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 static BOOLEAN __stdcall acquire_for_lazy_write(PVOID Context, BOOLEAN Wait) { 23 PFILE_OBJECT FileObject = Context; 24 fcb* fcb = FileObject->FsContext; 25 26 TRACE("(%p, %u)\n", Context, Wait); 27 28 if (!ExAcquireResourceSharedLite(&fcb->Vcb->tree_lock, Wait)) 29 return false; 30 31 if (!ExAcquireResourceExclusiveLite(fcb->Header.Resource, Wait)) { 32 ExReleaseResourceLite(&fcb->Vcb->tree_lock); 33 return false; 34 } 35 36 fcb->lazy_writer_thread = KeGetCurrentThread(); 37 38 IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP); 39 40 return true; 41 } 42 43 static void __stdcall release_from_lazy_write(PVOID Context) { 44 PFILE_OBJECT FileObject = Context; 45 fcb* fcb = FileObject->FsContext; 46 47 TRACE("(%p)\n", Context); 48 49 fcb->lazy_writer_thread = NULL; 50 51 ExReleaseResourceLite(fcb->Header.Resource); 52 53 ExReleaseResourceLite(&fcb->Vcb->tree_lock); 54 55 if (IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP) 56 IoSetTopLevelIrp(NULL); 57 } 58 59 static BOOLEAN __stdcall acquire_for_read_ahead(PVOID Context, BOOLEAN Wait) { 60 PFILE_OBJECT FileObject = Context; 61 fcb* fcb = FileObject->FsContext; 62 63 TRACE("(%p, %u)\n", Context, Wait); 64 65 if (!ExAcquireResourceSharedLite(fcb->Header.Resource, Wait)) 66 return false; 67 68 IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP); 69 70 return true; 71 } 72 73 static void __stdcall release_from_read_ahead(PVOID Context) { 74 PFILE_OBJECT FileObject = Context; 75 fcb* fcb = FileObject->FsContext; 76 77 TRACE("(%p)\n", Context); 78 79 ExReleaseResourceLite(fcb->Header.Resource); 80 81 if (IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP) 82 IoSetTopLevelIrp(NULL); 83 } 84 85 void init_cache() { 86 cache_callbacks.AcquireForLazyWrite = acquire_for_lazy_write; 87 cache_callbacks.ReleaseFromLazyWrite = release_from_lazy_write; 88 cache_callbacks.AcquireForReadAhead = acquire_for_read_ahead; 89 cache_callbacks.ReleaseFromReadAhead = release_from_read_ahead; 90 } 91