Reland: resolve FUSE and lower FS cache inconsistencies
Rf - Read FUSE, Wf - Write FUSE
Rl - Read lower fs, Wl - Write lower fs
File reads in the following scenarios may not see the latest data
because of different VFS caches:
1. Rf - Wl -Rf
2. Rl - Wf - Rl
To fix the scenarios above we dynamically return a FUSE or lower FS fd
from the MediaProvider#open or open with or without caching during
FUSE_OPEN. Here are the conditions:
MP open:
- Return FUSE fd if file already opened with caching via FUSE or we are
unable to SET_OFD_SETLK to F_RDLCK or F_WRLCK with fcntl(2).
- Return lower FS fd otherwise
FUSE open:
- Open with caching if F_OFD_GETLK with fcntl(2) returns F_UNLCK
- Open with direct_io otherwise
Unfortunately, we cannot place a F_RDLCK on a file opened in write
only mode and we cannot place a F_WRLCK twice. This means that if a
file is opened via MP in write only mode, we can only set a F_WRLCK
and subsequent opens will have to go through FUSE.
Pseudo code of algorithm implemented:
MP#opeFd
lowerFsFd = open(lowerPath)
useFuse = FuseD#shouldOpenWithFuse(lowerPath, fd)
if useFuse
upperFsFd = open(upperPath)
return upperFsFd
else
return lowerFsFd
FuseD#open
lowerFsFd = open(path)
hasLock = fcntl(get_lock, lowerFsFd)
if hasLock
return uncachedFileInfo
else
return cachedFileInfo
FuseD#shouldOpenWithFuse
if cached
return true
else
res = fcntl(set_read_or_write_lock, fd)
return res
Test: atest FuseDaemonHostTest#testVfsCacheConsistency
Test: atest FuseDaemonHostTest
Test: adb logcat -v color | grep --color=never -iE "using fuse|using lower|using direct|using cache"
Change-Id: I7726a75a51869c0e3ea3856103dd501b1aa19d14
FuseDaemon: [/storage/emulated] Using cache for /storage/emulated/0/DCIM/open_file_path_write_content_resolver.jpg
MediaProvider: Using FUSE for /storage/emulated/0/DCIM/open_file_path_write_content_resolver.jpg
FuseDaemon: [/storage/emulated] Using cache for /storage/emulated/0/DCIM/open_file_path_write_content_resolver.jpg
MediaProvider: Using lower FS for /storage/emulated/0/DCIM/open_content_resolver_write_content_resolver.jpg
FuseDaemon: [/storage/emulated] Using direct io for /storage/emulated/0/DCIM/open_content_resolver_write_content_resolver.jpg
FuseDaemon: [/storage/emulated] Using cache for /storage/emulated/0/DCIM/open_file_path_write_file_path.jpg
MediaProvider: Using FUSE for /storage/emulated/0/DCIM/open_file_path_write_file_path.jpg
FuseDaemon: [/storage/emulated] Using cache for /storage/emulated/0/DCIM/open_file_path_write_file_path.jpg
MediaProvider: Using lower FS for /storage/emulated/0/DCIM/open_content_resolver_write_file_path.jpg
FuseDaemon: [/storage/emulated] Using direct io for /storage/emulated/0/DCIM/open_content_resolver_write_file_path.jpg
MediaProvider: Using lower FS for /storage/emulated/0/DCIM/open_content_resolver_write_only.jpg
MediaProvider: Using FUSE for /storage/emulated/0/DCIM/open_content_resolver_write_only.jpg
FuseDaemon: [/storage/emulated] Using direct io for /storage/emulated/0/DCIM/open_content_resolver_write_only.jpg
MediaProvider: Using lower FS for /storage/emulated/0/DCIM/open_content_resolver_dup.jpg
FuseDaemon: [/storage/emulated] Using direct io for /storage/emulated/0/DCIM/open_content_resolver_dup.jpg
Bug: 135341433
diff --git a/jni/com_android_providers_media_FuseDaemon.cpp b/jni/com_android_providers_media_FuseDaemon.cpp
index 1633b99..caf00b2 100644
--- a/jni/com_android_providers_media_FuseDaemon.cpp
+++ b/jni/com_android_providers_media_FuseDaemon.cpp
@@ -30,9 +30,10 @@
constexpr const char* CLASS_NAME = "com/android/providers/media/fuse/FuseDaemon";
static jclass gFuseDaemonClass;
-jlong com_android_providers_media_FuseDaemon_new(JNIEnv* env, jobject self, jobject mediaProvider) {
+jlong com_android_providers_media_FuseDaemon_new(JNIEnv* env, jobject self,
+ jobject media_provider) {
LOG(DEBUG) << "Creating the FUSE daemon...";
- return reinterpret_cast<jlong>(new fuse::FuseDaemon(env, mediaProvider));
+ return reinterpret_cast<jlong>(new fuse::FuseDaemon(env, media_provider));
}
void com_android_providers_media_FuseDaemon_start(JNIEnv* env, jobject self, jlong java_daemon,
@@ -44,9 +45,8 @@
if (!utf_chars_path.c_str()) {
return;
}
- const std::string& string_path = std::string(utf_chars_path.c_str());
- daemon->Start(fd, string_path);
+ daemon->Start(fd, utf_chars_path.c_str());
}
void com_android_providers_media_FuseDaemon_delete(JNIEnv* env, jobject self, jlong java_daemon) {
@@ -55,13 +55,34 @@
delete daemon;
}
+jboolean com_android_providers_media_FuseDaemon_should_open_with_fuse(JNIEnv* env, jobject self,
+ jlong java_daemon,
+ jstring java_path,
+ jboolean for_read, jint fd) {
+ fuse::FuseDaemon* const daemon = reinterpret_cast<fuse::FuseDaemon*>(java_daemon);
+ if (daemon) {
+ ScopedUtfChars utf_chars_path(env, java_path);
+ if (!utf_chars_path.c_str()) {
+ // TODO(b/145741852): Throw exception
+ return JNI_FALSE;
+ }
+
+ return daemon->ShouldOpenWithFuse(fd, for_read, utf_chars_path.c_str());
+ }
+ // TODO(b/145741852): Throw exception
+ return JNI_FALSE;
+}
+
const JNINativeMethod methods[] = {
{"native_new", "(Lcom/android/providers/media/MediaProvider;)J",
reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_new)},
{"native_start", "(JILjava/lang/String;)V",
reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_start)},
{"native_delete", "(J)V",
- reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_delete)}};
+ reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_delete)},
+ {"native_should_open_with_fuse", "(JLjava/lang/String;ZI)Z",
+ reinterpret_cast<void*>(com_android_providers_media_FuseDaemon_should_open_with_fuse)}};
+
} // namespace
void register_android_providers_media_FuseDaemon(JNIEnv* env) {