/**
* ubifs_get_free_space_nolock - return amount of free space.
* @c: UBIFS file-system description object
*
* This function calculates amount of free space to report to user-space.
*
* Because UBIFS may introduce substantial overhead (the index, node headers,
* alignment, wastage at the end of LEBs, etc), it cannot report real amount of
* free flash space it has (well, because not all dirty space is reclaimable,
* UBIFS does not actually know the real amount). If UBIFS did so, it would
* bread user expectations about what free space is. Users seem to accustomed
* to assume that if the file-system reports N bytes of free space, they would
* be able to fit a file of N bytes to the FS. This almost works for
* traditional file-systems, because they have way less overhead than UBIFS.
* So, to keep users happy, UBIFS tries to take the overhead into account.
*/
long long ubifs_get_free_space_nolock(struct ubifs_info *c)
{
int rsvd_idx_lebs, lebs;
long long available, outstanding, free;
ubifs_assert(c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
outstanding = c->bi.data_growth + c->bi.dd_growth;
available = ubifs_calc_available(c, c->bi.min_idx_lebs);
/*
* When reporting free space to user-space, UBIFS guarantees that it is
* possible to write a file of free space size. This means that for
* empty LEBs we may use more precise calculations than
* 'ubifs_calc_available()' is using. Namely, we know that in empty
* LEBs we would waste only @c->leb_overhead bytes, not @c->dark_wm.
* Thus, amend the available space.
*
* Note, the calculations below are similar to what we have in
* 'do_budget_space()', so refer there for comments.
*/
if (c->bi.min_idx_lebs > c->lst.idx_lebs)
rsvd_idx_lebs = c->bi.min_idx_lebs - c->lst.idx_lebs;
else
rsvd_idx_lebs = 0;
lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
c->lst.taken_empty_lebs;
lebs -= rsvd_idx_lebs;
available += lebs * (c->dark_wm - c->leb_overhead);
if (available > outstanding)
free = ubifs_reported_space(c, available - outstanding);
else
free = 0;
return free;
}
/**
* ubifs_get_free_space - return amount of free space.
* @c: UBIFS file-system description object
*
* This function calculates amount of free space to report to user-space.
*
* Because UBIFS may introduce substantial overhead (the index, node headers,
* alighment, wastage at the end of eraseblocks, etc), it cannot report real
* amount of free flash space it has (well, because not all dirty space is
* reclamable, UBIFS does not actually know the real amount). If UBIFS did so,
* it would bread user expectetion about what free space is. Users seem to
* accustomed to assume that if the file-system reports N bytes of free space,
* they would be able to fit a file of N bytes to the FS. This almost works for
* traditional file-systems, because they have way less overhead than UBIFS.
* So, to keep users happy, UBIFS tries to take the overhead into account.
*/
long long ubifs_get_free_space(struct ubifs_info *c)
{
int min_idx_lebs, rsvd_idx_lebs, lebs;
long long available, outstanding, free;
spin_lock(&c->space_lock);
min_idx_lebs = ubifs_calc_min_idx_lebs(c);
outstanding = c->budg_data_growth + c->budg_dd_growth;
/*
* Force the amount available to the total size reported if the used
* space is zero.
*/
if (c->lst.total_used <= UBIFS_INO_NODE_SZ && !outstanding) {
spin_unlock(&c->space_lock);
return (long long)c->block_cnt << UBIFS_BLOCK_SHIFT;
}
available = ubifs_calc_available(c, min_idx_lebs);
/*
* When reporting free space to user-space, UBIFS guarantees that it is
* possible to write a file of free space size. This means that for
* empty LEBs we may use more precise calculations than
* 'ubifs_calc_available()' is using. Namely, we know that in empty
* LEBs we would waste only @c->leb_overhead bytes, not @c->dark_wm.
* Thus, amend the available space.
*
* Note, the calculations below are similar to what we have in
* 'do_budget_space()', so refer there for comments.
*/
if (min_idx_lebs > c->lst.idx_lebs)
rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs;
else
rsvd_idx_lebs = 0;
lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
c->lst.taken_empty_lebs;
lebs -= rsvd_idx_lebs;
available += lebs * (c->dark_wm - c->leb_overhead);
spin_unlock(&c->space_lock);
if (available > outstanding)
free = ubifs_reported_space(c, available - outstanding);
else
free = 0;
return free;
}
/**
* ubifs_release_dirty_inode_budget - release dirty inode budget.
* @c: UBIFS file-system description object
* @ui: UBIFS inode to release the budget for
*
* This function releases budget corresponding to a dirty inode. It is usually
* called when after the inode has been written to the media and marked as
* clean.
*/
void ubifs_release_dirty_inode_budget(struct ubifs_info *c,
struct ubifs_inode *ui)
{
struct ubifs_budget_req req = {.dd_growth = c->inode_budget,
.dirtied_ino_d = ui->data_len};
ubifs_release_budget(c, &req);
}
/**
* ubifs_budg_get_free_space - return amount of free space.
* @c: UBIFS file-system description object
*
* This function returns amount of free space on the file-system.
*/
long long ubifs_budg_get_free_space(struct ubifs_info *c)
{
int min_idx_lebs, rsvd_idx_lebs;
long long available, outstanding, free;
/* Do exactly the same calculations as in 'do_budget_space()' */
spin_lock(&c->space_lock);
min_idx_lebs = ubifs_calc_min_idx_lebs(c);
if (min_idx_lebs > c->lst.idx_lebs)
rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs;
else
rsvd_idx_lebs = 0;
if (rsvd_idx_lebs > c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt
- c->lst.taken_empty_lebs) {
spin_unlock(&c->space_lock);
return 0;
}
available = ubifs_calc_available(c, min_idx_lebs);
outstanding = c->budg_data_growth + c->budg_dd_growth;
c->min_idx_lebs = min_idx_lebs;
spin_unlock(&c->space_lock);
if (available > outstanding)
free = ubifs_reported_space(c, available - outstanding);
else
free = 0;
return free;
}
/*
* init_constants_master - initialize UBIFS constants.
* @c: UBIFS file-system description object
*
* This is a helper function which initializes various UBIFS constants after
* the master node has been read. It also checks various UBIFS parameters and
* makes sure they are all right.
*/
static void init_constants_master(struct ubifs_info *c)
{
long long tmp64;
c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);
/*
* Calculate total amount of FS blocks. This number is not used
* internally because it does not make much sense for UBIFS, but it is
* necessary to report something for the 'statfs()' call.
*
* Subtract the LEB reserved for GC, the LEB which is reserved for
* deletions, minimum LEBs for the index, and assume only one journal
* head is available.
*/
tmp64 = c->main_lebs - 1 - 1 - MIN_INDEX_LEBS - c->jhead_cnt + 1;
tmp64 *= (long long)c->leb_size - c->leb_overhead;
tmp64 = ubifs_reported_space(c, tmp64);
c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
}
if (c->vfs_sb->s_flags & MS_RDONLY)
dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
c->old_leb_cnt, c->leb_cnt);
else {
dbg_mnt("Auto resizing (sb) from %d LEBs to %d LEBs",
c->old_leb_cnt, c->leb_cnt);
sup->leb_cnt = cpu_to_le32(c->leb_cnt);
err = ubifs_write_sb_node(c, sup);
if (err)
goto out;
c->old_leb_cnt = c->leb_cnt;
}
}
c->log_bytes = (long long)c->log_lebs * c->leb_size;
c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
c->orph_first = c->lpt_last + 1;
c->orph_last = c->orph_first + c->orph_lebs - 1;
c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
c->main_first = c->leb_cnt - c->main_lebs;
c->report_rp_size = ubifs_reported_space(c, c->rp_size);
err = validate_sb(c, sup);
out:
kfree(sup);
return err;
}
