![Vratislav Bendel](/assets/img/avatar_default.png)
Due to an inverted logic mistake in xfs_buftarg_isolate() the xfs_buffers with zero b_lru_ref will take another trip around LRU, while isolating buffers with non-zero b_lru_ref. Additionally those isolated buffers end up right back on the LRU once they are released, because b_lru_ref remains elevated. Fix that circuitous route by leaving them on the LRU as originally intended. Signed-off-by: Vratislav Bendel <vbendel@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2157 lines
52 KiB
C
2157 lines
52 KiB
C
/*
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* Copyright (c) 2000-2006 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xfs.h"
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#include <linux/stddef.h>
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#include <linux/errno.h>
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#include <linux/gfp.h>
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#include <linux/pagemap.h>
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#include <linux/init.h>
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#include <linux/vmalloc.h>
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#include <linux/bio.h>
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#include <linux/sysctl.h>
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#include <linux/proc_fs.h>
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#include <linux/workqueue.h>
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#include <linux/percpu.h>
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#include <linux/blkdev.h>
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#include <linux/hash.h>
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#include <linux/kthread.h>
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#include <linux/migrate.h>
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#include <linux/backing-dev.h>
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#include <linux/freezer.h>
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#include <linux/sched/mm.h>
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#include "xfs_format.h"
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#include "xfs_log_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_sb.h"
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#include "xfs_mount.h"
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#include "xfs_trace.h"
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#include "xfs_log.h"
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#include "xfs_errortag.h"
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#include "xfs_error.h"
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static kmem_zone_t *xfs_buf_zone;
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#ifdef XFS_BUF_LOCK_TRACKING
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# define XB_SET_OWNER(bp) ((bp)->b_last_holder = current->pid)
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# define XB_CLEAR_OWNER(bp) ((bp)->b_last_holder = -1)
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# define XB_GET_OWNER(bp) ((bp)->b_last_holder)
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#else
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# define XB_SET_OWNER(bp) do { } while (0)
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# define XB_CLEAR_OWNER(bp) do { } while (0)
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# define XB_GET_OWNER(bp) do { } while (0)
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#endif
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#define xb_to_gfp(flags) \
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((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : GFP_NOFS) | __GFP_NOWARN)
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static inline int
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xfs_buf_is_vmapped(
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struct xfs_buf *bp)
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{
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/*
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* Return true if the buffer is vmapped.
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*
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* b_addr is null if the buffer is not mapped, but the code is clever
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* enough to know it doesn't have to map a single page, so the check has
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* to be both for b_addr and bp->b_page_count > 1.
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*/
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return bp->b_addr && bp->b_page_count > 1;
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}
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static inline int
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xfs_buf_vmap_len(
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struct xfs_buf *bp)
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{
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return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
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}
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/*
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* Bump the I/O in flight count on the buftarg if we haven't yet done so for
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* this buffer. The count is incremented once per buffer (per hold cycle)
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* because the corresponding decrement is deferred to buffer release. Buffers
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* can undergo I/O multiple times in a hold-release cycle and per buffer I/O
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* tracking adds unnecessary overhead. This is used for sychronization purposes
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* with unmount (see xfs_wait_buftarg()), so all we really need is a count of
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* in-flight buffers.
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*
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* Buffers that are never released (e.g., superblock, iclog buffers) must set
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* the XBF_NO_IOACCT flag before I/O submission. Otherwise, the buftarg count
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* never reaches zero and unmount hangs indefinitely.
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*/
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static inline void
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xfs_buf_ioacct_inc(
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struct xfs_buf *bp)
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{
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if (bp->b_flags & XBF_NO_IOACCT)
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return;
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ASSERT(bp->b_flags & XBF_ASYNC);
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spin_lock(&bp->b_lock);
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if (!(bp->b_state & XFS_BSTATE_IN_FLIGHT)) {
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bp->b_state |= XFS_BSTATE_IN_FLIGHT;
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percpu_counter_inc(&bp->b_target->bt_io_count);
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}
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spin_unlock(&bp->b_lock);
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}
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/*
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* Clear the in-flight state on a buffer about to be released to the LRU or
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* freed and unaccount from the buftarg.
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*/
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static inline void
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__xfs_buf_ioacct_dec(
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struct xfs_buf *bp)
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{
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lockdep_assert_held(&bp->b_lock);
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if (bp->b_state & XFS_BSTATE_IN_FLIGHT) {
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bp->b_state &= ~XFS_BSTATE_IN_FLIGHT;
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percpu_counter_dec(&bp->b_target->bt_io_count);
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}
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}
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static inline void
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xfs_buf_ioacct_dec(
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struct xfs_buf *bp)
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{
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spin_lock(&bp->b_lock);
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__xfs_buf_ioacct_dec(bp);
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spin_unlock(&bp->b_lock);
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}
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/*
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* When we mark a buffer stale, we remove the buffer from the LRU and clear the
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* b_lru_ref count so that the buffer is freed immediately when the buffer
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* reference count falls to zero. If the buffer is already on the LRU, we need
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* to remove the reference that LRU holds on the buffer.
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*
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* This prevents build-up of stale buffers on the LRU.
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*/
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void
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xfs_buf_stale(
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struct xfs_buf *bp)
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{
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ASSERT(xfs_buf_islocked(bp));
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bp->b_flags |= XBF_STALE;
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/*
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* Clear the delwri status so that a delwri queue walker will not
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* flush this buffer to disk now that it is stale. The delwri queue has
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* a reference to the buffer, so this is safe to do.
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*/
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bp->b_flags &= ~_XBF_DELWRI_Q;
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/*
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* Once the buffer is marked stale and unlocked, a subsequent lookup
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* could reset b_flags. There is no guarantee that the buffer is
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* unaccounted (released to LRU) before that occurs. Drop in-flight
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* status now to preserve accounting consistency.
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*/
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spin_lock(&bp->b_lock);
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__xfs_buf_ioacct_dec(bp);
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atomic_set(&bp->b_lru_ref, 0);
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if (!(bp->b_state & XFS_BSTATE_DISPOSE) &&
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(list_lru_del(&bp->b_target->bt_lru, &bp->b_lru)))
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atomic_dec(&bp->b_hold);
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ASSERT(atomic_read(&bp->b_hold) >= 1);
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spin_unlock(&bp->b_lock);
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}
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static int
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xfs_buf_get_maps(
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struct xfs_buf *bp,
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int map_count)
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{
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ASSERT(bp->b_maps == NULL);
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bp->b_map_count = map_count;
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if (map_count == 1) {
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bp->b_maps = &bp->__b_map;
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return 0;
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}
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bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map),
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KM_NOFS);
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if (!bp->b_maps)
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return -ENOMEM;
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return 0;
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}
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/*
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* Frees b_pages if it was allocated.
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*/
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static void
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xfs_buf_free_maps(
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struct xfs_buf *bp)
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{
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if (bp->b_maps != &bp->__b_map) {
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kmem_free(bp->b_maps);
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bp->b_maps = NULL;
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}
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}
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struct xfs_buf *
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_xfs_buf_alloc(
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struct xfs_buftarg *target,
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struct xfs_buf_map *map,
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int nmaps,
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xfs_buf_flags_t flags)
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{
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struct xfs_buf *bp;
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int error;
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int i;
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bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS);
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if (unlikely(!bp))
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return NULL;
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/*
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* We don't want certain flags to appear in b_flags unless they are
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* specifically set by later operations on the buffer.
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*/
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flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD);
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atomic_set(&bp->b_hold, 1);
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atomic_set(&bp->b_lru_ref, 1);
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init_completion(&bp->b_iowait);
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INIT_LIST_HEAD(&bp->b_lru);
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INIT_LIST_HEAD(&bp->b_list);
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INIT_LIST_HEAD(&bp->b_li_list);
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sema_init(&bp->b_sema, 0); /* held, no waiters */
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spin_lock_init(&bp->b_lock);
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XB_SET_OWNER(bp);
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bp->b_target = target;
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bp->b_flags = flags;
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/*
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* Set length and io_length to the same value initially.
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* I/O routines should use io_length, which will be the same in
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* most cases but may be reset (e.g. XFS recovery).
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*/
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error = xfs_buf_get_maps(bp, nmaps);
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if (error) {
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kmem_zone_free(xfs_buf_zone, bp);
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return NULL;
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}
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bp->b_bn = map[0].bm_bn;
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bp->b_length = 0;
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for (i = 0; i < nmaps; i++) {
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bp->b_maps[i].bm_bn = map[i].bm_bn;
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bp->b_maps[i].bm_len = map[i].bm_len;
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bp->b_length += map[i].bm_len;
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}
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bp->b_io_length = bp->b_length;
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atomic_set(&bp->b_pin_count, 0);
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init_waitqueue_head(&bp->b_waiters);
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XFS_STATS_INC(target->bt_mount, xb_create);
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trace_xfs_buf_init(bp, _RET_IP_);
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return bp;
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}
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/*
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* Allocate a page array capable of holding a specified number
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* of pages, and point the page buf at it.
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*/
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STATIC int
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_xfs_buf_get_pages(
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xfs_buf_t *bp,
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int page_count)
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{
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/* Make sure that we have a page list */
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if (bp->b_pages == NULL) {
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bp->b_page_count = page_count;
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if (page_count <= XB_PAGES) {
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bp->b_pages = bp->b_page_array;
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} else {
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bp->b_pages = kmem_alloc(sizeof(struct page *) *
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page_count, KM_NOFS);
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if (bp->b_pages == NULL)
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return -ENOMEM;
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}
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memset(bp->b_pages, 0, sizeof(struct page *) * page_count);
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}
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return 0;
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}
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/*
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* Frees b_pages if it was allocated.
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*/
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STATIC void
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_xfs_buf_free_pages(
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xfs_buf_t *bp)
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{
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if (bp->b_pages != bp->b_page_array) {
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kmem_free(bp->b_pages);
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bp->b_pages = NULL;
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}
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}
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/*
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* Releases the specified buffer.
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*
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* The modification state of any associated pages is left unchanged.
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* The buffer must not be on any hash - use xfs_buf_rele instead for
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* hashed and refcounted buffers
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*/
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void
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xfs_buf_free(
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xfs_buf_t *bp)
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{
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trace_xfs_buf_free(bp, _RET_IP_);
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ASSERT(list_empty(&bp->b_lru));
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if (bp->b_flags & _XBF_PAGES) {
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uint i;
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if (xfs_buf_is_vmapped(bp))
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vm_unmap_ram(bp->b_addr - bp->b_offset,
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bp->b_page_count);
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for (i = 0; i < bp->b_page_count; i++) {
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struct page *page = bp->b_pages[i];
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__free_page(page);
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}
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} else if (bp->b_flags & _XBF_KMEM)
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kmem_free(bp->b_addr);
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_xfs_buf_free_pages(bp);
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xfs_buf_free_maps(bp);
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kmem_zone_free(xfs_buf_zone, bp);
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}
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/*
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* Allocates all the pages for buffer in question and builds it's page list.
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*/
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STATIC int
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xfs_buf_allocate_memory(
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xfs_buf_t *bp,
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uint flags)
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{
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size_t size;
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size_t nbytes, offset;
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gfp_t gfp_mask = xb_to_gfp(flags);
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unsigned short page_count, i;
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xfs_off_t start, end;
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int error;
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/*
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* for buffers that are contained within a single page, just allocate
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* the memory from the heap - there's no need for the complexity of
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* page arrays to keep allocation down to order 0.
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*/
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size = BBTOB(bp->b_length);
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if (size < PAGE_SIZE) {
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bp->b_addr = kmem_alloc(size, KM_NOFS);
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if (!bp->b_addr) {
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/* low memory - use alloc_page loop instead */
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goto use_alloc_page;
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}
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if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) !=
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((unsigned long)bp->b_addr & PAGE_MASK)) {
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/* b_addr spans two pages - use alloc_page instead */
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kmem_free(bp->b_addr);
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bp->b_addr = NULL;
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goto use_alloc_page;
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}
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bp->b_offset = offset_in_page(bp->b_addr);
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bp->b_pages = bp->b_page_array;
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bp->b_pages[0] = virt_to_page(bp->b_addr);
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bp->b_page_count = 1;
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bp->b_flags |= _XBF_KMEM;
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return 0;
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}
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use_alloc_page:
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start = BBTOB(bp->b_maps[0].bm_bn) >> PAGE_SHIFT;
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end = (BBTOB(bp->b_maps[0].bm_bn + bp->b_length) + PAGE_SIZE - 1)
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>> PAGE_SHIFT;
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page_count = end - start;
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error = _xfs_buf_get_pages(bp, page_count);
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if (unlikely(error))
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return error;
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offset = bp->b_offset;
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bp->b_flags |= _XBF_PAGES;
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for (i = 0; i < bp->b_page_count; i++) {
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struct page *page;
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uint retries = 0;
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retry:
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page = alloc_page(gfp_mask);
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if (unlikely(page == NULL)) {
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if (flags & XBF_READ_AHEAD) {
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bp->b_page_count = i;
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error = -ENOMEM;
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goto out_free_pages;
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}
|
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|
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/*
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* This could deadlock.
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*
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* But until all the XFS lowlevel code is revamped to
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* handle buffer allocation failures we can't do much.
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*/
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if (!(++retries % 100))
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xfs_err(NULL,
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"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
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current->comm, current->pid,
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__func__, gfp_mask);
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|
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XFS_STATS_INC(bp->b_target->bt_mount, xb_page_retries);
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congestion_wait(BLK_RW_ASYNC, HZ/50);
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goto retry;
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}
|
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|
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XFS_STATS_INC(bp->b_target->bt_mount, xb_page_found);
|
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|
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nbytes = min_t(size_t, size, PAGE_SIZE - offset);
|
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size -= nbytes;
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bp->b_pages[i] = page;
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offset = 0;
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}
|
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return 0;
|
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|
|
out_free_pages:
|
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for (i = 0; i < bp->b_page_count; i++)
|
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__free_page(bp->b_pages[i]);
|
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bp->b_flags &= ~_XBF_PAGES;
|
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return error;
|
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}
|
|
|
|
/*
|
|
* Map buffer into kernel address-space if necessary.
|
|
*/
|
|
STATIC int
|
|
_xfs_buf_map_pages(
|
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xfs_buf_t *bp,
|
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uint flags)
|
|
{
|
|
ASSERT(bp->b_flags & _XBF_PAGES);
|
|
if (bp->b_page_count == 1) {
|
|
/* A single page buffer is always mappable */
|
|
bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
|
|
} else if (flags & XBF_UNMAPPED) {
|
|
bp->b_addr = NULL;
|
|
} else {
|
|
int retried = 0;
|
|
unsigned nofs_flag;
|
|
|
|
/*
|
|
* vm_map_ram() will allocate auxillary structures (e.g.
|
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* pagetables) with GFP_KERNEL, yet we are likely to be under
|
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* GFP_NOFS context here. Hence we need to tell memory reclaim
|
|
* that we are in such a context via PF_MEMALLOC_NOFS to prevent
|
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* memory reclaim re-entering the filesystem here and
|
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* potentially deadlocking.
|
|
*/
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nofs_flag = memalloc_nofs_save();
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do {
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bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
|
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-1, PAGE_KERNEL);
|
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if (bp->b_addr)
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break;
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vm_unmap_aliases();
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} while (retried++ <= 1);
|
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memalloc_nofs_restore(nofs_flag);
|
|
|
|
if (!bp->b_addr)
|
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return -ENOMEM;
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bp->b_addr += bp->b_offset;
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}
|
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|
|
return 0;
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|
}
|
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|
|
/*
|
|
* Finding and Reading Buffers
|
|
*/
|
|
static int
|
|
_xfs_buf_obj_cmp(
|
|
struct rhashtable_compare_arg *arg,
|
|
const void *obj)
|
|
{
|
|
const struct xfs_buf_map *map = arg->key;
|
|
const struct xfs_buf *bp = obj;
|
|
|
|
/*
|
|
* The key hashing in the lookup path depends on the key being the
|
|
* first element of the compare_arg, make sure to assert this.
|
|
*/
|
|
BUILD_BUG_ON(offsetof(struct xfs_buf_map, bm_bn) != 0);
|
|
|
|
if (bp->b_bn != map->bm_bn)
|
|
return 1;
|
|
|
|
if (unlikely(bp->b_length != map->bm_len)) {
|
|
/*
|
|
* found a block number match. If the range doesn't
|
|
* match, the only way this is allowed is if the buffer
|
|
* in the cache is stale and the transaction that made
|
|
* it stale has not yet committed. i.e. we are
|
|
* reallocating a busy extent. Skip this buffer and
|
|
* continue searching for an exact match.
|
|
*/
|
|
ASSERT(bp->b_flags & XBF_STALE);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static const struct rhashtable_params xfs_buf_hash_params = {
|
|
.min_size = 32, /* empty AGs have minimal footprint */
|
|
.nelem_hint = 16,
|
|
.key_len = sizeof(xfs_daddr_t),
|
|
.key_offset = offsetof(struct xfs_buf, b_bn),
|
|
.head_offset = offsetof(struct xfs_buf, b_rhash_head),
|
|
.automatic_shrinking = true,
|
|
.obj_cmpfn = _xfs_buf_obj_cmp,
|
|
};
|
|
|
|
int
|
|
xfs_buf_hash_init(
|
|
struct xfs_perag *pag)
|
|
{
|
|
spin_lock_init(&pag->pag_buf_lock);
|
|
return rhashtable_init(&pag->pag_buf_hash, &xfs_buf_hash_params);
|
|
}
|
|
|
|
void
|
|
xfs_buf_hash_destroy(
|
|
struct xfs_perag *pag)
|
|
{
|
|
rhashtable_destroy(&pag->pag_buf_hash);
|
|
}
|
|
|
|
/*
|
|
* Look up, and creates if absent, a lockable buffer for
|
|
* a given range of an inode. The buffer is returned
|
|
* locked. No I/O is implied by this call.
|
|
*/
|
|
xfs_buf_t *
|
|
_xfs_buf_find(
|
|
struct xfs_buftarg *btp,
|
|
struct xfs_buf_map *map,
|
|
int nmaps,
|
|
xfs_buf_flags_t flags,
|
|
xfs_buf_t *new_bp)
|
|
{
|
|
struct xfs_perag *pag;
|
|
xfs_buf_t *bp;
|
|
struct xfs_buf_map cmap = { .bm_bn = map[0].bm_bn };
|
|
xfs_daddr_t eofs;
|
|
int i;
|
|
|
|
for (i = 0; i < nmaps; i++)
|
|
cmap.bm_len += map[i].bm_len;
|
|
|
|
/* Check for IOs smaller than the sector size / not sector aligned */
|
|
ASSERT(!(BBTOB(cmap.bm_len) < btp->bt_meta_sectorsize));
|
|
ASSERT(!(BBTOB(cmap.bm_bn) & (xfs_off_t)btp->bt_meta_sectormask));
|
|
|
|
/*
|
|
* Corrupted block numbers can get through to here, unfortunately, so we
|
|
* have to check that the buffer falls within the filesystem bounds.
|
|
*/
|
|
eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks);
|
|
if (cmap.bm_bn < 0 || cmap.bm_bn >= eofs) {
|
|
/*
|
|
* XXX (dgc): we should really be returning -EFSCORRUPTED here,
|
|
* but none of the higher level infrastructure supports
|
|
* returning a specific error on buffer lookup failures.
|
|
*/
|
|
xfs_alert(btp->bt_mount,
|
|
"%s: daddr 0x%llx out of range, EOFS 0x%llx",
|
|
__func__, cmap.bm_bn, eofs);
|
|
WARN_ON(1);
|
|
return NULL;
|
|
}
|
|
|
|
pag = xfs_perag_get(btp->bt_mount,
|
|
xfs_daddr_to_agno(btp->bt_mount, cmap.bm_bn));
|
|
|
|
spin_lock(&pag->pag_buf_lock);
|
|
bp = rhashtable_lookup_fast(&pag->pag_buf_hash, &cmap,
|
|
xfs_buf_hash_params);
|
|
if (bp) {
|
|
atomic_inc(&bp->b_hold);
|
|
goto found;
|
|
}
|
|
|
|
/* No match found */
|
|
if (new_bp) {
|
|
/* the buffer keeps the perag reference until it is freed */
|
|
new_bp->b_pag = pag;
|
|
rhashtable_insert_fast(&pag->pag_buf_hash,
|
|
&new_bp->b_rhash_head,
|
|
xfs_buf_hash_params);
|
|
spin_unlock(&pag->pag_buf_lock);
|
|
} else {
|
|
XFS_STATS_INC(btp->bt_mount, xb_miss_locked);
|
|
spin_unlock(&pag->pag_buf_lock);
|
|
xfs_perag_put(pag);
|
|
}
|
|
return new_bp;
|
|
|
|
found:
|
|
spin_unlock(&pag->pag_buf_lock);
|
|
xfs_perag_put(pag);
|
|
|
|
if (!xfs_buf_trylock(bp)) {
|
|
if (flags & XBF_TRYLOCK) {
|
|
xfs_buf_rele(bp);
|
|
XFS_STATS_INC(btp->bt_mount, xb_busy_locked);
|
|
return NULL;
|
|
}
|
|
xfs_buf_lock(bp);
|
|
XFS_STATS_INC(btp->bt_mount, xb_get_locked_waited);
|
|
}
|
|
|
|
/*
|
|
* if the buffer is stale, clear all the external state associated with
|
|
* it. We need to keep flags such as how we allocated the buffer memory
|
|
* intact here.
|
|
*/
|
|
if (bp->b_flags & XBF_STALE) {
|
|
ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
|
|
ASSERT(bp->b_iodone == NULL);
|
|
bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
|
|
bp->b_ops = NULL;
|
|
}
|
|
|
|
trace_xfs_buf_find(bp, flags, _RET_IP_);
|
|
XFS_STATS_INC(btp->bt_mount, xb_get_locked);
|
|
return bp;
|
|
}
|
|
|
|
/*
|
|
* Assembles a buffer covering the specified range. The code is optimised for
|
|
* cache hits, as metadata intensive workloads will see 3 orders of magnitude
|
|
* more hits than misses.
|
|
*/
|
|
struct xfs_buf *
|
|
xfs_buf_get_map(
|
|
struct xfs_buftarg *target,
|
|
struct xfs_buf_map *map,
|
|
int nmaps,
|
|
xfs_buf_flags_t flags)
|
|
{
|
|
struct xfs_buf *bp;
|
|
struct xfs_buf *new_bp;
|
|
int error = 0;
|
|
|
|
bp = _xfs_buf_find(target, map, nmaps, flags, NULL);
|
|
if (likely(bp))
|
|
goto found;
|
|
|
|
new_bp = _xfs_buf_alloc(target, map, nmaps, flags);
|
|
if (unlikely(!new_bp))
|
|
return NULL;
|
|
|
|
error = xfs_buf_allocate_memory(new_bp, flags);
|
|
if (error) {
|
|
xfs_buf_free(new_bp);
|
|
return NULL;
|
|
}
|
|
|
|
bp = _xfs_buf_find(target, map, nmaps, flags, new_bp);
|
|
if (!bp) {
|
|
xfs_buf_free(new_bp);
|
|
return NULL;
|
|
}
|
|
|
|
if (bp != new_bp)
|
|
xfs_buf_free(new_bp);
|
|
|
|
found:
|
|
if (!bp->b_addr) {
|
|
error = _xfs_buf_map_pages(bp, flags);
|
|
if (unlikely(error)) {
|
|
xfs_warn(target->bt_mount,
|
|
"%s: failed to map pagesn", __func__);
|
|
xfs_buf_relse(bp);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Clear b_error if this is a lookup from a caller that doesn't expect
|
|
* valid data to be found in the buffer.
|
|
*/
|
|
if (!(flags & XBF_READ))
|
|
xfs_buf_ioerror(bp, 0);
|
|
|
|
XFS_STATS_INC(target->bt_mount, xb_get);
|
|
trace_xfs_buf_get(bp, flags, _RET_IP_);
|
|
return bp;
|
|
}
|
|
|
|
STATIC int
|
|
_xfs_buf_read(
|
|
xfs_buf_t *bp,
|
|
xfs_buf_flags_t flags)
|
|
{
|
|
ASSERT(!(flags & XBF_WRITE));
|
|
ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL);
|
|
|
|
bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
|
|
bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
|
|
|
|
if (flags & XBF_ASYNC) {
|
|
xfs_buf_submit(bp);
|
|
return 0;
|
|
}
|
|
return xfs_buf_submit_wait(bp);
|
|
}
|
|
|
|
xfs_buf_t *
|
|
xfs_buf_read_map(
|
|
struct xfs_buftarg *target,
|
|
struct xfs_buf_map *map,
|
|
int nmaps,
|
|
xfs_buf_flags_t flags,
|
|
const struct xfs_buf_ops *ops)
|
|
{
|
|
struct xfs_buf *bp;
|
|
|
|
flags |= XBF_READ;
|
|
|
|
bp = xfs_buf_get_map(target, map, nmaps, flags);
|
|
if (bp) {
|
|
trace_xfs_buf_read(bp, flags, _RET_IP_);
|
|
|
|
if (!(bp->b_flags & XBF_DONE)) {
|
|
XFS_STATS_INC(target->bt_mount, xb_get_read);
|
|
bp->b_ops = ops;
|
|
_xfs_buf_read(bp, flags);
|
|
} else if (flags & XBF_ASYNC) {
|
|
/*
|
|
* Read ahead call which is already satisfied,
|
|
* drop the buffer
|
|
*/
|
|
xfs_buf_relse(bp);
|
|
return NULL;
|
|
} else {
|
|
/* We do not want read in the flags */
|
|
bp->b_flags &= ~XBF_READ;
|
|
}
|
|
}
|
|
|
|
return bp;
|
|
}
|
|
|
|
/*
|
|
* If we are not low on memory then do the readahead in a deadlock
|
|
* safe manner.
|
|
*/
|
|
void
|
|
xfs_buf_readahead_map(
|
|
struct xfs_buftarg *target,
|
|
struct xfs_buf_map *map,
|
|
int nmaps,
|
|
const struct xfs_buf_ops *ops)
|
|
{
|
|
if (bdi_read_congested(target->bt_bdev->bd_bdi))
|
|
return;
|
|
|
|
xfs_buf_read_map(target, map, nmaps,
|
|
XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD, ops);
|
|
}
|
|
|
|
/*
|
|
* Read an uncached buffer from disk. Allocates and returns a locked
|
|
* buffer containing the disk contents or nothing.
|
|
*/
|
|
int
|
|
xfs_buf_read_uncached(
|
|
struct xfs_buftarg *target,
|
|
xfs_daddr_t daddr,
|
|
size_t numblks,
|
|
int flags,
|
|
struct xfs_buf **bpp,
|
|
const struct xfs_buf_ops *ops)
|
|
{
|
|
struct xfs_buf *bp;
|
|
|
|
*bpp = NULL;
|
|
|
|
bp = xfs_buf_get_uncached(target, numblks, flags);
|
|
if (!bp)
|
|
return -ENOMEM;
|
|
|
|
/* set up the buffer for a read IO */
|
|
ASSERT(bp->b_map_count == 1);
|
|
bp->b_bn = XFS_BUF_DADDR_NULL; /* always null for uncached buffers */
|
|
bp->b_maps[0].bm_bn = daddr;
|
|
bp->b_flags |= XBF_READ;
|
|
bp->b_ops = ops;
|
|
|
|
xfs_buf_submit_wait(bp);
|
|
if (bp->b_error) {
|
|
int error = bp->b_error;
|
|
xfs_buf_relse(bp);
|
|
return error;
|
|
}
|
|
|
|
*bpp = bp;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Return a buffer allocated as an empty buffer and associated to external
|
|
* memory via xfs_buf_associate_memory() back to it's empty state.
|
|
*/
|
|
void
|
|
xfs_buf_set_empty(
|
|
struct xfs_buf *bp,
|
|
size_t numblks)
|
|
{
|
|
if (bp->b_pages)
|
|
_xfs_buf_free_pages(bp);
|
|
|
|
bp->b_pages = NULL;
|
|
bp->b_page_count = 0;
|
|
bp->b_addr = NULL;
|
|
bp->b_length = numblks;
|
|
bp->b_io_length = numblks;
|
|
|
|
ASSERT(bp->b_map_count == 1);
|
|
bp->b_bn = XFS_BUF_DADDR_NULL;
|
|
bp->b_maps[0].bm_bn = XFS_BUF_DADDR_NULL;
|
|
bp->b_maps[0].bm_len = bp->b_length;
|
|
}
|
|
|
|
static inline struct page *
|
|
mem_to_page(
|
|
void *addr)
|
|
{
|
|
if ((!is_vmalloc_addr(addr))) {
|
|
return virt_to_page(addr);
|
|
} else {
|
|
return vmalloc_to_page(addr);
|
|
}
|
|
}
|
|
|
|
int
|
|
xfs_buf_associate_memory(
|
|
xfs_buf_t *bp,
|
|
void *mem,
|
|
size_t len)
|
|
{
|
|
int rval;
|
|
int i = 0;
|
|
unsigned long pageaddr;
|
|
unsigned long offset;
|
|
size_t buflen;
|
|
int page_count;
|
|
|
|
pageaddr = (unsigned long)mem & PAGE_MASK;
|
|
offset = (unsigned long)mem - pageaddr;
|
|
buflen = PAGE_ALIGN(len + offset);
|
|
page_count = buflen >> PAGE_SHIFT;
|
|
|
|
/* Free any previous set of page pointers */
|
|
if (bp->b_pages)
|
|
_xfs_buf_free_pages(bp);
|
|
|
|
bp->b_pages = NULL;
|
|
bp->b_addr = mem;
|
|
|
|
rval = _xfs_buf_get_pages(bp, page_count);
|
|
if (rval)
|
|
return rval;
|
|
|
|
bp->b_offset = offset;
|
|
|
|
for (i = 0; i < bp->b_page_count; i++) {
|
|
bp->b_pages[i] = mem_to_page((void *)pageaddr);
|
|
pageaddr += PAGE_SIZE;
|
|
}
|
|
|
|
bp->b_io_length = BTOBB(len);
|
|
bp->b_length = BTOBB(buflen);
|
|
|
|
return 0;
|
|
}
|
|
|
|
xfs_buf_t *
|
|
xfs_buf_get_uncached(
|
|
struct xfs_buftarg *target,
|
|
size_t numblks,
|
|
int flags)
|
|
{
|
|
unsigned long page_count;
|
|
int error, i;
|
|
struct xfs_buf *bp;
|
|
DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks);
|
|
|
|
/* flags might contain irrelevant bits, pass only what we care about */
|
|
bp = _xfs_buf_alloc(target, &map, 1, flags & XBF_NO_IOACCT);
|
|
if (unlikely(bp == NULL))
|
|
goto fail;
|
|
|
|
page_count = PAGE_ALIGN(numblks << BBSHIFT) >> PAGE_SHIFT;
|
|
error = _xfs_buf_get_pages(bp, page_count);
|
|
if (error)
|
|
goto fail_free_buf;
|
|
|
|
for (i = 0; i < page_count; i++) {
|
|
bp->b_pages[i] = alloc_page(xb_to_gfp(flags));
|
|
if (!bp->b_pages[i])
|
|
goto fail_free_mem;
|
|
}
|
|
bp->b_flags |= _XBF_PAGES;
|
|
|
|
error = _xfs_buf_map_pages(bp, 0);
|
|
if (unlikely(error)) {
|
|
xfs_warn(target->bt_mount,
|
|
"%s: failed to map pages", __func__);
|
|
goto fail_free_mem;
|
|
}
|
|
|
|
trace_xfs_buf_get_uncached(bp, _RET_IP_);
|
|
return bp;
|
|
|
|
fail_free_mem:
|
|
while (--i >= 0)
|
|
__free_page(bp->b_pages[i]);
|
|
_xfs_buf_free_pages(bp);
|
|
fail_free_buf:
|
|
xfs_buf_free_maps(bp);
|
|
kmem_zone_free(xfs_buf_zone, bp);
|
|
fail:
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Increment reference count on buffer, to hold the buffer concurrently
|
|
* with another thread which may release (free) the buffer asynchronously.
|
|
* Must hold the buffer already to call this function.
|
|
*/
|
|
void
|
|
xfs_buf_hold(
|
|
xfs_buf_t *bp)
|
|
{
|
|
trace_xfs_buf_hold(bp, _RET_IP_);
|
|
atomic_inc(&bp->b_hold);
|
|
}
|
|
|
|
/*
|
|
* Release a hold on the specified buffer. If the hold count is 1, the buffer is
|
|
* placed on LRU or freed (depending on b_lru_ref).
|
|
*/
|
|
void
|
|
xfs_buf_rele(
|
|
xfs_buf_t *bp)
|
|
{
|
|
struct xfs_perag *pag = bp->b_pag;
|
|
bool release;
|
|
bool freebuf = false;
|
|
|
|
trace_xfs_buf_rele(bp, _RET_IP_);
|
|
|
|
if (!pag) {
|
|
ASSERT(list_empty(&bp->b_lru));
|
|
if (atomic_dec_and_test(&bp->b_hold)) {
|
|
xfs_buf_ioacct_dec(bp);
|
|
xfs_buf_free(bp);
|
|
}
|
|
return;
|
|
}
|
|
|
|
ASSERT(atomic_read(&bp->b_hold) > 0);
|
|
|
|
release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock);
|
|
spin_lock(&bp->b_lock);
|
|
if (!release) {
|
|
/*
|
|
* Drop the in-flight state if the buffer is already on the LRU
|
|
* and it holds the only reference. This is racy because we
|
|
* haven't acquired the pag lock, but the use of _XBF_IN_FLIGHT
|
|
* ensures the decrement occurs only once per-buf.
|
|
*/
|
|
if ((atomic_read(&bp->b_hold) == 1) && !list_empty(&bp->b_lru))
|
|
__xfs_buf_ioacct_dec(bp);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* the last reference has been dropped ... */
|
|
__xfs_buf_ioacct_dec(bp);
|
|
if (!(bp->b_flags & XBF_STALE) && atomic_read(&bp->b_lru_ref)) {
|
|
/*
|
|
* If the buffer is added to the LRU take a new reference to the
|
|
* buffer for the LRU and clear the (now stale) dispose list
|
|
* state flag
|
|
*/
|
|
if (list_lru_add(&bp->b_target->bt_lru, &bp->b_lru)) {
|
|
bp->b_state &= ~XFS_BSTATE_DISPOSE;
|
|
atomic_inc(&bp->b_hold);
|
|
}
|
|
spin_unlock(&pag->pag_buf_lock);
|
|
} else {
|
|
/*
|
|
* most of the time buffers will already be removed from the
|
|
* LRU, so optimise that case by checking for the
|
|
* XFS_BSTATE_DISPOSE flag indicating the last list the buffer
|
|
* was on was the disposal list
|
|
*/
|
|
if (!(bp->b_state & XFS_BSTATE_DISPOSE)) {
|
|
list_lru_del(&bp->b_target->bt_lru, &bp->b_lru);
|
|
} else {
|
|
ASSERT(list_empty(&bp->b_lru));
|
|
}
|
|
|
|
ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
|
|
rhashtable_remove_fast(&pag->pag_buf_hash, &bp->b_rhash_head,
|
|
xfs_buf_hash_params);
|
|
spin_unlock(&pag->pag_buf_lock);
|
|
xfs_perag_put(pag);
|
|
freebuf = true;
|
|
}
|
|
|
|
out_unlock:
|
|
spin_unlock(&bp->b_lock);
|
|
|
|
if (freebuf)
|
|
xfs_buf_free(bp);
|
|
}
|
|
|
|
|
|
/*
|
|
* Lock a buffer object, if it is not already locked.
|
|
*
|
|
* If we come across a stale, pinned, locked buffer, we know that we are
|
|
* being asked to lock a buffer that has been reallocated. Because it is
|
|
* pinned, we know that the log has not been pushed to disk and hence it
|
|
* will still be locked. Rather than continuing to have trylock attempts
|
|
* fail until someone else pushes the log, push it ourselves before
|
|
* returning. This means that the xfsaild will not get stuck trying
|
|
* to push on stale inode buffers.
|
|
*/
|
|
int
|
|
xfs_buf_trylock(
|
|
struct xfs_buf *bp)
|
|
{
|
|
int locked;
|
|
|
|
locked = down_trylock(&bp->b_sema) == 0;
|
|
if (locked) {
|
|
XB_SET_OWNER(bp);
|
|
trace_xfs_buf_trylock(bp, _RET_IP_);
|
|
} else {
|
|
trace_xfs_buf_trylock_fail(bp, _RET_IP_);
|
|
}
|
|
return locked;
|
|
}
|
|
|
|
/*
|
|
* Lock a buffer object.
|
|
*
|
|
* If we come across a stale, pinned, locked buffer, we know that we
|
|
* are being asked to lock a buffer that has been reallocated. Because
|
|
* it is pinned, we know that the log has not been pushed to disk and
|
|
* hence it will still be locked. Rather than sleeping until someone
|
|
* else pushes the log, push it ourselves before trying to get the lock.
|
|
*/
|
|
void
|
|
xfs_buf_lock(
|
|
struct xfs_buf *bp)
|
|
{
|
|
trace_xfs_buf_lock(bp, _RET_IP_);
|
|
|
|
if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
|
|
xfs_log_force(bp->b_target->bt_mount, 0);
|
|
down(&bp->b_sema);
|
|
XB_SET_OWNER(bp);
|
|
|
|
trace_xfs_buf_lock_done(bp, _RET_IP_);
|
|
}
|
|
|
|
void
|
|
xfs_buf_unlock(
|
|
struct xfs_buf *bp)
|
|
{
|
|
ASSERT(xfs_buf_islocked(bp));
|
|
|
|
XB_CLEAR_OWNER(bp);
|
|
up(&bp->b_sema);
|
|
|
|
trace_xfs_buf_unlock(bp, _RET_IP_);
|
|
}
|
|
|
|
STATIC void
|
|
xfs_buf_wait_unpin(
|
|
xfs_buf_t *bp)
|
|
{
|
|
DECLARE_WAITQUEUE (wait, current);
|
|
|
|
if (atomic_read(&bp->b_pin_count) == 0)
|
|
return;
|
|
|
|
add_wait_queue(&bp->b_waiters, &wait);
|
|
for (;;) {
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
if (atomic_read(&bp->b_pin_count) == 0)
|
|
break;
|
|
io_schedule();
|
|
}
|
|
remove_wait_queue(&bp->b_waiters, &wait);
|
|
set_current_state(TASK_RUNNING);
|
|
}
|
|
|
|
/*
|
|
* Buffer Utility Routines
|
|
*/
|
|
|
|
void
|
|
xfs_buf_ioend(
|
|
struct xfs_buf *bp)
|
|
{
|
|
bool read = bp->b_flags & XBF_READ;
|
|
|
|
trace_xfs_buf_iodone(bp, _RET_IP_);
|
|
|
|
bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
|
|
|
|
/*
|
|
* Pull in IO completion errors now. We are guaranteed to be running
|
|
* single threaded, so we don't need the lock to read b_io_error.
|
|
*/
|
|
if (!bp->b_error && bp->b_io_error)
|
|
xfs_buf_ioerror(bp, bp->b_io_error);
|
|
|
|
/* Only validate buffers that were read without errors */
|
|
if (read && !bp->b_error && bp->b_ops) {
|
|
ASSERT(!bp->b_iodone);
|
|
bp->b_ops->verify_read(bp);
|
|
}
|
|
|
|
if (!bp->b_error)
|
|
bp->b_flags |= XBF_DONE;
|
|
|
|
if (bp->b_iodone)
|
|
(*(bp->b_iodone))(bp);
|
|
else if (bp->b_flags & XBF_ASYNC)
|
|
xfs_buf_relse(bp);
|
|
else
|
|
complete(&bp->b_iowait);
|
|
}
|
|
|
|
static void
|
|
xfs_buf_ioend_work(
|
|
struct work_struct *work)
|
|
{
|
|
struct xfs_buf *bp =
|
|
container_of(work, xfs_buf_t, b_ioend_work);
|
|
|
|
xfs_buf_ioend(bp);
|
|
}
|
|
|
|
static void
|
|
xfs_buf_ioend_async(
|
|
struct xfs_buf *bp)
|
|
{
|
|
INIT_WORK(&bp->b_ioend_work, xfs_buf_ioend_work);
|
|
queue_work(bp->b_ioend_wq, &bp->b_ioend_work);
|
|
}
|
|
|
|
void
|
|
__xfs_buf_ioerror(
|
|
xfs_buf_t *bp,
|
|
int error,
|
|
xfs_failaddr_t failaddr)
|
|
{
|
|
ASSERT(error <= 0 && error >= -1000);
|
|
bp->b_error = error;
|
|
trace_xfs_buf_ioerror(bp, error, failaddr);
|
|
}
|
|
|
|
void
|
|
xfs_buf_ioerror_alert(
|
|
struct xfs_buf *bp,
|
|
const char *func)
|
|
{
|
|
xfs_alert(bp->b_target->bt_mount,
|
|
"metadata I/O error in \"%s\" at daddr 0x%llx len %d error %d",
|
|
func, (uint64_t)XFS_BUF_ADDR(bp), bp->b_length,
|
|
-bp->b_error);
|
|
}
|
|
|
|
int
|
|
xfs_bwrite(
|
|
struct xfs_buf *bp)
|
|
{
|
|
int error;
|
|
|
|
ASSERT(xfs_buf_islocked(bp));
|
|
|
|
bp->b_flags |= XBF_WRITE;
|
|
bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
|
|
XBF_WRITE_FAIL | XBF_DONE);
|
|
|
|
error = xfs_buf_submit_wait(bp);
|
|
if (error) {
|
|
xfs_force_shutdown(bp->b_target->bt_mount,
|
|
SHUTDOWN_META_IO_ERROR);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static void
|
|
xfs_buf_bio_end_io(
|
|
struct bio *bio)
|
|
{
|
|
struct xfs_buf *bp = (struct xfs_buf *)bio->bi_private;
|
|
|
|
/*
|
|
* don't overwrite existing errors - otherwise we can lose errors on
|
|
* buffers that require multiple bios to complete.
|
|
*/
|
|
if (bio->bi_status) {
|
|
int error = blk_status_to_errno(bio->bi_status);
|
|
|
|
cmpxchg(&bp->b_io_error, 0, error);
|
|
}
|
|
|
|
if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
|
|
invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
|
|
|
|
if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
|
|
xfs_buf_ioend_async(bp);
|
|
bio_put(bio);
|
|
}
|
|
|
|
static void
|
|
xfs_buf_ioapply_map(
|
|
struct xfs_buf *bp,
|
|
int map,
|
|
int *buf_offset,
|
|
int *count,
|
|
int op,
|
|
int op_flags)
|
|
{
|
|
int page_index;
|
|
int total_nr_pages = bp->b_page_count;
|
|
int nr_pages;
|
|
struct bio *bio;
|
|
sector_t sector = bp->b_maps[map].bm_bn;
|
|
int size;
|
|
int offset;
|
|
|
|
/* skip the pages in the buffer before the start offset */
|
|
page_index = 0;
|
|
offset = *buf_offset;
|
|
while (offset >= PAGE_SIZE) {
|
|
page_index++;
|
|
offset -= PAGE_SIZE;
|
|
}
|
|
|
|
/*
|
|
* Limit the IO size to the length of the current vector, and update the
|
|
* remaining IO count for the next time around.
|
|
*/
|
|
size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count);
|
|
*count -= size;
|
|
*buf_offset += size;
|
|
|
|
next_chunk:
|
|
atomic_inc(&bp->b_io_remaining);
|
|
nr_pages = min(total_nr_pages, BIO_MAX_PAGES);
|
|
|
|
bio = bio_alloc(GFP_NOIO, nr_pages);
|
|
bio_set_dev(bio, bp->b_target->bt_bdev);
|
|
bio->bi_iter.bi_sector = sector;
|
|
bio->bi_end_io = xfs_buf_bio_end_io;
|
|
bio->bi_private = bp;
|
|
bio_set_op_attrs(bio, op, op_flags);
|
|
|
|
for (; size && nr_pages; nr_pages--, page_index++) {
|
|
int rbytes, nbytes = PAGE_SIZE - offset;
|
|
|
|
if (nbytes > size)
|
|
nbytes = size;
|
|
|
|
rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes,
|
|
offset);
|
|
if (rbytes < nbytes)
|
|
break;
|
|
|
|
offset = 0;
|
|
sector += BTOBB(nbytes);
|
|
size -= nbytes;
|
|
total_nr_pages--;
|
|
}
|
|
|
|
if (likely(bio->bi_iter.bi_size)) {
|
|
if (xfs_buf_is_vmapped(bp)) {
|
|
flush_kernel_vmap_range(bp->b_addr,
|
|
xfs_buf_vmap_len(bp));
|
|
}
|
|
submit_bio(bio);
|
|
if (size)
|
|
goto next_chunk;
|
|
} else {
|
|
/*
|
|
* This is guaranteed not to be the last io reference count
|
|
* because the caller (xfs_buf_submit) holds a count itself.
|
|
*/
|
|
atomic_dec(&bp->b_io_remaining);
|
|
xfs_buf_ioerror(bp, -EIO);
|
|
bio_put(bio);
|
|
}
|
|
|
|
}
|
|
|
|
STATIC void
|
|
_xfs_buf_ioapply(
|
|
struct xfs_buf *bp)
|
|
{
|
|
struct blk_plug plug;
|
|
int op;
|
|
int op_flags = 0;
|
|
int offset;
|
|
int size;
|
|
int i;
|
|
|
|
/*
|
|
* Make sure we capture only current IO errors rather than stale errors
|
|
* left over from previous use of the buffer (e.g. failed readahead).
|
|
*/
|
|
bp->b_error = 0;
|
|
|
|
/*
|
|
* Initialize the I/O completion workqueue if we haven't yet or the
|
|
* submitter has not opted to specify a custom one.
|
|
*/
|
|
if (!bp->b_ioend_wq)
|
|
bp->b_ioend_wq = bp->b_target->bt_mount->m_buf_workqueue;
|
|
|
|
if (bp->b_flags & XBF_WRITE) {
|
|
op = REQ_OP_WRITE;
|
|
if (bp->b_flags & XBF_SYNCIO)
|
|
op_flags = REQ_SYNC;
|
|
if (bp->b_flags & XBF_FUA)
|
|
op_flags |= REQ_FUA;
|
|
if (bp->b_flags & XBF_FLUSH)
|
|
op_flags |= REQ_PREFLUSH;
|
|
|
|
/*
|
|
* Run the write verifier callback function if it exists. If
|
|
* this function fails it will mark the buffer with an error and
|
|
* the IO should not be dispatched.
|
|
*/
|
|
if (bp->b_ops) {
|
|
bp->b_ops->verify_write(bp);
|
|
if (bp->b_error) {
|
|
xfs_force_shutdown(bp->b_target->bt_mount,
|
|
SHUTDOWN_CORRUPT_INCORE);
|
|
return;
|
|
}
|
|
} else if (bp->b_bn != XFS_BUF_DADDR_NULL) {
|
|
struct xfs_mount *mp = bp->b_target->bt_mount;
|
|
|
|
/*
|
|
* non-crc filesystems don't attach verifiers during
|
|
* log recovery, so don't warn for such filesystems.
|
|
*/
|
|
if (xfs_sb_version_hascrc(&mp->m_sb)) {
|
|
xfs_warn(mp,
|
|
"%s: no buf ops on daddr 0x%llx len %d",
|
|
__func__, bp->b_bn, bp->b_length);
|
|
xfs_hex_dump(bp->b_addr,
|
|
XFS_CORRUPTION_DUMP_LEN);
|
|
dump_stack();
|
|
}
|
|
}
|
|
} else if (bp->b_flags & XBF_READ_AHEAD) {
|
|
op = REQ_OP_READ;
|
|
op_flags = REQ_RAHEAD;
|
|
} else {
|
|
op = REQ_OP_READ;
|
|
}
|
|
|
|
/* we only use the buffer cache for meta-data */
|
|
op_flags |= REQ_META;
|
|
|
|
/*
|
|
* Walk all the vectors issuing IO on them. Set up the initial offset
|
|
* into the buffer and the desired IO size before we start -
|
|
* _xfs_buf_ioapply_vec() will modify them appropriately for each
|
|
* subsequent call.
|
|
*/
|
|
offset = bp->b_offset;
|
|
size = BBTOB(bp->b_io_length);
|
|
blk_start_plug(&plug);
|
|
for (i = 0; i < bp->b_map_count; i++) {
|
|
xfs_buf_ioapply_map(bp, i, &offset, &size, op, op_flags);
|
|
if (bp->b_error)
|
|
break;
|
|
if (size <= 0)
|
|
break; /* all done */
|
|
}
|
|
blk_finish_plug(&plug);
|
|
}
|
|
|
|
/*
|
|
* Asynchronous IO submission path. This transfers the buffer lock ownership and
|
|
* the current reference to the IO. It is not safe to reference the buffer after
|
|
* a call to this function unless the caller holds an additional reference
|
|
* itself.
|
|
*/
|
|
void
|
|
xfs_buf_submit(
|
|
struct xfs_buf *bp)
|
|
{
|
|
trace_xfs_buf_submit(bp, _RET_IP_);
|
|
|
|
ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
|
|
ASSERT(bp->b_flags & XBF_ASYNC);
|
|
|
|
/* on shutdown we stale and complete the buffer immediately */
|
|
if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
|
|
xfs_buf_ioerror(bp, -EIO);
|
|
bp->b_flags &= ~XBF_DONE;
|
|
xfs_buf_stale(bp);
|
|
xfs_buf_ioend(bp);
|
|
return;
|
|
}
|
|
|
|
if (bp->b_flags & XBF_WRITE)
|
|
xfs_buf_wait_unpin(bp);
|
|
|
|
/* clear the internal error state to avoid spurious errors */
|
|
bp->b_io_error = 0;
|
|
|
|
/*
|
|
* The caller's reference is released during I/O completion.
|
|
* This occurs some time after the last b_io_remaining reference is
|
|
* released, so after we drop our Io reference we have to have some
|
|
* other reference to ensure the buffer doesn't go away from underneath
|
|
* us. Take a direct reference to ensure we have safe access to the
|
|
* buffer until we are finished with it.
|
|
*/
|
|
xfs_buf_hold(bp);
|
|
|
|
/*
|
|
* Set the count to 1 initially, this will stop an I/O completion
|
|
* callout which happens before we have started all the I/O from calling
|
|
* xfs_buf_ioend too early.
|
|
*/
|
|
atomic_set(&bp->b_io_remaining, 1);
|
|
xfs_buf_ioacct_inc(bp);
|
|
_xfs_buf_ioapply(bp);
|
|
|
|
/*
|
|
* If _xfs_buf_ioapply failed, we can get back here with only the IO
|
|
* reference we took above. If we drop it to zero, run completion so
|
|
* that we don't return to the caller with completion still pending.
|
|
*/
|
|
if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
|
|
if (bp->b_error)
|
|
xfs_buf_ioend(bp);
|
|
else
|
|
xfs_buf_ioend_async(bp);
|
|
}
|
|
|
|
xfs_buf_rele(bp);
|
|
/* Note: it is not safe to reference bp now we've dropped our ref */
|
|
}
|
|
|
|
/*
|
|
* Synchronous buffer IO submission path, read or write.
|
|
*/
|
|
int
|
|
xfs_buf_submit_wait(
|
|
struct xfs_buf *bp)
|
|
{
|
|
int error;
|
|
|
|
trace_xfs_buf_submit_wait(bp, _RET_IP_);
|
|
|
|
ASSERT(!(bp->b_flags & (_XBF_DELWRI_Q | XBF_ASYNC)));
|
|
|
|
if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
|
|
xfs_buf_ioerror(bp, -EIO);
|
|
xfs_buf_stale(bp);
|
|
bp->b_flags &= ~XBF_DONE;
|
|
return -EIO;
|
|
}
|
|
|
|
if (bp->b_flags & XBF_WRITE)
|
|
xfs_buf_wait_unpin(bp);
|
|
|
|
/* clear the internal error state to avoid spurious errors */
|
|
bp->b_io_error = 0;
|
|
|
|
/*
|
|
* For synchronous IO, the IO does not inherit the submitters reference
|
|
* count, nor the buffer lock. Hence we cannot release the reference we
|
|
* are about to take until we've waited for all IO completion to occur,
|
|
* including any xfs_buf_ioend_async() work that may be pending.
|
|
*/
|
|
xfs_buf_hold(bp);
|
|
|
|
/*
|
|
* Set the count to 1 initially, this will stop an I/O completion
|
|
* callout which happens before we have started all the I/O from calling
|
|
* xfs_buf_ioend too early.
|
|
*/
|
|
atomic_set(&bp->b_io_remaining, 1);
|
|
_xfs_buf_ioapply(bp);
|
|
|
|
/*
|
|
* make sure we run completion synchronously if it raced with us and is
|
|
* already complete.
|
|
*/
|
|
if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
|
|
xfs_buf_ioend(bp);
|
|
|
|
/* wait for completion before gathering the error from the buffer */
|
|
trace_xfs_buf_iowait(bp, _RET_IP_);
|
|
wait_for_completion(&bp->b_iowait);
|
|
trace_xfs_buf_iowait_done(bp, _RET_IP_);
|
|
error = bp->b_error;
|
|
|
|
/*
|
|
* all done now, we can release the hold that keeps the buffer
|
|
* referenced for the entire IO.
|
|
*/
|
|
xfs_buf_rele(bp);
|
|
return error;
|
|
}
|
|
|
|
void *
|
|
xfs_buf_offset(
|
|
struct xfs_buf *bp,
|
|
size_t offset)
|
|
{
|
|
struct page *page;
|
|
|
|
if (bp->b_addr)
|
|
return bp->b_addr + offset;
|
|
|
|
offset += bp->b_offset;
|
|
page = bp->b_pages[offset >> PAGE_SHIFT];
|
|
return page_address(page) + (offset & (PAGE_SIZE-1));
|
|
}
|
|
|
|
/*
|
|
* Move data into or out of a buffer.
|
|
*/
|
|
void
|
|
xfs_buf_iomove(
|
|
xfs_buf_t *bp, /* buffer to process */
|
|
size_t boff, /* starting buffer offset */
|
|
size_t bsize, /* length to copy */
|
|
void *data, /* data address */
|
|
xfs_buf_rw_t mode) /* read/write/zero flag */
|
|
{
|
|
size_t bend;
|
|
|
|
bend = boff + bsize;
|
|
while (boff < bend) {
|
|
struct page *page;
|
|
int page_index, page_offset, csize;
|
|
|
|
page_index = (boff + bp->b_offset) >> PAGE_SHIFT;
|
|
page_offset = (boff + bp->b_offset) & ~PAGE_MASK;
|
|
page = bp->b_pages[page_index];
|
|
csize = min_t(size_t, PAGE_SIZE - page_offset,
|
|
BBTOB(bp->b_io_length) - boff);
|
|
|
|
ASSERT((csize + page_offset) <= PAGE_SIZE);
|
|
|
|
switch (mode) {
|
|
case XBRW_ZERO:
|
|
memset(page_address(page) + page_offset, 0, csize);
|
|
break;
|
|
case XBRW_READ:
|
|
memcpy(data, page_address(page) + page_offset, csize);
|
|
break;
|
|
case XBRW_WRITE:
|
|
memcpy(page_address(page) + page_offset, data, csize);
|
|
}
|
|
|
|
boff += csize;
|
|
data += csize;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Handling of buffer targets (buftargs).
|
|
*/
|
|
|
|
/*
|
|
* Wait for any bufs with callbacks that have been submitted but have not yet
|
|
* returned. These buffers will have an elevated hold count, so wait on those
|
|
* while freeing all the buffers only held by the LRU.
|
|
*/
|
|
static enum lru_status
|
|
xfs_buftarg_wait_rele(
|
|
struct list_head *item,
|
|
struct list_lru_one *lru,
|
|
spinlock_t *lru_lock,
|
|
void *arg)
|
|
|
|
{
|
|
struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru);
|
|
struct list_head *dispose = arg;
|
|
|
|
if (atomic_read(&bp->b_hold) > 1) {
|
|
/* need to wait, so skip it this pass */
|
|
trace_xfs_buf_wait_buftarg(bp, _RET_IP_);
|
|
return LRU_SKIP;
|
|
}
|
|
if (!spin_trylock(&bp->b_lock))
|
|
return LRU_SKIP;
|
|
|
|
/*
|
|
* clear the LRU reference count so the buffer doesn't get
|
|
* ignored in xfs_buf_rele().
|
|
*/
|
|
atomic_set(&bp->b_lru_ref, 0);
|
|
bp->b_state |= XFS_BSTATE_DISPOSE;
|
|
list_lru_isolate_move(lru, item, dispose);
|
|
spin_unlock(&bp->b_lock);
|
|
return LRU_REMOVED;
|
|
}
|
|
|
|
void
|
|
xfs_wait_buftarg(
|
|
struct xfs_buftarg *btp)
|
|
{
|
|
LIST_HEAD(dispose);
|
|
int loop = 0;
|
|
|
|
/*
|
|
* First wait on the buftarg I/O count for all in-flight buffers to be
|
|
* released. This is critical as new buffers do not make the LRU until
|
|
* they are released.
|
|
*
|
|
* Next, flush the buffer workqueue to ensure all completion processing
|
|
* has finished. Just waiting on buffer locks is not sufficient for
|
|
* async IO as the reference count held over IO is not released until
|
|
* after the buffer lock is dropped. Hence we need to ensure here that
|
|
* all reference counts have been dropped before we start walking the
|
|
* LRU list.
|
|
*/
|
|
while (percpu_counter_sum(&btp->bt_io_count))
|
|
delay(100);
|
|
flush_workqueue(btp->bt_mount->m_buf_workqueue);
|
|
|
|
/* loop until there is nothing left on the lru list. */
|
|
while (list_lru_count(&btp->bt_lru)) {
|
|
list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele,
|
|
&dispose, LONG_MAX);
|
|
|
|
while (!list_empty(&dispose)) {
|
|
struct xfs_buf *bp;
|
|
bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
|
|
list_del_init(&bp->b_lru);
|
|
if (bp->b_flags & XBF_WRITE_FAIL) {
|
|
xfs_alert(btp->bt_mount,
|
|
"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!",
|
|
(long long)bp->b_bn);
|
|
xfs_alert(btp->bt_mount,
|
|
"Please run xfs_repair to determine the extent of the problem.");
|
|
}
|
|
xfs_buf_rele(bp);
|
|
}
|
|
if (loop++ != 0)
|
|
delay(100);
|
|
}
|
|
}
|
|
|
|
static enum lru_status
|
|
xfs_buftarg_isolate(
|
|
struct list_head *item,
|
|
struct list_lru_one *lru,
|
|
spinlock_t *lru_lock,
|
|
void *arg)
|
|
{
|
|
struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru);
|
|
struct list_head *dispose = arg;
|
|
|
|
/*
|
|
* we are inverting the lru lock/bp->b_lock here, so use a trylock.
|
|
* If we fail to get the lock, just skip it.
|
|
*/
|
|
if (!spin_trylock(&bp->b_lock))
|
|
return LRU_SKIP;
|
|
/*
|
|
* Decrement the b_lru_ref count unless the value is already
|
|
* zero. If the value is already zero, we need to reclaim the
|
|
* buffer, otherwise it gets another trip through the LRU.
|
|
*/
|
|
if (atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
|
|
spin_unlock(&bp->b_lock);
|
|
return LRU_ROTATE;
|
|
}
|
|
|
|
bp->b_state |= XFS_BSTATE_DISPOSE;
|
|
list_lru_isolate_move(lru, item, dispose);
|
|
spin_unlock(&bp->b_lock);
|
|
return LRU_REMOVED;
|
|
}
|
|
|
|
static unsigned long
|
|
xfs_buftarg_shrink_scan(
|
|
struct shrinker *shrink,
|
|
struct shrink_control *sc)
|
|
{
|
|
struct xfs_buftarg *btp = container_of(shrink,
|
|
struct xfs_buftarg, bt_shrinker);
|
|
LIST_HEAD(dispose);
|
|
unsigned long freed;
|
|
|
|
freed = list_lru_shrink_walk(&btp->bt_lru, sc,
|
|
xfs_buftarg_isolate, &dispose);
|
|
|
|
while (!list_empty(&dispose)) {
|
|
struct xfs_buf *bp;
|
|
bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
|
|
list_del_init(&bp->b_lru);
|
|
xfs_buf_rele(bp);
|
|
}
|
|
|
|
return freed;
|
|
}
|
|
|
|
static unsigned long
|
|
xfs_buftarg_shrink_count(
|
|
struct shrinker *shrink,
|
|
struct shrink_control *sc)
|
|
{
|
|
struct xfs_buftarg *btp = container_of(shrink,
|
|
struct xfs_buftarg, bt_shrinker);
|
|
return list_lru_shrink_count(&btp->bt_lru, sc);
|
|
}
|
|
|
|
void
|
|
xfs_free_buftarg(
|
|
struct xfs_mount *mp,
|
|
struct xfs_buftarg *btp)
|
|
{
|
|
unregister_shrinker(&btp->bt_shrinker);
|
|
ASSERT(percpu_counter_sum(&btp->bt_io_count) == 0);
|
|
percpu_counter_destroy(&btp->bt_io_count);
|
|
list_lru_destroy(&btp->bt_lru);
|
|
|
|
xfs_blkdev_issue_flush(btp);
|
|
|
|
kmem_free(btp);
|
|
}
|
|
|
|
int
|
|
xfs_setsize_buftarg(
|
|
xfs_buftarg_t *btp,
|
|
unsigned int sectorsize)
|
|
{
|
|
/* Set up metadata sector size info */
|
|
btp->bt_meta_sectorsize = sectorsize;
|
|
btp->bt_meta_sectormask = sectorsize - 1;
|
|
|
|
if (set_blocksize(btp->bt_bdev, sectorsize)) {
|
|
xfs_warn(btp->bt_mount,
|
|
"Cannot set_blocksize to %u on device %pg",
|
|
sectorsize, btp->bt_bdev);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Set up device logical sector size mask */
|
|
btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev);
|
|
btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* When allocating the initial buffer target we have not yet
|
|
* read in the superblock, so don't know what sized sectors
|
|
* are being used at this early stage. Play safe.
|
|
*/
|
|
STATIC int
|
|
xfs_setsize_buftarg_early(
|
|
xfs_buftarg_t *btp,
|
|
struct block_device *bdev)
|
|
{
|
|
return xfs_setsize_buftarg(btp, bdev_logical_block_size(bdev));
|
|
}
|
|
|
|
xfs_buftarg_t *
|
|
xfs_alloc_buftarg(
|
|
struct xfs_mount *mp,
|
|
struct block_device *bdev,
|
|
struct dax_device *dax_dev)
|
|
{
|
|
xfs_buftarg_t *btp;
|
|
|
|
btp = kmem_zalloc(sizeof(*btp), KM_SLEEP | KM_NOFS);
|
|
|
|
btp->bt_mount = mp;
|
|
btp->bt_dev = bdev->bd_dev;
|
|
btp->bt_bdev = bdev;
|
|
btp->bt_daxdev = dax_dev;
|
|
|
|
if (xfs_setsize_buftarg_early(btp, bdev))
|
|
goto error_free;
|
|
|
|
if (list_lru_init(&btp->bt_lru))
|
|
goto error_free;
|
|
|
|
if (percpu_counter_init(&btp->bt_io_count, 0, GFP_KERNEL))
|
|
goto error_lru;
|
|
|
|
btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count;
|
|
btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan;
|
|
btp->bt_shrinker.seeks = DEFAULT_SEEKS;
|
|
btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE;
|
|
if (register_shrinker(&btp->bt_shrinker))
|
|
goto error_pcpu;
|
|
return btp;
|
|
|
|
error_pcpu:
|
|
percpu_counter_destroy(&btp->bt_io_count);
|
|
error_lru:
|
|
list_lru_destroy(&btp->bt_lru);
|
|
error_free:
|
|
kmem_free(btp);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Cancel a delayed write list.
|
|
*
|
|
* Remove each buffer from the list, clear the delwri queue flag and drop the
|
|
* associated buffer reference.
|
|
*/
|
|
void
|
|
xfs_buf_delwri_cancel(
|
|
struct list_head *list)
|
|
{
|
|
struct xfs_buf *bp;
|
|
|
|
while (!list_empty(list)) {
|
|
bp = list_first_entry(list, struct xfs_buf, b_list);
|
|
|
|
xfs_buf_lock(bp);
|
|
bp->b_flags &= ~_XBF_DELWRI_Q;
|
|
list_del_init(&bp->b_list);
|
|
xfs_buf_relse(bp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Add a buffer to the delayed write list.
|
|
*
|
|
* This queues a buffer for writeout if it hasn't already been. Note that
|
|
* neither this routine nor the buffer list submission functions perform
|
|
* any internal synchronization. It is expected that the lists are thread-local
|
|
* to the callers.
|
|
*
|
|
* Returns true if we queued up the buffer, or false if it already had
|
|
* been on the buffer list.
|
|
*/
|
|
bool
|
|
xfs_buf_delwri_queue(
|
|
struct xfs_buf *bp,
|
|
struct list_head *list)
|
|
{
|
|
ASSERT(xfs_buf_islocked(bp));
|
|
ASSERT(!(bp->b_flags & XBF_READ));
|
|
|
|
/*
|
|
* If the buffer is already marked delwri it already is queued up
|
|
* by someone else for imediate writeout. Just ignore it in that
|
|
* case.
|
|
*/
|
|
if (bp->b_flags & _XBF_DELWRI_Q) {
|
|
trace_xfs_buf_delwri_queued(bp, _RET_IP_);
|
|
return false;
|
|
}
|
|
|
|
trace_xfs_buf_delwri_queue(bp, _RET_IP_);
|
|
|
|
/*
|
|
* If a buffer gets written out synchronously or marked stale while it
|
|
* is on a delwri list we lazily remove it. To do this, the other party
|
|
* clears the _XBF_DELWRI_Q flag but otherwise leaves the buffer alone.
|
|
* It remains referenced and on the list. In a rare corner case it
|
|
* might get readded to a delwri list after the synchronous writeout, in
|
|
* which case we need just need to re-add the flag here.
|
|
*/
|
|
bp->b_flags |= _XBF_DELWRI_Q;
|
|
if (list_empty(&bp->b_list)) {
|
|
atomic_inc(&bp->b_hold);
|
|
list_add_tail(&bp->b_list, list);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Compare function is more complex than it needs to be because
|
|
* the return value is only 32 bits and we are doing comparisons
|
|
* on 64 bit values
|
|
*/
|
|
static int
|
|
xfs_buf_cmp(
|
|
void *priv,
|
|
struct list_head *a,
|
|
struct list_head *b)
|
|
{
|
|
struct xfs_buf *ap = container_of(a, struct xfs_buf, b_list);
|
|
struct xfs_buf *bp = container_of(b, struct xfs_buf, b_list);
|
|
xfs_daddr_t diff;
|
|
|
|
diff = ap->b_maps[0].bm_bn - bp->b_maps[0].bm_bn;
|
|
if (diff < 0)
|
|
return -1;
|
|
if (diff > 0)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* submit buffers for write.
|
|
*
|
|
* When we have a large buffer list, we do not want to hold all the buffers
|
|
* locked while we block on the request queue waiting for IO dispatch. To avoid
|
|
* this problem, we lock and submit buffers in groups of 50, thereby minimising
|
|
* the lock hold times for lists which may contain thousands of objects.
|
|
*
|
|
* To do this, we sort the buffer list before we walk the list to lock and
|
|
* submit buffers, and we plug and unplug around each group of buffers we
|
|
* submit.
|
|
*/
|
|
static int
|
|
xfs_buf_delwri_submit_buffers(
|
|
struct list_head *buffer_list,
|
|
struct list_head *wait_list)
|
|
{
|
|
struct xfs_buf *bp, *n;
|
|
LIST_HEAD (submit_list);
|
|
int pinned = 0;
|
|
struct blk_plug plug;
|
|
|
|
list_sort(NULL, buffer_list, xfs_buf_cmp);
|
|
|
|
blk_start_plug(&plug);
|
|
list_for_each_entry_safe(bp, n, buffer_list, b_list) {
|
|
if (!wait_list) {
|
|
if (xfs_buf_ispinned(bp)) {
|
|
pinned++;
|
|
continue;
|
|
}
|
|
if (!xfs_buf_trylock(bp))
|
|
continue;
|
|
} else {
|
|
xfs_buf_lock(bp);
|
|
}
|
|
|
|
/*
|
|
* Someone else might have written the buffer synchronously or
|
|
* marked it stale in the meantime. In that case only the
|
|
* _XBF_DELWRI_Q flag got cleared, and we have to drop the
|
|
* reference and remove it from the list here.
|
|
*/
|
|
if (!(bp->b_flags & _XBF_DELWRI_Q)) {
|
|
list_del_init(&bp->b_list);
|
|
xfs_buf_relse(bp);
|
|
continue;
|
|
}
|
|
|
|
trace_xfs_buf_delwri_split(bp, _RET_IP_);
|
|
|
|
/*
|
|
* We do all IO submission async. This means if we need
|
|
* to wait for IO completion we need to take an extra
|
|
* reference so the buffer is still valid on the other
|
|
* side. We need to move the buffer onto the io_list
|
|
* at this point so the caller can still access it.
|
|
*/
|
|
bp->b_flags &= ~(_XBF_DELWRI_Q | XBF_WRITE_FAIL);
|
|
bp->b_flags |= XBF_WRITE | XBF_ASYNC;
|
|
if (wait_list) {
|
|
xfs_buf_hold(bp);
|
|
list_move_tail(&bp->b_list, wait_list);
|
|
} else
|
|
list_del_init(&bp->b_list);
|
|
|
|
xfs_buf_submit(bp);
|
|
}
|
|
blk_finish_plug(&plug);
|
|
|
|
return pinned;
|
|
}
|
|
|
|
/*
|
|
* Write out a buffer list asynchronously.
|
|
*
|
|
* This will take the @buffer_list, write all non-locked and non-pinned buffers
|
|
* out and not wait for I/O completion on any of the buffers. This interface
|
|
* is only safely useable for callers that can track I/O completion by higher
|
|
* level means, e.g. AIL pushing as the @buffer_list is consumed in this
|
|
* function.
|
|
*/
|
|
int
|
|
xfs_buf_delwri_submit_nowait(
|
|
struct list_head *buffer_list)
|
|
{
|
|
return xfs_buf_delwri_submit_buffers(buffer_list, NULL);
|
|
}
|
|
|
|
/*
|
|
* Write out a buffer list synchronously.
|
|
*
|
|
* This will take the @buffer_list, write all buffers out and wait for I/O
|
|
* completion on all of the buffers. @buffer_list is consumed by the function,
|
|
* so callers must have some other way of tracking buffers if they require such
|
|
* functionality.
|
|
*/
|
|
int
|
|
xfs_buf_delwri_submit(
|
|
struct list_head *buffer_list)
|
|
{
|
|
LIST_HEAD (wait_list);
|
|
int error = 0, error2;
|
|
struct xfs_buf *bp;
|
|
|
|
xfs_buf_delwri_submit_buffers(buffer_list, &wait_list);
|
|
|
|
/* Wait for IO to complete. */
|
|
while (!list_empty(&wait_list)) {
|
|
bp = list_first_entry(&wait_list, struct xfs_buf, b_list);
|
|
|
|
list_del_init(&bp->b_list);
|
|
|
|
/* locking the buffer will wait for async IO completion. */
|
|
xfs_buf_lock(bp);
|
|
error2 = bp->b_error;
|
|
xfs_buf_relse(bp);
|
|
if (!error)
|
|
error = error2;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Push a single buffer on a delwri queue.
|
|
*
|
|
* The purpose of this function is to submit a single buffer of a delwri queue
|
|
* and return with the buffer still on the original queue. The waiting delwri
|
|
* buffer submission infrastructure guarantees transfer of the delwri queue
|
|
* buffer reference to a temporary wait list. We reuse this infrastructure to
|
|
* transfer the buffer back to the original queue.
|
|
*
|
|
* Note the buffer transitions from the queued state, to the submitted and wait
|
|
* listed state and back to the queued state during this call. The buffer
|
|
* locking and queue management logic between _delwri_pushbuf() and
|
|
* _delwri_queue() guarantee that the buffer cannot be queued to another list
|
|
* before returning.
|
|
*/
|
|
int
|
|
xfs_buf_delwri_pushbuf(
|
|
struct xfs_buf *bp,
|
|
struct list_head *buffer_list)
|
|
{
|
|
LIST_HEAD (submit_list);
|
|
int error;
|
|
|
|
ASSERT(bp->b_flags & _XBF_DELWRI_Q);
|
|
|
|
trace_xfs_buf_delwri_pushbuf(bp, _RET_IP_);
|
|
|
|
/*
|
|
* Isolate the buffer to a new local list so we can submit it for I/O
|
|
* independently from the rest of the original list.
|
|
*/
|
|
xfs_buf_lock(bp);
|
|
list_move(&bp->b_list, &submit_list);
|
|
xfs_buf_unlock(bp);
|
|
|
|
/*
|
|
* Delwri submission clears the DELWRI_Q buffer flag and returns with
|
|
* the buffer on the wait list with an associated reference. Rather than
|
|
* bounce the buffer from a local wait list back to the original list
|
|
* after I/O completion, reuse the original list as the wait list.
|
|
*/
|
|
xfs_buf_delwri_submit_buffers(&submit_list, buffer_list);
|
|
|
|
/*
|
|
* The buffer is now under I/O and wait listed as during typical delwri
|
|
* submission. Lock the buffer to wait for I/O completion. Rather than
|
|
* remove the buffer from the wait list and release the reference, we
|
|
* want to return with the buffer queued to the original list. The
|
|
* buffer already sits on the original list with a wait list reference,
|
|
* however. If we let the queue inherit that wait list reference, all we
|
|
* need to do is reset the DELWRI_Q flag.
|
|
*/
|
|
xfs_buf_lock(bp);
|
|
error = bp->b_error;
|
|
bp->b_flags |= _XBF_DELWRI_Q;
|
|
xfs_buf_unlock(bp);
|
|
|
|
return error;
|
|
}
|
|
|
|
int __init
|
|
xfs_buf_init(void)
|
|
{
|
|
xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf",
|
|
KM_ZONE_HWALIGN, NULL);
|
|
if (!xfs_buf_zone)
|
|
goto out;
|
|
|
|
return 0;
|
|
|
|
out:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
void
|
|
xfs_buf_terminate(void)
|
|
{
|
|
kmem_zone_destroy(xfs_buf_zone);
|
|
}
|
|
|
|
void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
|
|
{
|
|
/*
|
|
* Set the lru reference count to 0 based on the error injection tag.
|
|
* This allows userspace to disrupt buffer caching for debug/testing
|
|
* purposes.
|
|
*/
|
|
if (XFS_TEST_ERROR(false, bp->b_target->bt_mount,
|
|
XFS_ERRTAG_BUF_LRU_REF))
|
|
lru_ref = 0;
|
|
|
|
atomic_set(&bp->b_lru_ref, lru_ref);
|
|
}
|