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Diffstat (limited to 'libblkid/src/topology/topology.c')
| -rw-r--r-- | libblkid/src/topology/topology.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/libblkid/src/topology/topology.c b/libblkid/src/topology/topology.c new file mode 100644 index 0000000..38e4c95 --- /dev/null +++ b/libblkid/src/topology/topology.c @@ -0,0 +1,360 @@ +/* + * topology - gathers information about device topology + * + * Copyright 2009 Red Hat, Inc. All rights reserved. + * + * This file may be redistributed under the terms of the + * GNU Lesser General Public License. + */ + +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <stddef.h> + +#include "topology.h" + +/** + * SECTION:topology + * @title: Topology information + * @short_description: block device topology information. + * + * The topology chain provides details about Linux block devices, for more + * information see: + * + * Linux kernel Documentation/ABI/testing/sysfs-block + * + * NAME=value (tags) interface is enabled by blkid_probe_enable_topology(), + * and provides: + * + * @LOGICAL_SECTOR_SIZE: this is the smallest unit the storage device can + * address. It is typically 512 bytes. + * + * @PHYSICAL_SECTOR_SIZE: this is the smallest unit a physical storage device + * can write atomically. It is usually the same as the + * logical sector size but may be bigger. + * + * @MINIMUM_IO_SIZE: minimum size which is the device's preferred unit of I/O. + * For RAID arrays it is often the stripe chunk size. + * + * @OPTIMAL_IO_SIZE: usually the stripe width for RAID or zero. For RAID arrays + * it is usually the stripe width or the internal track size. + * + * @ALIGNMENT_OFFSET: indicates how many bytes the beginning of the device is + * offset from the disk's natural alignment. + * + * The NAME=value tags are not defined when the corresponding topology value + * is zero. The MINIMUM_IO_SIZE should be always defined if kernel provides + * topology information. + * + * Binary interface: + * + * blkid_probe_get_topology() + * + * blkid_topology_get_'VALUENAME'() + */ +static int topology_probe(blkid_probe pr, struct blkid_chain *chn); +static void topology_free(blkid_probe pr, void *data); +static int topology_is_complete(blkid_probe pr); +static int topology_set_logical_sector_size(blkid_probe pr); + +/* + * Binary interface + */ +struct blkid_struct_topology { + unsigned long alignment_offset; + unsigned long minimum_io_size; + unsigned long optimal_io_size; + unsigned long logical_sector_size; + unsigned long physical_sector_size; +}; + +/* + * Topology chain probing functions + */ +static const struct blkid_idinfo *idinfos[] = +{ +#ifdef __linux__ + &ioctl_tp_idinfo, + &sysfs_tp_idinfo, + &md_tp_idinfo, + &dm_tp_idinfo, + &lvm_tp_idinfo, + &evms_tp_idinfo +#endif +}; + + +/* + * Driver definition + */ +const struct blkid_chaindrv topology_drv = { + .id = BLKID_CHAIN_TOPLGY, + .name = "topology", + .dflt_enabled = FALSE, + .idinfos = idinfos, + .nidinfos = ARRAY_SIZE(idinfos), + .probe = topology_probe, + .safeprobe = topology_probe, + .free_data = topology_free +}; + +/** + * blkid_probe_enable_topology: + * @pr: probe + * @enable: TRUE/FALSE + * + * Enables/disables the topology probing for non-binary interface. + * + * Returns: 0 on success, or -1 in case of error. + */ +int blkid_probe_enable_topology(blkid_probe pr, int enable) +{ + pr->chains[BLKID_CHAIN_TOPLGY].enabled = enable; + return 0; +} + +/** + * blkid_probe_get_topology: + * @pr: probe + * + * This is a binary interface for topology values. See also blkid_topology_* + * functions. + * + * This function is independent on blkid_do_[safe,full]probe() and + * blkid_probe_enable_topology() calls. + * + * WARNING: the returned object will be overwritten by the next + * blkid_probe_get_topology() call for the same @pr. If you want to + * use more blkid_topology objects in the same time you have to create + * more blkid_probe handlers (see blkid_new_probe()). + * + * Returns: blkid_topology, or NULL in case of error. + */ +blkid_topology blkid_probe_get_topology(blkid_probe pr) +{ + return (blkid_topology) blkid_probe_get_binary_data(pr, + &pr->chains[BLKID_CHAIN_TOPLGY]); +} + +/* + * The blkid_do_probe() backend. + */ +static int topology_probe(blkid_probe pr, struct blkid_chain *chn) +{ + size_t i; + + if (chn->idx < -1) + return -1; + + if (!S_ISBLK(pr->mode)) + return -EINVAL; /* nothing, works with block devices only */ + + if (chn->binary) { + DBG(LOWPROBE, ul_debug("initialize topology binary data")); + + if (chn->data) + /* reset binary data */ + memset(chn->data, 0, + sizeof(struct blkid_struct_topology)); + else { + chn->data = calloc(1, + sizeof(struct blkid_struct_topology)); + if (!chn->data) + return -ENOMEM; + } + } + + blkid_probe_chain_reset_values(pr, chn); + + DBG(LOWPROBE, ul_debug("--> starting probing loop [TOPOLOGY idx=%d]", + chn->idx)); + + i = chn->idx < 0 ? 0 : chn->idx + 1U; + + for ( ; i < ARRAY_SIZE(idinfos); i++) { + const struct blkid_idinfo *id = idinfos[i]; + + chn->idx = i; + + if (id->probefunc) { + DBG(LOWPROBE, ul_debug("%s: call probefunc()", id->name)); + if (id->probefunc(pr, NULL) != 0) + continue; + } + + if (!topology_is_complete(pr)) + continue; + + /* generic for all probing drivers */ + topology_set_logical_sector_size(pr); + + DBG(LOWPROBE, ul_debug("<-- leaving probing loop (type=%s) [TOPOLOGY idx=%d]", + id->name, chn->idx)); + return BLKID_PROBE_OK; + } + + DBG(LOWPROBE, ul_debug("<-- leaving probing loop (failed) [TOPOLOGY idx=%d]", + chn->idx)); + return BLKID_PROBE_NONE; +} + +static void topology_free(blkid_probe pr __attribute__((__unused__)), + void *data) +{ + free(data); +} + +static int topology_set_value(blkid_probe pr, const char *name, + size_t structoff, unsigned long data) +{ + struct blkid_chain *chn = blkid_probe_get_chain(pr); + + if (!chn) + return -1; + if (!data) + return 0; /* ignore zeros */ + + if (chn->binary) { + memcpy((char *) chn->data + structoff, &data, sizeof(data)); + return 0; + } + return blkid_probe_sprintf_value(pr, name, "%lu", data); +} + + +/* the topology info is complete when we have at least "minimum_io_size" which + * is provided by all blkid topology drivers */ +static int topology_is_complete(blkid_probe pr) +{ + struct blkid_chain *chn = blkid_probe_get_chain(pr); + + if (!chn) + return FALSE; + + if (chn->binary && chn->data) { + blkid_topology tp = (blkid_topology) chn->data; + if (tp->minimum_io_size) + return TRUE; + } + + return __blkid_probe_lookup_value(pr, "MINIMUM_IO_SIZE") ? TRUE : FALSE; +} + +int blkid_topology_set_alignment_offset(blkid_probe pr, int val) +{ + unsigned long xval; + + /* Welcome to Hell. The kernel is able to return -1 as an + * alignment_offset if no compatible sizes and alignments + * exist for stacked devices. + * + * There is no way how libblkid caller can respond to the value -1, so + * we will hide this corner case... + * + * (TODO: maybe we can export an extra boolean value 'misaligned' rather + * then complete hide this problem.) + */ + xval = val < 0 ? 0 : val; + + return topology_set_value(pr, + "ALIGNMENT_OFFSET", + offsetof(struct blkid_struct_topology, alignment_offset), + xval); +} + +int blkid_topology_set_minimum_io_size(blkid_probe pr, unsigned long val) +{ + return topology_set_value(pr, + "MINIMUM_IO_SIZE", + offsetof(struct blkid_struct_topology, minimum_io_size), + val); +} + +int blkid_topology_set_optimal_io_size(blkid_probe pr, unsigned long val) +{ + return topology_set_value(pr, + "OPTIMAL_IO_SIZE", + offsetof(struct blkid_struct_topology, optimal_io_size), + val); +} + +/* BLKSSZGET is provided on all systems since 2.3.3 -- so we don't have to + * waste time with sysfs. + */ +static int topology_set_logical_sector_size(blkid_probe pr) +{ + unsigned long val = blkid_probe_get_sectorsize(pr); + + if (!val) + return -1; + + return topology_set_value(pr, + "LOGICAL_SECTOR_SIZE", + offsetof(struct blkid_struct_topology, logical_sector_size), + val); +} + +int blkid_topology_set_physical_sector_size(blkid_probe pr, unsigned long val) +{ + return topology_set_value(pr, + "PHYSICAL_SECTOR_SIZE", + offsetof(struct blkid_struct_topology, physical_sector_size), + val); +} + +/** + * blkid_topology_get_alignment_offset: + * @tp: topology + * + * Returns: alignment offset in bytes or 0. + */ +unsigned long blkid_topology_get_alignment_offset(blkid_topology tp) +{ + return tp->alignment_offset; +} + +/** + * blkid_topology_get_minimum_io_size: + * @tp: topology + * + * Returns: minimum io size in bytes or 0. + */ +unsigned long blkid_topology_get_minimum_io_size(blkid_topology tp) +{ + return tp->minimum_io_size; +} + +/** + * blkid_topology_get_optimal_io_size + * @tp: topology + * + * Returns: optimal io size in bytes or 0. + */ +unsigned long blkid_topology_get_optimal_io_size(blkid_topology tp) +{ + return tp->optimal_io_size; +} + +/** + * blkid_topology_get_logical_sector_size + * @tp: topology + * + * Returns: logical sector size (BLKSSZGET ioctl) in bytes or 0. + */ +unsigned long blkid_topology_get_logical_sector_size(blkid_topology tp) +{ + return tp->logical_sector_size; +} + +/** + * blkid_topology_get_physical_sector_size + * @tp: topology + * + * Returns: logical sector size (BLKSSZGET ioctl) in bytes or 0. + */ +unsigned long blkid_topology_get_physical_sector_size(blkid_topology tp) +{ + return tp->physical_sector_size; +} + |