cregit-Linux how code gets into the kernel

Release 4.10 fs/xfs/xfs_refcount_item.c

Directory: fs/xfs
/*
 * Copyright (C) 2016 Oracle.  All Rights Reserved.
 *
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_buf_item.h"
#include "xfs_refcount_item.h"
#include "xfs_log.h"
#include "xfs_refcount.h"



kmem_zone_t	*xfs_cui_zone;

kmem_zone_t	*xfs_cud_zone;


static inline struct xfs_cui_log_item *CUI_ITEM(struct xfs_log_item *lip) { return container_of(lip, struct xfs_cui_log_item, cui_item); }

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void xfs_cui_item_free( struct xfs_cui_log_item *cuip) { if (cuip->cui_format.cui_nextents > XFS_CUI_MAX_FAST_EXTENTS) kmem_free(cuip); else kmem_zone_free(xfs_cui_zone, cuip); }

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STATIC void xfs_cui_item_size( struct xfs_log_item *lip, int *nvecs, int *nbytes) { struct xfs_cui_log_item *cuip = CUI_ITEM(lip); *nvecs += 1; *nbytes += xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents); }

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/* * This is called to fill in the vector of log iovecs for the * given cui log item. We use only 1 iovec, and we point that * at the cui_log_format structure embedded in the cui item. * It is at this point that we assert that all of the extent * slots in the cui item have been filled. */
STATIC void xfs_cui_item_format( struct xfs_log_item *lip, struct xfs_log_vec *lv) { struct xfs_cui_log_item *cuip = CUI_ITEM(lip); struct xfs_log_iovec *vecp = NULL; ASSERT(atomic_read(&cuip->cui_next_extent) == cuip->cui_format.cui_nextents); cuip->cui_format.cui_type = XFS_LI_CUI; cuip->cui_format.cui_size = 1; xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_CUI_FORMAT, &cuip->cui_format, xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents)); }

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/* * Pinning has no meaning for an cui item, so just return. */
STATIC void xfs_cui_item_pin( struct xfs_log_item *lip) { }

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/* * The unpin operation is the last place an CUI is manipulated in the log. It is * either inserted in the AIL or aborted in the event of a log I/O error. In * either case, the CUI transaction has been successfully committed to make it * this far. Therefore, we expect whoever committed the CUI to either construct * and commit the CUD or drop the CUD's reference in the event of error. Simply * drop the log's CUI reference now that the log is done with it. */
STATIC void xfs_cui_item_unpin( struct xfs_log_item *lip, int remove) { struct xfs_cui_log_item *cuip = CUI_ITEM(lip); xfs_cui_release(cuip); }

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/* * CUI items have no locking or pushing. However, since CUIs are pulled from * the AIL when their corresponding CUDs are committed to disk, their situation * is very similar to being pinned. Return XFS_ITEM_PINNED so that the caller * will eventually flush the log. This should help in getting the CUI out of * the AIL. */
STATIC uint xfs_cui_item_push( struct xfs_log_item *lip, struct list_head *buffer_list) { return XFS_ITEM_PINNED; }

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/* * The CUI has been either committed or aborted if the transaction has been * cancelled. If the transaction was cancelled, an CUD isn't going to be * constructed and thus we free the CUI here directly. */
STATIC void xfs_cui_item_unlock( struct xfs_log_item *lip) { if (lip->li_flags & XFS_LI_ABORTED) xfs_cui_item_free(CUI_ITEM(lip)); }

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/* * The CUI is logged only once and cannot be moved in the log, so simply return * the lsn at which it's been logged. */
STATIC xfs_lsn_t xfs_cui_item_committed( struct xfs_log_item *lip, xfs_lsn_t lsn) { return lsn; }

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/* * The CUI dependency tracking op doesn't do squat. It can't because * it doesn't know where the free extent is coming from. The dependency * tracking has to be handled by the "enclosing" metadata object. For * example, for inodes, the inode is locked throughout the extent freeing * so the dependency should be recorded there. */
STATIC void xfs_cui_item_committing( struct xfs_log_item *lip, xfs_lsn_t lsn) { }

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/* * This is the ops vector shared by all cui log items. */ static const struct xfs_item_ops xfs_cui_item_ops = { .iop_size = xfs_cui_item_size, .iop_format = xfs_cui_item_format, .iop_pin = xfs_cui_item_pin, .iop_unpin = xfs_cui_item_unpin, .iop_unlock = xfs_cui_item_unlock, .iop_committed = xfs_cui_item_committed, .iop_push = xfs_cui_item_push, .iop_committing = xfs_cui_item_committing, }; /* * Allocate and initialize an cui item with the given number of extents. */
struct xfs_cui_log_item * xfs_cui_init( struct xfs_mount *mp, uint nextents) { struct xfs_cui_log_item *cuip; ASSERT(nextents > 0); if (nextents > XFS_CUI_MAX_FAST_EXTENTS) cuip = kmem_zalloc(xfs_cui_log_item_sizeof(nextents), KM_SLEEP); else cuip = kmem_zone_zalloc(xfs_cui_zone, KM_SLEEP); xfs_log_item_init(mp, &cuip->cui_item, XFS_LI_CUI, &xfs_cui_item_ops); cuip->cui_format.cui_nextents = nextents; cuip->cui_format.cui_id = (uintptr_t)(void *)cuip; atomic_set(&cuip->cui_next_extent, 0); atomic_set(&cuip->cui_refcount, 2); return cuip; }

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/* * Freeing the CUI requires that we remove it from the AIL if it has already * been placed there. However, the CUI may not yet have been placed in the AIL * when called by xfs_cui_release() from CUD processing due to the ordering of * committed vs unpin operations in bulk insert operations. Hence the reference * count to ensure only the last caller frees the CUI. */
void xfs_cui_release( struct xfs_cui_log_item *cuip) { if (atomic_dec_and_test(&cuip->cui_refcount)) { xfs_trans_ail_remove(&cuip->cui_item, SHUTDOWN_LOG_IO_ERROR); xfs_cui_item_free(cuip); } }

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static inline struct xfs_cud_log_item *CUD_ITEM(struct xfs_log_item *lip) { return container_of(lip, struct xfs_cud_log_item, cud_item); }

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STATIC void xfs_cud_item_size( struct xfs_log_item *lip, int *nvecs, int *nbytes) { *nvecs += 1; *nbytes += sizeof(struct xfs_cud_log_format); }

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/* * This is called to fill in the vector of log iovecs for the * given cud log item. We use only 1 iovec, and we point that * at the cud_log_format structure embedded in the cud item. * It is at this point that we assert that all of the extent * slots in the cud item have been filled. */
STATIC void xfs_cud_item_format( struct xfs_log_item *lip, struct xfs_log_vec *lv) { struct xfs_cud_log_item *cudp = CUD_ITEM(lip); struct xfs_log_iovec *vecp = NULL; cudp->cud_format.cud_type = XFS_LI_CUD; cudp->cud_format.cud_size = 1; xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_CUD_FORMAT, &cudp->cud_format, sizeof(struct xfs_cud_log_format)); }

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/* * Pinning has no meaning for an cud item, so just return. */
STATIC void xfs_cud_item_pin( struct xfs_log_item *lip) { }

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/* * Since pinning has no meaning for an cud item, unpinning does * not either. */
STATIC void xfs_cud_item_unpin( struct xfs_log_item *lip, int remove) { }

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/* * There isn't much you can do to push on an cud item. It is simply stuck * waiting for the log to be flushed to disk. */
STATIC uint xfs_cud_item_push( struct xfs_log_item *lip, struct list_head *buffer_list) { return XFS_ITEM_PINNED; }

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/* * The CUD is either committed or aborted if the transaction is cancelled. If * the transaction is cancelled, drop our reference to the CUI and free the * CUD. */
STATIC void xfs_cud_item_unlock( struct xfs_log_item *lip) { struct xfs_cud_log_item *cudp = CUD_ITEM(lip); if (lip->li_flags & XFS_LI_ABORTED) { xfs_cui_release(cudp->cud_cuip); kmem_zone_free(xfs_cud_zone, cudp); } }

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/* * When the cud item is committed to disk, all we need to do is delete our * reference to our partner cui item and then free ourselves. Since we're * freeing ourselves we must return -1 to keep the transaction code from * further referencing this item. */
STATIC xfs_lsn_t xfs_cud_item_committed( struct xfs_log_item *lip, xfs_lsn_t lsn) { struct xfs_cud_log_item *cudp = CUD_ITEM(lip); /* * Drop the CUI reference regardless of whether the CUD has been * aborted. Once the CUD transaction is constructed, it is the sole * responsibility of the CUD to release the CUI (even if the CUI is * aborted due to log I/O error). */ xfs_cui_release(cudp->cud_cuip); kmem_zone_free(xfs_cud_zone, cudp); return (xfs_lsn_t)-1; }

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/* * The CUD dependency tracking op doesn't do squat. It can't because * it doesn't know where the free extent is coming from. The dependency * tracking has to be handled by the "enclosing" metadata object. For * example, for inodes, the inode is locked throughout the extent freeing * so the dependency should be recorded there. */
STATIC void xfs_cud_item_committing( struct xfs_log_item *lip, xfs_lsn_t lsn) { }

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darrick j. wongdarrick j. wong13100.00%1100.00%
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/* * This is the ops vector shared by all cud log items. */ static const struct xfs_item_ops xfs_cud_item_ops = { .iop_size = xfs_cud_item_size, .iop_format = xfs_cud_item_format, .iop_pin = xfs_cud_item_pin, .iop_unpin = xfs_cud_item_unpin, .iop_unlock = xfs_cud_item_unlock, .iop_committed = xfs_cud_item_committed, .iop_push = xfs_cud_item_push, .iop_committing = xfs_cud_item_committing, }; /* * Allocate and initialize an cud item with the given number of extents. */
struct xfs_cud_log_item * xfs_cud_init( struct xfs_mount *mp, struct xfs_cui_log_item *cuip) { struct xfs_cud_log_item *cudp; cudp = kmem_zone_zalloc(xfs_cud_zone, KM_SLEEP); xfs_log_item_init(mp, &cudp->cud_item, XFS_LI_CUD, &xfs_cud_item_ops); cudp->cud_cuip = cuip; cudp->cud_format.cud_cui_id = cuip->cui_format.cui_id; return cudp; }

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/* * Process a refcount update intent item that was recovered from the log. * We need to update the refcountbt. */
int xfs_cui_recover( struct xfs_mount *mp, struct xfs_cui_log_item *cuip) { int i; int error = 0; unsigned int refc_type; struct xfs_phys_extent *refc; xfs_fsblock_t startblock_fsb; bool op_ok; struct xfs_cud_log_item *cudp; struct xfs_trans *tp; struct xfs_btree_cur *rcur = NULL; enum xfs_refcount_intent_type type; xfs_fsblock_t firstfsb; xfs_fsblock_t new_fsb; xfs_extlen_t new_len; struct xfs_bmbt_irec irec; struct xfs_defer_ops dfops; bool requeue_only = false; ASSERT(!test_bit(XFS_CUI_RECOVERED, &cuip->cui_flags)); /* * First check the validity of the extents described by the * CUI. If any are bad, then assume that all are bad and * just toss the CUI. */ for (i = 0; i < cuip->cui_format.cui_nextents; i++) { refc = &cuip->cui_format.cui_extents[i]; startblock_fsb = XFS_BB_TO_FSB(mp, XFS_FSB_TO_DADDR(mp, refc->pe_startblock)); switch (refc->pe_flags & XFS_REFCOUNT_EXTENT_TYPE_MASK) { case XFS_REFCOUNT_INCREASE: case XFS_REFCOUNT_DECREASE: case XFS_REFCOUNT_ALLOC_COW: case XFS_REFCOUNT_FREE_COW: op_ok = true; break; default: op_ok = false; break; } if (!op_ok || startblock_fsb == 0 || refc->pe_len == 0 || startblock_fsb >= mp->m_sb.sb_dblocks || refc->pe_len >= mp->m_sb.sb_agblocks || (refc->pe_flags & ~XFS_REFCOUNT_EXTENT_FLAGS)) { /* * This will pull the CUI from the AIL and * free the memory associated with it. */ set_bit(XFS_CUI_RECOVERED, &cuip->cui_flags); xfs_cui_release(cuip); return -EIO; } } /* * Under normal operation, refcount updates are deferred, so we * wouldn't be adding them directly to a transaction. All * refcount updates manage reservation usage internally and * dynamically by deferring work that won't fit in the * transaction. Normally, any work that needs to be deferred * gets attached to the same defer_ops that scheduled the * refcount update. However, we're in log recovery here, so we * we create our own defer_ops and use that to finish up any * work that doesn't fit. */ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); if (error) return error; cudp = xfs_trans_get_cud(tp, cuip); xfs_defer_init(&dfops, &firstfsb); for (i = 0; i < cuip->cui_format.cui_nextents; i++) { refc = &cuip->cui_format.cui_extents[i]; refc_type = refc->pe_flags & XFS_REFCOUNT_EXTENT_TYPE_MASK; switch (refc_type) { case XFS_REFCOUNT_INCREASE: case XFS_REFCOUNT_DECREASE: case XFS_REFCOUNT_ALLOC_COW: case XFS_REFCOUNT_FREE_COW: type = refc_type; break; default: error = -EFSCORRUPTED; goto abort_error; } if (requeue_only) { new_fsb = refc->pe_startblock; new_len = refc->pe_len; } else error = xfs_trans_log_finish_refcount_update(tp, cudp, &dfops, type, refc->pe_startblock, refc->pe_len, &new_fsb, &new_len, &rcur); if (error) goto abort_error; /* Requeue what we didn't finish. */ if (new_len > 0) { irec.br_startblock = new_fsb; irec.br_blockcount = new_len; switch (type) { case XFS_REFCOUNT_INCREASE: error = xfs_refcount_increase_extent( tp->t_mountp, &dfops, &irec); break; case XFS_REFCOUNT_DECREASE: error = xfs_refcount_decrease_extent( tp->t_mountp, &dfops, &irec); break; case XFS_REFCOUNT_ALLOC_COW: error = xfs_refcount_alloc_cow_extent( tp->t_mountp, &dfops, irec.br_startblock, irec.br_blockcount); break; case XFS_REFCOUNT_FREE_COW: error = xfs_refcount_free_cow_extent( tp->t_mountp, &dfops, irec.br_startblock, irec.br_blockcount); break; default: ASSERT(0); } if (error) goto abort_error; requeue_only = true; } } xfs_refcount_finish_one_cleanup(tp, rcur, error); error = xfs_defer_finish(&tp, &dfops, NULL); if (error) goto abort_defer; set_bit(XFS_CUI_RECOVERED, &cuip->cui_flags); error = xfs_trans_commit(tp); return error; abort_error: xfs_refcount_finish_one_cleanup(tp, rcur, error); abort_defer: xfs_defer_cancel(&dfops); xfs_trans_cancel(tp); return error; }

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Directory: fs/xfs
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