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Commit 4c80edf9 authored by Bowgo Tsai's avatar Bowgo Tsai
Browse files

fstab: allow mounting other slot 

Adding a new fs_mgr flag 'slotselect_other' to mount _b when _a is
active, or vice versa.

Bug: 113182233
Bug: 112103720
Test: `mount_all fstab.test` with one line using `slotselect_other`.

Change-Id: I96c63141df7722dc30ca9817b0b154e493b9eef9
parent 42c9e7e3

fs_mgr/fs_mgr_fstab.cpp

+5 −6
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ struct fs_mgr_flag_values { 


struct flag_list {

    const char *name;

    unsigned int flag;

    uint64_t flag;

};



static struct flag_list mount_flags[] = {
@@ -116,6 +116,7 @@ static struct flag_list fs_mgr_flags[] = { 
        {"logical", MF_LOGICAL},

        {"checkpoint=block", MF_CHECKPOINT_BLK},

        {"checkpoint=fs", MF_CHECKPOINT_FS},

        {"slotselect_other", MF_SLOTSELECT_OTHER},

        {0, 0},

};
@@ -207,11 +208,9 @@ static bool read_dt_file(const std::string& file_name, std::string* dt_value) 
    return false;

}



static int parse_flags(char *flags, struct flag_list *fl,

                       struct fs_mgr_flag_values *flag_vals,

                       char *fs_options, int fs_options_len)

{

    int f = 0;

static uint64_t parse_flags(char* flags, struct flag_list* fl, struct fs_mgr_flag_values* flag_vals,

                            char* fs_options, int fs_options_len) {

    uint64_t f = 0;

    int i;

    char *p;

    char *savep;

fs_mgr/fs_mgr_priv.h

+2 −0
Original line number Diff line number Diff line
@@ -120,6 +120,8 @@ 
#define MF_CHECKPOINT_FS  0x40000000

#define MF_FIRST_STAGE_MOUNT \

                          0x80000000

#define MF_SLOTSELECT_OTHER  \

                         0x100000000

// clang-format on



#define DM_BUF_SIZE 4096

fs_mgr/fs_mgr_slotselect.cpp

+18 −3
Original line number Diff line number Diff line
@@ -21,6 +21,19 @@ 
#include "fs_mgr.h"

#include "fs_mgr_priv.h"



// https://source.android.com/devices/tech/ota/ab/ab_implement#partitions

// All partitions that are A/B-ed should be named as follows (slots are always

// named a, b, etc.): boot_a, boot_b, system_a, system_b, vendor_a, vendor_b.

static std::string other_suffix(const std::string& slot_suffix) {

    if (slot_suffix == "_a") {

        return "_b";

    }

    if (slot_suffix == "_b") {

        return "_a";

    }

    return "";

}



// Returns "_a" or "_b" based on androidboot.slot_suffix in kernel cmdline, or an empty string

// if that parameter does not exist.

std::string fs_mgr_get_slot_suffix() {
@@ -35,7 +48,7 @@ bool fs_mgr_update_for_slotselect(Fstab* fstab) { 
    std::string ab_suffix;



    for (auto& entry : *fstab) {

        if (!entry.fs_mgr_flags.slot_select) {

        if (!entry.fs_mgr_flags.slot_select && !entry.fs_mgr_flags.slot_select_other) {

            continue;

        }
@@ -45,8 +58,10 @@ bool fs_mgr_update_for_slotselect(Fstab* fstab) { 
            if (ab_suffix.empty()) return false;

        }



        entry.blk_device = entry.blk_device + ab_suffix;

        entry.logical_partition_name = entry.logical_partition_name + ab_suffix;

        const auto& update_suffix =

                entry.fs_mgr_flags.slot_select ? ab_suffix : other_suffix(ab_suffix);

        entry.blk_device = entry.blk_device + update_suffix;

        entry.logical_partition_name = entry.logical_partition_name + update_suffix;

    }

    return true;

}

fs_mgr/include_fstab/fstab/fstab.h

+12 −2
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ struct fstab_rec { 
    char* fs_type;

    unsigned long flags;

    char* fs_options;

    int fs_mgr_flags;

    uint64_t fs_mgr_flags;

    char* key_loc;

    char* key_dir;

    char* verity_loc;
@@ -123,8 +123,9 @@ struct FstabEntry { 
    // TODO: Remove this union once fstab_rec is deprecated. It only serves as a

    // convenient way to convert between fstab_rec::fs_mgr_flags and these bools.

    union {

        int val;

        uint64_t val;

        struct {

            // bit 0

            bool wait : 1;

            bool check : 1;

            bool crypt : 1;
@@ -133,6 +134,8 @@ struct FstabEntry { 
            bool length : 1;

            bool recovery_only : 1;

            bool swap_prio : 1;



            // bit 8

            bool zram_size : 1;

            bool verify : 1;

            bool force_crypt : 1;
@@ -142,6 +145,8 @@ struct FstabEntry { 
            bool file_encryption : 1;

            bool formattable : 1;

            bool slot_select : 1;



            // bit 16

            bool force_fde_or_fbe : 1;

            bool late_mount : 1;

            bool no_fail : 1;
@@ -150,6 +155,8 @@ struct FstabEntry { 
            bool reserved_size : 1;

            bool quota : 1;

            bool erase_blk_size : 1;



            // bit 24

            bool logical_blk_size : 1;

            bool avb : 1;

            bool key_directory : 1;
@@ -158,6 +165,9 @@ struct FstabEntry { 
            bool checkpoint_blk : 1;

            bool checkpoint_fs : 1;

            bool first_stage_mount : 1;



            // bit 32

            bool slot_select_other : 1;

        };

    } fs_mgr_flags;