*/
static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
{
- if (vol_id == UBI_LAYOUT_VOL_ID)
+ if (vol_id == UBI_LAYOUT_VOLUME_ID)
return UBI_LAYOUT_VOLUME_COMPAT;
return 0;
}
{
struct ubi_ltree_entry *le, *le1, *le_free;
- le = kmem_cache_alloc(ubi_ltree_slab, GFP_NOFS);
+ le = kmalloc(sizeof(struct ubi_ltree_entry), GFP_NOFS);
if (!le)
return ERR_PTR(-ENOMEM);
+ le->users = 0;
+ init_rwsem(&le->mutex);
le->vol_id = vol_id;
le->lnum = lnum;
spin_unlock(&ubi->ltree_lock);
if (le_free)
- kmem_cache_free(ubi_ltree_slab, le_free);
+ kfree(le_free);
return le;
}
up_read(&le->mutex);
if (free)
- kmem_cache_free(ubi_ltree_slab, le);
+ kfree(le);
}
/**
return 0;
}
+/**
+ * leb_write_lock - lock logical eraseblock for writing.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ *
+ * This function locks a logical eraseblock for writing if there is no
+ * contention and does nothing if there is contention. Returns %0 in case of
+ * success, %1 in case of contention, and and a negative error code in case of
+ * failure.
+ */
+static int leb_write_trylock(struct ubi_device *ubi, int vol_id, int lnum)
+{
+ int free;
+ struct ubi_ltree_entry *le;
+
+ le = ltree_add_entry(ubi, vol_id, lnum);
+ if (IS_ERR(le))
+ return PTR_ERR(le);
+ if (down_write_trylock(&le->mutex))
+ return 0;
+
+ /* Contention, cancel */
+ spin_lock(&ubi->ltree_lock);
+ le->users -= 1;
+ ubi_assert(le->users >= 0);
+ if (le->users == 0) {
+ rb_erase(&le->rb, &ubi->ltree);
+ free = 1;
+ } else
+ free = 0;
+ spin_unlock(&ubi->ltree_lock);
+ if (free)
+ kfree(le);
+
+ return 1;
+}
+
/**
* leb_write_unlock - unlock logical eraseblock.
* @ubi: UBI device description object
up_write(&le->mutex);
if (free)
- kmem_cache_free(ubi_ltree_slab, le);
+ kfree(le);
}
/**
/*
* ubi_eba_atomic_leb_change - change logical eraseblock atomically.
* @ubi: UBI device description object
- * @vol: volume escription object
+ * @vol: volume description object
* @lnum: logical eraseblock number
* @buf: data to write
* @len: how many bytes to write
if (ubi->ro_mode)
return -EROFS;
+ if (len == 0) {
+ /*
+ * Special case when data length is zero. In this case the LEB
+ * has to be unmapped and mapped somewhere else.
+ */
+ err = ubi_eba_unmap_leb(ubi, vol, lnum);
+ if (err)
+ return err;
+ return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0, dtype);
+ }
+
vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
if (!vid_hdr)
return -ENOMEM;
*
* This function copies logical eraseblock from physical eraseblock @from to
* physical eraseblock @to. The @vid_hdr buffer may be changed by this
- * function. Returns zero in case of success, %UBI_IO_BITFLIPS if the operation
- * was canceled because bit-flips were detected at the target PEB, and a
- * negative error code in case of failure.
+ * function. Returns:
+ * o %0 in case of success;
+ * o %1 if the operation was canceled and should be tried later (e.g.,
+ * because a bit-flip was detected at the target PEB);
+ * o %2 if the volume is being deleted and this LEB should not be moved.
*/
int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
struct ubi_vid_hdr *vid_hdr)
{
- int err, vol_id, lnum, data_size, aldata_size, pnum, idx;
+ int err, vol_id, lnum, data_size, aldata_size, idx;
struct ubi_volume *vol;
uint32_t crc;
data_size = aldata_size =
ubi->leb_size - be32_to_cpu(vid_hdr->data_pad);
- /*
- * We do not want anybody to write to this logical eraseblock while we
- * are moving it, so we lock it.
- */
- err = leb_write_lock(ubi, vol_id, lnum);
- if (err)
- return err;
-
- mutex_lock(&ubi->buf_mutex);
-
- /*
- * But the logical eraseblock might have been put by this time.
- * Cancel if it is true.
- */
idx = vol_id2idx(ubi, vol_id);
-
+ spin_lock(&ubi->volumes_lock);
/*
- * We may race with volume deletion/re-size, so we have to hold
- * @ubi->volumes_lock.
+ * Note, we may race with volume deletion, which means that the volume
+ * this logical eraseblock belongs to might be being deleted. Since the
+ * volume deletion unmaps all the volume's logical eraseblocks, it will
+ * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
*/
- spin_lock(&ubi->volumes_lock);
vol = ubi->volumes[idx];
if (!vol) {
- dbg_eba("volume %d was removed meanwhile", vol_id);
+ /* No need to do further work, cancel */
+ dbg_eba("volume %d is being removed, cancel", vol_id);
spin_unlock(&ubi->volumes_lock);
- goto out_unlock;
+ return 2;
}
+ spin_unlock(&ubi->volumes_lock);
- pnum = vol->eba_tbl[lnum];
- if (pnum != from) {
- dbg_eba("LEB %d:%d is no longer mapped to PEB %d, mapped to "
- "PEB %d, cancel", vol_id, lnum, from, pnum);
- spin_unlock(&ubi->volumes_lock);
- goto out_unlock;
+ /*
+ * We do not want anybody to write to this logical eraseblock while we
+ * are moving it, so lock it.
+ *
+ * Note, we are using non-waiting locking here, because we cannot sleep
+ * on the LEB, since it may cause deadlocks. Indeed, imagine a task is
+ * unmapping the LEB which is mapped to the PEB we are going to move
+ * (@from). This task locks the LEB and goes sleep in the
+ * 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are
+ * holding @ubi->move_mutex and go sleep on the LEB lock. So, if the
+ * LEB is already locked, we just do not move it and return %1.
+ */
+ err = leb_write_trylock(ubi, vol_id, lnum);
+ if (err) {
+ dbg_eba("contention on LEB %d:%d, cancel", vol_id, lnum);
+ return err;
}
- spin_unlock(&ubi->volumes_lock);
- /* OK, now the LEB is locked and we can safely start moving it */
+ /*
+ * The LEB might have been put meanwhile, and the task which put it is
+ * probably waiting on @ubi->move_mutex. No need to continue the work,
+ * cancel it.
+ */
+ if (vol->eba_tbl[lnum] != from) {
+ dbg_eba("LEB %d:%d is no longer mapped to PEB %d, mapped to "
+ "PEB %d, cancel", vol_id, lnum, from,
+ vol->eba_tbl[lnum]);
+ err = 1;
+ goto out_unlock_leb;
+ }
+ /*
+ * OK, now the LEB is locked and we can safely start moving iy. Since
+ * this function utilizes thie @ubi->peb1_buf buffer which is shared
+ * with some other functions, so lock the buffer by taking the
+ * @ubi->buf_mutex.
+ */
+ mutex_lock(&ubi->buf_mutex);
dbg_eba("read %d bytes of data", aldata_size);
err = ubi_io_read_data(ubi, ubi->peb_buf1, from, 0, aldata_size);
if (err && err != UBI_IO_BITFLIPS) {
ubi_warn("error %d while reading data from PEB %d",
err, from);
- goto out_unlock;
+ goto out_unlock_buf;
}
/*
err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
if (err)
- goto out_unlock;
+ goto out_unlock_buf;
cond_resched();
if (err) {
if (err != UBI_IO_BITFLIPS)
ubi_warn("cannot read VID header back from PEB %d", to);
- goto out_unlock;
+ else
+ err = 1;
+ goto out_unlock_buf;
}
if (data_size > 0) {
err = ubi_io_write_data(ubi, ubi->peb_buf1, to, 0, aldata_size);
if (err)
- goto out_unlock;
+ goto out_unlock_buf;
cond_resched();
if (err != UBI_IO_BITFLIPS)
ubi_warn("cannot read data back from PEB %d",
to);
- goto out_unlock;
+ else
+ err = 1;
+ goto out_unlock_buf;
}
cond_resched();
if (memcmp(ubi->peb_buf1, ubi->peb_buf2, aldata_size)) {
ubi_warn("read data back from PEB %d - it is different",
to);
- goto out_unlock;
+ goto out_unlock_buf;
}
}
ubi_assert(vol->eba_tbl[lnum] == from);
vol->eba_tbl[lnum] = to;
-out_unlock:
+out_unlock_buf:
mutex_unlock(&ubi->buf_mutex);
+out_unlock_leb:
leb_write_unlock(ubi, vol_id, lnum);
return err;
}
projects / linux-2.6 / blobdiff