlock(&journal->j_state_lock); + return tid; +} + +#ifdef __KERNEL__ + +#define buffer_trace_init(bh) do {} while (0) +#define print_buffer_fields(bh) do {} while (0) +#define print_buffer_trace(bh) do {} while (0) +#define BUFFER_TRACE(bh, info) do {} while (0) +#define BUFFER_TRACE2(bh, bh2, info) do {} while (0) +#define JBUFFER_TRACE(jh, info) do {} while (0) + +#endif /* __KERNEL__ */ + +#endif /* _LINUX_JBD2_H */ |