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blockdev-util: Introduce fd_get_whole_disk()

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Extracted from find_devno() in udevadm-lock.c.
This commit is contained in:
Daan De Meyer
2022-07-27 23:11:37 +02:00
parent 2d2efed2ee
commit 26aa4800f8
3 changed files with 56 additions and 39 deletions
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48
src/shared/blockdev-util.c
View File

@@ -377,3 +377,51 @@ int path_is_encrypted(const char *path) {
return blockdev_is_encrypted(p, 10 /* safety net: maximum recursion depth */);
}
int fd_get_whole_disk(int fd, bool backing, dev_t *ret) {
dev_t devt;
struct stat st;
int r;
assert(ret);
if (fstat(fd, &st) < 0)
return -errno;
if (S_ISBLK(st.st_mode))
devt = st.st_rdev;
else if (!backing)
return -ENOTBLK;
else if (!S_ISREG(st.st_mode) && !S_ISDIR(st.st_mode))
return -ENOTBLK;
else if (major(st.st_dev) != 0)
devt = st.st_dev;
else {
_cleanup_close_ int regfd = -1;
/* If major(st.st_dev) is zero, this might mean we are backed by btrfs, which needs special
* handing, to get the backing device node. */
regfd = fd_reopen(fd, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
if (regfd < 0)
return regfd;
r = btrfs_get_block_device_fd(regfd, &devt);
if (r == -ENOTTY)
return -ENOTBLK;
if (r < 0)
return r;
}
return block_get_whole_disk(devt, ret);
}
int path_get_whole_disk(const char *path, bool backing, dev_t *ret) {
_cleanup_close_ int fd = -1;
fd = open(path, O_CLOEXEC|O_PATH);
if (fd < 0)
return -errno;
return fd_get_whole_disk(fd, backing, ret);
}

3
src/shared/blockdev-util.h
View File

@@ -27,3 +27,6 @@ int blockdev_partscan_enabled(int fd);
int fd_is_encrypted(int fd);
int path_is_encrypted(const char *path);
int fd_get_whole_disk(int fd, bool backing, dev_t *ret);
int path_get_whole_disk(const char *path, bool backing, dev_t *ret);

44
src/udev/udevadm-lock.c
View File

@@ -144,9 +144,7 @@ static int find_devno(
const char *device,
bool backing) {
_cleanup_close_ int fd = -1;
dev_t devt, whole_devt;
struct stat st;
dev_t devt;
int r;
assert(devnos);
@@ -154,51 +152,19 @@ static int find_devno(
assert(*devnos || *n_devnos == 0);
assert(device);
fd = open(device, O_CLOEXEC|O_PATH);
if (fd < 0)
return log_error_errno(errno, "Failed to open '%s': %m", device);
if (fstat(fd, &st) < 0)
return log_error_errno(errno, "Failed to stat '%s': %m", device);
if (S_ISBLK(st.st_mode))
devt = st.st_rdev;
else if (!backing)
return log_error_errno(SYNTHETIC_ERRNO(ENOTBLK), "Not a block device: %s", device);
else if (!S_ISREG(st.st_mode) && !S_ISDIR(st.st_mode))
return log_error_errno(SYNTHETIC_ERRNO(ENOTBLK), "Not a block device, regular file or directory: %s", device);
else if (major(st.st_dev) != 0)
devt = st.st_dev;
else {
_cleanup_close_ int regfd = -1;
/* If major(st.st_dev) is zero, this might mean we are backed by btrfs, which needs special
* handing, to get the backing device node. */
regfd = fd_reopen(fd, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
if (regfd < 0)
return log_error_errno(regfd, "Failed to open '%s': %m", device);
r = btrfs_get_block_device_fd(regfd, &devt);
if (r == -ENOTTY)
return log_error_errno(SYNTHETIC_ERRNO(ENOTBLK), "Path '%s' not backed by block device.", device);
if (r < 0)
return log_error_errno(r, "Failed to acquire btrfs backing device of '%s': %m", device);
}
r = block_get_whole_disk(devt, &whole_devt);
r = path_get_whole_disk(device, backing, &devt);
if (r < 0)
return log_error_errno(r, "Failed to find whole block device for '%s': %m", device);
if (typesafe_bsearch(&whole_devt, *devnos, *n_devnos, devt_compare_func)) {
log_debug("Device %u:%u already listed for locking, ignoring.", major(whole_devt), minor(whole_devt));
if (typesafe_bsearch(&devt, *devnos, *n_devnos, devt_compare_func)) {
log_debug("Device %u:%u already listed for locking, ignoring.", major(devt), minor(devt));
return 0;
}
if (!GREEDY_REALLOC(*devnos, *n_devnos + 1))
return log_oom();
(*devnos)[(*n_devnos)++] = whole_devt;
(*devnos)[(*n_devnos)++] = devt;
/* Immediately sort again, to ensure the binary search above will work for the next device we add */
typesafe_qsort(*devnos, *n_devnos, devt_compare_func);