drivers/filesystems/btrfs/cache.c

   1 /* Copyright (c) Mark Harmstone 2016-17
   2  *
   3  * This file is part of WinBtrfs.
   4  *
   5  * WinBtrfs is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public Licence as published by
   7  * the Free Software Foundation, either version 3 of the Licence, or
   8  * (at your option) any later version.
   9  *
  10  * WinBtrfs is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU Lesser General Public Licence for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public Licence
  16  * along with WinBtrfs.  If not, see <http://www.gnu.org/licenses/>. */
  17
  18 #include "btrfs_drv.h"
  19
  20 CACHE_MANAGER_CALLBACKS* cache_callbacks;
  21
  22 #ifdef __REACTOS__
  23 static BOOLEAN NTAPI acquire_for_lazy_write(PVOID Context, BOOLEAN Wait) {
  24 #else
  25 static BOOLEAN acquire_for_lazy_write(PVOID Context, BOOLEAN Wait) {
  26 #endif
  27     PFILE_OBJECT FileObject = Context;
  28     fcb* fcb = FileObject->FsContext;
  29
  30     TRACE("(%p, %u)\n", Context, Wait);
  31
  32     if (!ExAcquireResourceSharedLite(&fcb->Vcb->tree_lock, Wait))
  33         return FALSE;
  34
  35     if (!ExAcquireResourceExclusiveLite(fcb->Header.Resource, Wait)) {
  36         ExReleaseResourceLite(&fcb->Vcb->tree_lock);
  37         return FALSE;
  38     }
  39
  40     fcb->lazy_writer_thread = KeGetCurrentThread();
  41
  42     IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
  43
  44     return TRUE;
  45 }
  46
  47 #ifdef __REACTOS__
  48 static void NTAPI release_from_lazy_write(PVOID Context) {
  49 #else
  50 static void release_from_lazy_write(PVOID Context) {
  51 #endif
  52     PFILE_OBJECT FileObject = Context;
  53     fcb* fcb = FileObject->FsContext;
  54
  55     TRACE("(%p)\n", Context);
  56
  57     fcb->lazy_writer_thread = NULL;
  58
  59     ExReleaseResourceLite(fcb->Header.Resource);
  60
  61     ExReleaseResourceLite(&fcb->Vcb->tree_lock);
  62
  63     if (IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP)
  64         IoSetTopLevelIrp(NULL);
  65 }
  66
  67 #ifdef __REACTOS__
  68 static BOOLEAN NTAPI acquire_for_read_ahead(PVOID Context, BOOLEAN Wait) {
  69 #else
  70 static BOOLEAN acquire_for_read_ahead(PVOID Context, BOOLEAN Wait) {
  71 #endif
  72     PFILE_OBJECT FileObject = Context;
  73     fcb* fcb = FileObject->FsContext;
  74
  75     TRACE("(%p, %u)\n", Context, Wait);
  76
  77     if (!ExAcquireResourceSharedLite(fcb->Header.Resource, Wait))
  78         return FALSE;
  79
  80     IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
  81
  82     return TRUE;
  83 }
  84
  85 #ifdef __REACTOS__
  86 static void NTAPI release_from_read_ahead(PVOID Context) {
  87 #else
  88 static void release_from_read_ahead(PVOID Context) {
  89 #endif
  90     PFILE_OBJECT FileObject = Context;
  91     fcb* fcb = FileObject->FsContext;
  92
  93     TRACE("(%p)\n", Context);
  94
  95     ExReleaseResourceLite(fcb->Header.Resource);
  96
  97     if (IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP)
  98         IoSetTopLevelIrp(NULL);
  99 }
 100
 101 NTSTATUS init_cache() {
 102     cache_callbacks = ExAllocatePoolWithTag(NonPagedPool, sizeof(CACHE_MANAGER_CALLBACKS), ALLOC_TAG);
 103     if (!cache_callbacks) {
 104         ERR("out of memory\n");
 105         return STATUS_INSUFFICIENT_RESOURCES;
 106     }
 107
 108     cache_callbacks->AcquireForLazyWrite = acquire_for_lazy_write;
 109     cache_callbacks->ReleaseFromLazyWrite = release_from_lazy_write;
 110     cache_callbacks->AcquireForReadAhead = acquire_for_read_ahead;
 111     cache_callbacks->ReleaseFromReadAhead = release_from_read_ahead;
 112
 113     return STATUS_SUCCESS;
 114 }
 115
 116 void free_cache() {
 117     ExFreePool(cache_callbacks);
 118 }