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In doing an investigation into AIL push stalls, I was looking at the log force code to see if an async CIL push could be done instead. This lead me to xfs_log_force_lsn() and looking at how it works. xfs_log_force_lsn() is only called from inode synchronisation contexts such as fsync(), and it takes the ip->i_itemp->ili_last_lsn value as the LSN to sync the log to. This gets passed to xlog_cil_force_lsn() via xfs_log_force_lsn() to flush the CIL to the journal, and then used by xfs_log_force_lsn() to flush the iclogs to the journal. The problem is that ip->i_itemp->ili_last_lsn does not store a log sequence number. What it stores is passed to it from the ->iop_committing method, which is called by xfs_log_commit_cil(). The value this passes to the iop_committing method is the CIL context sequence number that the item was committed to. As it turns out, xlog_cil_force_lsn() converts the sequence to an actual commit LSN for the related context and returns that to xfs_log_force_lsn(). xfs_log_force_lsn() overwrites it's "lsn" variable that contained a sequence with an actual LSN and then uses that to sync the iclogs. This caused me some confusion for a while, even though I originally wrote all this code a decade ago. ->iop_committing is only used by a couple of log item types, and only inode items use the sequence number it is passed. Let's clean up the API, CIL structures and inode log item to call it a sequence number, and make it clear that the high level code is using CIL sequence numbers and not on-disk LSNs for integrity synchronisation purposes. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
146 lines
4.1 KiB
C
146 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*/
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#ifndef __XFS_LOG_H__
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#define __XFS_LOG_H__
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struct xfs_cil_ctx;
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struct xfs_log_vec {
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struct xfs_log_vec *lv_next; /* next lv in build list */
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int lv_niovecs; /* number of iovecs in lv */
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struct xfs_log_iovec *lv_iovecp; /* iovec array */
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struct xfs_log_item *lv_item; /* owner */
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char *lv_buf; /* formatted buffer */
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int lv_bytes; /* accounted space in buffer */
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int lv_buf_len; /* aligned size of buffer */
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int lv_size; /* size of allocated lv */
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};
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#define XFS_LOG_VEC_ORDERED (-1)
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static inline void *
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xlog_prepare_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp,
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uint type)
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{
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struct xfs_log_iovec *vec = *vecp;
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if (vec) {
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ASSERT(vec - lv->lv_iovecp < lv->lv_niovecs);
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vec++;
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} else {
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vec = &lv->lv_iovecp[0];
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}
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vec->i_type = type;
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vec->i_addr = lv->lv_buf + lv->lv_buf_len;
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ASSERT(IS_ALIGNED((unsigned long)vec->i_addr, sizeof(uint64_t)));
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*vecp = vec;
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return vec->i_addr;
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}
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/*
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* We need to make sure the next buffer is naturally aligned for the biggest
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* basic data type we put into it. We already accounted for this padding when
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* sizing the buffer.
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*
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* However, this padding does not get written into the log, and hence we have to
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* track the space used by the log vectors separately to prevent log space hangs
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* due to inaccurate accounting (i.e. a leak) of the used log space through the
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* CIL context ticket.
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*/
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static inline void
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xlog_finish_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec *vec, int len)
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{
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lv->lv_buf_len += round_up(len, sizeof(uint64_t));
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lv->lv_bytes += len;
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vec->i_len = len;
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}
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static inline void *
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xlog_copy_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp,
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uint type, void *data, int len)
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{
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void *buf;
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buf = xlog_prepare_iovec(lv, vecp, type);
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memcpy(buf, data, len);
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xlog_finish_iovec(lv, *vecp, len);
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return buf;
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}
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/*
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* By comparing each component, we don't have to worry about extra
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* endian issues in treating two 32 bit numbers as one 64 bit number
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*/
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static inline xfs_lsn_t _lsn_cmp(xfs_lsn_t lsn1, xfs_lsn_t lsn2)
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{
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if (CYCLE_LSN(lsn1) != CYCLE_LSN(lsn2))
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return (CYCLE_LSN(lsn1)<CYCLE_LSN(lsn2))? -999 : 999;
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if (BLOCK_LSN(lsn1) != BLOCK_LSN(lsn2))
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return (BLOCK_LSN(lsn1)<BLOCK_LSN(lsn2))? -999 : 999;
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return 0;
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}
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#define XFS_LSN_CMP(x,y) _lsn_cmp(x,y)
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/*
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* Flags to xfs_log_force()
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*
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* XFS_LOG_SYNC: Synchronous force in-core log to disk
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*/
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#define XFS_LOG_SYNC 0x1
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/* Log manager interfaces */
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struct xfs_mount;
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struct xlog_in_core;
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struct xlog_ticket;
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struct xfs_log_item;
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struct xfs_item_ops;
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struct xfs_trans;
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int xfs_log_force(struct xfs_mount *mp, uint flags);
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int xfs_log_force_seq(struct xfs_mount *mp, xfs_csn_t seq, uint flags,
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int *log_forced);
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int xfs_log_mount(struct xfs_mount *mp,
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struct xfs_buftarg *log_target,
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xfs_daddr_t start_block,
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int num_bblocks);
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int xfs_log_mount_finish(struct xfs_mount *mp);
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void xfs_log_mount_cancel(struct xfs_mount *);
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xfs_lsn_t xlog_assign_tail_lsn(struct xfs_mount *mp);
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xfs_lsn_t xlog_assign_tail_lsn_locked(struct xfs_mount *mp);
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void xfs_log_space_wake(struct xfs_mount *mp);
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int xfs_log_reserve(struct xfs_mount *mp,
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int length,
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int count,
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struct xlog_ticket **ticket,
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uint8_t clientid,
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bool permanent);
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int xfs_log_regrant(struct xfs_mount *mp, struct xlog_ticket *tic);
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void xfs_log_unmount(struct xfs_mount *mp);
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int xfs_log_force_umount(struct xfs_mount *mp, int logerror);
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bool xfs_log_writable(struct xfs_mount *mp);
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struct xlog_ticket *xfs_log_ticket_get(struct xlog_ticket *ticket);
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void xfs_log_ticket_put(struct xlog_ticket *ticket);
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void xlog_cil_process_committed(struct list_head *list);
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bool xfs_log_item_in_current_chkpt(struct xfs_log_item *lip);
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void xfs_log_work_queue(struct xfs_mount *mp);
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int xfs_log_quiesce(struct xfs_mount *mp);
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void xfs_log_clean(struct xfs_mount *mp);
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bool xfs_log_check_lsn(struct xfs_mount *, xfs_lsn_t);
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bool xfs_log_in_recovery(struct xfs_mount *);
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xfs_lsn_t xlog_grant_push_threshold(struct xlog *log, int need_bytes);
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#endif /* __XFS_LOG_H__ */
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