forked from luck/tmp_suning_uos_patched
UBIFS: simplify make_free_space
The 'make_free_space()' function was too complex and this patch simplifies it. It also fixes a bug - the freespace test failed straight away on UBI volumes with 512 bytes LEB size. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Artem Bityutskiy
parent
2edc2025c2
commit
2acf806758
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@ -37,13 +37,10 @@
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/*
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* When pessimistic budget calculations say that there is no enough space,
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* UBIFS starts writing back dirty inodes and pages, doing garbage collection,
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* or committing. The below constants define maximum number of times UBIFS
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* or committing. The below constant defines maximum number of times UBIFS
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* repeats the operations.
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*/
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#define MAX_SHRINK_RETRIES 8
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#define MAX_GC_RETRIES 4
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#define MAX_CMT_RETRIES 2
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#define MAX_NOSPC_RETRIES 1
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#define MAX_MKSPC_RETRIES 3
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/*
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* The below constant defines amount of dirty pages which should be written
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@ -51,30 +48,6 @@
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*/
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#define NR_TO_WRITE 16
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/**
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* struct retries_info - information about re-tries while making free space.
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* @prev_liability: previous liability
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* @shrink_cnt: how many times the liability was shrinked
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* @shrink_retries: count of liability shrink re-tries (increased when
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* liability does not shrink)
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* @try_gc: GC should be tried first
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* @gc_retries: how many times GC was run
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* @cmt_retries: how many times commit has been done
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* @nospc_retries: how many times GC returned %-ENOSPC
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*
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* Since we consider budgeting to be the fast-path, and this structure has to
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* be allocated on stack and zeroed out, we make it smaller using bit-fields.
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*/
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struct retries_info {
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long long prev_liability;
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unsigned int shrink_cnt;
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unsigned int shrink_retries:5;
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unsigned int try_gc:1;
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unsigned int gc_retries:4;
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unsigned int cmt_retries:3;
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unsigned int nospc_retries:1;
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};
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/**
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* shrink_liability - write-back some dirty pages/inodes.
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* @c: UBIFS file-system description object
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@ -146,10 +119,26 @@ static int run_gc(struct ubifs_info *c)
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return 0;
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}
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/**
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* get_liability - calculate current liability.
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* @c: UBIFS file-system description object
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*
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* This function calculates and returns current UBIFS liability, i.e. the
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* amount of bytes UBIFS has "promised" to write to the media.
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*/
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static long long get_liability(struct ubifs_info *c)
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{
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long long liab;
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spin_lock(&c->space_lock);
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liab = c->budg_idx_growth + c->budg_data_growth + c->budg_dd_growth;
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spin_unlock(&c->space_lock);
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return liab;
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}
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/**
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* make_free_space - make more free space on the file-system.
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* @c: UBIFS file-system description object
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* @ri: information about previous invocations of this function
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*
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* This function is called when an operation cannot be budgeted because there
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* is supposedly no free space. But in most cases there is some free space:
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@ -165,87 +154,42 @@ static int run_gc(struct ubifs_info *c)
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* Returns %-ENOSPC if it couldn't do more free space, and other negative error
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* codes on failures.
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*/
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static int make_free_space(struct ubifs_info *c, struct retries_info *ri)
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static int make_free_space(struct ubifs_info *c)
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{
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int err;
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int err, retries = 0;
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long long liab1, liab2;
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/*
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* If we have some dirty pages and inodes (liability), try to write
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* them back unless this was tried too many times without effect
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* already.
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*/
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if (ri->shrink_retries < MAX_SHRINK_RETRIES && !ri->try_gc) {
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long long liability;
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do {
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liab1 = get_liability(c);
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/*
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* We probably have some dirty pages or inodes (liability), try
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* to write them back.
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*/
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dbg_budg("liability %lld, run write-back", liab1);
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shrink_liability(c, NR_TO_WRITE);
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spin_lock(&c->space_lock);
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liability = c->budg_idx_growth + c->budg_data_growth +
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c->budg_dd_growth;
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spin_unlock(&c->space_lock);
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liab2 = get_liability(c);
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if (liab2 < liab1)
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return -EAGAIN;
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if (ri->prev_liability >= liability) {
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/* Liability does not shrink, next time try GC then */
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ri->shrink_retries += 1;
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if (ri->gc_retries < MAX_GC_RETRIES)
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ri->try_gc = 1;
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dbg_budg("liability did not shrink: retries %d of %d",
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ri->shrink_retries, MAX_SHRINK_RETRIES);
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}
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dbg_budg("new liability %lld (not shrinked)", liab2);
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dbg_budg("force write-back (count %d)", ri->shrink_cnt);
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shrink_liability(c, NR_TO_WRITE + ri->shrink_cnt);
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ri->prev_liability = liability;
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ri->shrink_cnt += 1;
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return -EAGAIN;
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}
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/*
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* Try to run garbage collector unless it was already tried too many
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* times.
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*/
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if (ri->gc_retries < MAX_GC_RETRIES) {
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ri->gc_retries += 1;
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dbg_budg("run GC, retries %d of %d",
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ri->gc_retries, MAX_GC_RETRIES);
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ri->try_gc = 0;
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/* Liability did not shrink again, try GC */
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dbg_budg("Run GC");
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err = run_gc(c);
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if (!err)
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return -EAGAIN;
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if (err == -EAGAIN) {
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dbg_budg("GC asked to commit");
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err = ubifs_run_commit(c);
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if (err)
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return err;
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return -EAGAIN;
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}
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if (err != -ENOSPC)
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if (err != -EAGAIN && err != -ENOSPC)
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/* Some real error happened */
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return err;
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/*
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* GC could not make any progress. If this is the first time,
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* then it makes sense to try to commit, because it might make
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* some dirty space.
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*/
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dbg_budg("GC returned -ENOSPC, retries %d",
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ri->nospc_retries);
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if (ri->nospc_retries >= MAX_NOSPC_RETRIES)
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return err;
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ri->nospc_retries += 1;
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}
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/* Neither GC nor write-back helped, try to commit */
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if (ri->cmt_retries < MAX_CMT_RETRIES) {
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ri->cmt_retries += 1;
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dbg_budg("run commit, retries %d of %d",
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ri->cmt_retries, MAX_CMT_RETRIES);
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dbg_budg("Run commit (retries %d)", retries);
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err = ubifs_run_commit(c);
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if (err)
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return err;
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return -EAGAIN;
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}
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} while (retries++ < MAX_MKSPC_RETRIES);
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return -ENOSPC;
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}
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@ -523,8 +467,7 @@ static int calc_dd_growth(const struct ubifs_info *c,
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int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)
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{
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int uninitialized_var(cmt_retries), uninitialized_var(wb_retries);
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int err, idx_growth, data_growth, dd_growth;
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struct retries_info ri;
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int err, idx_growth, data_growth, dd_growth, retried = 0;
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ubifs_assert(req->new_page <= 1);
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ubifs_assert(req->dirtied_page <= 1);
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@ -542,7 +485,6 @@ int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)
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if (!data_growth && !dd_growth)
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return 0;
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idx_growth = calc_idx_growth(c, req);
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memset(&ri, 0, sizeof(struct retries_info));
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again:
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spin_lock(&c->space_lock);
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@ -580,12 +522,17 @@ int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)
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return err;
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}
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err = make_free_space(c, &ri);
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err = make_free_space(c);
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cond_resched();
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if (err == -EAGAIN) {
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dbg_budg("try again");
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cond_resched();
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goto again;
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} else if (err == -ENOSPC) {
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if (!retried) {
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retried = 1;
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dbg_budg("-ENOSPC, but anyway try once again");
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goto again;
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}
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dbg_budg("FS is full, -ENOSPC");
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c->nospace = 1;
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if (can_use_rp(c) || c->rp_size == 0)
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