#include "ubifs.h"
#include <linux/writeback.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
/*
* When pessimistic budget calculations say that there is no enough space,
* UBIFS starts writing back dirty inodes and pages, doing garbage collection,
- * or committing. The below constants define maximum number of times UBIFS
+ * or committing. The below constant defines maximum number of times UBIFS
* repeats the operations.
*/
-#define MAX_SHRINK_RETRIES 8
-#define MAX_GC_RETRIES 4
-#define MAX_CMT_RETRIES 2
-#define MAX_NOSPC_RETRIES 1
+#define MAX_MKSPC_RETRIES 3
/*
* The below constant defines amount of dirty pages which should be written
*/
#define NR_TO_WRITE 16
-/**
- * struct retries_info - information about re-tries while making free space.
- * @prev_liability: previous liability
- * @shrink_cnt: how many times the liability was shrinked
- * @shrink_retries: count of liability shrink re-tries (increased when
- * liability does not shrink)
- * @try_gc: GC should be tried first
- * @gc_retries: how many times GC was run
- * @cmt_retries: how many times commit has been done
- * @nospc_retries: how many times GC returned %-ENOSPC
- *
- * Since we consider budgeting to be the fast-path, and this structure has to
- * be allocated on stack and zeroed out, we make it smaller using bit-fields.
- */
-struct retries_info {
- long long prev_liability;
- unsigned int shrink_cnt;
- unsigned int shrink_retries:5;
- unsigned int try_gc:1;
- unsigned int gc_retries:4;
- unsigned int cmt_retries:3;
- unsigned int nospc_retries:1;
-};
-
/**
* shrink_liability - write-back some dirty pages/inodes.
* @c: UBIFS file-system description object
return 0;
}
+/**
+ * get_liability - calculate current liability.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates and returns current UBIFS liability, i.e. the
+ * amount of bytes UBIFS has "promised" to write to the media.
+ */
+static long long get_liability(struct ubifs_info *c)
+{
+ long long liab;
+
+ spin_lock(&c->space_lock);
+ liab = c->budg_idx_growth + c->budg_data_growth + c->budg_dd_growth;
+ spin_unlock(&c->space_lock);
+ return liab;
+}
+
/**
* make_free_space - make more free space on the file-system.
* @c: UBIFS file-system description object
- * @ri: information about previous invocations of this function
*
* This function is called when an operation cannot be budgeted because there
* is supposedly no free space. But in most cases there is some free space:
* Returns %-ENOSPC if it couldn't do more free space, and other negative error
* codes on failures.
*/
-static int make_free_space(struct ubifs_info *c, struct retries_info *ri)
+static int make_free_space(struct ubifs_info *c)
{
- int err;
-
- /*
- * If we have some dirty pages and inodes (liability), try to write
- * them back unless this was tried too many times without effect
- * already.
- */
- if (ri->shrink_retries < MAX_SHRINK_RETRIES && !ri->try_gc) {
- long long liability;
-
- spin_lock(&c->space_lock);
- liability = c->budg_idx_growth + c->budg_data_growth +
- c->budg_dd_growth;
- spin_unlock(&c->space_lock);
+ int err, retries = 0;
+ long long liab1, liab2;
- if (ri->prev_liability >= liability) {
- /* Liability does not shrink, next time try GC then */
- ri->shrink_retries += 1;
- if (ri->gc_retries < MAX_GC_RETRIES)
- ri->try_gc = 1;
- dbg_budg("liability did not shrink: retries %d of %d",
- ri->shrink_retries, MAX_SHRINK_RETRIES);
- }
+ do {
+ liab1 = get_liability(c);
+ /*
+ * We probably have some dirty pages or inodes (liability), try
+ * to write them back.
+ */
+ dbg_budg("liability %lld, run write-back", liab1);
+ shrink_liability(c, NR_TO_WRITE);
- dbg_budg("force write-back (count %d)", ri->shrink_cnt);
- shrink_liability(c, NR_TO_WRITE + ri->shrink_cnt);
+ liab2 = get_liability(c);
+ if (liab2 < liab1)
+ return -EAGAIN;
- ri->prev_liability = liability;
- ri->shrink_cnt += 1;
- return -EAGAIN;
- }
+ dbg_budg("new liability %lld (not shrinked)", liab2);
- /*
- * Try to run garbage collector unless it was already tried too many
- * times.
- */
- if (ri->gc_retries < MAX_GC_RETRIES) {
- ri->gc_retries += 1;
- dbg_budg("run GC, retries %d of %d",
- ri->gc_retries, MAX_GC_RETRIES);
-
- ri->try_gc = 0;
+ /* Liability did not shrink again, try GC */
+ dbg_budg("Run GC");
err = run_gc(c);
if (!err)
return -EAGAIN;
- if (err == -EAGAIN) {
- dbg_budg("GC asked to commit");
- err = ubifs_run_commit(c);
- if (err)
- return err;
- return -EAGAIN;
- }
-
- if (err != -ENOSPC)
- return err;
-
- /*
- * GC could not make any progress. If this is the first time,
- * then it makes sense to try to commit, because it might make
- * some dirty space.
- */
- dbg_budg("GC returned -ENOSPC, retries %d",
- ri->nospc_retries);
- if (ri->nospc_retries >= MAX_NOSPC_RETRIES)
+ if (err != -EAGAIN && err != -ENOSPC)
+ /* Some real error happened */
return err;
- ri->nospc_retries += 1;
- }
- /* Neither GC nor write-back helped, try to commit */
- if (ri->cmt_retries < MAX_CMT_RETRIES) {
- ri->cmt_retries += 1;
- dbg_budg("run commit, retries %d of %d",
- ri->cmt_retries, MAX_CMT_RETRIES);
+ dbg_budg("Run commit (retries %d)", retries);
err = ubifs_run_commit(c);
if (err)
return err;
- return -EAGAIN;
- }
+ } while (retries++ < MAX_MKSPC_RETRIES);
+
return -ENOSPC;
}
*/
int ubifs_calc_min_idx_lebs(struct ubifs_info *c)
{
- int ret;
- uint64_t idx_size;
+ int idx_lebs, eff_leb_size = c->leb_size - c->max_idx_node_sz;
+ long long idx_size;
idx_size = c->old_idx_sz + c->budg_idx_growth + c->budg_uncommitted_idx;
* pair, nor similarly the two variables for the new index size, so we
* have to do this costly 64-bit division on fast-path.
*/
- if (do_div(idx_size, c->leb_size - c->max_idx_node_sz))
- ret = idx_size + 1;
- else
- ret = idx_size;
+ idx_size += eff_leb_size - 1;
+ idx_lebs = div_u64(idx_size, eff_leb_size);
/*
* The index head is not available for the in-the-gaps method, so add an
* extra LEB to compensate.
*/
- ret += 1;
- /*
- * At present the index needs at least 2 LEBs: one for the index head
- * and one for in-the-gaps method (which currently does not cater for
- * the index head and so excludes it from consideration).
- */
- if (ret < 2)
- ret = 2;
- return ret;
+ idx_lebs += 1;
+ if (idx_lebs < MIN_INDEX_LEBS)
+ idx_lebs = MIN_INDEX_LEBS;
+ return idx_lebs;
}
/**
int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)
{
int uninitialized_var(cmt_retries), uninitialized_var(wb_retries);
- int err, idx_growth, data_growth, dd_growth;
- struct retries_info ri;
+ int err, idx_growth, data_growth, dd_growth, retried = 0;
ubifs_assert(req->new_page <= 1);
ubifs_assert(req->dirtied_page <= 1);
if (!data_growth && !dd_growth)
return 0;
idx_growth = calc_idx_growth(c, req);
- memset(&ri, 0, sizeof(struct retries_info));
again:
spin_lock(&c->space_lock);
return err;
}
- err = make_free_space(c, &ri);
+ err = make_free_space(c);
+ cond_resched();
if (err == -EAGAIN) {
dbg_budg("try again");
- cond_resched();
goto again;
} else if (err == -ENOSPC) {
+ if (!retried) {
+ retried = 1;
+ dbg_budg("-ENOSPC, but anyway try once again");
+ goto again;
+ }
dbg_budg("FS is full, -ENOSPC");
c->nospace = 1;
if (can_use_rp(c) || c->rp_size == 0)
* user-space. User-space application tend to expect that if the file-system
* (e.g., via the 'statfs()' call) reports that it has N bytes available, they
* are able to write a file of size N. UBIFS attaches node headers to each data
- * node and it has to write indexind nodes as well. This introduces additional
- * overhead, and UBIFS it has to report sligtly less free space to meet the
- * above expectetion.
+ * node and it has to write indexing nodes as well. This introduces additional
+ * overhead, and UBIFS has to report slightly less free space to meet the above
+ * expectations.
*
* This function assumes free space is made up of uncompressed data nodes and
* full index nodes (one per data node, tripled because we always allow enough
* Note, the calculation is pessimistic, which means that most of the time
* UBIFS reports less space than it actually has.
*/
-long long ubifs_reported_space(const struct ubifs_info *c, uint64_t free)
+long long ubifs_reported_space(const struct ubifs_info *c, long long free)
{
int divisor, factor, f;
* of data nodes, f - fanout. Because effective UBIFS fanout is twice
* as less than maximum fanout, we assume that each data node
* introduces 3 * @c->max_idx_node_sz / (@c->fanout/2 - 1) bytes.
- * Note, the multiplier 3 is because UBIFS reseves thrice as more space
+ * Note, the multiplier 3 is because UBIFS reserves thrice as more space
* for the index.
*/
f = c->fanout > 3 ? c->fanout >> 1 : 2;
divisor = UBIFS_MAX_DATA_NODE_SZ;
divisor += (c->max_idx_node_sz * 3) / (f - 1);
free *= factor;
- do_div(free, divisor);
- return free;
+ return div_u64(free, divisor);
}
/**
* 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
+ * alignment, 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
+ * 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.
long long available, outstanding, free;
spin_lock(&c->space_lock);
- min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+ min_idx_lebs = c->min_idx_lebs;
+ ubifs_assert(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);
/*
git.samba.org / sfrench / cifs-2.6.git / blobdiff