#include <linux/ext3_jbd.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
-#include <linux/vs_base.h>
#include <linux/vs_dlimit.h>
/*
return NULL;
}
+ smp_rmb();
- group_desc = block_group / EXT3_DESC_PER_BLOCK(sb);
- desc = block_group % EXT3_DESC_PER_BLOCK(sb);
+ group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb);
+ desc = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1);
if (!EXT3_SB(sb)->s_group_desc[group_desc]) {
ext3_error (sb, "ext3_get_group_desc",
"Group descriptor not loaded - "
error_out:
return bh;
}
+/*
+ * The reservation window structure operations
+ * --------------------------------------------
+ * Operations include:
+ * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
+ *
+ * We use sorted double linked list for the per-filesystem reservation
+ * window list. (like in vm_region).
+ *
+ * Initially, we keep those small operations in the abstract functions,
+ * so later if we need a better searching tree than double linked-list,
+ * we could easily switch to that without changing too much
+ * code.
+ */
+#if 0
+static void __rsv_window_dump(struct rb_root *root, int verbose,
+ const char *fn)
+{
+ struct rb_node *n;
+ struct ext3_reserve_window_node *rsv, *prev;
+ int bad;
+
+restart:
+ n = rb_first(root);
+ bad = 0;
+ prev = NULL;
+
+ printk("Block Allocation Reservation Windows Map (%s):\n", fn);
+ while (n) {
+ rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node);
+ if (verbose)
+ printk("reservation window 0x%p "
+ "start: %d, end: %d\n",
+ rsv, rsv->rsv_start, rsv->rsv_end);
+ if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
+ printk("Bad reservation %p (start >= end)\n",
+ rsv);
+ bad = 1;
+ }
+ if (prev && prev->rsv_end >= rsv->rsv_start) {
+ printk("Bad reservation %p (prev->end >= start)\n",
+ rsv);
+ bad = 1;
+ }
+ if (bad) {
+ if (!verbose) {
+ printk("Restarting reservation walk in verbose mode\n");
+ verbose = 1;
+ goto restart;
+ }
+ }
+ n = rb_next(n);
+ prev = rsv;
+ }
+ printk("Window map complete.\n");
+ if (bad)
+ BUG();
+}
+#define rsv_window_dump(root, verbose) \
+ __rsv_window_dump((root), (verbose), __FUNCTION__)
+#else
+#define rsv_window_dump(root, verbose) do {} while (0)
+#endif
+
+static int
+goal_in_my_reservation(struct ext3_reserve_window *rsv, int goal,
+ unsigned int group, struct super_block * sb)
+{
+ unsigned long group_first_block, group_last_block;
+
+ group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
+ group * EXT3_BLOCKS_PER_GROUP(sb);
+ group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
+
+ if ((rsv->_rsv_start > group_last_block) ||
+ (rsv->_rsv_end < group_first_block))
+ return 0;
+ if ((goal >= 0) && ((goal + group_first_block < rsv->_rsv_start)
+ || (goal + group_first_block > rsv->_rsv_end)))
+ return 0;
+ return 1;
+}
+
+/*
+ * Find the reserved window which includes the goal, or the previous one
+ * if the goal is not in any window.
+ * Returns NULL if there are no windows or if all windows start after the goal.
+ */
+static struct ext3_reserve_window_node *
+search_reserve_window(struct rb_root *root, unsigned long goal)
+{
+ struct rb_node *n = root->rb_node;
+ struct ext3_reserve_window_node *rsv;
+
+ if (!n)
+ return NULL;
+
+ do {
+ rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
+
+ if (goal < rsv->rsv_start)
+ n = n->rb_left;
+ else if (goal > rsv->rsv_end)
+ n = n->rb_right;
+ else
+ return rsv;
+ } while (n);
+ /*
+ * We've fallen off the end of the tree: the goal wasn't inside
+ * any particular node. OK, the previous node must be to one
+ * side of the interval containing the goal. If it's the RHS,
+ * we need to back up one.
+ */
+ if (rsv->rsv_start > goal) {
+ n = rb_prev(&rsv->rsv_node);
+ rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
+ }
+ return rsv;
+}
+
+void ext3_rsv_window_add(struct super_block *sb,
+ struct ext3_reserve_window_node *rsv)
+{
+ struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root;
+ struct rb_node *node = &rsv->rsv_node;
+ unsigned int start = rsv->rsv_start;
+
+ struct rb_node ** p = &root->rb_node;
+ struct rb_node * parent = NULL;
+ struct ext3_reserve_window_node *this;
+
+ while (*p)
+ {
+ parent = *p;
+ this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node);
+
+ if (start < this->rsv_start)
+ p = &(*p)->rb_left;
+ else if (start > this->rsv_end)
+ p = &(*p)->rb_right;
+ else
+ BUG();
+ }
+
+ rb_link_node(node, parent, p);
+ rb_insert_color(node, root);
+}
+
+static void rsv_window_remove(struct super_block *sb,
+ struct ext3_reserve_window_node *rsv)
+{
+ rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+ rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+ atomic_set(&rsv->rsv_alloc_hit, 0);
+ rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root);
+}
+
+static inline int rsv_is_empty(struct ext3_reserve_window *rsv)
+{
+ /* a valid reservation end block could not be 0 */
+ return (rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED);
+}
+
+void ext3_discard_reservation(struct inode *inode)
+{
+ struct ext3_inode_info *ei = EXT3_I(inode);
+ struct ext3_reserve_window_node *rsv = &ei->i_rsv_window;
+ spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock;
+
+ if (!rsv_is_empty(&rsv->rsv_window)) {
+ spin_lock(rsv_lock);
+ rsv_window_remove(inode->i_sb, rsv);
+ spin_unlock(rsv_lock);
+ }
+}
/* Free given blocks, update quota and i_blocks field */
-void ext3_free_blocks (handle_t *handle, struct inode * inode,
- unsigned long block, unsigned long count)
+void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb,
+ unsigned long block, unsigned long count,
+ int *pdquot_freed_blocks)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gd_bh;
unsigned long bit;
unsigned long i;
unsigned long overflow;
- struct super_block * sb;
struct ext3_group_desc * gdp;
struct ext3_super_block * es;
struct ext3_sb_info *sbi;
int err = 0, ret;
- int dquot_freed_blocks = 0;
- sb = inode->i_sb;
- if (!sb) {
- printk ("ext3_free_blocks: nonexistent device");
- return;
- }
+ *pdquot_freed_blocks = 0;
sbi = EXT3_SB(sb);
es = EXT3_SB(sb)->s_es;
if (block < le32_to_cpu(es->s_first_data_block) ||
}
jbd_lock_bh_state(bitmap_bh);
#endif
+ if (need_resched()) {
+ jbd_unlock_bh_state(bitmap_bh);
+ cond_resched();
+ jbd_lock_bh_state(bitmap_bh);
+ }
/* @@@ This prevents newly-allocated data from being
* freed and then reallocated within the same
* transaction.
jbd_lock_bh_state(bitmap_bh);
BUFFER_TRACE(bitmap_bh, "bit already cleared");
} else {
- dquot_freed_blocks++;
+ (*pdquot_freed_blocks)++;
}
}
jbd_unlock_bh_state(bitmap_bh);
spin_lock(sb_bgl_lock(sbi, block_group));
gdp->bg_free_blocks_count =
cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) +
- dquot_freed_blocks);
+ *pdquot_freed_blocks);
spin_unlock(sb_bgl_lock(sbi, block_group));
percpu_counter_mod(&sbi->s_freeblocks_counter, count);
error_return:
brelse(bitmap_bh);
ext3_std_error(sb, err);
+ return;
+}
+
+/* Free given blocks, update quota and i_blocks field */
+void ext3_free_blocks(handle_t *handle, struct inode *inode,
+ unsigned long block, unsigned long count)
+{
+ struct super_block * sb;
+ int dquot_freed_blocks;
+
+ sb = inode->i_sb;
+ if (!sb) {
+ printk ("ext3_free_blocks: nonexistent device");
+ return;
+ }
+ ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks);
if (dquot_freed_blocks) {
DLIMIT_FREE_BLOCK(sb, inode->i_xid, dquot_freed_blocks);
DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
* data-writes at some point, and disable it for metadata allocations or
* sync-data inodes.
*/
-static inline int ext3_test_allocatable(int nr, struct buffer_head *bh)
+static int ext3_test_allocatable(int nr, struct buffer_head *bh)
{
int ret;
struct journal_head *jh = bh2jh(bh);
return ret;
}
+static int
+bitmap_search_next_usable_block(int start, struct buffer_head *bh,
+ int maxblocks)
+{
+ int next;
+ struct journal_head *jh = bh2jh(bh);
+
+ /*
+ * The bitmap search --- search forward alternately through the actual
+ * bitmap and the last-committed copy until we find a bit free in
+ * both
+ */
+ while (start < maxblocks) {
+ next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start);
+ if (next >= maxblocks)
+ return -1;
+ if (ext3_test_allocatable(next, bh))
+ return next;
+ jbd_lock_bh_state(bh);
+ if (jh->b_committed_data)
+ start = ext3_find_next_zero_bit(jh->b_committed_data,
+ maxblocks, next);
+ jbd_unlock_bh_state(bh);
+ }
+ return -1;
+}
+
/*
* Find an allocatable block in a bitmap. We honour both the bitmap and
* its last-committed copy (if that exists), and perform the "most
{
int here, next;
char *p, *r;
- struct journal_head *jh = bh2jh(bh);
if (start > 0) {
/*
* next 64-bit boundary is simple..
*/
int end_goal = (start + 63) & ~63;
+ if (end_goal > maxblocks)
+ end_goal = maxblocks;
here = ext3_find_next_zero_bit(bh->b_data, end_goal, start);
if (here < end_goal && ext3_test_allocatable(here, bh))
return here;
r = memscan(p, 0, (maxblocks - here + 7) >> 3);
next = (r - ((char *)bh->b_data)) << 3;
- if (next < maxblocks && ext3_test_allocatable(next, bh))
+ if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh))
return next;
/*
* bitmap and the last-committed copy until we find a bit free in
* both
*/
- while (here < maxblocks) {
- next = ext3_find_next_zero_bit(bh->b_data, maxblocks, here);
- if (next >= maxblocks)
- return -1;
- if (ext3_test_allocatable(next, bh))
- return next;
- jbd_lock_bh_state(bh);
- if (jh->b_committed_data)
- here = ext3_find_next_zero_bit(jh->b_committed_data,
- maxblocks, next);
- jbd_unlock_bh_state(bh);
- }
- return -1;
+ here = bitmap_search_next_usable_block(here, bh, maxblocks);
+ return here;
}
/*
*/
static int
ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
- struct buffer_head *bitmap_bh, int goal, int *errp)
+ struct buffer_head *bitmap_bh, int goal, struct ext3_reserve_window *my_rsv)
{
- int i;
- int fatal;
- int credits = 0;
-
- *errp = 0;
-
- /*
- * Make sure we use undo access for the bitmap, because it is critical
- * that we do the frozen_data COW on bitmap buffers in all cases even
- * if the buffer is in BJ_Forget state in the committing transaction.
- */
- BUFFER_TRACE(bitmap_bh, "get undo access for new block");
- fatal = ext3_journal_get_undo_access(handle, bitmap_bh, &credits);
- if (fatal) {
- *errp = fatal;
- goto fail;
+ int group_first_block, start, end;
+
+ /* we do allocation within the reservation window if we have a window */
+ if (my_rsv) {
+ group_first_block =
+ le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
+ group * EXT3_BLOCKS_PER_GROUP(sb);
+ if (my_rsv->_rsv_start >= group_first_block)
+ start = my_rsv->_rsv_start - group_first_block;
+ else
+ /* reservation window cross group boundary */
+ start = 0;
+ end = my_rsv->_rsv_end - group_first_block + 1;
+ if (end > EXT3_BLOCKS_PER_GROUP(sb))
+ /* reservation window crosses group boundary */
+ end = EXT3_BLOCKS_PER_GROUP(sb);
+ if ((start <= goal) && (goal < end))
+ start = goal;
+ else
+ goal = -1;
+ } else {
+ if (goal > 0)
+ start = goal;
+ else
+ start = 0;
+ end = EXT3_BLOCKS_PER_GROUP(sb);
}
+ BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb));
+
repeat:
if (goal < 0 || !ext3_test_allocatable(goal, bitmap_bh)) {
- goal = find_next_usable_block(goal, bitmap_bh,
- EXT3_BLOCKS_PER_GROUP(sb));
+ goal = find_next_usable_block(start, bitmap_bh, end);
if (goal < 0)
goto fail_access;
-
- for (i = 0; i < 7 && goal > 0 &&
- ext3_test_allocatable(goal - 1, bitmap_bh);
- i++, goal--);
+ if (!my_rsv) {
+ int i;
+
+ for (i = 0; i < 7 && goal > start &&
+ ext3_test_allocatable(goal - 1,
+ bitmap_bh);
+ i++, goal--)
+ ;
+ }
}
+ start = goal;
if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), goal, bitmap_bh)) {
/*
* The block was allocated by another thread, or it was
* allocated and then freed by another thread
*/
+ start++;
goal++;
- if (goal >= EXT3_BLOCKS_PER_GROUP(sb))
+ if (start >= end)
goto fail_access;
goto repeat;
}
+ return goal;
+fail_access:
+ return -1;
+}
- BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for bitmap block");
- fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
+/**
+ * find_next_reservable_window():
+ * find a reservable space within the given range.
+ * It does not allocate the reservation window for now:
+ * alloc_new_reservation() will do the work later.
+ *
+ * @search_head: the head of the searching list;
+ * This is not necessarily the list head of the whole filesystem
+ *
+ * We have both head and start_block to assist the search
+ * for the reservable space. The list starts from head,
+ * but we will shift to the place where start_block is,
+ * then start from there, when looking for a reservable space.
+ *
+ * @size: the target new reservation window size
+ *
+ * @group_first_block: the first block we consider to start
+ * the real search from
+ *
+ * @last_block:
+ * the maximum block number that our goal reservable space
+ * could start from. This is normally the last block in this
+ * group. The search will end when we found the start of next
+ * possible reservable space is out of this boundary.
+ * This could handle the cross boundary reservation window
+ * request.
+ *
+ * basically we search from the given range, rather than the whole
+ * reservation double linked list, (start_block, last_block)
+ * to find a free region that is of my size and has not
+ * been reserved.
+ *
+ * on succeed, it returns the reservation window to be appended to.
+ * failed, return NULL.
+ */
+static struct ext3_reserve_window_node *find_next_reservable_window(
+ struct ext3_reserve_window_node *search_head,
+ unsigned long size, int *start_block,
+ int last_block)
+{
+ struct rb_node *next;
+ struct ext3_reserve_window_node *rsv, *prev;
+ int cur;
+
+ /* TODO: make the start of the reservation window byte-aligned */
+ /* cur = *start_block & ~7;*/
+ cur = *start_block;
+ rsv = search_head;
+ if (!rsv)
+ return NULL;
+
+ while (1) {
+ if (cur <= rsv->rsv_end)
+ cur = rsv->rsv_end + 1;
+
+ /* TODO?
+ * in the case we could not find a reservable space
+ * that is what is expected, during the re-search, we could
+ * remember what's the largest reservable space we could have
+ * and return that one.
+ *
+ * For now it will fail if we could not find the reservable
+ * space with expected-size (or more)...
+ */
+ if (cur > last_block)
+ return NULL; /* fail */
+
+ prev = rsv;
+ next = rb_next(&rsv->rsv_node);
+ rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
+
+ /*
+ * Reached the last reservation, we can just append to the
+ * previous one.
+ */
+ if (!next)
+ break;
+
+ if (cur + size <= rsv->rsv_start) {
+ /*
+ * Found a reserveable space big enough. We could
+ * have a reservation across the group boundary here
+ */
+ break;
+ }
+ }
+ /*
+ * we come here either :
+ * when we reach the end of the whole list,
+ * and there is empty reservable space after last entry in the list.
+ * append it to the end of the list.
+ *
+ * or we found one reservable space in the middle of the list,
+ * return the reservation window that we could append to.
+ * succeed.
+ */
+ *start_block = cur;
+ return prev;
+}
+
+/**
+ * alloc_new_reservation()--allocate a new reservation window
+ *
+ * To make a new reservation, we search part of the filesystem
+ * reservation list (the list that inside the group). We try to
+ * allocate a new reservation window near the allocation goal,
+ * or the beginning of the group, if there is no goal.
+ *
+ * We first find a reservable space after the goal, then from
+ * there, we check the bitmap for the first free block after
+ * it. If there is no free block until the end of group, then the
+ * whole group is full, we failed. Otherwise, check if the free
+ * block is inside the expected reservable space, if so, we
+ * succeed.
+ * If the first free block is outside the reservable space, then
+ * start from the first free block, we search for next available
+ * space, and go on.
+ *
+ * on succeed, a new reservation will be found and inserted into the list
+ * It contains at least one free block, and it does not overlap with other
+ * reservation windows.
+ *
+ * failed: we failed to find a reservation window in this group
+ *
+ * @rsv: the reservation
+ *
+ * @goal: The goal (group-relative). It is where the search for a
+ * free reservable space should start from.
+ * if we have a goal(goal >0 ), then start from there,
+ * no goal(goal = -1), we start from the first block
+ * of the group.
+ *
+ * @sb: the super block
+ * @group: the group we are trying to allocate in
+ * @bitmap_bh: the block group block bitmap
+ */
+static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
+ int goal, struct super_block *sb,
+ unsigned int group, struct buffer_head *bitmap_bh)
+{
+ struct ext3_reserve_window_node *search_head;
+ int group_first_block, group_end_block, start_block;
+ int first_free_block;
+ int reservable_space_start;
+ struct ext3_reserve_window_node *prev_rsv;
+ struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
+ unsigned long size;
+
+ group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
+ group * EXT3_BLOCKS_PER_GROUP(sb);
+ group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
+
+ if (goal < 0)
+ start_block = group_first_block;
+ else
+ start_block = goal + group_first_block;
+
+ size = atomic_read(&my_rsv->rsv_goal_size);
+ if (!rsv_is_empty(&my_rsv->rsv_window)) {
+ /*
+ * if the old reservation is cross group boundary
+ * and if the goal is inside the old reservation window,
+ * we will come here when we just failed to allocate from
+ * the first part of the window. We still have another part
+ * that belongs to the next group. In this case, there is no
+ * point to discard our window and try to allocate a new one
+ * in this group(which will fail). we should
+ * keep the reservation window, just simply move on.
+ *
+ * Maybe we could shift the start block of the reservation
+ * window to the first block of next group.
+ */
+
+ if ((my_rsv->rsv_start <= group_end_block) &&
+ (my_rsv->rsv_end > group_end_block) &&
+ (start_block >= my_rsv->rsv_start))
+ return -1;
+
+ if ((atomic_read(&my_rsv->rsv_alloc_hit) >
+ (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
+ /*
+ * if we previously allocation hit ration is greater than half
+ * we double the size of reservation window next time
+ * otherwise keep the same
+ */
+ size = size * 2;
+ if (size > EXT3_MAX_RESERVE_BLOCKS)
+ size = EXT3_MAX_RESERVE_BLOCKS;
+ atomic_set(&my_rsv->rsv_goal_size, size);
+ }
+ }
+ /*
+ * shift the search start to the window near the goal block
+ */
+ search_head = search_reserve_window(fs_rsv_root, start_block);
+
+ /*
+ * find_next_reservable_window() simply finds a reservable window
+ * inside the given range(start_block, group_end_block).
+ *
+ * To make sure the reservation window has a free bit inside it, we
+ * need to check the bitmap after we found a reservable window.
+ */
+retry:
+ prev_rsv = find_next_reservable_window(search_head, size,
+ &start_block, group_end_block);
+ if (prev_rsv == NULL)
+ goto failed;
+ reservable_space_start = start_block;
+ /*
+ * On success, find_next_reservable_window() returns the
+ * reservation window where there is a reservable space after it.
+ * Before we reserve this reservable space, we need
+ * to make sure there is at least a free block inside this region.
+ *
+ * searching the first free bit on the block bitmap and copy of
+ * last committed bitmap alternatively, until we found a allocatable
+ * block. Search start from the start block of the reservable space
+ * we just found.
+ */
+ first_free_block = bitmap_search_next_usable_block(
+ reservable_space_start - group_first_block,
+ bitmap_bh, group_end_block - group_first_block + 1);
+
+ if (first_free_block < 0) {
+ /*
+ * no free block left on the bitmap, no point
+ * to reserve the space. return failed.
+ */
+ goto failed;
+ }
+ start_block = first_free_block + group_first_block;
+ /*
+ * check if the first free block is within the
+ * free space we just found
+ */
+ if ((start_block >= reservable_space_start) &&
+ (start_block < reservable_space_start + size))
+ goto found_rsv_window;
+ /*
+ * if the first free bit we found is out of the reservable space
+ * this means there is no free block on the reservable space
+ * we should continue search for next reservable space,
+ * start from where the free block is,
+ * we also shift the list head to where we stopped last time
+ */
+ search_head = prev_rsv;
+ goto retry;
+
+found_rsv_window:
+ /*
+ * great! the reservable space contains some free blocks.
+ * if the search returns that we should add the new
+ * window just next to where the old window, we don't
+ * need to remove the old window first then add it to the
+ * same place, just update the new start and new end.
+ */
+ if (my_rsv != prev_rsv) {
+ if (!rsv_is_empty(&my_rsv->rsv_window))
+ rsv_window_remove(sb, my_rsv);
+ }
+ my_rsv->rsv_start = reservable_space_start;
+ my_rsv->rsv_end = my_rsv->rsv_start + size - 1;
+ atomic_set(&my_rsv->rsv_alloc_hit, 0);
+ if (my_rsv != prev_rsv) {
+ ext3_rsv_window_add(sb, my_rsv);
+ }
+ return 0; /* succeed */
+failed:
+ /*
+ * failed to find a new reservation window in the current
+ * group, remove the current(stale) reservation window
+ * if there is any
+ */
+ if (!rsv_is_empty(&my_rsv->rsv_window))
+ rsv_window_remove(sb, my_rsv);
+ return -1; /* failed */
+}
+
+/*
+ * This is the main function used to allocate a new block and its reservation
+ * window.
+ *
+ * Each time when a new block allocation is need, first try to allocate from
+ * its own reservation. If it does not have a reservation window, instead of
+ * looking for a free bit on bitmap first, then look up the reservation list to
+ * see if it is inside somebody else's reservation window, we try to allocate a
+ * reservation window for it starting from the goal first. Then do the block
+ * allocation within the reservation window.
+ *
+ * This will avoid keeping on searching the reservation list again and
+ * again when someboday is looking for a free block (without
+ * reservation), and there are lots of free blocks, but they are all
+ * being reserved.
+ *
+ * We use a sorted double linked list for the per-filesystem reservation list.
+ * The insert, remove and find a free space(non-reserved) operations for the
+ * sorted double linked list should be fast.
+ *
+ */
+static int
+ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
+ unsigned int group, struct buffer_head *bitmap_bh,
+ int goal, struct ext3_reserve_window_node * my_rsv,
+ int *errp)
+{
+ spinlock_t *rsv_lock;
+ unsigned long group_first_block;
+ int ret = 0;
+ int fatal;
+ int credits = 0;
+
+ *errp = 0;
+
+ /*
+ * Make sure we use undo access for the bitmap, because it is critical
+ * that we do the frozen_data COW on bitmap buffers in all cases even
+ * if the buffer is in BJ_Forget state in the committing transaction.
+ */
+ BUFFER_TRACE(bitmap_bh, "get undo access for new block");
+ fatal = ext3_journal_get_undo_access(handle, bitmap_bh, &credits);
if (fatal) {
*errp = fatal;
- goto fail;
+ return -1;
+ }
+
+ /*
+ * we don't deal with reservation when
+ * filesystem is mounted without reservation
+ * or the file is not a regular file
+ * or last attempt to allocate a block with reservation turned on failed
+ */
+ if (my_rsv == NULL ) {
+ ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal, NULL);
+ goto out;
+ }
+ rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
+ /*
+ * goal is a group relative block number (if there is a goal)
+ * 0 < goal < EXT3_BLOCKS_PER_GROUP(sb)
+ * first block is a filesystem wide block number
+ * first block is the block number of the first block in this group
+ */
+ group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
+ group * EXT3_BLOCKS_PER_GROUP(sb);
+
+ /*
+ * Basically we will allocate a new block from inode's reservation
+ * window.
+ *
+ * We need to allocate a new reservation window, if:
+ * a) inode does not have a reservation window; or
+ * b) last attempt to allocate a block from existing reservation
+ * failed; or
+ * c) we come here with a goal and with a reservation window
+ *
+ * We do not need to allocate a new reservation window if we come here
+ * at the beginning with a goal and the goal is inside the window, or
+ * we don't have a goal but already have a reservation window.
+ * then we could go to allocate from the reservation window directly.
+ */
+ while (1) {
+ struct ext3_reserve_window rsv_copy;
+ unsigned int seq;
+
+ do {
+ seq = read_seqbegin(&my_rsv->rsv_seqlock);
+ rsv_copy._rsv_start = my_rsv->rsv_start;
+ rsv_copy._rsv_end = my_rsv->rsv_end;
+ } while (read_seqretry(&my_rsv->rsv_seqlock, seq));
+
+ if (rsv_is_empty(&rsv_copy) || (ret < 0) ||
+ !goal_in_my_reservation(&rsv_copy, goal, group, sb)) {
+ spin_lock(rsv_lock);
+ write_seqlock(&my_rsv->rsv_seqlock);
+ ret = alloc_new_reservation(my_rsv, goal, sb,
+ group, bitmap_bh);
+ rsv_copy._rsv_start = my_rsv->rsv_start;
+ rsv_copy._rsv_end = my_rsv->rsv_end;
+ write_sequnlock(&my_rsv->rsv_seqlock);
+ spin_unlock(rsv_lock);
+ if (ret < 0)
+ break; /* failed */
+
+ if (!goal_in_my_reservation(&rsv_copy, goal, group, sb))
+ goal = -1;
+ }
+ if ((rsv_copy._rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb))
+ || (rsv_copy._rsv_end < group_first_block))
+ BUG();
+ ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal,
+ &rsv_copy);
+ if (ret >= 0) {
+ if (!read_seqretry(&my_rsv->rsv_seqlock, seq))
+ atomic_inc(&my_rsv->rsv_alloc_hit);
+ break; /* succeed */
+ }
+ }
+out:
+ if (ret >= 0) {
+ BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
+ "bitmap block");
+ fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
+ if (fatal) {
+ *errp = fatal;
+ return -1;
+ }
+ return ret;
}
- return goal;
-fail_access:
BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
ext3_journal_release_buffer(handle, bitmap_bh, credits);
-fail:
- return -1;
+ return ret;
}
static int ext3_has_free_blocks(struct super_block *sb)
* bitmap, and then for any free bit if that fails.
* This function also updates quota and i_blocks field.
*/
-int
-ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal,
- u32 *prealloc_count, u32 *prealloc_block, int *errp)
+int ext3_new_block(handle_t *handle, struct inode *inode,
+ unsigned long goal, int *errp)
{
- struct buffer_head *bitmap_bh = NULL; /* bh */
- struct buffer_head *gdp_bh; /* bh2 */
- int group_no; /* i */
- int ret_block; /* j */
- int bgi; /* blockgroup iteration index */
- int target_block; /* tmp */
+ struct buffer_head *bitmap_bh = NULL;
+ struct buffer_head *gdp_bh;
+ int group_no;
+ int goal_group;
+ int ret_block;
+ int bgi; /* blockgroup iteration index */
+ int target_block;
int fatal = 0, err;
int performed_allocation = 0;
int free_blocks;
struct ext3_group_desc *gdp;
struct ext3_super_block *es;
struct ext3_sb_info *sbi;
+ struct ext3_reserve_window_node *my_rsv = NULL;
+ struct ext3_reserve_window_node *rsv = &EXT3_I(inode)->i_rsv_window;
+ unsigned short windowsz = 0;
#ifdef EXT3FS_DEBUG
static int goal_hits, goal_attempts;
#endif
+ unsigned long ngroups;
+
*errp = -ENOSPC;
sb = inode->i_sb;
if (!sb) {
sbi = EXT3_SB(sb);
es = EXT3_SB(sb)->s_es;
ext3_debug("goal=%lu.\n", goal);
-
+ /*
+ * Allocate a block from reservation only when
+ * filesystem is mounted with reservation(default,-o reservation), and
+ * it's a regular file, and
+ * the desired window size is greater than 0 (One could use ioctl
+ * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off
+ * reservation on that particular file)
+ */
+ windowsz = atomic_read(&rsv->rsv_goal_size);
+ if (test_opt(sb, RESERVATION) &&
+ S_ISREG(inode->i_mode) && (windowsz > 0))
+ my_rsv = rsv;
if (!ext3_has_free_blocks(sb)) {
*errp = -ENOSPC;
goto out;
if (!gdp)
goto io_error;
+ goal_group = group_no;
+retry:
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
if (free_blocks > 0) {
ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) %
bitmap_bh = read_block_bitmap(sb, group_no);
if (!bitmap_bh)
goto io_error;
- ret_block = ext3_try_to_allocate(sb, handle, group_no,
- bitmap_bh, ret_block, &fatal);
+ ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no,
+ bitmap_bh, ret_block, my_rsv, &fatal);
if (fatal)
goto out;
if (ret_block >= 0)
goto allocated;
}
+ ngroups = EXT3_SB(sb)->s_groups_count;
+ smp_rmb();
+
/*
* Now search the rest of the groups. We assume that
* i and gdp correctly point to the last group visited.
*/
- for (bgi = 0; bgi < EXT3_SB(sb)->s_groups_count; bgi++) {
+ for (bgi = 0; bgi < ngroups; bgi++) {
group_no++;
- if (group_no >= EXT3_SB(sb)->s_groups_count)
+ if (group_no >= ngroups)
group_no = 0;
gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
if (!gdp) {
goto out;
}
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
- if (free_blocks <= 0)
+ /*
+ * skip this group if the number of
+ * free blocks is less than half of the reservation
+ * window size.
+ */
+ if (free_blocks <= (windowsz/2))
continue;
brelse(bitmap_bh);
bitmap_bh = read_block_bitmap(sb, group_no);
if (!bitmap_bh)
goto io_error;
- ret_block = ext3_try_to_allocate(sb, handle, group_no,
- bitmap_bh, -1, &fatal);
+ ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no,
+ bitmap_bh, -1, my_rsv, &fatal);
if (fatal)
goto out;
if (ret_block >= 0)
goto allocated;
}
-
+ /*
+ * We may end up a bogus ealier ENOSPC error due to
+ * filesystem is "full" of reservations, but
+ * there maybe indeed free blocks avaliable on disk
+ * In this case, we just forget about the reservations
+ * just do block allocation as without reservations.
+ */
+ if (my_rsv) {
+ my_rsv = NULL;
+ group_no = goal_group;
+ goto retry;
+ }
/* No space left on the device */
*errp = -ENOSPC;
goto out;
unsigned long desc_count;
struct ext3_group_desc *gdp;
int i;
+ unsigned long ngroups;
#ifdef EXT3FS_DEBUG
struct ext3_super_block *es;
unsigned long bitmap_count, x;
return bitmap_count;
#else
desc_count = 0;
- for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
+ ngroups = EXT3_SB(sb)->s_groups_count;
+ smp_rmb();
+ for (i = 0; i < ngroups; i++) {
gdp = ext3_get_group_desc(sb, i, NULL);
if (!gdp)
continue;
static inline int test_root(int a, int b)
{
- if (a == 0)
- return 1;
- while (1) {
- if (a == 1)
- return 1;
- if (a % b)
- return 0;
- a = a / b;
- }
+ int num = b;
+
+ while (a > num)
+ num *= b;
+ return num == a;
}
-int ext3_group_sparse(int group)
+static int ext3_group_sparse(int group)
{
+ if (group <= 1)
+ return 1;
return (test_root(group, 3) || test_root(group, 5) ||
test_root(group, 7));
}
git://git.onelab.eu / linux-2.6.git / blobdiff