#include "clusterautoconfig.h"

#include <string.h>

#include <inttypes.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include "libgfs2.h"

#define PAGE_SIZE (4096)

#define DIV_RU(x, y) (((x) + (y) - 1) / (y))

int compute_heightsize(unsigned bsize, uint64_t *heightsize,

	uint32_t *maxheight, uint32_t bsize1, int diptrs, int inptrs)

{

	heightsize[0] = bsize - sizeof(struct gfs2_dinode);

	heightsize[1] = (uint64_t)bsize1 * diptrs;

	for (*maxheight = 2;; (*maxheight)++) {

		uint64_t space, d;

		uint32_t m;

		space = heightsize[*maxheight - 1] * inptrs;

		m = space % inptrs;

		d = space / inptrs;

		if (d != heightsize[*maxheight - 1] || m)

			break;

		heightsize[*maxheight] = space;

	}

	if (*maxheight > GFS2_MAX_META_HEIGHT) {

		errno = EINVAL;

		return -1;

	}

	return 0;

}

int compute_constants(struct gfs2_sbd *sdp)

{

	uint32_t hash_blocks, ind_blocks, leaf_blocks;

	uint32_t tmp_blocks;

	sdp->md.next_inum = 1;

	sdp->sd_sb.sb_bsize_shift = ffs(sdp->bsize) - 1;

	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -

		GFS2_BASIC_BLOCK_SHIFT;

	sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;

	sdp->sd_diptrs = (sdp->bsize - sizeof(struct gfs2_dinode)) /

		sizeof(uint64_t);

	sdp->sd_inptrs = (sdp->bsize - sizeof(struct gfs2_meta_header)) /

		sizeof(uint64_t);

	sdp->sd_jbsize = sdp->bsize - sizeof(struct gfs2_meta_header);

	sdp->sd_hash_bsize = sdp->bsize / 2;

	sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;

	sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(uint64_t);

	sdp->sd_blocks_per_bitmap = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header))

	                             * GFS2_NBBY;

	/*  Compute maximum reservation required to add a entry to a directory  */

	hash_blocks = DIV_RU(sizeof(uint64_t) * (1 << GFS2_DIR_MAX_DEPTH),

			     sdp->sd_jbsize);

	ind_blocks = 0;

	for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {

		tmp_blocks = DIV_RU(tmp_blocks, sdp->sd_inptrs);

		ind_blocks += tmp_blocks;

	}

	leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;

	sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;

	if (compute_heightsize(sdp->bsize, sdp->sd_heightsize, &sdp->sd_max_height,

				sdp->bsize, sdp->sd_diptrs, sdp->sd_inptrs)) {

		return -1;

	}

	if (compute_heightsize(sdp->bsize, sdp->sd_jheightsize, &sdp->sd_max_jheight,

				sdp->sd_jbsize, sdp->sd_diptrs, sdp->sd_inptrs)) {

		return -1;

	}

	return 0;

}

/* Returns 0 if fd1 and fd2 refer to the same device/file, 1 otherwise, or -1 on error */

static int fdcmp(int fd1, int fd2)

{

	struct stat st1, st2;

	if (fd1 < 0 || fd2 < 0)

		return -1;

	if ((fstat(fd1, &st1) != 0) || (fstat(fd2, &st2) != 0))

		return -1;

	if (S_ISBLK(st1.st_mode) && S_ISBLK(st2.st_mode)) {

		if (st1.st_rdev == st2.st_rdev) {

			return 0;

		}

	} else if ((st1.st_dev == st2.st_dev) && (st1.st_ino == st2.st_ino)) {

			return 0;

	}

	return 1;

}

int lgfs2_open_mnt(const char *path, int dirflags, int *dirfd, int devflags, int *devfd, struct mntent **mnt)

{

	FILE *fp = setmntent("/proc/mounts", "r");

	if (fp == NULL) {

		perror("open: /proc/mounts");

		return 1;

	}

	/* Assume path is mount point until we know better. */

	*dirfd = open(path, dirflags);

	if (*dirfd < 0)

		return 1;

	while ((*mnt = getmntent(fp)) != NULL) {

		int fd;

		if (strcmp((*mnt)->mnt_type, "gfs2") != 0)

			continue;

		*devfd = open((*mnt)->mnt_fsname, devflags);

		/* Defer checking *devfd until later: whether it's ok to ignore

		 * the error depends on whether we find the mount point. */

		if (strcmp(path, (*mnt)->mnt_dir) == 0)

			break;

		if (strcmp(path, (*mnt)->mnt_fsname) == 0 || fdcmp(*dirfd, *devfd) == 0) {

			/* We have a match but our above assumption was

			   incorrect and *dirfd is actually the device. */

			close(*dirfd);

			*dirfd = open((*mnt)->mnt_dir, dirflags);

			break;

		}

		fd = open((*mnt)->mnt_dir, dirflags);

		if (fd >= 0) {

			int diff = fdcmp(*dirfd, fd);

			close(fd);

			if (diff == 0)

				break;

		}

		if (*devfd >= 0)

			close(*devfd);

	}

	endmntent(fp);

	if (*mnt == NULL) {

		close(*dirfd);

		return 0; /* Success. Answer is no. Both fds closed. */

	}

	if (*dirfd < 0) {

		close(*devfd);

		return 1;

	}

	if (*devfd < 0) {

		close(*dirfd);

		return 1;

	}

	return 0; /* Success. Answer is yes. Both fds open. */

}

int lgfs2_open_mnt_dev(const char *path, int flags, struct mntent **mnt)

{

	int dirfd = -1;

	int devfd = -1;

	if (lgfs2_open_mnt(path, O_RDONLY, &dirfd, flags, &devfd, mnt) != 0)

		return -1;

	if (*mnt != NULL)

		close(dirfd);

	return devfd;

}

int lgfs2_open_mnt_dir(const char *path, int flags, struct mntent **mnt)

{

	int dirfd = -1;

	int devfd = -1;

	if (lgfs2_open_mnt(path, flags, &dirfd, O_RDONLY, &devfd, mnt) != 0)

		return -1;

	if (*mnt != NULL)

		close(devfd);

	return dirfd;

}