DattoBD 0.11.10 Release (#400)

* Rewrote priorities of blk_alloc_queue variants (#5)

`blk_alloc_queue` had problems with correct priorities of definitions being used, which led to usage of `blk_alloc_queue(NUMA_NO_NODE)` instead of `blk_alloc_queue(GFP_KERNEL)` in some specific cases.

* Kernel 6.X support (#7)

* Implemented struct bdev_handle to replace it on older kernels; Modified fields of snap_device and surrounding functions to use bdev_handle instead of block_device.

* Modified bdev_freeze/thaw references according to Kernel 6.8

* Added emulation of debian/control file for Ubuntu 24.04 LTS

* Discovered that dpkg-gensymbols looks for debian/control only in current directory

* Fixed includes to handle bdev_handle correctly

* Kernel 6.6+ uses super_block as block_device holder

* Tracer destroy now destroys bdev_handle correctly

* Added vm_area_struct_vm_lock feature test

* Made functions inside cow_get_file_extents to return correct error codes, not shadowed ones

* Added test for vma_lock cache area

* Added vm_lock initialization during page stealing at cow_get_file_extents

* Fixed symbol test newline

* Renamed dattobd_blkdev_by_path so we will have correct prefix

dattobd_blkdev_by_path was previously named dattodb_blkdev_by_path, which is incorrect, as our module is called dattobd.

* Fixed symbol-tests again

It used CRLF instead of LF which led to incorrect behavior

* Patch to support Rocky 9.5

* Fix usage of old filp

* Version bump

* Patch to have a workaround with DKMS bug

Dell introduced a logic-breaking change in dell/dkms#461 which led to incorrect DattoBD installation behavior on RHEL systems. This patch has a small workaround to deal with that.

* Improved stability of DKMS workaround

Improved stability of DKMS workaround as it was proposed in dell/dkms#461

dist/dattobd.spec

@@ -117,7 +117,7 @@
 
 
 Name:            dattobd
-Version:         0.11.9
+Version:         0.11.10
 Release:         1%{?dist}
 Summary:         Kernel module and utilities for enabling low-level live backups
 Vendor:          Datto, Inc.
@@ -320,6 +320,13 @@ sed -e "s:@prefix@:%{_prefix}:g" \
 # Generate symbols for library package (Debian/Ubuntu only)
 %if "%{_vendor}" == "debbuild"
 mkdir -p %{buildroot}/%{libname}/DEBIAN
+
+# Ubuntu 24.04 LTS have broken dpkg-gensymbols usage without debian/control file. So, let us emulate it.
+%if 0%{?ubuntu} && 0%{?ubuntu} >= 2404
+mkdir debian
+touch debian/control
+%endif
+
 dpkg-gensymbols -P%{buildroot} -p%{libname} -v%{version}-%{release} -e%{buildroot}%{_libdir}/%{libprefix}.so.%{?!libsover:0}%{?libsover} -e%{buildroot}%{_libdir}/%{libprefix}.so.%{?!libsover:0}%{?libsover}.* -O%{buildroot}/%{libname}/DEBIAN/symbols
 %endif
 
@@ -425,6 +432,10 @@ if [ "$1" -ge "1" ]; then
     if [ -f /usr/lib/dkms/common.postinst ]; then
         /usr/lib/dkms/common.postinst %{name} %{version}
         exit $?
+    else
+        dkms add -m %{name} -v %{version} %{?rpm_dkms_opt:--rpm_safe_upgrade}
+        dkms install -m %{name} -v %{version} --force
+        exit $?
     fi
 fi
 

src/bdev_state_handler.c

@@ -65,7 +65,7 @@ int __handle_bdev_mount_nowrite(const struct vfsmount *mnt,
         {
                 if (!dev || !test_bit(ACTIVE, &dev->sd_state) ||
                     tracer_read_fail_state(dev) ||
-                    dev->sd_base_dev != mnt->mnt_sb->s_bdev)
+                    dev->sd_base_dev->bdev != mnt->mnt_sb->s_bdev)
                         continue;
 
                 if (mnt == dev->sd_cow->dfilp->mnt) {
@@ -105,7 +105,7 @@ int __handle_bdev_mount_writable(const char *dir_name,
         int ret;
         unsigned int i;
         struct snap_device *dev;
-        struct block_device *cur_bdev;
+        struct bdev_wrapper *cur_bdev;
 
         LOG_DEBUG("ENTER %s", __func__);
         tracer_for_each(dev, i)
@@ -121,7 +121,7 @@ int __handle_bdev_mount_writable(const char *dir_name,
                 if (test_bit(UNVERIFIED, &dev->sd_state)) {
                         // get the block device for the unverified tracer we are
                         // looking into
-                        cur_bdev = dattodb_blkdev_by_path(dev->sd_bdev_path,
+                        cur_bdev = dattobd_blkdev_by_path(dev->sd_bdev_path,
                                                       FMODE_READ, NULL);
                         if (IS_ERR(cur_bdev)) {
                                 cur_bdev = NULL;
@@ -130,7 +130,7 @@ int __handle_bdev_mount_writable(const char *dir_name,
 
                         // if the tracer's block device exists and matches the
                         // one being mounted perform transition
-                        if (cur_bdev == bdev) {
+                        if (cur_bdev->bdev == bdev) {
                                 LOG_DEBUG("block device mount detected for "
                                           "unverified device %d",
                                           i);
@@ -144,7 +144,7 @@ int __handle_bdev_mount_writable(const char *dir_name,
                         // put the block device
                         dattobd_blkdev_put(cur_bdev);
 
-                } else if (dev->sd_base_dev == bdev) {
+                } else if (dev->sd_base_dev->bdev == bdev) {
                         LOG_DEBUG(
                                 "block device mount detected for dormant device %d",
                                 i);
@@ -259,15 +259,15 @@ void post_umount_check(int dormant_ret, int umount_ret, unsigned int idx,
         // if we successfully went dormant, but the umount call failed,
         // reactivate
         if (umount_ret) {
-                struct block_device *bdev;
-                bdev = dattodb_blkdev_by_path(dev->sd_bdev_path, FMODE_READ, NULL);
-                if (!bdev || IS_ERR(bdev)) {
+                struct bdev_wrapper *bdev_w;
+                bdev_w = dattobd_blkdev_by_path(dev->sd_bdev_path, FMODE_READ, NULL);
+                if (IS_ERR_OR_NULL(bdev_w)) {
                         LOG_DEBUG("device gone, moving to error state");
                         tracer_set_fail_state(dev, -ENODEV);
                         return;
                 }
 
-                dattobd_blkdev_put(bdev);
+                dattobd_blkdev_put(bdev_w);
 
                 LOG_DEBUG("umount call failed, reactivating tracer %u", idx);
                 auto_transition_active(idx, dir_name);
@@ -279,7 +279,7 @@ void post_umount_check(int dormant_ret, int umount_ret, unsigned int idx,
 
         // if we went dormant, but the block device is still mounted somewhere,
         // goto fail state
-        sb = dattobd_get_super(dev->sd_base_dev);
+        sb = dattobd_get_super(dev->sd_base_dev->bdev);
         if (sb) {
                 if (!(sb->s_flags & MS_RDONLY)) {
                         LOG_ERROR(

src/blkdev.c

@@ -6,8 +6,9 @@
 
 #include "blkdev.h"
 #include "logging.h"
+#include <linux/version.h>
 
-#if !defined HAVE_BLKDEV_GET_BY_PATH && !defined HAVE_BLKDEV_GET_BY_PATH_4
+#if !defined HAVE_BLKDEV_GET_BY_PATH && !defined HAVE_BLKDEV_GET_BY_PATH_4 && !defined HAVE_BDEV_OPEN_BY_PATH && !defined HAVE_BDEV_FILE_OPEN_BY_PATH
 
 /**
  * dattobd_lookup_bdev() - Looks up the inode associated with the path, verifies
@@ -91,30 +92,44 @@ static struct block_device *_blkdev_get_by_path(const char *pathname, fmode_t mo
 #endif
 
 /**
- * dattodb_blkdev_by_path() - Fetches the @block_device struct associated with the
+ * dattobd_blkdev_by_path() - Fetches the @block_device struct associated with the
  * @path. This function uses different methods based on available kernel functions
- * to retrieve the block device.
+ * to retrieve the block device. Returns @bdev_handle struct which contains
+ * information about @block_device and @holder. Made to be in compliance with kernel
+ * version 6.8+ standard.
  *
  * @path: the path name of a block special file.
  * @mode: The mode used to open the block special file, likely just FMODE_READ.
  * @holder: unused.
  *
  * Return:
- * On success the @block_device structure otherwise an error created via
+ * On success the @bdev_handle structure otherwise an error created via
  * ERR_PTR().
  */
-struct block_device *dattodb_blkdev_by_path(const char *path, fmode_t mode,
+struct bdev_wrapper *dattobd_blkdev_by_path(const char *path, fmode_t mode,
                                         void *holder)
 {
-#if defined HAVE_BLKDEV_GET_BY_PATH_4
-        return blkdev_get_by_path(path, mode, holder, NULL);
+        struct bdev_wrapper *bw = kmalloc(sizeof(struct bdev_wrapper), GFP_KERNEL);
 
-#elif defined HAVE_BLKDEV_GET_BY_PATH
-        return blkdev_get_by_path(path, mode, holder);
+        if(IS_ERR_OR_NULL(bw)){
+                return ERR_PTR(-ENOMEM);
+        } 
 
+#if defined HAVE_BDEV_OPEN_BY_PATH
+        bw->_internal.handle = bdev_open_by_path(path, mode, holder, NULL);
+        bw->bdev = bw->_internal.handle->bdev;
+#elif defined HAVE_BLKDEV_GET_BY_PATH_4
+        bw->bdev = blkdev_get_by_path(path, mode, holder, NULL);
+#elif defined HAVE_BLKDEV_GET_BY_PATH
+        bw->bdev = blkdev_get_by_path(path, mode, holder);
+#elif defined HAVE_BDEV_FILE_OPEN_BY_PATH
+        bw->_internal.file = bdev_file_open_by_path(path, mode, holder, NULL);
+        bw->bdev = file_bdev(bw->_internal.file);
 #else
-        return _blkdev_get_by_path(path, mode, holder);
+        bw->bdev = _blkdev_get_by_path(path, mode, holder);
 #endif
+
+        return bw;
 }
 
 /**
@@ -131,13 +146,15 @@ struct super_block *dattobd_get_super(struct block_device * bd)
 {
 #if defined HAVE_BD_SUPER
         return (bd != NULL) ? bd->bd_super : NULL;
-
 #elif defined HAVE_GET_SUPER
         return get_super(bdev);
-
-#else
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6,6,0)
+        return (struct super_block*)(bd -> bd_holder);
+#elif GET_ACTIVE_SUPER_ADDR != 0
         struct super_block* (*get_active_superblock)(struct block_device*)= (GET_ACTIVE_SUPER_ADDR != 0) ? (struct super_block* (*)(struct block_device*))(GET_ACTIVE_SUPER_ADDR +(long long)(((void*)kfree)-(void*)KFREE_ADDR)):NULL;
         return get_active_superblock(bd);
+#else
+        #error "Could not determine super block of block device"
 #endif
 }
 
@@ -155,12 +172,14 @@ void dattobd_drop_super(struct super_block *sb)
 {
 #if defined HAVE_BD_SUPER
         return;
-
 #elif defined HAVE_GET_SUPER
         return drop_super(sb);
-
-#else
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6,6,0)
+        return;
+#elif GET_ACTIVE_SUPER_ADDR != 0
         return;
+#else
+        #error "Could not determine super block of block device"
 #endif
 }
 
@@ -169,22 +188,30 @@ void dattobd_drop_super(struct super_block *sb)
  * This function performs the appropriate action based on the available
  * kernel functions to release block device.
  *
- * @bd: block device structure pointer to be released.
+ * @bh: bdev_handle structure pointer to be released.
  *
  * Return:
  * void.
  */
-void dattobd_blkdev_put(struct block_device *bd) 
+void dattobd_blkdev_put(struct bdev_wrapper *bw) 
 {
-#if defined HAVE_BLKDEV_PUT_1
-        return blkdev_put(bd);
-
+        if(unlikely(IS_ERR_OR_NULL(bw)))
+                return;
+
+#ifdef USE_BDEV_AS_FILE
+        if(bw->_internal.file)
+                bdev_fput(bw->_internal.file);
+#elif defined HAVE_BDEV_RELEASE
+        if(bw->_internal.handle)
+                bdev_release(bw->_internal.handle);
+#elif defined HAVE_BLKDEV_PUT_1
+        blkdev_put(bw->bdev);
 #elif defined HAVE_BLKDEV_PUT_2
-        return blkdev_put(bd,NULL);
-
+        blkdev_put(bw->bdev, NULL);
 #else
-        return blkdev_put(bd, FMODE_READ);
+        blkdev_put(bw->bdev, FMODE_READ);
 #endif
+        kfree(bw);
 }
 
 /**
@@ -219,7 +246,7 @@ int dattobd_get_start_sect_by_gendisk_for_bio(struct gendisk* gd, u8 partno, sec
         LOG_ERROR(-1, "Unreachable code.");
         return -1;
 #else
-        #error Could not determine starting sector of partition by gendisk and partition number
+        #error "Could not determine starting sector of partition by gendisk and partition number"
 #endif
 }
 

src/blkdev.h

@@ -7,6 +7,7 @@
 #ifndef BLKDEV_H_
 #define BLKDEV_H_
 
+#include "config.h"
 #include "includes.h"
 
 struct block_device;
@@ -16,6 +17,21 @@ struct block_device;
 #define bdev_whole(bdev) ((bdev)->bd_contains)
 #endif
 
+struct bdev_wrapper{
+    struct block_device* bdev;
+
+    union {
+#ifdef HAVE_BDEV_HANDLE
+        struct bdev_handle* handle;
+#endif
+// Kernel 6.9+ manages block_device with struct file and file_bdev has to be used to find block_device from file.
+// For us, file_bdev function is marker to check if we have to use 
+#ifdef USE_BDEV_AS_FILE
+        struct file* file;
+#endif
+    } _internal;
+};
+
 #ifndef HAVE_HD_STRUCT
 //#if LINUX_VERSION_CODE < KERNEL_VERSION(5,11,0)
 #define dattobd_bdev_size(bdev) (bdev_nr_sectors(bdev))
@@ -27,14 +43,14 @@ struct block_device;
 #endif
 
 
-struct block_device *dattodb_blkdev_by_path(const char *path, fmode_t mode,
+struct bdev_wrapper *dattobd_blkdev_by_path(const char *path, fmode_t mode,
                                         void *holder);
 
 struct super_block *dattobd_get_super(struct block_device * bd);
 
 void dattobd_drop_super(struct super_block *sb);
 
-void dattobd_blkdev_put(struct block_device *bd);
+void dattobd_blkdev_put(struct bdev_wrapper *bd);
 
 int dattobd_get_start_sect_by_gendisk_for_bio(struct gendisk* gd, u8 partno, sector_t* result);
 

src/config.h

@@ -0,0 +1,5 @@
+#if defined HAVE_BDEV_FILE_OPEN_BY_PATH && defined HAVE_FILE_BDEV
+
+#define USE_BDEV_AS_FILE
+
+#endif

src/configure-tests/feature-tests/bdev_file_open_by_path.c

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (C) 2024 Datto Inc.
+ */
+
+#include "includes.h"
+
+MODULE_LICENSE("GPL");
+
+static inline void dummy(void){
+	struct file *file __attribute__ ((unused)) = NULL;
+    const char *path = "";
+    fmode_t mode = 0;
+    void *holder = NULL;
+    struct blk_holder_ops h;
+
+    file = bdev_file_open_by_path(path, mode, holder, &h);
+}

src/configure-tests/feature-tests/bdev_freeze.c

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (C) 2024 Datto Inc.
+ */
+
+#include "includes.h"
+
+MODULE_LICENSE("GPL");
+
+static inline void dummy(void){
+	struct block_device bh;
+
+    bdev_freeze(&bh);
+}

src/configure-tests/feature-tests/bdev_handle.c

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (C) 2024 Datto Inc.
+ */
+
+#include "includes.h"
+
+MODULE_LICENSE("GPL");
+
+static inline void dummy(void){
+	struct bdev_handle bh;
+
+    struct block_device bd;
+    int holder;
+
+    bh.bdev = &bd;
+    bh.holder = (void*)&holder;
+}

src/configure-tests/feature-tests/bdev_open_by_path.c

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (C) 2024 Datto Inc.
+ */
+
+#include "includes.h"
+
+MODULE_LICENSE("GPL");
+
+static inline void dummy(void){
+	struct bdev_handle* bh;
+
+    const char *path;
+    blk_mode_t mode;
+    int holder;
+    const struct blk_holder_ops bho;
+
+    bh = bdev_open_by_path(path, mode, (void*)&holder, &bho);
+}