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loop-util: always tell kernel explicitly about loopback sector size

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Let's not leave the sector size unspecified: either set a user supplied
value, or auto-detect the right size by probing the disk image
accordingly.
This commit is contained in:
Lennart Poettering
2023-01-18 10:47:17 +01:00
parent 05c4c59ff1
commit 22ee78a898
11 changed files with 102 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/namespace.c
+1
View File
@@ -2093,6 +2093,7 @@ int setup_namespace(
r = loop_device_make_by_path(
root_image,
FLAGS_SET(dissect_image_flags, DISSECT_IMAGE_DEVICE_READ_ONLY) ? O_RDONLY : -1 /* < 0 means writable if possible, read-only as fallback */,
/* sector_size= */ UINT32_MAX,
FLAGS_SET(dissect_image_flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&loop_device);
src/dissect/dissect.c
+2 -2
View File
@@ -1437,9 +1437,9 @@ static int run(int argc, char *argv[]) {
loop_flags = FLAGS_SET(arg_flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN;
if (arg_in_memory)
r = loop_device_make_by_path_memory(arg_image, open_flags, loop_flags, LOCK_SH, &d);
r = loop_device_make_by_path_memory(arg_image, open_flags, /* sector_size= */ UINT32_MAX, loop_flags, LOCK_SH, &d);
else
r = loop_device_make_by_path(arg_image, open_flags, loop_flags, LOCK_SH, &d);
r = loop_device_make_by_path(arg_image, open_flags, /* sector_size= */ UINT32_MAX, loop_flags, LOCK_SH, &d);
if (r < 0)
return log_error_errno(r, "Failed to set up loopback device for %s: %m", arg_image);
src/home/homework-luks.c
+18 -2
View File
@@ -1378,7 +1378,15 @@ int home_setup_luks(
return r;
}
r = loop_device_make(setup->image_fd, O_RDWR, offset, size, user_record_luks_sector_size(h), 0, LOCK_UN, &setup->loop);
r = loop_device_make(
setup->image_fd,
O_RDWR,
offset,
size,
h->luks_sector_size == UINT64_MAX ? UINT32_MAX : user_record_luks_sector_size(h), /* if sector size is not specified, select UINT32_MAX, i.e. auto-probe */
/* loop_flags= */ 0,
LOCK_UN,
&setup->loop);
if (r == -ENOENT) {
log_error_errno(r, "Loopback block device support is not available on this system.");
return -ENOLINK; /* make recognizable */
@@ -2319,7 +2327,15 @@ int home_create_luks(
log_info("Writing of partition table completed.");
r = loop_device_make(setup->image_fd, O_RDWR, partition_offset, partition_size, user_record_luks_sector_size(h), 0, LOCK_EX, &setup->loop);
r = loop_device_make(
setup->image_fd,
O_RDWR,
partition_offset,
partition_size,
user_record_luks_sector_size(h),
0,
LOCK_EX,
&setup->loop);
if (r < 0) {
if (r == -ENOENT) { /* this means /dev/loop-control doesn't exist, i.e. we are in a container
* or similar and loopback bock devices are not available, return a
src/nspawn/nspawn.c
+1
View File
@@ -5726,6 +5726,7 @@ static int run(int argc, char *argv[]) {
r = loop_device_make_by_path(
arg_image,
arg_read_only ? O_RDONLY : O_RDWR,
/* sector_size= */ UINT32_MAX,
FLAGS_SET(dissect_image_flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&loop);
src/portable/portable.c
+1 -1
View File
@@ -335,7 +335,7 @@ static int portable_extract_by_path(
assert(path);
r = loop_device_make_by_path(path, O_RDONLY, LO_FLAGS_PARTSCAN, LOCK_SH, &d);
r = loop_device_make_by_path(path, O_RDONLY, /* sector_size= */ UINT32_MAX, LO_FLAGS_PARTSCAN, LOCK_SH, &d);
if (r == -EISDIR) {
_cleanup_free_ char *image_name = NULL;
src/shared/discover-image.c
+1 -1
View File
@@ -1197,7 +1197,7 @@ int image_read_metadata(Image *i) {
_cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
r = loop_device_make_by_path(i->path, O_RDONLY, LO_FLAGS_PARTSCAN, LOCK_SH, &d);
r = loop_device_make_by_path(i->path, O_RDONLY, /* sector_size= */ UINT32_MAX, LO_FLAGS_PARTSCAN, LOCK_SH, &d);
if (r < 0)
return r;
src/shared/dissect-image.c
+14 -1
View File
@@ -546,6 +546,7 @@ static int dissect_image(
assert(!verity || verity->root_hash_sig || verity->root_hash_sig_size == 0);
assert(!verity || (verity->root_hash || !verity->root_hash_sig));
assert(!((flags & DISSECT_IMAGE_GPT_ONLY) && (flags & DISSECT_IMAGE_NO_PARTITION_TABLE)));
assert(m->sector_size > 0);
/* Probes a disk image, and returns information about what it found in *ret.
*
@@ -594,6 +595,11 @@ static int dissect_image(
if (r != 0)
return errno_or_else(ENOMEM);
errno = 0;
r = blkid_probe_set_sectorsize(b, m->sector_size);
if (r != 0)
return errno_or_else(EIO);
if ((flags & DISSECT_IMAGE_GPT_ONLY) == 0) {
/* Look for file system superblocks, unless we only shall look for GPT partition tables */
blkid_probe_enable_superblocks(b, 1);
@@ -1326,6 +1332,10 @@ int dissect_image_file(
if (r < 0)
return r;
r = probe_sector_size(fd, &m->sector_size);
if (r < 0)
return r;
r = dissect_image(m, fd, path, verity, mount_options, flags);
if (r < 0)
return r;
@@ -3143,6 +3153,7 @@ int dissect_loop_device(
return r;
m->loop = loop_device_ref(loop);
m->sector_size = m->loop->sector_size;
r = dissect_image(m, loop->fd, loop->node, verity, mount_options, flags);
if (r < 0)
@@ -3318,6 +3329,7 @@ int mount_image_privately_interactively(
r = loop_device_make_by_path(
image,
FLAGS_SET(flags, DISSECT_IMAGE_DEVICE_READ_ONLY) ? O_RDONLY : O_RDWR,
/* sector_size= */ UINT32_MAX,
FLAGS_SET(flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&d);
@@ -3409,7 +3421,8 @@ int verity_dissect_and_mount(
* accepted by LOOP_CONFIGURE, so just let loop_device_make_by_path reopen it as a regular FD. */
r = loop_device_make_by_path(
src_fd >= 0 ? FORMAT_PROC_FD_PATH(src_fd) : src,
-1,
/* open_flags= */ -1,
/* sector_size= */ UINT32_MAX,
verity.data_path ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&loop_device);
src/shared/dissect-image.h
+2
View File
@@ -93,6 +93,8 @@ struct DissectedImage {
DissectedPartition partitions[_PARTITION_DESIGNATOR_MAX];
DecryptedImage *decrypted_image;
uint32_t sector_size;
/* Meta information extracted from /etc/os-release and similar */
char *image_name;
sd_id128_t image_uuid;
src/shared/loop-util.c
+57 -6
View File
@@ -20,6 +20,7 @@
#include "data-fd-util.h"
#include "device-util.h"
#include "devnum-util.h"
#include "dissect-image.h"
#include "env-util.h"
#include "errno-util.h"
#include "fd-util.h"
@@ -409,6 +410,7 @@ static int loop_configure(
.diskseq = diskseq,
.uevent_seqnum_not_before = seqnum,
.timestamp_not_before = timestamp,
.sector_size = c->block_size,
};
*ret = TAKE_PTR(d);
@@ -421,7 +423,7 @@ static int loop_device_make_internal(
int open_flags,
uint64_t offset,
uint64_t size,
uint32_t block_size,
uint32_t sector_size,
uint32_t loop_flags,
int lock_op,
LoopDevice **ret) {
@@ -492,9 +494,50 @@ static int loop_device_make_internal(
if (control < 0)
return -errno;
if (sector_size == 0)
/* If no sector size is specified, default to the classic default */
sector_size = 512;
else if (sector_size == UINT32_MAX) {
if (S_ISBLK(st.st_mode))
/* If the sector size is specified as UINT32_MAX we'll propagate the sector size of
* the underlying block device. */
r = blockdev_get_sector_size(fd, &sector_size);
else {
_cleanup_close_ int non_direct_io_fd = -1;
int probe_fd;
assert(S_ISREG(st.st_mode));
/* If sector size is specified as UINT32_MAX, we'll try to probe the right sector
* size of the image in question by looking for the GPT partition header at various
* offsets. This of course only works if the image already has a disk label.
*
* So here we actually want to read the file contents ourselves. This is quite likely
* not going to work if we managed to enable O_DIRECT, because in such a case there
* are some pretty strict alignment requirements to offset, size and target, but
* there's no way to query what alignment specifically is actually required. Hence,
* let's avoid the mess, and temporarily open an fd without O_DIRECT for the probing
* logic. */
if (FLAGS_SET(loop_flags, LO_FLAGS_DIRECT_IO)) {
non_direct_io_fd = fd_reopen(fd, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
if (non_direct_io_fd < 0)
return non_direct_io_fd;
probe_fd = non_direct_io_fd;
} else
probe_fd = fd;
r = probe_sector_size(probe_fd, &sector_size);
}
if (r < 0)
return r;
}
config = (struct loop_config) {
.fd = fd,
.block_size = block_size,
.block_size = sector_size,
.info = {
/* Use the specified flags, but configure the read-only flag from the open flags, and force autoclear */
.lo_flags = (loop_flags & ~LO_FLAGS_READ_ONLY) | ((open_flags & O_ACCMODE) == O_RDONLY ? LO_FLAGS_READ_ONLY : 0) | LO_FLAGS_AUTOCLEAR,
@@ -578,7 +621,7 @@ int loop_device_make(
int open_flags,
uint64_t offset,
uint64_t size,
uint32_t block_size,
uint32_t sector_size,
uint32_t loop_flags,
int lock_op,
LoopDevice **ret) {
@@ -592,7 +635,7 @@ int loop_device_make(
open_flags,
offset,
size,
block_size,
sector_size,
loop_flags_mangle(loop_flags),
lock_op,
ret);
@@ -601,6 +644,7 @@ int loop_device_make(
int loop_device_make_by_path(
const char *path,
int open_flags,
uint32_t sector_size,
uint32_t loop_flags,
int lock_op,
LoopDevice **ret) {
@@ -656,12 +700,13 @@ int loop_device_make_by_path(
direct ? "enabled" : "disabled",
direct != (direct_flags != 0) ? " (O_DIRECT was requested but not supported)" : "");
return loop_device_make_internal(path, fd, open_flags, 0, 0, 0, loop_flags, lock_op, ret);
return loop_device_make_internal(path, fd, open_flags, 0, 0, sector_size, loop_flags, lock_op, ret);
}
int loop_device_make_by_path_memory(
const char *path,
int open_flags,
uint32_t sector_size,
uint32_t loop_flags,
int lock_op,
LoopDevice **ret) {
@@ -697,7 +742,7 @@ int loop_device_make_by_path_memory(
fd = safe_close(fd); /* Let's close the original early */
return loop_device_make_internal(NULL, mfd, open_flags, 0, 0, 0, loop_flags, lock_op, ret);
return loop_device_make_internal(NULL, mfd, open_flags, 0, 0, sector_size, loop_flags, lock_op, ret);
}
static LoopDevice* loop_device_free(LoopDevice *d) {
@@ -839,6 +884,11 @@ int loop_device_open(
if (r < 0 && r != -EOPNOTSUPP)
return r;
uint32_t sector_size;
r = blockdev_get_sector_size(fd, &sector_size);
if (r < 0)
return r;
r = sd_device_get_devnum(dev, &devnum);
if (r < 0)
return r;
@@ -868,6 +918,7 @@ int loop_device_open(
.diskseq = diskseq,
.uevent_seqnum_not_before = UINT64_MAX,
.timestamp_not_before = USEC_INFINITY,
.sector_size = sector_size,
};
*ret = d;
src/shared/loop-util.h
+4 -3
View File
@@ -23,14 +23,15 @@ struct LoopDevice {
uint64_t diskseq; /* Block device sequence number, monothonically incremented by the kernel on create/attach, or 0 if we don't know */
uint64_t uevent_seqnum_not_before; /* uevent sequm right before we attached the loopback device, or UINT64_MAX if we don't know */
usec_t timestamp_not_before; /* CLOCK_MONOTONIC timestamp taken immediately before attaching the loopback device, or USEC_INFINITY if we don't know */
uint32_t sector_size;
};
/* Returns true if LoopDevice object is not actually a loopback device but some other block device we just wrap */
#define LOOP_DEVICE_IS_FOREIGN(d) ((d)->nr < 0)
int loop_device_make(int fd, int open_flags, uint64_t offset, uint64_t size, uint32_t block_size, uint32_t loop_flags, int lock_op, LoopDevice **ret);
int loop_device_make_by_path(const char *path, int open_flags, uint32_t loop_flags, int lock_op, LoopDevice **ret);
int loop_device_make_by_path_memory(const char *path, int open_flags, uint32_t loop_flags, int lock_op, LoopDevice **ret);
int loop_device_make(int fd, int open_flags, uint64_t offset, uint64_t size, uint32_t sector_size, uint32_t loop_flags, int lock_op, LoopDevice **ret);
int loop_device_make_by_path(const char *path, int open_flags, uint32_t sector_size, uint32_t loop_flags, int lock_op, LoopDevice **ret);
int loop_device_make_by_path_memory(const char *path, int open_flags, uint32_t sector_size, uint32_t loop_flags, int lock_op, LoopDevice **ret);
int loop_device_open(sd_device *dev, int open_flags, int lock_op, LoopDevice **ret);
int loop_device_open_from_fd(int fd, int open_flags, int lock_op, LoopDevice **ret);
int loop_device_open_from_path(const char *path, int open_flags, int lock_op, LoopDevice **ret);
src/sysext/sysext.c
+1
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@@ -540,6 +540,7 @@ static int merge_subprocess(Hashmap *images, const char *workspace) {
r = loop_device_make_by_path(
img->path,
O_RDONLY,
/* sector_size= */ UINT32_MAX,
FLAGS_SET(flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&d);