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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-06-26 22:47:20 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-06-26 22:47:20 +0300 |
commit | a0433f8cae3ac51f59b4b1863032822aaa2d8164 (patch) | |
tree | 9eb7b096aa9f7fa53921e6ff247488f3a55471f5 /block/early-lookup.c | |
parent | 0aa69d53ac7c30f6184f88f2e310d808b32b35a5 (diff) | |
parent | fcaa174a9c995cf0af3967e55644a1543ea07e36 (diff) | |
download | linux-a0433f8cae3ac51f59b4b1863032822aaa2d8164.tar.xz |
Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull request via Keith:
- Various cleanups all around (Irvin, Chaitanya, Christophe)
- Better struct packing (Christophe JAILLET)
- Reduce controller error logs for optional commands (Keith)
- Support for >=64KiB block sizes (Daniel Gomez)
- Fabrics fixes and code organization (Max, Chaitanya, Daniel
Wagner)
- bcache updates via Coly:
- Fix a race at init time (Mingzhe Zou)
- Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye)
- use page pinning in the block layer for dio (David)
- convert old block dio code to page pinning (David, Christoph)
- cleanups for pktcdvd (Andy)
- cleanups for rnbd (Guoqing)
- use the unchecked __bio_add_page() for the initial single page
additions (Johannes)
- fix overflows in the Amiga partition handling code (Michael)
- improve mq-deadline zoned device support (Bart)
- keep passthrough requests out of the IO schedulers (Christoph, Ming)
- improve support for flush requests, making them less special to deal
with (Christoph)
- add bdev holder ops and shutdown methods (Christoph)
- fix the name_to_dev_t() situation and use cases (Christoph)
- decouple the block open flags from fmode_t (Christoph)
- ublk updates and cleanups, including adding user copy support (Ming)
- BFQ sanity checking (Bart)
- convert brd from radix to xarray (Pankaj)
- constify various structures (Thomas, Ivan)
- more fine grained persistent reservation ioctl capability checks
(Jingbo)
- misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan,
Jordy, Li, Min, Yu, Zhong, Waiman)
* tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits)
scsi/sg: don't grab scsi host module reference
ext4: Fix warning in blkdev_put()
block: don't return -EINVAL for not found names in devt_from_devname
cdrom: Fix spectre-v1 gadget
block: Improve kernel-doc headers
blk-mq: don't insert passthrough request into sw queue
bsg: make bsg_class a static const structure
ublk: make ublk_chr_class a static const structure
aoe: make aoe_class a static const structure
block/rnbd: make all 'class' structures const
block: fix the exclusive open mask in disk_scan_partitions
block: add overflow checks for Amiga partition support
block: change all __u32 annotations to __be32 in affs_hardblocks.h
block: fix signed int overflow in Amiga partition support
block: add capacity validation in bdev_add_partition()
block: fine-granular CAP_SYS_ADMIN for Persistent Reservation
block: disallow Persistent Reservation on partitions
reiserfs: fix blkdev_put() warning from release_journal_dev()
block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()
block: document the holder argument to blkdev_get_by_path
...
Diffstat (limited to 'block/early-lookup.c')
-rw-r--r-- | block/early-lookup.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/block/early-lookup.c b/block/early-lookup.c new file mode 100644 index 000000000000..3effbd0d35e9 --- /dev/null +++ b/block/early-lookup.c @@ -0,0 +1,316 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Code for looking up block devices in the early boot code before mounting the + * root file system. + */ +#include <linux/blkdev.h> +#include <linux/ctype.h> + +struct uuidcmp { + const char *uuid; + int len; +}; + +/** + * match_dev_by_uuid - callback for finding a partition using its uuid + * @dev: device passed in by the caller + * @data: opaque pointer to the desired struct uuidcmp to match + * + * Returns 1 if the device matches, and 0 otherwise. + */ +static int __init match_dev_by_uuid(struct device *dev, const void *data) +{ + struct block_device *bdev = dev_to_bdev(dev); + const struct uuidcmp *cmp = data; + + if (!bdev->bd_meta_info || + strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len)) + return 0; + return 1; +} + +/** + * devt_from_partuuid - looks up the dev_t of a partition by its UUID + * @uuid_str: char array containing ascii UUID + * @devt: dev_t result + * + * The function will return the first partition which contains a matching + * UUID value in its partition_meta_info struct. This does not search + * by filesystem UUIDs. + * + * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be + * extracted and used as an offset from the partition identified by the UUID. + * + * Returns 0 on success or a negative error code on failure. + */ +static int __init devt_from_partuuid(const char *uuid_str, dev_t *devt) +{ + struct uuidcmp cmp; + struct device *dev = NULL; + int offset = 0; + char *slash; + + cmp.uuid = uuid_str; + + slash = strchr(uuid_str, '/'); + /* Check for optional partition number offset attributes. */ + if (slash) { + char c = 0; + + /* Explicitly fail on poor PARTUUID syntax. */ + if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1) + goto out_invalid; + cmp.len = slash - uuid_str; + } else { + cmp.len = strlen(uuid_str); + } + + if (!cmp.len) + goto out_invalid; + + dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid); + if (!dev) + return -ENODEV; + + if (offset) { + /* + * Attempt to find the requested partition by adding an offset + * to the partition number found by UUID. + */ + *devt = part_devt(dev_to_disk(dev), + dev_to_bdev(dev)->bd_partno + offset); + } else { + *devt = dev->devt; + } + + put_device(dev); + return 0; + +out_invalid: + pr_err("VFS: PARTUUID= is invalid.\n" + "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); + return -EINVAL; +} + +/** + * match_dev_by_label - callback for finding a partition using its label + * @dev: device passed in by the caller + * @data: opaque pointer to the label to match + * + * Returns 1 if the device matches, and 0 otherwise. + */ +static int __init match_dev_by_label(struct device *dev, const void *data) +{ + struct block_device *bdev = dev_to_bdev(dev); + const char *label = data; + + if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname)) + return 0; + return 1; +} + +static int __init devt_from_partlabel(const char *label, dev_t *devt) +{ + struct device *dev; + + dev = class_find_device(&block_class, NULL, label, &match_dev_by_label); + if (!dev) + return -ENODEV; + *devt = dev->devt; + put_device(dev); + return 0; +} + +static dev_t __init blk_lookup_devt(const char *name, int partno) +{ + dev_t devt = MKDEV(0, 0); + struct class_dev_iter iter; + struct device *dev; + + class_dev_iter_init(&iter, &block_class, NULL, &disk_type); + while ((dev = class_dev_iter_next(&iter))) { + struct gendisk *disk = dev_to_disk(dev); + + if (strcmp(dev_name(dev), name)) + continue; + + if (partno < disk->minors) { + /* We need to return the right devno, even + * if the partition doesn't exist yet. + */ + devt = MKDEV(MAJOR(dev->devt), + MINOR(dev->devt) + partno); + } else { + devt = part_devt(disk, partno); + if (devt) + break; + } + } + class_dev_iter_exit(&iter); + return devt; +} + +static int __init devt_from_devname(const char *name, dev_t *devt) +{ + int part; + char s[32]; + char *p; + + if (strlen(name) > 31) + return -EINVAL; + strcpy(s, name); + for (p = s; *p; p++) { + if (*p == '/') + *p = '!'; + } + + *devt = blk_lookup_devt(s, 0); + if (*devt) + return 0; + + /* + * Try non-existent, but valid partition, which may only exist after + * opening the device, like partitioned md devices. + */ + while (p > s && isdigit(p[-1])) + p--; + if (p == s || !*p || *p == '0') + return -ENODEV; + + /* try disk name without <part number> */ + part = simple_strtoul(p, NULL, 10); + *p = '\0'; + *devt = blk_lookup_devt(s, part); + if (*devt) + return 0; + + /* try disk name without p<part number> */ + if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') + return -ENODEV; + p[-1] = '\0'; + *devt = blk_lookup_devt(s, part); + if (*devt) + return 0; + return -ENODEV; +} + +static int __init devt_from_devnum(const char *name, dev_t *devt) +{ + unsigned maj, min, offset; + char *p, dummy; + + if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 || + sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) { + *devt = MKDEV(maj, min); + if (maj != MAJOR(*devt) || min != MINOR(*devt)) + return -EINVAL; + } else { + *devt = new_decode_dev(simple_strtoul(name, &p, 16)); + if (*p) + return -EINVAL; + } + + return 0; +} + +/* + * Convert a name into device number. We accept the following variants: + * + * 1) <hex_major><hex_minor> device number in hexadecimal represents itself + * no leading 0x, for example b302. + * 3) /dev/<disk_name> represents the device number of disk + * 4) /dev/<disk_name><decimal> represents the device number + * of partition - device number of disk plus the partition number + * 5) /dev/<disk_name>p<decimal> - same as the above, that form is + * used when disk name of partitioned disk ends on a digit. + * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the + * unique id of a partition if the partition table provides it. + * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS + * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- + * filled hex representation of the 32-bit "NT disk signature", and PP + * is a zero-filled hex representation of the 1-based partition number. + * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to + * a partition with a known unique id. + * 8) <major>:<minor> major and minor number of the device separated by + * a colon. + * 9) PARTLABEL=<name> with name being the GPT partition label. + * MSDOS partitions do not support labels! + * + * If name doesn't have fall into the categories above, we return (0,0). + * block_class is used to check if something is a disk name. If the disk + * name contains slashes, the device name has them replaced with + * bangs. + */ +int __init early_lookup_bdev(const char *name, dev_t *devt) +{ + if (strncmp(name, "PARTUUID=", 9) == 0) + return devt_from_partuuid(name + 9, devt); + if (strncmp(name, "PARTLABEL=", 10) == 0) + return devt_from_partlabel(name + 10, devt); + if (strncmp(name, "/dev/", 5) == 0) + return devt_from_devname(name + 5, devt); + return devt_from_devnum(name, devt); +} + +static char __init *bdevt_str(dev_t devt, char *buf) +{ + if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { + char tbuf[BDEVT_SIZE]; + snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt)); + snprintf(buf, BDEVT_SIZE, "%-9s", tbuf); + } else + snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt)); + + return buf; +} + +/* + * print a full list of all partitions - intended for places where the root + * filesystem can't be mounted and thus to give the victim some idea of what + * went wrong + */ +void __init printk_all_partitions(void) +{ + struct class_dev_iter iter; + struct device *dev; + + class_dev_iter_init(&iter, &block_class, NULL, &disk_type); + while ((dev = class_dev_iter_next(&iter))) { + struct gendisk *disk = dev_to_disk(dev); + struct block_device *part; + char devt_buf[BDEVT_SIZE]; + unsigned long idx; + + /* + * Don't show empty devices or things that have been + * suppressed + */ + if (get_capacity(disk) == 0 || (disk->flags & GENHD_FL_HIDDEN)) + continue; + + /* + * Note, unlike /proc/partitions, I am showing the numbers in + * hex - the same format as the root= option takes. + */ + rcu_read_lock(); + xa_for_each(&disk->part_tbl, idx, part) { + if (!bdev_nr_sectors(part)) + continue; + printk("%s%s %10llu %pg %s", + bdev_is_partition(part) ? " " : "", + bdevt_str(part->bd_dev, devt_buf), + bdev_nr_sectors(part) >> 1, part, + part->bd_meta_info ? + part->bd_meta_info->uuid : ""); + if (bdev_is_partition(part)) + printk("\n"); + else if (dev->parent && dev->parent->driver) + printk(" driver: %s\n", + dev->parent->driver->name); + else + printk(" (driver?)\n"); + } + rcu_read_unlock(); + } + class_dev_iter_exit(&iter); +} |