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-rw-r--r--libblkid/libfdisk/src/alignment.c654
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diff --git a/libblkid/libfdisk/src/alignment.c b/libblkid/libfdisk/src/alignment.c
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+++ b/libblkid/libfdisk/src/alignment.c
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+
+#ifdef HAVE_LIBBLKID
+#include <blkid.h>
+#endif
+#include "blkdev.h"
+
+#include "fdiskP.h"
+
+/**
+ * SECTION: alignment
+ * @title: Alignment
+ * @short_description: functions to align partitions and work with disk topology and geometry
+ *
+ * The libfdisk aligns the end of the partitions to make it possible to align
+ * the next partition to the "grain" (see fdisk_get_grain()). The grain is
+ * usually 1MiB (or more for devices where optimal I/O is greater than 1MiB).
+ *
+ * It means that the library does not align strictly to physical sector size
+ * (or minimal or optimal I/O), but it uses greater granularity. It makes
+ * partition tables more portable. If you copy disk layout from 512-sector to
+ * 4K-sector device, all partitions are still aligned to physical sectors.
+ *
+ * This unified concept also makes partition tables more user friendly, all
+ * tables look same, LBA of the first partition is 2048 sectors everywhere, etc.
+ *
+ * It's recommended to not change any alignment or device properties. All is
+ * initialized by default by fdisk_assign_device().
+ *
+ * Note that terminology used by libfdisk is:
+ * - device properties: I/O limits (topology), geometry, sector size, ...
+ * - alignment: first, last LBA, grain, ...
+ *
+ * The alignment setting may be modified by disk label driver.
+ */
+
+/*
+ * Alignment according to logical granularity (usually 1MiB)
+ */
+static int lba_is_aligned(struct fdisk_context *cxt, fdisk_sector_t lba)
+{
+ unsigned long granularity = max(cxt->phy_sector_size, cxt->min_io_size);
+ uintmax_t offset;
+
+ if (cxt->grain > granularity)
+ granularity = cxt->grain;
+ offset = (lba * cxt->sector_size) & (granularity - 1);
+
+ return !((granularity + cxt->alignment_offset - offset) & (granularity - 1));
+}
+
+/*
+ * Alignment according to physical device topology (usually minimal i/o size)
+ */
+static int lba_is_phy_aligned(struct fdisk_context *cxt, fdisk_sector_t lba)
+{
+ unsigned long granularity = max(cxt->phy_sector_size, cxt->min_io_size);
+ uintmax_t offset = (lba * cxt->sector_size) & (granularity - 1);
+
+ return !((granularity + cxt->alignment_offset - offset) & (granularity - 1));
+}
+
+/**
+ * fdisk_align_lba:
+ * @cxt: context
+ * @lba: address to align
+ * @direction: FDISK_ALIGN_{UP,DOWN,NEAREST}
+ *
+ * This function aligns @lba to the "grain" (see fdisk_get_grain()). If the
+ * device uses alignment offset then the result is moved according the offset
+ * to be on the physical boundary.
+ *
+ * Returns: alignment LBA.
+ */
+fdisk_sector_t fdisk_align_lba(struct fdisk_context *cxt, fdisk_sector_t lba, int direction)
+{
+ fdisk_sector_t res;
+
+ if (lba_is_aligned(cxt, lba))
+ res = lba;
+ else {
+ fdisk_sector_t sects_in_phy = cxt->grain / cxt->sector_size;
+
+ if (lba < cxt->first_lba)
+ res = cxt->first_lba;
+
+ else if (direction == FDISK_ALIGN_UP)
+ res = ((lba + sects_in_phy) / sects_in_phy) * sects_in_phy;
+
+ else if (direction == FDISK_ALIGN_DOWN)
+ res = (lba / sects_in_phy) * sects_in_phy;
+
+ else /* FDISK_ALIGN_NEAREST */
+ res = ((lba + sects_in_phy / 2) / sects_in_phy) * sects_in_phy;
+
+ if (cxt->alignment_offset && !lba_is_aligned(cxt, res) &&
+ res > cxt->alignment_offset / cxt->sector_size) {
+ /*
+ * apply alignment_offset
+ *
+ * On disk with alignment compensation physical blocks starts
+ * at LBA < 0 (usually LBA -1). It means we have to move LBA
+ * according the offset to be on the physical boundary.
+ */
+ /* fprintf(stderr, "LBA: %llu apply alignment_offset\n", res); */
+ res -= (max(cxt->phy_sector_size, cxt->min_io_size) -
+ cxt->alignment_offset) / cxt->sector_size;
+
+ if (direction == FDISK_ALIGN_UP && res < lba)
+ res += sects_in_phy;
+ }
+ }
+
+ if (lba != res)
+ DBG(CXT, ul_debugobj(cxt, "LBA %ju -aligned-to-> %ju",
+ (uintmax_t) lba,
+ (uintmax_t) res));
+ return res;
+}
+
+/**
+ * fdisk_align_lba_in_range:
+ * @cxt: context
+ * @lba: LBA
+ * @start: range start
+ * @stop: range stop
+ *
+ * Align @lba, the result has to be between @start and @stop
+ *
+ * Returns: aligned LBA
+ */
+fdisk_sector_t fdisk_align_lba_in_range(struct fdisk_context *cxt,
+ fdisk_sector_t lba, fdisk_sector_t start, fdisk_sector_t stop)
+{
+ fdisk_sector_t res;
+
+ start = fdisk_align_lba(cxt, start, FDISK_ALIGN_UP);
+ stop = fdisk_align_lba(cxt, stop, FDISK_ALIGN_DOWN);
+ lba = fdisk_align_lba(cxt, lba, FDISK_ALIGN_NEAREST);
+
+ if (lba < start)
+ res = start;
+ else if (lba > stop)
+ res = stop;
+ else
+ res = lba;
+
+ DBG(CXT, ul_debugobj(cxt, "LBA %ju range:<%ju..%ju>, result: %ju",
+ (uintmax_t) lba,
+ (uintmax_t) start,
+ (uintmax_t) stop,
+ (uintmax_t) res));
+ return res;
+}
+
+/**
+ * fdisk_lba_is_phy_aligned:
+ * @cxt: context
+ * @lba: LBA to check
+ *
+ * Check if the @lba is aligned to physical sector boundary.
+ *
+ * Returns: 1 if aligned.
+ */
+int fdisk_lba_is_phy_aligned(struct fdisk_context *cxt, fdisk_sector_t lba)
+{
+ return lba_is_phy_aligned(cxt, lba);
+}
+
+static unsigned long get_sector_size(int fd)
+{
+ int sect_sz;
+
+ if (!blkdev_get_sector_size(fd, &sect_sz))
+ return (unsigned long) sect_sz;
+ return DEFAULT_SECTOR_SIZE;
+}
+
+static void recount_geometry(struct fdisk_context *cxt)
+{
+ if (!cxt->geom.heads)
+ cxt->geom.heads = 255;
+ if (!cxt->geom.sectors)
+ cxt->geom.sectors = 63;
+
+ cxt->geom.cylinders = cxt->total_sectors /
+ (cxt->geom.heads * cxt->geom.sectors);
+}
+
+/**
+ * fdisk_override_geometry:
+ * @cxt: fdisk context
+ * @cylinders: user specified cylinders
+ * @heads: user specified heads
+ * @sectors: user specified sectors
+ *
+ * Overrides auto-discovery. The function fdisk_reset_device_properties()
+ * restores the original setting.
+ *
+ * The difference between fdisk_override_geometry() and fdisk_save_user_geometry()
+ * is that saved user geometry is persistent setting and it's applied always
+ * when device is assigned to the context or device properties are reseted.
+ *
+ * Returns: 0 on success, < 0 on error.
+ */
+int fdisk_override_geometry(struct fdisk_context *cxt,
+ unsigned int cylinders,
+ unsigned int heads,
+ unsigned int sectors)
+{
+ if (!cxt)
+ return -EINVAL;
+ if (heads)
+ cxt->geom.heads = heads;
+ if (sectors)
+ cxt->geom.sectors = sectors;
+
+ if (cylinders)
+ cxt->geom.cylinders = cylinders;
+ else
+ recount_geometry(cxt);
+
+ fdisk_reset_alignment(cxt);
+
+ DBG(CXT, ul_debugobj(cxt, "override C/H/S: %u/%u/%u",
+ (unsigned) cxt->geom.cylinders,
+ (unsigned) cxt->geom.heads,
+ (unsigned) cxt->geom.sectors));
+
+ return 0;
+}
+
+/**
+ * fdisk_save_user_geometry:
+ * @cxt: context
+ * @cylinders: C
+ * @heads: H
+ * @sectors: S
+ *
+ * Save user defined geometry to use it for partitioning.
+ *
+ * The user properties are applied by fdisk_assign_device() or
+ * fdisk_reset_device_properties().
+
+ * Returns: <0 on error, 0 on success.
+ */
+int fdisk_save_user_geometry(struct fdisk_context *cxt,
+ unsigned int cylinders,
+ unsigned int heads,
+ unsigned int sectors)
+{
+ if (!cxt)
+ return -EINVAL;
+
+ if (heads)
+ cxt->user_geom.heads = heads > 256 ? 0 : heads;
+ if (sectors)
+ cxt->user_geom.sectors = sectors >= 64 ? 0 : sectors;
+ if (cylinders)
+ cxt->user_geom.cylinders = cylinders;
+
+ DBG(CXT, ul_debugobj(cxt, "user C/H/S: %u/%u/%u",
+ (unsigned) cxt->user_geom.cylinders,
+ (unsigned) cxt->user_geom.heads,
+ (unsigned) cxt->user_geom.sectors));
+
+ return 0;
+}
+
+/**
+ * fdisk_save_user_sector_size:
+ * @cxt: context
+ * @phy: physical sector size
+ * @log: logicla sector size
+ *
+ * Save user defined sector sizes to use it for partitioning.
+ *
+ * The user properties are applied by fdisk_assign_device() or
+ * fdisk_reset_device_properties().
+ *
+ * Returns: <0 on error, 0 on success.
+ */
+int fdisk_save_user_sector_size(struct fdisk_context *cxt,
+ unsigned int phy,
+ unsigned int log)
+{
+ if (!cxt)
+ return -EINVAL;
+
+ DBG(CXT, ul_debugobj(cxt, "user phy/log sector size: %u/%u", phy, log));
+
+ cxt->user_pyh_sector = phy;
+ cxt->user_log_sector = log;
+
+ return 0;
+}
+
+/**
+ * fdisk_has_user_device_properties:
+ * @cxt: context
+ *
+ * Returns: 1 if user specified any properties
+ */
+int fdisk_has_user_device_properties(struct fdisk_context *cxt)
+{
+ return (cxt->user_pyh_sector
+ || cxt->user_log_sector
+ || cxt->user_geom.heads
+ || cxt->user_geom.sectors
+ || cxt->user_geom.cylinders);
+}
+
+int fdisk_apply_user_device_properties(struct fdisk_context *cxt)
+{
+ if (!cxt)
+ return -EINVAL;
+
+ DBG(CXT, ul_debugobj(cxt, "appling user device properties"));
+
+ if (cxt->user_pyh_sector)
+ cxt->phy_sector_size = cxt->user_pyh_sector;
+ if (cxt->user_log_sector)
+ cxt->sector_size = cxt->min_io_size =
+ cxt->io_size = cxt->user_log_sector;
+
+ if (cxt->user_geom.heads)
+ cxt->geom.heads = cxt->user_geom.heads;
+ if (cxt->user_geom.sectors)
+ cxt->geom.sectors = cxt->user_geom.sectors;
+
+ if (cxt->user_geom.cylinders)
+ cxt->geom.cylinders = cxt->user_geom.cylinders;
+ else if (cxt->user_geom.heads || cxt->user_geom.sectors)
+ recount_geometry(cxt);
+
+ fdisk_reset_alignment(cxt);
+ if (cxt->firstsector_bufsz != cxt->sector_size)
+ fdisk_read_firstsector(cxt);
+
+ DBG(CXT, ul_debugobj(cxt, "new C/H/S: %u/%u/%u",
+ (unsigned) cxt->geom.cylinders,
+ (unsigned) cxt->geom.heads,
+ (unsigned) cxt->geom.sectors));
+ DBG(CXT, ul_debugobj(cxt, "new log/phy sector size: %u/%u",
+ (unsigned) cxt->sector_size,
+ (unsigned) cxt->phy_sector_size));
+
+ return 0;
+}
+
+void fdisk_zeroize_device_properties(struct fdisk_context *cxt)
+{
+ assert(cxt);
+
+ cxt->io_size = 0;
+ cxt->optimal_io_size = 0;
+ cxt->min_io_size = 0;
+ cxt->phy_sector_size = 0;
+ cxt->sector_size = 0;
+ cxt->alignment_offset = 0;
+ cxt->grain = 0;
+ cxt->first_lba = 0;
+ cxt->last_lba = 0;
+ cxt->total_sectors = 0;
+
+ memset(&cxt->geom, 0, sizeof(struct fdisk_geometry));
+}
+
+/**
+ * fdisk_reset_device_properties:
+ * @cxt: context
+ *
+ * Resets and discovery topology (I/O limits), geometry, re-read the first
+ * rector on the device if necessary and apply user device setting (geometry
+ * and sector size), then initialize alignment according to label driver (see
+ * fdisk_reset_alignment()).
+ *
+ * You don't have to use this function by default, fdisk_assign_device() is
+ * smart enough to initialize all necessary setting.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int fdisk_reset_device_properties(struct fdisk_context *cxt)
+{
+ int rc;
+
+ if (!cxt)
+ return -EINVAL;
+
+ DBG(CXT, ul_debugobj(cxt, "*** reseting device properties"));
+
+ fdisk_zeroize_device_properties(cxt);
+ fdisk_discover_topology(cxt);
+ fdisk_discover_geometry(cxt);
+
+ rc = fdisk_read_firstsector(cxt);
+ if (rc)
+ return rc;
+
+ fdisk_apply_user_device_properties(cxt);
+ return 0;
+}
+
+/*
+ * Generic (label independent) geometry
+ */
+int fdisk_discover_geometry(struct fdisk_context *cxt)
+{
+ fdisk_sector_t nsects;
+
+ assert(cxt);
+ assert(cxt->geom.heads == 0);
+
+ DBG(CXT, ul_debugobj(cxt, "%s: discovering geometry...", cxt->dev_path));
+
+ /* get number of 512-byte sectors, and convert it the real sectors */
+ if (!blkdev_get_sectors(cxt->dev_fd, (unsigned long long *) &nsects))
+ cxt->total_sectors = (nsects / (cxt->sector_size >> 9));
+
+ DBG(CXT, ul_debugobj(cxt, "total sectors: %ju (ioctl=%ju)",
+ (uintmax_t) cxt->total_sectors,
+ (uintmax_t) nsects));
+
+ /* what the kernel/bios thinks the geometry is */
+ blkdev_get_geometry(cxt->dev_fd, &cxt->geom.heads, (unsigned int *) &cxt->geom.sectors);
+
+ /* obtained heads and sectors */
+ recount_geometry(cxt);
+
+ DBG(CXT, ul_debugobj(cxt, "result: C/H/S: %u/%u/%u",
+ (unsigned) cxt->geom.cylinders,
+ (unsigned) cxt->geom.heads,
+ (unsigned) cxt->geom.sectors));
+ return 0;
+}
+
+int fdisk_discover_topology(struct fdisk_context *cxt)
+{
+#ifdef HAVE_LIBBLKID
+ blkid_probe pr;
+#endif
+ assert(cxt);
+ assert(cxt->sector_size == 0);
+
+ DBG(CXT, ul_debugobj(cxt, "%s: discovering topology...", cxt->dev_path));
+#ifdef HAVE_LIBBLKID
+ DBG(CXT, ul_debugobj(cxt, "initialize libblkid prober"));
+
+ pr = blkid_new_probe();
+ if (pr && blkid_probe_set_device(pr, cxt->dev_fd, 0, 0) == 0) {
+ blkid_topology tp = blkid_probe_get_topology(pr);
+
+ if (tp) {
+ cxt->min_io_size = blkid_topology_get_minimum_io_size(tp);
+ cxt->optimal_io_size = blkid_topology_get_optimal_io_size(tp);
+ cxt->phy_sector_size = blkid_topology_get_physical_sector_size(tp);
+ cxt->alignment_offset = blkid_topology_get_alignment_offset(tp);
+
+ /* I/O size used by fdisk */
+ cxt->io_size = cxt->optimal_io_size;
+ if (!cxt->io_size)
+ /* optimal IO is optional, default to minimum IO */
+ cxt->io_size = cxt->min_io_size;
+ }
+ }
+ blkid_free_probe(pr);
+#endif
+
+ cxt->sector_size = get_sector_size(cxt->dev_fd);
+ if (!cxt->phy_sector_size) /* could not discover physical size */
+ cxt->phy_sector_size = cxt->sector_size;
+
+ /* no blkid or error, use default values */
+ if (!cxt->min_io_size)
+ cxt->min_io_size = cxt->sector_size;
+ if (!cxt->io_size)
+ cxt->io_size = cxt->sector_size;
+
+ DBG(CXT, ul_debugobj(cxt, "result: log/phy sector size: %ld/%ld",
+ cxt->sector_size, cxt->phy_sector_size));
+ DBG(CXT, ul_debugobj(cxt, "result: fdisk/min/optimal io: %ld/%ld/%ld",
+ cxt->io_size, cxt->optimal_io_size, cxt->min_io_size));
+ return 0;
+}
+
+static int has_topology(struct fdisk_context *cxt)
+{
+ /*
+ * Assume that the device provides topology info if
+ * optimal_io_size is set or alignment_offset is set or
+ * minimum_io_size is not power of 2.
+ */
+ if (cxt &&
+ (cxt->optimal_io_size ||
+ cxt->alignment_offset ||
+ !is_power_of_2(cxt->min_io_size)))
+ return 1;
+ return 0;
+}
+
+/*
+ * The LBA of the first partition is based on the device geometry and topology.
+ * This offset is generic (and recommended) for all labels.
+ *
+ * Returns: 0 on error or number of logical sectors.
+ */
+static fdisk_sector_t topology_get_first_lba(struct fdisk_context *cxt)
+{
+ fdisk_sector_t x = 0, res;
+
+ if (!cxt)
+ return 0;
+
+ if (!cxt->io_size)
+ fdisk_discover_topology(cxt);
+
+ /*
+ * Align the begin of partitions to:
+ *
+ * a) topology
+ * a2) alignment offset
+ * a1) or physical sector (minimal_io_size, aka "grain")
+ *
+ * b) or default to 1MiB (2048 sectrors, Windows Vista default)
+ *
+ * c) or for very small devices use 1 phy.sector
+ */
+ if (has_topology(cxt)) {
+ if (cxt->alignment_offset)
+ x = cxt->alignment_offset;
+ else if (cxt->io_size > 2048 * 512)
+ x = cxt->io_size;
+ }
+ /* default to 1MiB */
+ if (!x)
+ x = 2048 * 512;
+
+ res = x / cxt->sector_size;
+
+ /* don't use huge offset on small devices */
+ if (cxt->total_sectors <= res * 4)
+ res = cxt->phy_sector_size / cxt->sector_size;
+
+ return res;
+}
+
+static unsigned long topology_get_grain(struct fdisk_context *cxt)
+{
+ unsigned long res;
+
+ if (!cxt)
+ return 0;
+
+ if (!cxt->io_size)
+ fdisk_discover_topology(cxt);
+
+ res = cxt->io_size;
+
+ /* use 1MiB grain always when possible */
+ if (res < 2048 * 512)
+ res = 2048 * 512;
+
+ /* don't use huge grain on small devices */
+ if (cxt->total_sectors <= (res * 4 / cxt->sector_size))
+ res = cxt->phy_sector_size;
+
+ return res;
+}
+
+/**
+ * fdisk_reset_alignment:
+ * @cxt: fdisk context
+ *
+ * Resets alignment setting to the default and label specific values. This
+ * function does not change device properties (I/O limits, geometry etc.).
+ *
+ * Returns: 0 on success, < 0 in case of error.
+ */
+int fdisk_reset_alignment(struct fdisk_context *cxt)
+{
+ int rc = 0;
+
+ if (!cxt)
+ return -EINVAL;
+
+ DBG(CXT, ul_debugobj(cxt, "reseting alignment..."));
+
+ /* default */
+ cxt->grain = topology_get_grain(cxt);
+ cxt->first_lba = topology_get_first_lba(cxt);
+ cxt->last_lba = cxt->total_sectors - 1;
+
+ /* overwrite default by label stuff */
+ if (cxt->label && cxt->label->op->reset_alignment)
+ rc = cxt->label->op->reset_alignment(cxt);
+
+ DBG(CXT, ul_debugobj(cxt, "alignment reseted to: "
+ "first LBA=%ju, last LBA=%ju, grain=%lu [rc=%d]",
+ (uintmax_t) cxt->first_lba, (uintmax_t) cxt->last_lba,
+ cxt->grain, rc));
+ return rc;
+}
+
+
+fdisk_sector_t fdisk_scround(struct fdisk_context *cxt, fdisk_sector_t num)
+{
+ fdisk_sector_t un = fdisk_get_units_per_sector(cxt);
+ return (num + un - 1) / un;
+}
+
+fdisk_sector_t fdisk_cround(struct fdisk_context *cxt, fdisk_sector_t num)
+{
+ return fdisk_use_cylinders(cxt) ?
+ (num / fdisk_get_units_per_sector(cxt)) + 1 : num;
+}
+
+/**
+ * fdisk_reread_partition_table:
+ * @cxt: context
+ *
+ * Force *kernel* to re-read partition table on block devices.
+ *
+ * Returns: 0 on success, < 0 in case of error.
+ */
+int fdisk_reread_partition_table(struct fdisk_context *cxt)
+{
+ int i;
+ struct stat statbuf;
+
+ assert(cxt);
+ assert(cxt->dev_fd >= 0);
+
+ i = fstat(cxt->dev_fd, &statbuf);
+ if (i == 0 && S_ISBLK(statbuf.st_mode)) {
+ sync();
+#ifdef BLKRRPART
+ fdisk_info(cxt, _("Calling ioctl() to re-read partition table."));
+ i = ioctl(cxt->dev_fd, BLKRRPART);
+#else
+ errno = ENOSYS;
+ i = 1;
+#endif
+ }
+
+ if (i) {
+ fdisk_warn(cxt, _("Re-reading the partition table failed."));
+ fdisk_info(cxt, _(
+ "The kernel still uses the old table. The "
+ "new table will be used at the next reboot "
+ "or after you run partprobe(8) or kpartx(8)."));
+ return -errno;
+ }
+
+ return 0;
+}