From b6e6ee758704a7044bb6cdf7a17f9e1d1f7ac195 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@google.com>
Date: Fri, 8 Dec 2017 13:19:23 -0800
Subject: f2fs: support f2fs by setting unmovable bit for package file

This enables to use uncrypt for f2fs update-on-reboot.
It requires kernel patch named:
    "f2fs: add an ioctl to disable GC for specific file"

If any operation fails during uncrypt, please delete package file as soon as
possible, and create the file again to move forward. IOWs, don't leave the
package file for a long time.

Bug: 70309376
Bug: 30170612
Change-Id: I3b4233e7da756f107be35364521699deaf2e7139
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
---
 uncrypt/uncrypt.cpp | 42 ++++++++++++++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/uncrypt/uncrypt.cpp b/uncrypt/uncrypt.cpp
index 645faadbf..16036f9ce 100644
--- a/uncrypt/uncrypt.cpp
+++ b/uncrypt/uncrypt.cpp
@@ -172,10 +172,15 @@ static struct fstab* read_fstab() {
     return fstab;
 }
 
-static const char* find_block_device(const char* path, bool* encryptable, bool* encrypted) {
+static const char* find_block_device(const char* path, bool* encryptable,
+                                     bool* encrypted, bool* f2fs_fs) {
     // Look for a volume whose mount point is the prefix of path and
     // return its block device.  Set encrypted if it's currently
     // encrypted.
+
+    // ensure f2fs_fs is set to false first.
+    *f2fs_fs = false;
+
     for (int i = 0; i < fstab->num_entries; ++i) {
         struct fstab_rec* v = &fstab->recs[i];
         if (!v->mount_point) {
@@ -192,6 +197,9 @@ static const char* find_block_device(const char* path, bool* encryptable, bool*
                     *encrypted = true;
                 }
             }
+            if (strcmp(v->fs_type, "f2fs") == 0) {
+                *f2fs_fs = true;
+            }
             return v->blk_device;
         }
     }
@@ -244,7 +252,7 @@ static int retry_fibmap(const int fd, const char* name, int* block, const int he
 }
 
 static int produce_block_map(const char* path, const char* map_file, const char* blk_dev,
-                             bool encrypted, int socket) {
+                             bool encrypted, bool f2fs_fs, int socket) {
     std::string err;
     if (!android::base::RemoveFileIfExists(map_file, &err)) {
         LOG(ERROR) << "failed to remove the existing map file " << map_file << ": " << err;
@@ -307,6 +315,31 @@ static int produce_block_map(const char* path, const char* map_file, const char*
         }
     }
 
+// F2FS-specific ioctl
+// It requires the below kernel commit merged in v4.16-rc1.
+//   1ad71a27124c ("f2fs: add an ioctl to disable GC for specific file")
+// In android-4.4,
+//   56ee1e817908 ("f2fs: updates on v4.16-rc1")
+// In android-4.9,
+//   2f17e34672a8 ("f2fs: updates on v4.16-rc1")
+// In android-4.14,
+//   ce767d9a55bc ("f2fs: updates on v4.16-rc1")
+#ifndef F2FS_IOC_SET_PIN_FILE
+#ifndef F2FS_IOCTL_MAGIC
+#define F2FS_IOCTL_MAGIC		0xf5
+#endif
+#define F2FS_IOC_SET_PIN_FILE	_IOW(F2FS_IOCTL_MAGIC, 13, __u32)
+#define F2FS_IOC_GET_PIN_FILE	_IOW(F2FS_IOCTL_MAGIC, 14, __u32)
+#endif
+    if (f2fs_fs) {
+        int error = ioctl(fd, F2FS_IOC_SET_PIN_FILE);
+        // Don't break the old kernels which don't support it.
+        if (error && errno != ENOTTY && errno != ENOTSUP) {
+            PLOG(ERROR) << "Failed to set pin_file for f2fs: " << path << " on " << blk_dev;
+            return kUncryptIoctlError;
+        }
+    }
+
     off64_t pos = 0;
     int last_progress = 0;
     while (pos < sb.st_size) {
@@ -458,7 +491,8 @@ static int uncrypt(const char* input_path, const char* map_file, const int socke
 
     bool encryptable;
     bool encrypted;
-    const char* blk_dev = find_block_device(path, &encryptable, &encrypted);
+    bool f2fs_fs;
+    const char* blk_dev = find_block_device(path, &encryptable, &encrypted, &f2fs_fs);
     if (blk_dev == nullptr) {
         LOG(ERROR) << "failed to find block device for " << path;
         return kUncryptBlockDeviceFindError;
@@ -479,7 +513,7 @@ static int uncrypt(const char* input_path, const char* map_file, const int socke
     // and /sdcard we leave the file alone.
     if (strncmp(path, "/data/", 6) == 0) {
         LOG(INFO) << "writing block map " << map_file;
-        return produce_block_map(path, map_file, blk_dev, encrypted, socket);
+        return produce_block_map(path, map_file, blk_dev, encrypted, f2fs_fs, socket);
     }
 
     return 0;
-- 
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