fs_mgr: support to reserved some blocks for an ext2/3/4 partition.
These reserved blocks used to root or claim to CAP_SYS_RESOURCES process.
Change-Id: I4893bdb08399bf31a7640d4a63f4952cd636576f
Merged-In: I4893bdb08399bf31a7640d4a63f4952cd636576f
Signed-off-by: liminghao <liminghao@xiaomi.com>
diff --git a/fs_mgr/fs_mgr.c b/fs_mgr/fs_mgr.c
index e0d46d3..f682216 100644
--- a/fs_mgr/fs_mgr.c
+++ b/fs_mgr/fs_mgr.c
@@ -22,6 +22,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/swap.h>
@@ -38,6 +39,7 @@
#include <ext4_utils/ext4_sb.h>
#include <ext4_utils/ext4_utils.h>
#include <ext4_utils/wipe.h>
+#include <linux/fs.h>
#include <linux/loop.h>
#include <logwrap/logwrap.h>
#include <private/android_filesystem_config.h>
@@ -50,8 +52,9 @@
#define KEY_IN_FOOTER "footer"
#define E2FSCK_BIN "/system/bin/e2fsck"
-#define F2FS_FSCK_BIN "/system/bin/fsck.f2fs"
+#define F2FS_FSCK_BIN "/system/bin/fsck.f2fs"
#define MKSWAP_BIN "/system/bin/mkswap"
+#define TUNE2FS_BIN "/system/bin/tune2fs"
#define FSCK_LOG_FILE "/dev/fscklogs/log"
@@ -180,6 +183,99 @@
return;
}
+/* Function to read the primary superblock */
+static int read_super_block(int fd, struct ext4_super_block *sb)
+{
+ off64_t ret;
+
+ ret = lseek64(fd, 1024, SEEK_SET);
+ if (ret < 0)
+ return ret;
+
+ ret = read(fd, sb, sizeof(*sb));
+ if (ret < 0)
+ return ret;
+ if (ret != sizeof(*sb))
+ return ret;
+
+ return 0;
+}
+
+static ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
+{
+ return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
+ le32_to_cpu(es->s_blocks_count_lo);
+}
+
+static ext4_fsblk_t ext4_r_blocks_count(struct ext4_super_block *es)
+{
+ return ((ext4_fsblk_t)le32_to_cpu(es->s_r_blocks_count_hi) << 32) |
+ le32_to_cpu(es->s_r_blocks_count_lo);
+}
+
+static void do_reserved_size(char *blk_device, char *fs_type, struct fstab_rec *rec)
+{
+ /* Check for the types of filesystems we know how to check */
+ if (!strcmp(fs_type, "ext2") || !strcmp(fs_type, "ext3") || !strcmp(fs_type, "ext4")) {
+ /*
+ * Some system images do not have tune2fs for licensing reasons
+ * Detect these and skip reserve blocks.
+ */
+ if (access(TUNE2FS_BIN, X_OK)) {
+ ERROR("Not running %s on %s (executable not in system image)\n",
+ TUNE2FS_BIN, blk_device);
+ } else {
+ INFO("Running %s on %s\n", TUNE2FS_BIN, blk_device);
+
+ int status = 0;
+ int ret = 0;
+ unsigned long reserved_blocks = 0;
+ int fd = TEMP_FAILURE_RETRY(open(blk_device, O_RDONLY | O_CLOEXEC));
+ if (fd >= 0) {
+ struct ext4_super_block sb;
+ ret = read_super_block(fd, &sb);
+ if (ret < 0) {
+ ERROR("Can't read '%s' super block: %s\n", blk_device, strerror(errno));
+ goto out;
+ }
+ reserved_blocks = rec->reserved_size / EXT4_BLOCK_SIZE(&sb);
+ unsigned long reserved_threshold = ext4_blocks_count(&sb) * 0.02;
+ if (reserved_threshold < reserved_blocks) {
+ WARNING("Reserved blocks %lu is too large\n", reserved_blocks);
+ reserved_blocks = reserved_threshold;
+ }
+
+ if (ext4_r_blocks_count(&sb) == reserved_blocks) {
+ INFO("Have reserved same blocks\n");
+ goto out;
+ }
+ } else {
+ ERROR("Failed to open '%s': %s\n", blk_device, strerror(errno));
+ return;
+ }
+
+ char buf[16] = {0};
+ snprintf(buf, sizeof (buf), "-r %lu", reserved_blocks);
+ char *tune2fs_argv[] = {
+ TUNE2FS_BIN,
+ buf,
+ blk_device,
+ };
+
+ ret = android_fork_execvp_ext(ARRAY_SIZE(tune2fs_argv), tune2fs_argv,
+ &status, true, LOG_KLOG | LOG_FILE,
+ true, NULL, NULL, 0);
+
+ if (ret < 0) {
+ /* No need to check for error in fork, we can't really handle it now */
+ ERROR("Failed trying to run %s\n", TUNE2FS_BIN);
+ }
+ out:
+ close(fd);
+ }
+ }
+}
+
static void remove_trailing_slashes(char *n)
{
int len;
@@ -325,6 +421,12 @@
check_fs(fstab->recs[i].blk_device, fstab->recs[i].fs_type,
fstab->recs[i].mount_point);
}
+
+ if (fstab->recs[i].fs_mgr_flags & MF_RESERVEDSIZE) {
+ do_reserved_size(fstab->recs[i].blk_device, fstab->recs[i].fs_type,
+ &fstab->recs[i]);
+ }
+
if (!__mount(fstab->recs[i].blk_device, fstab->recs[i].mount_point, &fstab->recs[i])) {
*attempted_idx = i;
mounted = 1;
@@ -690,6 +792,10 @@
fstab->recs[i].mount_point);
}
+ if (fstab->recs[i].fs_mgr_flags & MF_RESERVEDSIZE) {
+ do_reserved_size(n_blk_device, fstab->recs[i].fs_type, &fstab->recs[i]);
+ }
+
if ((fstab->recs[i].fs_mgr_flags & MF_VERIFY) && device_is_secure()) {
int rc = fs_mgr_setup_verity(&fstab->recs[i]);
if (__android_log_is_debuggable() && rc == FS_MGR_SETUP_VERITY_DISABLED) {
diff --git a/fs_mgr/fs_mgr_fstab.c b/fs_mgr/fs_mgr_fstab.c
index b219b38..472b421 100644
--- a/fs_mgr/fs_mgr_fstab.c
+++ b/fs_mgr/fs_mgr_fstab.c
@@ -33,6 +33,7 @@
int swap_prio;
int max_comp_streams;
unsigned int zram_size;
+ uint64_t reserved_size;
};
struct flag_list {
@@ -80,6 +81,7 @@
{ "slotselect", MF_SLOTSELECT },
{ "nofail", MF_NOFAIL },
{ "latemount", MF_LATEMOUNT },
+ { "reservedsize=", MF_RESERVEDSIZE },
{ "defaults", 0 },
{ 0, 0 },
};
@@ -97,6 +99,20 @@
return total;
}
+static uint64_t parse_size(const char *arg)
+{
+ char *endptr;
+ uint64_t size = strtoull(arg, &endptr, 10);
+ if (*endptr == 'k' || *endptr == 'K')
+ size *= 1024LL;
+ else if (*endptr == 'm' || *endptr == 'M')
+ size *= 1024LL * 1024LL;
+ else if (*endptr == 'g' || *endptr == 'G')
+ size *= 1024LL * 1024LL * 1024LL;
+
+ return size;
+}
+
static int parse_flags(char *flags, struct flag_list *fl,
struct fs_mgr_flag_values *flag_vals,
char *fs_options, int fs_options_len)
@@ -191,6 +207,11 @@
flag_vals->zram_size = calculate_zram_size(val);
else
flag_vals->zram_size = val;
+ } else if ((fl[i].flag == MF_RESERVEDSIZE) && flag_vals) {
+ /* The reserved flag is followed by an = and the
+ * reserved size of the partition. Get it and return it.
+ */
+ flag_vals->reserved_size = parse_size(strchr(p, '=') + 1);
}
break;
}
@@ -335,6 +356,7 @@
fstab->recs[cnt].swap_prio = flag_vals.swap_prio;
fstab->recs[cnt].max_comp_streams = flag_vals.max_comp_streams;
fstab->recs[cnt].zram_size = flag_vals.zram_size;
+ fstab->recs[cnt].reserved_size = flag_vals.reserved_size;
cnt++;
}
/* If an A/B partition, modify block device to be the real block device */
diff --git a/fs_mgr/fs_mgr_priv.h b/fs_mgr/fs_mgr_priv.h
index 741f5e9..23c97e4 100644
--- a/fs_mgr/fs_mgr_priv.h
+++ b/fs_mgr/fs_mgr_priv.h
@@ -86,6 +86,7 @@
#define MF_LATEMOUNT 0x20000
#define MF_NOFAIL 0x40000
#define MF_MAX_COMP_STREAMS 0x100000
+#define MF_RESERVEDSIZE 0x200000
#define DM_BUF_SIZE 4096
diff --git a/fs_mgr/include/fs_mgr.h b/fs_mgr/include/fs_mgr.h
index 37df8f8..43aef20 100644
--- a/fs_mgr/include/fs_mgr.h
+++ b/fs_mgr/include/fs_mgr.h
@@ -75,6 +75,7 @@
int swap_prio;
int max_comp_streams;
unsigned int zram_size;
+ uint64_t reserved_size;
};
// Callback function for verity status