btrfs-progs: fix regression preventing send -p with subvolumes mounted on "/"

[btrfs-progs-unstable/devel.git] / cmds-fi-du.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <getopt.h>
#include <fcntl.h>
#include <dirent.h>

#include <sys/ioctl.h>
#include <linux/fs.h>
#include <linux/version.h>
#include <linux/fiemap.h>

#if !defined(FIEMAP_EXTENT_SHARED) && (HAVE_OWN_FIEMAP_EXTENT_SHARED_DEFINE == 1)
#define FIEMAP_EXTENT_SHARED           0x00002000
#endif

#include "utils.h"
#include "commands.h"
#include "kerncompat.h"
#include "rbtree.h"

#include "interval_tree_generic.h"
#include "help.h"
#include "fsfeatures.h"

static int summarize = 0;
static unsigned unit_mode = UNITS_RAW;
static char path[PATH_MAX] = { 0, };
static char *pathp = path;
static char *path_max = &path[PATH_MAX - 1];

struct shared_extent {
        struct rb_node  rb;
        u64     start;  /* Start of interval */
        u64     last;   /* Last location _in_ interval */
        u64     __subtree_last;
};

/*
 * extent_tree_* functions are defined in the massive interval tree
 * macro below. This serves to illustrate the api in human-readable
 * terms.
 */
static void
extent_tree_insert(struct shared_extent *node, struct rb_root *root);

static void
extent_tree_remove(struct shared_extent *node, struct rb_root *root);

static struct shared_extent *
extent_tree_iter_first(struct rb_root *root,
                       u64 start, u64 last);

static struct shared_extent *
extent_tree_iter_next(struct shared_extent *node,
                        u64 start, u64 last);

#define START(node) ((node)->start)
#define LAST(node)  ((node)->last)

INTERVAL_TREE_DEFINE(struct shared_extent, rb,
                     u64, __subtree_last,
                     START, LAST, static, extent_tree)

static int add_shared_extent(u64 start, u64 len, struct rb_root *root)
{
        struct shared_extent *sh;

        ASSERT(len != 0);

        sh = calloc(1, sizeof(*sh));
        if (!sh)
                return -ENOMEM;

        sh->start = start;
        sh->last = (start + len - 1);

        extent_tree_insert(sh, root);

        return 0;
}

static void cleanup_shared_extents(struct rb_root *root)
{
        struct shared_extent *s;
        struct shared_extent *tmp;

        if (!root)
                return;

        s = extent_tree_iter_first(root, 0, -1ULL);
        while (s) {
                tmp = extent_tree_iter_next(s, 0, -1ULL);
                extent_tree_remove(s, root);

                free(s);
                s = tmp;
        }
}

#define dbgprintf(...)

/*
 * Find all extents which overlap 'n', calculate the space
 * covered by them and remove those nodes from the tree.
 */
static u64 count_unique_bytes(struct rb_root *root, struct shared_extent *n)
{
        struct shared_extent *tmp;
        u64 wstart = n->start;
        u64 wlast = n->last;

        dbgprintf("Count overlaps:");

        do {
                /*
                 * Expand our search window based on the lastest
                 * overlapping extent. Doing this will allow us to
                 * find all possible overlaps
                 */
                if (wstart > n->start)
                        wstart = n->start;
                if (wlast < n->last)
                        wlast = n->last;

                dbgprintf(" (%llu, %llu)", n->start, n->last);

                tmp = n;
                n = extent_tree_iter_next(n, wstart, wlast);

                extent_tree_remove(tmp, root);
                free(tmp);
        } while (n);

        dbgprintf("; wstart: %llu wlast: %llu total: %llu\n", wstart,
                wlast, wlast - wstart + 1);

        return wlast - wstart + 1;
}

/*
 * What we want to do here is get a count of shared bytes within the
 * set of extents we have collected. Specifically, we don't want to
 * count any byte more than once, so just adding them up doesn't
 * work.
 *
 * For each set of overlapping extents we find the lowest start and
 * highest end. From there we have the actual number of bytes which is
 * shared across all of the extents in our set. A sum of each sets
 * extent length is returned.
 */
static void count_shared_bytes(struct rb_root *root, u64 *ret_cnt)
{
        u64 count = 0;
        struct shared_extent *s = extent_tree_iter_first(root,
                                                         0, -1ULL);

        if (!s)
                goto out;

        while (s) {
                /*
                 * Find all extents which overlap 's', calculate the space
                 * covered by them and remove those nodes from the tree.
                 */
                count += count_unique_bytes(root, s);

                /*
                 * Since count_unique_bytes will be emptying the tree,
                 * we can grab the first node here
                 */
                s = extent_tree_iter_first(root, 0, -1ULL);
        }

        BUG_ON(!RB_EMPTY_ROOT(root));
out:
        *ret_cnt = count;
}

/* Track which inodes we've seen for the purposes of hardlink detection. */
struct seen_inode {
        struct rb_node  i_node;
        u64             i_ino;
        u64             i_subvol;
};
static struct rb_root seen_inodes = RB_ROOT;

static int cmp_si(struct seen_inode *si, u64 ino, u64 subvol)
{
        if (ino < si->i_ino)
                return -1;
        else if (ino > si->i_ino)
                return 1;
        if (subvol < si->i_subvol)
                return -1;
        else if (subvol > si->i_subvol)
                return 1;
        return 0;
}

static int mark_inode_seen(u64 ino, u64 subvol)
{
        int cmp;
        struct rb_node **p = &seen_inodes.rb_node;
        struct rb_node *parent = NULL;
        struct seen_inode *si;

        while (*p) {
                parent = *p;

                si = rb_entry(parent, struct seen_inode, i_node);
                cmp = cmp_si(si, ino, subvol);
                if (cmp < 0)
                        p = &(*p)->rb_left;
                else if (cmp > 0)
                        p = &(*p)->rb_right;
                else
                        return -EEXIST;
        }

        si = calloc(1, sizeof(*si));
        if (!si)
                return -ENOMEM;

        si->i_ino = ino;
        si->i_subvol = subvol;

        rb_link_node(&si->i_node, parent, p);
        rb_insert_color(&si->i_node, &seen_inodes);

        return 0;
}

static int inode_seen(u64 ino, u64 subvol)
{
        int cmp;
        struct rb_node *n = seen_inodes.rb_node;
        struct seen_inode *si;

        while (n) {
                si = rb_entry(n, struct seen_inode, i_node);

                cmp = cmp_si(si, ino, subvol);
                if (cmp < 0)
                        n = n->rb_left;
                else if (cmp > 0)
                        n = n->rb_right;
                else
                        return -EEXIST;
        }
        return 0;
}

static void clear_seen_inodes(void)
{
        struct rb_node *n = rb_first(&seen_inodes);
        struct seen_inode *si;

        while (n) {
                si = rb_entry(n, struct seen_inode, i_node);

                rb_erase(&si->i_node, &seen_inodes);
                free(si);

                n = rb_first(&seen_inodes);
        }
}

/*
 * Inline extents are skipped because they do not take data space,
 * delalloc and unknown are skipped because we do not know how much
 * space they will use yet.
 */
#define SKIP_FLAGS      (FIEMAP_EXTENT_UNKNOWN|FIEMAP_EXTENT_DELALLOC|FIEMAP_EXTENT_DATA_INLINE)
static int du_calc_file_space(int fd, struct rb_root *shared_extents,
                              u64 *ret_total, u64 *ret_shared)
{
        char buf[16384];
        struct fiemap *fiemap = (struct fiemap *)buf;
        struct fiemap_extent *fm_ext = &fiemap->fm_extents[0];
        int count = (sizeof(buf) - sizeof(*fiemap)) /
                        sizeof(struct fiemap_extent);
        unsigned int i, ret;
        int last = 0;
        int rc;
        u64 ext_len;
        u64 file_total = 0;
        u64 file_shared = 0;
        u32 flags;

        memset(fiemap, 0, sizeof(struct fiemap));

        do {
                fiemap->fm_length = ~0ULL;
                fiemap->fm_extent_count = count;
                rc = ioctl(fd, FS_IOC_FIEMAP, (unsigned long) fiemap);
                if (rc < 0) {
                        ret = -errno;
                        goto out;
                }

                /* If 0 extents are returned, then more ioctls are not needed */
                if (fiemap->fm_mapped_extents == 0)
                        break;

                for (i = 0; i < fiemap->fm_mapped_extents; i++) {
                        ext_len = fm_ext[i].fe_length;
                        flags = fm_ext[i].fe_flags;

                        if (flags & FIEMAP_EXTENT_LAST)
                                last = 1;

                        if (flags & SKIP_FLAGS)
                                continue;

                        if (ext_len == 0) {
                                warning("extent %llu has length 0, skipping",
                                        (unsigned long long)fm_ext[i].fe_physical);
                                continue;
                        }

                        file_total += ext_len;
                        if (flags & FIEMAP_EXTENT_SHARED) {
                                file_shared += ext_len;

                                if (shared_extents) {
                                        ret = add_shared_extent(fm_ext[i].fe_physical,
                                                                ext_len,
                                                                shared_extents);
                                        if (ret)
                                                goto out;
                                }
                        }
                }

                fiemap->fm_start = (fm_ext[i - 1].fe_logical +
                                    fm_ext[i - 1].fe_length);
        } while (last == 0);

        *ret_total = file_total;
        *ret_shared = file_shared;

        ret = 0;
out:
        return ret;
}

struct du_dir_ctxt {
        u64             bytes_total;
        u64             bytes_shared;
        DIR             *dirstream;
        struct rb_root  shared_extents;
};
#define INIT_DU_DIR_CTXT        (struct du_dir_ctxt) { 0ULL, 0ULL, NULL, RB_ROOT }

static int du_add_file(const char *filename, int dirfd,
                       struct rb_root *shared_extents, u64 *ret_total,
                       u64 *ret_shared, int top_level);

static int du_walk_dir(struct du_dir_ctxt *ctxt, struct rb_root *shared_extents)
{
        int ret, type;
        struct dirent *entry;
        DIR *dirstream = ctxt->dirstream;

        ret = 0;
        do {
                u64 tot, shr;

                errno = 0;
                entry = readdir(dirstream);
                if (entry) {
                        if (strcmp(entry->d_name, ".") == 0
                            || strcmp(entry->d_name, "..") == 0)
                                continue;

                        type = entry->d_type;
                        if (type == DT_REG || type == DT_DIR) {
                                tot = shr = 0;

                                ret = du_add_file(entry->d_name,
                                                  dirfd(dirstream),
                                                  shared_extents, &tot, &shr,
                                                  0);
                                if (ret == -ENOTTY) {
                                        ret = 0;
                                        continue;
                                } else if (ret) {
                                        fprintf(stderr,
                                                "failed to walk dir/file: %s :%s\n",
                                                entry->d_name, strerror(-ret));
                                        break;
                                }

                                ctxt->bytes_total += tot;
                                ctxt->bytes_shared += shr;
                        }
                }
        } while (entry != NULL);

        return ret;
}

static int du_add_file(const char *filename, int dirfd,
                       struct rb_root *shared_extents, u64 *ret_total,
                       u64 *ret_shared, int top_level)
{
        int ret, len = strlen(filename);
        char *pathtmp;
        struct stat st;
        struct du_dir_ctxt dir = INIT_DU_DIR_CTXT;
        int is_dir = 0;
        u64 file_total = 0;
        u64 file_shared = 0;
        u64 dir_set_shared = 0;
        int fd;
        DIR *dirstream = NULL;

        ret = fstatat(dirfd, filename, &st, 0);
        if (ret)
                return -errno;

        if (!S_ISREG(st.st_mode) && !S_ISDIR(st.st_mode))
                return 0;

        if (len > (path_max - pathp)) {
                error("path too long: %s %s", path, filename);
                return -ENAMETOOLONG;
        }

        pathtmp = pathp;
        if (pathp == path || *(pathp - 1) == '/')
                ret = sprintf(pathp, "%s", filename);
        else
                ret = sprintf(pathp, "/%s", filename);
        pathp += ret;

        fd = open_file_or_dir3(path, &dirstream, O_RDONLY);
        if (fd < 0) {
                ret = -errno;
                goto out;
        }

        /*
         * If st.st_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ==2, there is no any
         * related tree
         */
        if (st.st_ino != BTRFS_EMPTY_SUBVOL_DIR_OBJECTID) {
                u64 subvol;

                ret = lookup_path_rootid(fd, &subvol);
                if (ret)
                        goto out_close;

                if (inode_seen(st.st_ino, subvol))
                        goto out_close;

                ret = mark_inode_seen(st.st_ino, subvol);
                if (ret)
                        goto out_close;
        }

        if (S_ISREG(st.st_mode)) {
                ret = du_calc_file_space(fd, shared_extents, &file_total,
                                         &file_shared);
                if (ret)
                        goto out_close;
        } else if (S_ISDIR(st.st_mode)) {
                struct rb_root *root = shared_extents;

                /*
                 * We collect shared extents in an rb_root, the top
                 * level caller will not pass a root down, so use the
                 * one on our dir context.
                 */
                if (top_level)
                        root = &dir.shared_extents;

                is_dir = 1;

                dir.dirstream = dirstream;
                ret = du_walk_dir(&dir, root);
                *pathp = '\0';
                if (ret) {
                        if (top_level)
                                cleanup_shared_extents(root);
                        goto out_close;
                }

                file_total = dir.bytes_total;
                file_shared = dir.bytes_shared;
                if (top_level)
                        count_shared_bytes(root, &dir_set_shared);
        }

        if (!summarize || top_level) {
                u64 excl = file_total - file_shared;

                if (top_level) {
                        u64 set_shared = file_shared;

                        if (is_dir)
                                set_shared = dir_set_shared;

                        printf("%10s  %10s  %10s  %s\n",
                               pretty_size_mode(file_total, unit_mode),
                               pretty_size_mode(excl, unit_mode),
                               pretty_size_mode(set_shared, unit_mode),
                               path);
                } else {
                        printf("%10s  %10s  %10s  %s\n",
                               pretty_size_mode(file_total, unit_mode),
                               pretty_size_mode(excl, unit_mode),
                               "-", path);
                }
        }

        if (ret_total)
                *ret_total = file_total;
        if (ret_shared)
                *ret_shared = file_shared;

out_close:
        close_file_or_dir(fd, dirstream);
out:
        /* reset path to just before this element */
        pathp = pathtmp;

        return ret;
}

const char * const cmd_filesystem_du_usage[] = {
        "btrfs filesystem du [options] <path> [<path>..]",
        "Summarize disk usage of each file.",
        "-s|--summarize     display only a total for each argument",
        HELPINFO_UNITS_LONG,
        NULL
};

int cmd_filesystem_du(int argc, char **argv)
{
        int ret = 0, err = 0;
        int i;
        u32 kernel_version;

        unit_mode = get_unit_mode_from_arg(&argc, argv, 1);

        while (1) {
                static const struct option long_options[] = {
                        { "summarize", no_argument, NULL, 's'},
                        { NULL, 0, NULL, 0 }
                };
                int c = getopt_long(argc, argv, "s", long_options, NULL);

                if (c < 0)
                        break;
                switch (c) {
                case 's':
                        summarize = 1;
                        break;
                default:
                        usage(cmd_filesystem_du_usage);
                }
        }

        if (check_argc_min(argc - optind, 1))
                usage(cmd_filesystem_du_usage);

        kernel_version = get_running_kernel_version();

        if (kernel_version < KERNEL_VERSION(2,6,33)) {
                warning(
"old kernel version detected, shared space will be reported as exclusive\n"
"due to missing support for FIEMAP_EXTENT_SHARED flag");
        }

        printf("%10s  %10s  %10s  %s\n", "Total", "Exclusive", "Set shared",
                        "Filename");

        for (i = optind; i < argc; i++) {
                ret = du_add_file(argv[i], AT_FDCWD, NULL, NULL, NULL, 1);
                if (ret) {
                        error("cannot check space of '%s': %s", argv[i],
                                        strerror(-ret));
                        err = 1;
                }

                /* reset hard-link detection for each argument */
                clear_seen_inodes();
        }

        return err;
}