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aha/fs/xfs/xfs_log_priv.h
Dave Chinner cc09c0dc57 [XFS] Fix double free of log tickets 
When an I/O error occurs during an intermediate commit on a rolling
transaction, xfs_trans_commit() will free the transaction structure
and the related ticket. However, the duplicate transaction that
gets used as the transaction continues still contains a pointer
to the ticket. Hence when the duplicate transaction is cancelled
and freed, we free the ticket a second time.

Add reference counting to the ticket so that we hold an extra
reference to the ticket over the transaction commit. We drop the
extra reference once we have checked that the transaction commit
did not return an error, thus avoiding a double free on commit
error.

Credit to Nick Piggin for tripping over the problem.

SGI-PV: 989741

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
2008-11-17 17:37:10 +11:00

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/*
* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_LOG_PRIV_H__
#define __XFS_LOG_PRIV_H__
struct xfs_buf;
struct ktrace;
struct log;
struct xlog_ticket;
struct xfs_buf_cancel;
struct xfs_mount;
/*
* Macros, structures, prototypes for internal log manager use.
*/
#define XLOG_MIN_ICLOGS 2
#define XLOG_MAX_ICLOGS 8
#define XLOG_HEADER_MAGIC_NUM 0xFEEDbabe /* Invalid cycle number */
#define XLOG_VERSION_1 1
#define XLOG_VERSION_2 2 /* Large IClogs, Log sunit */
#define XLOG_VERSION_OKBITS (XLOG_VERSION_1 | XLOG_VERSION_2)
#define XLOG_MIN_RECORD_BSIZE (16*1024) /* eventually 32k */
#define XLOG_BIG_RECORD_BSIZE (32*1024) /* 32k buffers */
#define XLOG_MAX_RECORD_BSIZE (256*1024)
#define XLOG_HEADER_CYCLE_SIZE (32*1024) /* cycle data in header */
#define XLOG_MIN_RECORD_BSHIFT 14 /* 16384 == 1 << 14 */
#define XLOG_BIG_RECORD_BSHIFT 15 /* 32k == 1 << 15 */
#define XLOG_MAX_RECORD_BSHIFT 18 /* 256k == 1 << 18 */
#define XLOG_BTOLSUNIT(log, b) (((b)+(log)->l_mp->m_sb.sb_logsunit-1) / \
(log)->l_mp->m_sb.sb_logsunit)
#define XLOG_LSUNITTOB(log, su) ((su) * (log)->l_mp->m_sb.sb_logsunit)
#define XLOG_HEADER_SIZE 512
#define XLOG_REC_SHIFT(log) \
BTOBB(1 << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
#define XLOG_TOTAL_REC_SHIFT(log) \
BTOBB(XLOG_MAX_ICLOGS << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
{
return ((xfs_lsn_t)cycle << 32) | block;
}
static inline uint xlog_get_cycle(char *ptr)
{
if (be32_to_cpu(*(__be32 *)ptr) == XLOG_HEADER_MAGIC_NUM)
return be32_to_cpu(*((__be32 *)ptr + 1));
else
return be32_to_cpu(*(__be32 *)ptr);
}
#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
#ifdef __KERNEL__
/*
* get client id from packed copy.
*
* this hack is here because the xlog_pack code copies four bytes
* of xlog_op_header containing the fields oh_clientid, oh_flags
* and oh_res2 into the packed copy.
*
* later on this four byte chunk is treated as an int and the
* client id is pulled out.
*
* this has endian issues, of course.
*/
static inline uint xlog_get_client_id(__be32 i)
{
return be32_to_cpu(i) >> 24;
}
#define xlog_panic(args...) cmn_err(CE_PANIC, ## args)
#define xlog_exit(args...) cmn_err(CE_PANIC, ## args)
#define xlog_warn(args...) cmn_err(CE_WARN, ## args)
/*
* In core log state
*/
#define XLOG_STATE_ACTIVE 0x0001 /* Current IC log being written to */
#define XLOG_STATE_WANT_SYNC 0x0002 /* Want to sync this iclog; no more writes */
#define XLOG_STATE_SYNCING 0x0004 /* This IC log is syncing */
#define XLOG_STATE_DONE_SYNC 0x0008 /* Done syncing to disk */
#define XLOG_STATE_DO_CALLBACK \
0x0010 /* Process callback functions */
#define XLOG_STATE_CALLBACK 0x0020 /* Callback functions now */
#define XLOG_STATE_DIRTY 0x0040 /* Dirty IC log, not ready for ACTIVE status*/
#define XLOG_STATE_IOERROR 0x0080 /* IO error happened in sync'ing log */
#define XLOG_STATE_ALL 0x7FFF /* All possible valid flags */
#define XLOG_STATE_NOTUSED 0x8000 /* This IC log not being used */
#endif /* __KERNEL__ */
/*
* Flags to log operation header
*
* The first write of a new transaction will be preceded with a start
* record, XLOG_START_TRANS. Once a transaction is committed, a commit
* record is written, XLOG_COMMIT_TRANS. If a single region can not fit into
* the remainder of the current active in-core log, it is split up into
* multiple regions. Each partial region will be marked with a
* XLOG_CONTINUE_TRANS until the last one, which gets marked with XLOG_END_TRANS.
*
*/
#define XLOG_START_TRANS 0x01 /* Start a new transaction */
#define XLOG_COMMIT_TRANS 0x02 /* Commit this transaction */
#define XLOG_CONTINUE_TRANS 0x04 /* Cont this trans into new region */
#define XLOG_WAS_CONT_TRANS 0x08 /* Cont this trans into new region */
#define XLOG_END_TRANS 0x10 /* End a continued transaction */
#define XLOG_UNMOUNT_TRANS 0x20 /* Unmount a filesystem transaction */
#ifdef __KERNEL__
/*
* Flags to log ticket
*/
#define XLOG_TIC_INITED 0x1 /* has been initialized */
#define XLOG_TIC_PERM_RESERV 0x2 /* permanent reservation */
#define XLOG_TIC_IN_Q 0x4
#endif /* __KERNEL__ */
#define XLOG_UNMOUNT_TYPE 0x556e /* Un for Unmount */
/*
* Flags for log structure
*/
#define XLOG_CHKSUM_MISMATCH 0x1 /* used only during recovery */
#define XLOG_ACTIVE_RECOVERY 0x2 /* in the middle of recovery */
#define XLOG_RECOVERY_NEEDED 0x4 /* log was recovered */
#define XLOG_IO_ERROR 0x8 /* log hit an I/O error, and being
shutdown */
typedef __uint32_t xlog_tid_t;
#ifdef __KERNEL__
/*
* Below are states for covering allocation transactions.
* By covering, we mean changing the h_tail_lsn in the last on-disk
* log write such that no allocation transactions will be re-done during
* recovery after a system crash. Recovery starts at the last on-disk
* log write.
*
* These states are used to insert dummy log entries to cover
* space allocation transactions which can undo non-transactional changes
* after a crash. Writes to a file with space
* already allocated do not result in any transactions. Allocations
* might include space beyond the EOF. So if we just push the EOF a
* little, the last transaction for the file could contain the wrong
* size. If there is no file system activity, after an allocation
* transaction, and the system crashes, the allocation transaction
* will get replayed and the file will be truncated. This could
* be hours/days/... after the allocation occurred.
*
* The fix for this is to do two dummy transactions when the
* system is idle. We need two dummy transaction because the h_tail_lsn
* in the log record header needs to point beyond the last possible
* non-dummy transaction. The first dummy changes the h_tail_lsn to
* the first transaction before the dummy. The second dummy causes
* h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn.
*
* These dummy transactions get committed when everything
* is idle (after there has been some activity).
*
* There are 5 states used to control this.
*
* IDLE -- no logging has been done on the file system or
* we are done covering previous transactions.
* NEED -- logging has occurred and we need a dummy transaction
* when the log becomes idle.
* DONE -- we were in the NEED state and have committed a dummy
* transaction.
* NEED2 -- we detected that a dummy transaction has gone to the
* on disk log with no other transactions.
* DONE2 -- we committed a dummy transaction when in the NEED2 state.
*
* There are two places where we switch states:
*
* 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2.
* We commit the dummy transaction and switch to DONE or DONE2,
* respectively. In all other states, we don't do anything.
*
* 2.) When we finish writing the on-disk log (xlog_state_clean_log).
*
* No matter what state we are in, if this isn't the dummy
* transaction going out, the next state is NEED.
* So, if we aren't in the DONE or DONE2 states, the next state
* is NEED. We can't be finishing a write of the dummy record
* unless it was committed and the state switched to DONE or DONE2.
*
* If we are in the DONE state and this was a write of the
* dummy transaction, we move to NEED2.
*
* If we are in the DONE2 state and this was a write of the
* dummy transaction, we move to IDLE.
*
*
* Writing only one dummy transaction can get appended to
* one file space allocation. When this happens, the log recovery
* code replays the space allocation and a file could be truncated.
* This is why we have the NEED2 and DONE2 states before going idle.
*/
#define XLOG_STATE_COVER_IDLE 0
#define XLOG_STATE_COVER_NEED 1
#define XLOG_STATE_COVER_DONE 2
#define XLOG_STATE_COVER_NEED2 3
#define XLOG_STATE_COVER_DONE2 4
#define XLOG_COVER_OPS 5
/* Ticket reservation region accounting */
#define XLOG_TIC_LEN_MAX 15
/*
* Reservation region
* As would be stored in xfs_log_iovec but without the i_addr which
* we don't care about.
*/
typedef struct xlog_res {
uint r_len; /* region length :4 */
uint r_type; /* region's transaction type :4 */
} xlog_res_t;
typedef struct xlog_ticket {
sv_t t_wait; /* ticket wait queue : 20 */
struct xlog_ticket *t_next; /* :4|8 */
struct xlog_ticket *t_prev; /* :4|8 */
xlog_tid_t t_tid; /* transaction identifier : 4 */
atomic_t t_ref; /* ticket reference count : 4 */
int t_curr_res; /* current reservation in bytes : 4 */
int t_unit_res; /* unit reservation in bytes : 4 */
char t_ocnt; /* original count : 1 */
char t_cnt; /* current count : 1 */
char t_clientid; /* who does this belong to; : 1 */
char t_flags; /* properties of reservation : 1 */
uint t_trans_type; /* transaction type : 4 */
/* reservation array fields */
uint t_res_num; /* num in array : 4 */
uint t_res_num_ophdrs; /* num op hdrs : 4 */
uint t_res_arr_sum; /* array sum : 4 */
uint t_res_o_flow; /* sum overflow : 4 */
xlog_res_t t_res_arr[XLOG_TIC_LEN_MAX]; /* array of res : 8 * 15 */
} xlog_ticket_t;
#endif
typedef struct xlog_op_header {
__be32 oh_tid; /* transaction id of operation : 4 b */
__be32 oh_len; /* bytes in data region : 4 b */
__u8 oh_clientid; /* who sent me this : 1 b */
__u8 oh_flags; /* : 1 b */
__u16 oh_res2; /* 32 bit align : 2 b */
} xlog_op_header_t;
/* valid values for h_fmt */
#define XLOG_FMT_UNKNOWN 0
#define XLOG_FMT_LINUX_LE 1
#define XLOG_FMT_LINUX_BE 2
#define XLOG_FMT_IRIX_BE 3
/* our fmt */
#ifdef XFS_NATIVE_HOST
#define XLOG_FMT XLOG_FMT_LINUX_BE
#else
#define XLOG_FMT XLOG_FMT_LINUX_LE
#endif
typedef struct xlog_rec_header {
__be32 h_magicno; /* log record (LR) identifier : 4 */
__be32 h_cycle; /* write cycle of log : 4 */
__be32 h_version; /* LR version : 4 */
__be32 h_len; /* len in bytes; should be 64-bit aligned: 4 */
__be64 h_lsn; /* lsn of this LR : 8 */
__be64 h_tail_lsn; /* lsn of 1st LR w/ buffers not committed: 8 */
__be32 h_chksum; /* may not be used; non-zero if used : 4 */
__be32 h_prev_block; /* block number to previous LR : 4 */
__be32 h_num_logops; /* number of log operations in this LR : 4 */
__be32 h_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE];
/* new fields */
__be32 h_fmt; /* format of log record : 4 */
uuid_t h_fs_uuid; /* uuid of FS : 16 */
__be32 h_size; /* iclog size : 4 */
} xlog_rec_header_t;
typedef struct xlog_rec_ext_header {
__be32 xh_cycle; /* write cycle of log : 4 */
__be32 xh_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE]; /* : 256 */
} xlog_rec_ext_header_t;
#ifdef __KERNEL__
/*
* - A log record header is 512 bytes. There is plenty of room to grow the
* xlog_rec_header_t into the reserved space.
* - ic_data follows, so a write to disk can start at the beginning of
* the iclog.
* - ic_forcewait is used to implement synchronous forcing of the iclog to disk.
* - ic_next is the pointer to the next iclog in the ring.
* - ic_bp is a pointer to the buffer used to write this incore log to disk.
* - ic_log is a pointer back to the global log structure.
* - ic_callback is a linked list of callback function/argument pairs to be
* called after an iclog finishes writing.
* - ic_size is the full size of the header plus data.
* - ic_offset is the current number of bytes written to in this iclog.
* - ic_refcnt is bumped when someone is writing to the log.
* - ic_state is the state of the iclog.
*
* Because of cacheline contention on large machines, we need to separate
* various resources onto different cachelines. To start with, make the
* structure cacheline aligned. The following fields can be contended on
* by independent processes:
*
* - ic_callback_*
* - ic_refcnt
* - fields protected by the global l_icloglock
*
* so we need to ensure that these fields are located in separate cachelines.
* We'll put all the read-only and l_icloglock fields in the first cacheline,
* and move everything else out to subsequent cachelines.
*/
typedef struct xlog_iclog_fields {
sv_t ic_force_wait;
sv_t ic_write_wait;
struct xlog_in_core *ic_next;
struct xlog_in_core *ic_prev;
struct xfs_buf *ic_bp;
struct log *ic_log;
int ic_size;
int ic_offset;
int ic_bwritecnt;
ushort_t ic_state;
char *ic_datap; /* pointer to iclog data */
#ifdef XFS_LOG_TRACE
struct ktrace *ic_trace;
#endif
/* Callback structures need their own cacheline */
spinlock_t ic_callback_lock ____cacheline_aligned_in_smp;
xfs_log_callback_t *ic_callback;
xfs_log_callback_t **ic_callback_tail;
/* reference counts need their own cacheline */
atomic_t ic_refcnt ____cacheline_aligned_in_smp;
} xlog_iclog_fields_t;
typedef union xlog_in_core2 {
xlog_rec_header_t hic_header;
xlog_rec_ext_header_t hic_xheader;
char hic_sector[XLOG_HEADER_SIZE];
} xlog_in_core_2_t;
typedef struct xlog_in_core {
xlog_iclog_fields_t hic_fields;
xlog_in_core_2_t *hic_data;
} xlog_in_core_t;
/*
* Defines to save our code from this glop.
*/
#define ic_force_wait hic_fields.ic_force_wait
#define ic_write_wait hic_fields.ic_write_wait
#define ic_next hic_fields.ic_next
#define ic_prev hic_fields.ic_prev
#define ic_bp hic_fields.ic_bp
#define ic_log hic_fields.ic_log
#define ic_callback hic_fields.ic_callback
#define ic_callback_lock hic_fields.ic_callback_lock
#define ic_callback_tail hic_fields.ic_callback_tail
#define ic_trace hic_fields.ic_trace
#define ic_size hic_fields.ic_size
#define ic_offset hic_fields.ic_offset
#define ic_refcnt hic_fields.ic_refcnt
#define ic_bwritecnt hic_fields.ic_bwritecnt
#define ic_state hic_fields.ic_state
#define ic_datap hic_fields.ic_datap
#define ic_header hic_data->hic_header
/*
* The reservation head lsn is not made up of a cycle number and block number.
* Instead, it uses a cycle number and byte number. Logs don't expect to
* overflow 31 bits worth of byte offset, so using a byte number will mean
* that round off problems won't occur when releasing partial reservations.
*/
typedef struct log {
/* The following fields don't need locking */
struct xfs_mount *l_mp; /* mount point */
struct xfs_ail *l_ailp; /* AIL log is working with */
struct xfs_buf *l_xbuf; /* extra buffer for log
* wrapping */
struct xfs_buftarg *l_targ; /* buftarg of log */
uint l_flags;
uint l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
struct xfs_buf_cancel **l_buf_cancel_table;
int l_iclog_hsize; /* size of iclog header */
int l_iclog_heads; /* # of iclog header sectors */
uint l_sectbb_log; /* log2 of sector size in BBs */
uint l_sectbb_mask; /* sector size (in BBs)
* alignment mask */
int l_iclog_size; /* size of log in bytes */
int l_iclog_size_log; /* log power size of log */
int l_iclog_bufs; /* number of iclog buffers */
xfs_daddr_t l_logBBstart; /* start block of log */
int l_logsize; /* size of log in bytes */
int l_logBBsize; /* size of log in BB chunks */
/* The following block of fields are changed while holding icloglock */
sv_t l_flush_wait ____cacheline_aligned_in_smp;
/* waiting for iclog flush */
int l_covered_state;/* state of "covering disk
* log entries" */
xlog_in_core_t *l_iclog; /* head log queue */
spinlock_t l_icloglock; /* grab to change iclog state */
xfs_lsn_t l_tail_lsn; /* lsn of 1st LR with unflushed
* buffers */
xfs_lsn_t l_last_sync_lsn;/* lsn of last LR on disk */
int l_curr_cycle; /* Cycle number of log writes */
int l_prev_cycle; /* Cycle number before last
* block increment */
int l_curr_block; /* current logical log block */
int l_prev_block; /* previous logical log block */
/* The following block of fields are changed while holding grant_lock */
spinlock_t l_grant_lock ____cacheline_aligned_in_smp;
xlog_ticket_t *l_reserve_headq;
xlog_ticket_t *l_write_headq;
int l_grant_reserve_cycle;
int l_grant_reserve_bytes;
int l_grant_write_cycle;
int l_grant_write_bytes;
#ifdef XFS_LOG_TRACE
struct ktrace *l_grant_trace;
#endif
/* The following field are used for debugging; need to hold icloglock */
#ifdef DEBUG
char *l_iclog_bak[XLOG_MAX_ICLOGS];
#endif
} xlog_t;
#define XLOG_FORCED_SHUTDOWN(log) ((log)->l_flags & XLOG_IO_ERROR)
/* common routines */
extern xfs_lsn_t xlog_assign_tail_lsn(struct xfs_mount *mp);
extern int xlog_find_tail(xlog_t *log,
xfs_daddr_t *head_blk,
xfs_daddr_t *tail_blk);
extern int xlog_recover(xlog_t *log);
extern int xlog_recover_finish(xlog_t *log);
extern void xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int);
extern void xlog_recover_process_iunlinks(xlog_t *log);
extern struct xfs_buf *xlog_get_bp(xlog_t *, int);
extern void xlog_put_bp(struct xfs_buf *);
extern int xlog_bread(xlog_t *, xfs_daddr_t, int, struct xfs_buf *);
extern kmem_zone_t *xfs_log_ticket_zone;
/* iclog tracing */
#define XLOG_TRACE_GRAB_FLUSH 1
#define XLOG_TRACE_REL_FLUSH 2
#define XLOG_TRACE_SLEEP_FLUSH 3
#define XLOG_TRACE_WAKE_FLUSH 4
/*
* Unmount record type is used as a pseudo transaction type for the ticket.
* It's value must be outside the range of XFS_TRANS_* values.
*/
#define XLOG_UNMOUNT_REC_TYPE (-1U)
#endif /* __KERNEL__ */
#endif /* __XFS_LOG_PRIV_H__ */
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