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2329 lines
56 KiB
2329 lines
56 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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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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#include "xfs.h" |
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#include <linux/backing-dev.h> |
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|
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#include "xfs_shared.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_mount.h" |
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#include "xfs_trace.h" |
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#include "xfs_log.h" |
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#include "xfs_log_recover.h" |
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#include "xfs_trans.h" |
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#include "xfs_buf_item.h" |
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#include "xfs_errortag.h" |
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#include "xfs_error.h" |
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#include "xfs_ag.h" |
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|
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static kmem_zone_t *xfs_buf_zone; |
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|
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/* |
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* Locking orders |
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* |
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* xfs_buf_ioacct_inc: |
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* xfs_buf_ioacct_dec: |
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* b_sema (caller holds) |
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* b_lock |
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* |
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* xfs_buf_stale: |
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* b_sema (caller holds) |
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* b_lock |
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* lru_lock |
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* |
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* xfs_buf_rele: |
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* b_lock |
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* pag_buf_lock |
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* lru_lock |
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* |
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* xfs_buftarg_drain_rele |
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* lru_lock |
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* b_lock (trylock due to inversion) |
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* |
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* xfs_buftarg_isolate |
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* lru_lock |
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* b_lock (trylock due to inversion) |
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*/ |
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|
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static int __xfs_buf_submit(struct xfs_buf *bp, bool wait); |
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|
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static inline int |
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xfs_buf_submit( |
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struct xfs_buf *bp) |
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{ |
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return __xfs_buf_submit(bp, !(bp->b_flags & XBF_ASYNC)); |
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} |
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|
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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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|
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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); |
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} |
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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_buftarg_drain()), 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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|
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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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/* |
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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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|
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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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|
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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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/* |
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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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|
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bp->b_flags |= XBF_STALE; |
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|
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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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/* |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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/* |
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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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|
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static int |
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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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struct xfs_buf **bpp) |
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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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|
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*bpp = NULL; |
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bp = kmem_cache_zalloc(xfs_buf_zone, GFP_NOFS | __GFP_NOFAIL); |
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|
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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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bp->b_target = target; |
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bp->b_mount = target->bt_mount; |
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bp->b_flags = flags; |
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|
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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_cache_free(xfs_buf_zone, bp); |
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return error; |
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} |
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|
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bp->b_rhash_key = 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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atomic_set(&bp->b_pin_count, 0); |
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init_waitqueue_head(&bp->b_waiters); |
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XFS_STATS_INC(bp->b_mount, xb_create); |
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trace_xfs_buf_init(bp, _RET_IP_); |
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|
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*bpp = bp; |
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return 0; |
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} |
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|
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static void |
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xfs_buf_free_pages( |
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struct xfs_buf *bp) |
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{ |
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uint i; |
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|
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ASSERT(bp->b_flags & _XBF_PAGES); |
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|
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if (xfs_buf_is_vmapped(bp)) |
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vm_unmap_ram(bp->b_addr, bp->b_page_count); |
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|
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for (i = 0; i < bp->b_page_count; i++) { |
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if (bp->b_pages[i]) |
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__free_page(bp->b_pages[i]); |
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} |
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if (current->reclaim_state) |
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current->reclaim_state->reclaimed_slab += bp->b_page_count; |
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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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bp->b_flags &= ~_XBF_PAGES; |
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} |
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|
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static void |
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xfs_buf_free( |
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struct xfs_buf *bp) |
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{ |
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trace_xfs_buf_free(bp, _RET_IP_); |
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|
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ASSERT(list_empty(&bp->b_lru)); |
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|
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if (bp->b_flags & _XBF_PAGES) |
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xfs_buf_free_pages(bp); |
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else if (bp->b_flags & _XBF_KMEM) |
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kmem_free(bp->b_addr); |
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|
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xfs_buf_free_maps(bp); |
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kmem_cache_free(xfs_buf_zone, bp); |
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} |
|
|
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static int |
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xfs_buf_alloc_kmem( |
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struct xfs_buf *bp, |
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xfs_buf_flags_t flags) |
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{ |
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xfs_km_flags_t kmflag_mask = KM_NOFS; |
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size_t size = BBTOB(bp->b_length); |
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|
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/* Assure zeroed buffer for non-read cases. */ |
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if (!(flags & XBF_READ)) |
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kmflag_mask |= KM_ZERO; |
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|
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bp->b_addr = kmem_alloc(size, kmflag_mask); |
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if (!bp->b_addr) |
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return -ENOMEM; |
|
|
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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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return -ENOMEM; |
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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] = kmem_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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} |
|
|
|
static int |
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xfs_buf_alloc_pages( |
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struct xfs_buf *bp, |
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xfs_buf_flags_t flags) |
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{ |
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gfp_t gfp_mask = __GFP_NOWARN; |
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long filled = 0; |
|
|
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if (flags & XBF_READ_AHEAD) |
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gfp_mask |= __GFP_NORETRY; |
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else |
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gfp_mask |= GFP_NOFS; |
|
|
|
/* Make sure that we have a page list */ |
|
bp->b_page_count = DIV_ROUND_UP(BBTOB(bp->b_length), PAGE_SIZE); |
|
if (bp->b_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 = kzalloc(sizeof(struct page *) * bp->b_page_count, |
|
gfp_mask); |
|
if (!bp->b_pages) |
|
return -ENOMEM; |
|
} |
|
bp->b_flags |= _XBF_PAGES; |
|
|
|
/* Assure zeroed buffer for non-read cases. */ |
|
if (!(flags & XBF_READ)) |
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gfp_mask |= __GFP_ZERO; |
|
|
|
/* |
|
* Bulk filling of pages can take multiple calls. Not filling the entire |
|
* array is not an allocation failure, so don't back off if we get at |
|
* least one extra page. |
|
*/ |
|
for (;;) { |
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long last = filled; |
|
|
|
filled = alloc_pages_bulk_array(gfp_mask, bp->b_page_count, |
|
bp->b_pages); |
|
if (filled == bp->b_page_count) { |
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XFS_STATS_INC(bp->b_mount, xb_page_found); |
|
break; |
|
} |
|
|
|
if (filled != last) |
|
continue; |
|
|
|
if (flags & XBF_READ_AHEAD) { |
|
xfs_buf_free_pages(bp); |
|
return -ENOMEM; |
|
} |
|
|
|
XFS_STATS_INC(bp->b_mount, xb_page_retries); |
|
congestion_wait(BLK_RW_ASYNC, HZ / 50); |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* Map buffer into kernel address-space if necessary. |
|
*/ |
|
STATIC int |
|
_xfs_buf_map_pages( |
|
struct xfs_buf *bp, |
|
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]); |
|
} else if (flags & XBF_UNMAPPED) { |
|
bp->b_addr = NULL; |
|
} else { |
|
int retried = 0; |
|
unsigned nofs_flag; |
|
|
|
/* |
|
* vm_map_ram() will allocate auxiliary structures (e.g. |
|
* pagetables) with GFP_KERNEL, yet we are likely to be under |
|
* GFP_NOFS context here. Hence we need to tell memory reclaim |
|
* that we are in such a context via PF_MEMALLOC_NOFS to prevent |
|
* memory reclaim re-entering the filesystem here and |
|
* potentially deadlocking. |
|
*/ |
|
nofs_flag = memalloc_nofs_save(); |
|
do { |
|
bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count, |
|
-1); |
|
if (bp->b_addr) |
|
break; |
|
vm_unmap_aliases(); |
|
} while (retried++ <= 1); |
|
memalloc_nofs_restore(nofs_flag); |
|
|
|
if (!bp->b_addr) |
|
return -ENOMEM; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* 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_rhash_key != 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_rhash_key), |
|
.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 a buffer in the buffer cache and return it referenced and locked |
|
* in @found_bp. |
|
* |
|
* If @new_bp is supplied and we have a lookup miss, insert @new_bp into the |
|
* cache. |
|
* |
|
* If XBF_TRYLOCK is set in @flags, only try to lock the buffer and return |
|
* -EAGAIN if we fail to lock it. |
|
* |
|
* Return values are: |
|
* -EFSCORRUPTED if have been supplied with an invalid address |
|
* -EAGAIN on trylock failure |
|
* -ENOENT if we fail to find a match and @new_bp was NULL |
|
* 0, with @found_bp: |
|
* - @new_bp if we inserted it into the cache |
|
* - the buffer we found and locked. |
|
*/ |
|
static int |
|
xfs_buf_find( |
|
struct xfs_buftarg *btp, |
|
struct xfs_buf_map *map, |
|
int nmaps, |
|
xfs_buf_flags_t flags, |
|
struct xfs_buf *new_bp, |
|
struct xfs_buf **found_bp) |
|
{ |
|
struct xfs_perag *pag; |
|
struct xfs_buf *bp; |
|
struct xfs_buf_map cmap = { .bm_bn = map[0].bm_bn }; |
|
xfs_daddr_t eofs; |
|
int i; |
|
|
|
*found_bp = NULL; |
|
|
|
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) { |
|
xfs_alert(btp->bt_mount, |
|
"%s: daddr 0x%llx out of range, EOFS 0x%llx", |
|
__func__, cmap.bm_bn, eofs); |
|
WARN_ON(1); |
|
return -EFSCORRUPTED; |
|
} |
|
|
|
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) { |
|
XFS_STATS_INC(btp->bt_mount, xb_miss_locked); |
|
spin_unlock(&pag->pag_buf_lock); |
|
xfs_perag_put(pag); |
|
return -ENOENT; |
|
} |
|
|
|
/* 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); |
|
*found_bp = new_bp; |
|
return 0; |
|
|
|
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 -EAGAIN; |
|
} |
|
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); |
|
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); |
|
*found_bp = bp; |
|
return 0; |
|
} |
|
|
|
struct xfs_buf * |
|
xfs_buf_incore( |
|
struct xfs_buftarg *target, |
|
xfs_daddr_t blkno, |
|
size_t numblks, |
|
xfs_buf_flags_t flags) |
|
{ |
|
struct xfs_buf *bp; |
|
int error; |
|
DEFINE_SINGLE_BUF_MAP(map, blkno, numblks); |
|
|
|
error = xfs_buf_find(target, &map, 1, flags, NULL, &bp); |
|
if (error) |
|
return NULL; |
|
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. |
|
*/ |
|
int |
|
xfs_buf_get_map( |
|
struct xfs_buftarg *target, |
|
struct xfs_buf_map *map, |
|
int nmaps, |
|
xfs_buf_flags_t flags, |
|
struct xfs_buf **bpp) |
|
{ |
|
struct xfs_buf *bp; |
|
struct xfs_buf *new_bp; |
|
int error; |
|
|
|
*bpp = NULL; |
|
error = xfs_buf_find(target, map, nmaps, flags, NULL, &bp); |
|
if (!error) |
|
goto found; |
|
if (error != -ENOENT) |
|
return error; |
|
|
|
error = _xfs_buf_alloc(target, map, nmaps, flags, &new_bp); |
|
if (error) |
|
return error; |
|
|
|
/* |
|
* For buffers that fit entirely within a single page, first attempt to |
|
* allocate the memory from the heap to minimise memory usage. If we |
|
* can't get heap memory for these small buffers, we fall back to using |
|
* the page allocator. |
|
*/ |
|
if (BBTOB(new_bp->b_length) >= PAGE_SIZE || |
|
xfs_buf_alloc_kmem(new_bp, flags) < 0) { |
|
error = xfs_buf_alloc_pages(new_bp, flags); |
|
if (error) |
|
goto out_free_buf; |
|
} |
|
|
|
error = xfs_buf_find(target, map, nmaps, flags, new_bp, &bp); |
|
if (error) |
|
goto out_free_buf; |
|
|
|
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_ratelimited(target->bt_mount, |
|
"%s: failed to map %u pages", __func__, |
|
bp->b_page_count); |
|
xfs_buf_relse(bp); |
|
return error; |
|
} |
|
} |
|
|
|
/* |
|
* 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_); |
|
*bpp = bp; |
|
return 0; |
|
out_free_buf: |
|
xfs_buf_free(new_bp); |
|
return error; |
|
} |
|
|
|
int |
|
_xfs_buf_read( |
|
struct xfs_buf *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 | XBF_DONE); |
|
bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD); |
|
|
|
return xfs_buf_submit(bp); |
|
} |
|
|
|
/* |
|
* Reverify a buffer found in cache without an attached ->b_ops. |
|
* |
|
* If the caller passed an ops structure and the buffer doesn't have ops |
|
* assigned, set the ops and use it to verify the contents. If verification |
|
* fails, clear XBF_DONE. We assume the buffer has no recorded errors and is |
|
* already in XBF_DONE state on entry. |
|
* |
|
* Under normal operations, every in-core buffer is verified on read I/O |
|
* completion. There are two scenarios that can lead to in-core buffers without |
|
* an assigned ->b_ops. The first is during log recovery of buffers on a V4 |
|
* filesystem, though these buffers are purged at the end of recovery. The |
|
* other is online repair, which intentionally reads with a NULL buffer ops to |
|
* run several verifiers across an in-core buffer in order to establish buffer |
|
* type. If repair can't establish that, the buffer will be left in memory |
|
* with NULL buffer ops. |
|
*/ |
|
int |
|
xfs_buf_reverify( |
|
struct xfs_buf *bp, |
|
const struct xfs_buf_ops *ops) |
|
{ |
|
ASSERT(bp->b_flags & XBF_DONE); |
|
ASSERT(bp->b_error == 0); |
|
|
|
if (!ops || bp->b_ops) |
|
return 0; |
|
|
|
bp->b_ops = ops; |
|
bp->b_ops->verify_read(bp); |
|
if (bp->b_error) |
|
bp->b_flags &= ~XBF_DONE; |
|
return bp->b_error; |
|
} |
|
|
|
int |
|
xfs_buf_read_map( |
|
struct xfs_buftarg *target, |
|
struct xfs_buf_map *map, |
|
int nmaps, |
|
xfs_buf_flags_t flags, |
|
struct xfs_buf **bpp, |
|
const struct xfs_buf_ops *ops, |
|
xfs_failaddr_t fa) |
|
{ |
|
struct xfs_buf *bp; |
|
int error; |
|
|
|
flags |= XBF_READ; |
|
*bpp = NULL; |
|
|
|
error = xfs_buf_get_map(target, map, nmaps, flags, &bp); |
|
if (error) |
|
return error; |
|
|
|
trace_xfs_buf_read(bp, flags, _RET_IP_); |
|
|
|
if (!(bp->b_flags & XBF_DONE)) { |
|
/* Initiate the buffer read and wait. */ |
|
XFS_STATS_INC(target->bt_mount, xb_get_read); |
|
bp->b_ops = ops; |
|
error = _xfs_buf_read(bp, flags); |
|
|
|
/* Readahead iodone already dropped the buffer, so exit. */ |
|
if (flags & XBF_ASYNC) |
|
return 0; |
|
} else { |
|
/* Buffer already read; all we need to do is check it. */ |
|
error = xfs_buf_reverify(bp, ops); |
|
|
|
/* Readahead already finished; drop the buffer and exit. */ |
|
if (flags & XBF_ASYNC) { |
|
xfs_buf_relse(bp); |
|
return 0; |
|
} |
|
|
|
/* We do not want read in the flags */ |
|
bp->b_flags &= ~XBF_READ; |
|
ASSERT(bp->b_ops != NULL || ops == NULL); |
|
} |
|
|
|
/* |
|
* If we've had a read error, then the contents of the buffer are |
|
* invalid and should not be used. To ensure that a followup read tries |
|
* to pull the buffer from disk again, we clear the XBF_DONE flag and |
|
* mark the buffer stale. This ensures that anyone who has a current |
|
* reference to the buffer will interpret it's contents correctly and |
|
* future cache lookups will also treat it as an empty, uninitialised |
|
* buffer. |
|
*/ |
|
if (error) { |
|
if (!xfs_is_shutdown(target->bt_mount)) |
|
xfs_buf_ioerror_alert(bp, fa); |
|
|
|
bp->b_flags &= ~XBF_DONE; |
|
xfs_buf_stale(bp); |
|
xfs_buf_relse(bp); |
|
|
|
/* bad CRC means corrupted metadata */ |
|
if (error == -EFSBADCRC) |
|
error = -EFSCORRUPTED; |
|
return error; |
|
} |
|
|
|
*bpp = bp; |
|
return 0; |
|
} |
|
|
|
/* |
|
* 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) |
|
{ |
|
struct xfs_buf *bp; |
|
|
|
if (bdi_read_congested(target->bt_bdev->bd_disk->bdi)) |
|
return; |
|
|
|
xfs_buf_read_map(target, map, nmaps, |
|
XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD, &bp, ops, |
|
__this_address); |
|
} |
|
|
|
/* |
|
* Read an uncached buffer from disk. Allocates and returns a locked |
|
* buffer containing the disk contents or nothing. Uncached buffers always have |
|
* a cache index of XFS_BUF_DADDR_NULL so we can easily determine if the buffer |
|
* is cached or uncached during fault diagnosis. |
|
*/ |
|
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; |
|
int error; |
|
|
|
*bpp = NULL; |
|
|
|
error = xfs_buf_get_uncached(target, numblks, flags, &bp); |
|
if (error) |
|
return error; |
|
|
|
/* set up the buffer for a read IO */ |
|
ASSERT(bp->b_map_count == 1); |
|
bp->b_rhash_key = XFS_BUF_DADDR_NULL; |
|
bp->b_maps[0].bm_bn = daddr; |
|
bp->b_flags |= XBF_READ; |
|
bp->b_ops = ops; |
|
|
|
xfs_buf_submit(bp); |
|
if (bp->b_error) { |
|
error = bp->b_error; |
|
xfs_buf_relse(bp); |
|
return error; |
|
} |
|
|
|
*bpp = bp; |
|
return 0; |
|
} |
|
|
|
int |
|
xfs_buf_get_uncached( |
|
struct xfs_buftarg *target, |
|
size_t numblks, |
|
int flags, |
|
struct xfs_buf **bpp) |
|
{ |
|
int error; |
|
struct xfs_buf *bp; |
|
DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks); |
|
|
|
*bpp = NULL; |
|
|
|
/* flags might contain irrelevant bits, pass only what we care about */ |
|
error = _xfs_buf_alloc(target, &map, 1, flags & XBF_NO_IOACCT, &bp); |
|
if (error) |
|
return error; |
|
|
|
error = xfs_buf_alloc_pages(bp, flags); |
|
if (error) |
|
goto fail_free_buf; |
|
|
|
error = _xfs_buf_map_pages(bp, 0); |
|
if (unlikely(error)) { |
|
xfs_warn(target->bt_mount, |
|
"%s: failed to map pages", __func__); |
|
goto fail_free_buf; |
|
} |
|
|
|
trace_xfs_buf_get_uncached(bp, _RET_IP_); |
|
*bpp = bp; |
|
return 0; |
|
|
|
fail_free_buf: |
|
xfs_buf_free(bp); |
|
return error; |
|
} |
|
|
|
/* |
|
* 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( |
|
struct xfs_buf *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( |
|
struct xfs_buf *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); |
|
|
|
/* |
|
* We grab the b_lock here first to serialise racing xfs_buf_rele() |
|
* calls. The pag_buf_lock being taken on the last reference only |
|
* serialises against racing lookups in xfs_buf_find(). IOWs, the second |
|
* to last reference we drop here is not serialised against the last |
|
* reference until we take bp->b_lock. Hence if we don't grab b_lock |
|
* first, the last "release" reference can win the race to the lock and |
|
* free the buffer before the second-to-last reference is processed, |
|
* leading to a use-after-free scenario. |
|
*/ |
|
spin_lock(&bp->b_lock); |
|
release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_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) |
|
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_mount, 0); |
|
down(&bp->b_sema); |
|
|
|
trace_xfs_buf_lock_done(bp, _RET_IP_); |
|
} |
|
|
|
void |
|
xfs_buf_unlock( |
|
struct xfs_buf *bp) |
|
{ |
|
ASSERT(xfs_buf_islocked(bp)); |
|
|
|
up(&bp->b_sema); |
|
trace_xfs_buf_unlock(bp, _RET_IP_); |
|
} |
|
|
|
STATIC void |
|
xfs_buf_wait_unpin( |
|
struct xfs_buf *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); |
|
} |
|
|
|
static void |
|
xfs_buf_ioerror_alert_ratelimited( |
|
struct xfs_buf *bp) |
|
{ |
|
static unsigned long lasttime; |
|
static struct xfs_buftarg *lasttarg; |
|
|
|
if (bp->b_target != lasttarg || |
|
time_after(jiffies, (lasttime + 5*HZ))) { |
|
lasttime = jiffies; |
|
xfs_buf_ioerror_alert(bp, __this_address); |
|
} |
|
lasttarg = bp->b_target; |
|
} |
|
|
|
/* |
|
* Account for this latest trip around the retry handler, and decide if |
|
* we've failed enough times to constitute a permanent failure. |
|
*/ |
|
static bool |
|
xfs_buf_ioerror_permanent( |
|
struct xfs_buf *bp, |
|
struct xfs_error_cfg *cfg) |
|
{ |
|
struct xfs_mount *mp = bp->b_mount; |
|
|
|
if (cfg->max_retries != XFS_ERR_RETRY_FOREVER && |
|
++bp->b_retries > cfg->max_retries) |
|
return true; |
|
if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER && |
|
time_after(jiffies, cfg->retry_timeout + bp->b_first_retry_time)) |
|
return true; |
|
|
|
/* At unmount we may treat errors differently */ |
|
if (xfs_is_unmounting(mp) && mp->m_fail_unmount) |
|
return true; |
|
|
|
return false; |
|
} |
|
|
|
/* |
|
* On a sync write or shutdown we just want to stale the buffer and let the |
|
* caller handle the error in bp->b_error appropriately. |
|
* |
|
* If the write was asynchronous then no one will be looking for the error. If |
|
* this is the first failure of this type, clear the error state and write the |
|
* buffer out again. This means we always retry an async write failure at least |
|
* once, but we also need to set the buffer up to behave correctly now for |
|
* repeated failures. |
|
* |
|
* If we get repeated async write failures, then we take action according to the |
|
* error configuration we have been set up to use. |
|
* |
|
* Returns true if this function took care of error handling and the caller must |
|
* not touch the buffer again. Return false if the caller should proceed with |
|
* normal I/O completion handling. |
|
*/ |
|
static bool |
|
xfs_buf_ioend_handle_error( |
|
struct xfs_buf *bp) |
|
{ |
|
struct xfs_mount *mp = bp->b_mount; |
|
struct xfs_error_cfg *cfg; |
|
|
|
/* |
|
* If we've already decided to shutdown the filesystem because of I/O |
|
* errors, there's no point in giving this a retry. |
|
*/ |
|
if (xfs_is_shutdown(mp)) |
|
goto out_stale; |
|
|
|
xfs_buf_ioerror_alert_ratelimited(bp); |
|
|
|
/* |
|
* We're not going to bother about retrying this during recovery. |
|
* One strike! |
|
*/ |
|
if (bp->b_flags & _XBF_LOGRECOVERY) { |
|
xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR); |
|
return false; |
|
} |
|
|
|
/* |
|
* Synchronous writes will have callers process the error. |
|
*/ |
|
if (!(bp->b_flags & XBF_ASYNC)) |
|
goto out_stale; |
|
|
|
trace_xfs_buf_iodone_async(bp, _RET_IP_); |
|
|
|
cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error); |
|
if (bp->b_last_error != bp->b_error || |
|
!(bp->b_flags & (XBF_STALE | XBF_WRITE_FAIL))) { |
|
bp->b_last_error = bp->b_error; |
|
if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER && |
|
!bp->b_first_retry_time) |
|
bp->b_first_retry_time = jiffies; |
|
goto resubmit; |
|
} |
|
|
|
/* |
|
* Permanent error - we need to trigger a shutdown if we haven't already |
|
* to indicate that inconsistency will result from this action. |
|
*/ |
|
if (xfs_buf_ioerror_permanent(bp, cfg)) { |
|
xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR); |
|
goto out_stale; |
|
} |
|
|
|
/* Still considered a transient error. Caller will schedule retries. */ |
|
if (bp->b_flags & _XBF_INODES) |
|
xfs_buf_inode_io_fail(bp); |
|
else if (bp->b_flags & _XBF_DQUOTS) |
|
xfs_buf_dquot_io_fail(bp); |
|
else |
|
ASSERT(list_empty(&bp->b_li_list)); |
|
xfs_buf_ioerror(bp, 0); |
|
xfs_buf_relse(bp); |
|
return true; |
|
|
|
resubmit: |
|
xfs_buf_ioerror(bp, 0); |
|
bp->b_flags |= (XBF_DONE | XBF_WRITE_FAIL); |
|
xfs_buf_submit(bp); |
|
return true; |
|
out_stale: |
|
xfs_buf_stale(bp); |
|
bp->b_flags |= XBF_DONE; |
|
bp->b_flags &= ~XBF_WRITE; |
|
trace_xfs_buf_error_relse(bp, _RET_IP_); |
|
return false; |
|
} |
|
|
|
static void |
|
xfs_buf_ioend( |
|
struct xfs_buf *bp) |
|
{ |
|
trace_xfs_buf_iodone(bp, _RET_IP_); |
|
|
|
/* |
|
* 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); |
|
|
|
if (bp->b_flags & XBF_READ) { |
|
if (!bp->b_error && bp->b_ops) |
|
bp->b_ops->verify_read(bp); |
|
if (!bp->b_error) |
|
bp->b_flags |= XBF_DONE; |
|
} else { |
|
if (!bp->b_error) { |
|
bp->b_flags &= ~XBF_WRITE_FAIL; |
|
bp->b_flags |= XBF_DONE; |
|
} |
|
|
|
if (unlikely(bp->b_error) && xfs_buf_ioend_handle_error(bp)) |
|
return; |
|
|
|
/* clear the retry state */ |
|
bp->b_last_error = 0; |
|
bp->b_retries = 0; |
|
bp->b_first_retry_time = 0; |
|
|
|
/* |
|
* Note that for things like remote attribute buffers, there may |
|
* not be a buffer log item here, so processing the buffer log |
|
* item must remain optional. |
|
*/ |
|
if (bp->b_log_item) |
|
xfs_buf_item_done(bp); |
|
|
|
if (bp->b_flags & _XBF_INODES) |
|
xfs_buf_inode_iodone(bp); |
|
else if (bp->b_flags & _XBF_DQUOTS) |
|
xfs_buf_dquot_iodone(bp); |
|
|
|
} |
|
|
|
bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD | |
|
_XBF_LOGRECOVERY); |
|
|
|
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, struct xfs_buf, 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_mount->m_buf_workqueue, &bp->b_ioend_work); |
|
} |
|
|
|
void |
|
__xfs_buf_ioerror( |
|
struct xfs_buf *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, |
|
xfs_failaddr_t func) |
|
{ |
|
xfs_buf_alert_ratelimited(bp, "XFS: metadata IO error", |
|
"metadata I/O error in \"%pS\" at daddr 0x%llx len %d error %d", |
|
func, (uint64_t)xfs_buf_daddr(bp), |
|
bp->b_length, -bp->b_error); |
|
} |
|
|
|
/* |
|
* To simulate an I/O failure, the buffer must be locked and held with at least |
|
* three references. The LRU reference is dropped by the stale call. The buf |
|
* item reference is dropped via ioend processing. The third reference is owned |
|
* by the caller and is dropped on I/O completion if the buffer is XBF_ASYNC. |
|
*/ |
|
void |
|
xfs_buf_ioend_fail( |
|
struct xfs_buf *bp) |
|
{ |
|
bp->b_flags &= ~XBF_DONE; |
|
xfs_buf_stale(bp); |
|
xfs_buf_ioerror(bp, -EIO); |
|
xfs_buf_ioend(bp); |
|
} |
|
|
|
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_DONE); |
|
|
|
error = xfs_buf_submit(bp); |
|
if (error) |
|
xfs_force_shutdown(bp->b_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; |
|
|
|
if (!bio->bi_status && |
|
(bp->b_flags & XBF_WRITE) && (bp->b_flags & XBF_ASYNC) && |
|
XFS_TEST_ERROR(false, bp->b_mount, XFS_ERRTAG_BUF_IOERROR)) |
|
bio->bi_status = BLK_STS_IOERR; |
|
|
|
/* |
|
* 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 page_index; |
|
unsigned 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 = bio_max_segs(total_nr_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->bi_opf = op; |
|
|
|
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 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; |
|
|
|
if (bp->b_flags & XBF_WRITE) { |
|
op = REQ_OP_WRITE; |
|
|
|
/* |
|
* 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_mount, |
|
SHUTDOWN_CORRUPT_INCORE); |
|
return; |
|
} |
|
} else if (bp->b_rhash_key != XFS_BUF_DADDR_NULL) { |
|
struct xfs_mount *mp = bp->b_mount; |
|
|
|
/* |
|
* non-crc filesystems don't attach verifiers during |
|
* log recovery, so don't warn for such filesystems. |
|
*/ |
|
if (xfs_has_crc(mp)) { |
|
xfs_warn(mp, |
|
"%s: no buf ops on daddr 0x%llx len %d", |
|
__func__, xfs_buf_daddr(bp), |
|
bp->b_length); |
|
xfs_hex_dump(bp->b_addr, |
|
XFS_CORRUPTION_DUMP_LEN); |
|
dump_stack(); |
|
} |
|
} |
|
} else { |
|
op = REQ_OP_READ; |
|
if (bp->b_flags & XBF_READ_AHEAD) |
|
op |= REQ_RAHEAD; |
|
} |
|
|
|
/* we only use the buffer cache for meta-data */ |
|
op |= 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_length); |
|
blk_start_plug(&plug); |
|
for (i = 0; i < bp->b_map_count; i++) { |
|
xfs_buf_ioapply_map(bp, i, &offset, &size, op); |
|
if (bp->b_error) |
|
break; |
|
if (size <= 0) |
|
break; /* all done */ |
|
} |
|
blk_finish_plug(&plug); |
|
} |
|
|
|
/* |
|
* Wait for I/O completion of a sync buffer and return the I/O error code. |
|
*/ |
|
static int |
|
xfs_buf_iowait( |
|
struct xfs_buf *bp) |
|
{ |
|
ASSERT(!(bp->b_flags & XBF_ASYNC)); |
|
|
|
trace_xfs_buf_iowait(bp, _RET_IP_); |
|
wait_for_completion(&bp->b_iowait); |
|
trace_xfs_buf_iowait_done(bp, _RET_IP_); |
|
|
|
return bp->b_error; |
|
} |
|
|
|
/* |
|
* Buffer I/O submission path, read or write. Asynchronous submission 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. |
|
*/ |
|
static int |
|
__xfs_buf_submit( |
|
struct xfs_buf *bp, |
|
bool wait) |
|
{ |
|
int error = 0; |
|
|
|
trace_xfs_buf_submit(bp, _RET_IP_); |
|
|
|
ASSERT(!(bp->b_flags & _XBF_DELWRI_Q)); |
|
|
|
/* on shutdown we stale and complete the buffer immediately */ |
|
if (xfs_is_shutdown(bp->b_mount)) { |
|
xfs_buf_ioend_fail(bp); |
|
return -EIO; |
|
} |
|
|
|
/* |
|
* Grab a reference so the buffer does not go away underneath us. For |
|
* async buffers, I/O completion drops the callers reference, which |
|
* could occur before submission returns. |
|
*/ |
|
xfs_buf_hold(bp); |
|
|
|
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; |
|
|
|
/* |
|
* 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); |
|
if (bp->b_flags & XBF_ASYNC) |
|
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 || !(bp->b_flags & XBF_ASYNC)) |
|
xfs_buf_ioend(bp); |
|
else |
|
xfs_buf_ioend_async(bp); |
|
} |
|
|
|
if (wait) |
|
error = xfs_buf_iowait(bp); |
|
|
|
/* |
|
* Release the hold that keeps the buffer referenced for the entire |
|
* I/O. Note that if the buffer is async, it is not safe to reference |
|
* after this release. |
|
*/ |
|
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; |
|
|
|
page = bp->b_pages[offset >> PAGE_SHIFT]; |
|
return page_address(page) + (offset & (PAGE_SIZE-1)); |
|
} |
|
|
|
void |
|
xfs_buf_zero( |
|
struct xfs_buf *bp, |
|
size_t boff, |
|
size_t bsize) |
|
{ |
|
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_length) - boff); |
|
|
|
ASSERT((csize + page_offset) <= PAGE_SIZE); |
|
|
|
memset(page_address(page) + page_offset, 0, csize); |
|
|
|
boff += csize; |
|
} |
|
} |
|
|
|
/* |
|
* Log a message about and stale a buffer that a caller has decided is corrupt. |
|
* |
|
* This function should be called for the kinds of metadata corruption that |
|
* cannot be detect from a verifier, such as incorrect inter-block relationship |
|
* data. Do /not/ call this function from a verifier function. |
|
* |
|
* The buffer must be XBF_DONE prior to the call. Afterwards, the buffer will |
|
* be marked stale, but b_error will not be set. The caller is responsible for |
|
* releasing the buffer or fixing it. |
|
*/ |
|
void |
|
__xfs_buf_mark_corrupt( |
|
struct xfs_buf *bp, |
|
xfs_failaddr_t fa) |
|
{ |
|
ASSERT(bp->b_flags & XBF_DONE); |
|
|
|
xfs_buf_corruption_error(bp, fa); |
|
xfs_buf_stale(bp); |
|
} |
|
|
|
/* |
|
* 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_drain_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_drain_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; |
|
} |
|
|
|
/* |
|
* Wait for outstanding I/O on the buftarg to complete. |
|
*/ |
|
void |
|
xfs_buftarg_wait( |
|
struct xfs_buftarg *btp) |
|
{ |
|
/* |
|
* 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); |
|
} |
|
|
|
void |
|
xfs_buftarg_drain( |
|
struct xfs_buftarg *btp) |
|
{ |
|
LIST_HEAD(dispose); |
|
int loop = 0; |
|
bool write_fail = false; |
|
|
|
xfs_buftarg_wait(btp); |
|
|
|
/* 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_drain_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) { |
|
write_fail = true; |
|
xfs_buf_alert_ratelimited(bp, |
|
"XFS: Corruption Alert", |
|
"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!", |
|
(long long)xfs_buf_daddr(bp)); |
|
} |
|
xfs_buf_rele(bp); |
|
} |
|
if (loop++ != 0) |
|
delay(100); |
|
} |
|
|
|
/* |
|
* If one or more failed buffers were freed, that means dirty metadata |
|
* was thrown away. This should only ever happen after I/O completion |
|
* handling has elevated I/O error(s) to permanent failures and shuts |
|
* down the fs. |
|
*/ |
|
if (write_fail) { |
|
ASSERT(xfs_is_shutdown(btp->bt_mount)); |
|
xfs_alert(btp->bt_mount, |
|
"Please run xfs_repair to determine the extent of the problem."); |
|
} |
|
} |
|
|
|
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_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); |
|
|
|
blkdev_issue_flush(btp->bt_bdev); |
|
|
|
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_NOFS); |
|
|
|
btp->bt_mount = mp; |
|
btp->bt_dev = bdev->bd_dev; |
|
btp->bt_bdev = bdev; |
|
btp->bt_daxdev = dax_dev; |
|
|
|
/* |
|
* Buffer IO error rate limiting. Limit it to no more than 10 messages |
|
* per 30 seconds so as to not spam logs too much on repeated errors. |
|
*/ |
|
ratelimit_state_init(&btp->bt_ioerror_rl, 30 * HZ, |
|
DEFAULT_RATELIMIT_BURST); |
|
|
|
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, |
|
const struct list_head *a, |
|
const 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. If wait_list is specified, the buffers are |
|
* submitted using sync I/O and placed on the wait list such that the caller can |
|
* iowait each buffer. Otherwise async I/O is used and the buffers are released |
|
* at I/O completion time. In either case, buffers remain locked until I/O |
|
* completes and the buffer is released from the queue. |
|
*/ |
|
static int |
|
xfs_buf_delwri_submit_buffers( |
|
struct list_head *buffer_list, |
|
struct list_head *wait_list) |
|
{ |
|
struct xfs_buf *bp, *n; |
|
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_); |
|
|
|
/* |
|
* If we have a wait list, each buffer (and associated delwri |
|
* queue reference) transfers to it and is submitted |
|
* synchronously. Otherwise, drop the buffer from the delwri |
|
* queue and submit async. |
|
*/ |
|
bp->b_flags &= ~_XBF_DELWRI_Q; |
|
bp->b_flags |= XBF_WRITE; |
|
if (wait_list) { |
|
bp->b_flags &= ~XBF_ASYNC; |
|
list_move_tail(&bp->b_list, wait_list); |
|
} else { |
|
bp->b_flags |= XBF_ASYNC; |
|
list_del_init(&bp->b_list); |
|
} |
|
__xfs_buf_submit(bp, false); |
|
} |
|
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. |
|
* |
|
* Note: this function will skip buffers it would block on, and in doing so |
|
* leaves them on @buffer_list so they can be retried on a later pass. As such, |
|
* it is up to the caller to ensure that the buffer list is fully submitted or |
|
* cancelled appropriately when they are finished with the list. Failure to |
|
* cancel or resubmit the list until it is empty will result in leaked buffers |
|
* at unmount time. |
|
*/ |
|
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); |
|
|
|
/* |
|
* Wait on the locked buffer, check for errors and unlock and |
|
* release the delwri queue reference. |
|
*/ |
|
error2 = xfs_buf_iowait(bp); |
|
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 the original 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 locked, under I/O and wait listed on the original |
|
* delwri queue. Wait for I/O completion, restore the DELWRI_Q flag and |
|
* return with the buffer unlocked and on the original queue. |
|
*/ |
|
error = xfs_buf_iowait(bp); |
|
bp->b_flags |= _XBF_DELWRI_Q; |
|
xfs_buf_unlock(bp); |
|
|
|
return error; |
|
} |
|
|
|
int __init |
|
xfs_buf_init(void) |
|
{ |
|
xfs_buf_zone = kmem_cache_create("xfs_buf", sizeof(struct xfs_buf), 0, |
|
SLAB_HWCACHE_ALIGN | |
|
SLAB_RECLAIM_ACCOUNT | |
|
SLAB_MEM_SPREAD, |
|
NULL); |
|
if (!xfs_buf_zone) |
|
goto out; |
|
|
|
return 0; |
|
|
|
out: |
|
return -ENOMEM; |
|
} |
|
|
|
void |
|
xfs_buf_terminate(void) |
|
{ |
|
kmem_cache_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_mount, XFS_ERRTAG_BUF_LRU_REF)) |
|
lru_ref = 0; |
|
|
|
atomic_set(&bp->b_lru_ref, lru_ref); |
|
} |
|
|
|
/* |
|
* Verify an on-disk magic value against the magic value specified in the |
|
* verifier structure. The verifier magic is in disk byte order so the caller is |
|
* expected to pass the value directly from disk. |
|
*/ |
|
bool |
|
xfs_verify_magic( |
|
struct xfs_buf *bp, |
|
__be32 dmagic) |
|
{ |
|
struct xfs_mount *mp = bp->b_mount; |
|
int idx; |
|
|
|
idx = xfs_has_crc(mp); |
|
if (WARN_ON(!bp->b_ops || !bp->b_ops->magic[idx])) |
|
return false; |
|
return dmagic == bp->b_ops->magic[idx]; |
|
} |
|
/* |
|
* Verify an on-disk magic value against the magic value specified in the |
|
* verifier structure. The verifier magic is in disk byte order so the caller is |
|
* expected to pass the value directly from disk. |
|
*/ |
|
bool |
|
xfs_verify_magic16( |
|
struct xfs_buf *bp, |
|
__be16 dmagic) |
|
{ |
|
struct xfs_mount *mp = bp->b_mount; |
|
int idx; |
|
|
|
idx = xfs_has_crc(mp); |
|
if (WARN_ON(!bp->b_ops || !bp->b_ops->magic16[idx])) |
|
return false; |
|
return dmagic == bp->b_ops->magic16[idx]; |
|
}
|
|
|