diff options
Diffstat (limited to 'src/shared/blockdev-util.c')
| -rw-r--r-- | src/shared/blockdev-util.c | 60 |
1 files changed, 48 insertions, 12 deletions
diff --git a/src/shared/blockdev-util.c b/src/shared/blockdev-util.c index 99e37fd..3be617b 100644 --- a/src/shared/blockdev-util.c +++ b/src/shared/blockdev-util.c @@ -410,15 +410,43 @@ int blockdev_partscan_enabled(int fd) { * is 1, which can be check with 'ext_range' sysfs attribute. Explicit flag ('GENHD_FL_NO_PART_SCAN') * can be obtained from 'capability' sysattr. * - * With https://github.com/torvalds/linux/commit/1ebe2e5f9d68e94c524aba876f27b945669a7879 (v5.17), we - * can check the flag from 'ext_range' sysfs attribute directly. + * With https://github.com/torvalds/linux/commit/46e7eac647b34ed4106a8262f8bedbb90801fadd (v5.17), + * the flag is renamed to GENHD_FL_NO_PART. + * + * With https://github.com/torvalds/linux/commit/1ebe2e5f9d68e94c524aba876f27b945669a7879 (v5.17), + * we can check the flag from 'ext_range' sysfs attribute directly. + * + * With https://github.com/torvalds/linux/commit/430cc5d3ab4d0ba0bd011cfbb0035e46ba92920c (v5.17), + * the value of GENHD_FL_NO_PART is changed from 0x0200 to 0x0004. 💣💣💣 + * Note, the new value was used by the GENHD_FL_MEDIA_CHANGE_NOTIFY flag, which was introduced by + * 86ce18d7b7925bfd6b64c061828ca2a857ee83b8 (v2.6.22), and removed by + * 9243c6f3e012a92dd900d97ef45efaf8a8edc448 (v5.7). If we believe the commit message of + * e81cd5a983bb35dabd38ee472cf3fea1c63e0f23, the flag was never used. So, fortunately, we can use + * both the new and old values safely. + * + * With https://github.com/torvalds/linux/commit/b9684a71fca793213378dd410cd11675d973eaa1 (v5.19), + * another flag GD_SUPPRESS_PART_SCAN is introduced for loopback block device, and partition scanning + * is done only when both GENHD_FL_NO_PART and GD_SUPPRESS_PART_SCAN are not set. Before the commit, + * LO_FLAGS_PARTSCAN flag was directly tied with GENHD_FL_NO_PART. But with this change now it is + * tied with GD_SUPPRESS_PART_SCAN. So, LO_FLAGS_PARTSCAN cannot be obtained from 'ext_range' + * sysattr, which corresponds to GENHD_FL_NO_PART, and we need to read 'loop/partscan'. 💣💣💣 + * + * With https://github.com/torvalds/linux/commit/73a166d9749230d598320fdae3b687cdc0e2e205 (v6.3), + * the GD_SUPPRESS_PART_SCAN flag is also introduced for userspace block device (ublk). Though, not + * sure if we should support the device... * * With https://github.com/torvalds/linux/commit/e81cd5a983bb35dabd38ee472cf3fea1c63e0f23 (v6.3), - * the 'capability' sysfs attribute is deprecated, hence we cannot check the flag from it. + * the 'capability' sysfs attribute is deprecated, hence we cannot check flags from it. 💣💣💣 + * + * With https://github.com/torvalds/linux/commit/a4217c6740dc64a3eb6815868a9260825e8c68c6 (v6.10, + * backported to v6.9), the partscan status is directly exposed as 'partscan' sysattr. * - * To support both old and new kernels, we need to do the following: first check 'ext_range' sysfs - * attribute, and if '1' we can conclude partition scanning is disabled, otherwise check 'capability' - * sysattr for older version. */ + * To support both old and new kernels, we need to do the following: + * 1) check 'partscan' sysfs attribute where the information is made directly available, + * 2) check 'loop/partscan' sysfs attribute for loopback block devices, and if '0' we can conclude + * partition scanning is disabled, + * 3) check 'ext_range' sysfs attribute, and if '1' we can conclude partition scanning is disabled, + * 4) otherwise check 'capability' sysfs attribute for ancient version. */ assert(fd >= 0); @@ -426,6 +454,16 @@ int blockdev_partscan_enabled(int fd) { if (r < 0) return r; + /* For v6.10 or newer. */ + r = device_get_sysattr_bool(dev, "partscan"); + if (r != -ENOENT) + return r; + + /* For loopback block device, especially for v5.19 or newer. Even if this is enabled, we also need to + * check GENHD_FL_NO_PART flag through 'ext_range' and 'capability' sysfs attributes below. */ + if (device_get_sysattr_bool(dev, "loop/partscan") == 0) + return false; + r = device_get_sysattr_int(dev, "ext_range", &ext_range); if (r == -ENOENT) /* If the ext_range file doesn't exist then we are most likely looking at a * partition block device, not the whole block device. And that means we have no @@ -445,12 +483,10 @@ int blockdev_partscan_enabled(int fd) { if (r < 0) return r; -#ifndef GENHD_FL_NO_PART_SCAN -#define GENHD_FL_NO_PART_SCAN (0x0200) -#endif - - /* If 0x200 is set, part scanning is definitely off. */ - if (FLAGS_SET(capability, GENHD_FL_NO_PART_SCAN)) +#define GENHD_FL_NO_PART_OLD 0x0200 +#define GENHD_FL_NO_PART_NEW 0x0004 + /* If one of the NO_PART flags is set, part scanning is definitely off. */ + if ((capability & (GENHD_FL_NO_PART_OLD | GENHD_FL_NO_PART_NEW)) != 0) return false; /* Otherwise, assume part scanning is on, we have no further checks available. Assume the best. */ |