}
return used_blocks;
}
+
/* Initializes an uninitialized block bitmap if given, and returns the
* number of blocks free in the group. */
unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
*/
return bh;
}
-/*
- * The reservation window structure operations
- * --------------------------------------------
- * Operations include:
- * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
- *
- * We use a red-black tree to represent per-filesystem reservation
- * windows.
- *
- */
-
-/**
- * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
- * @rb_root: root of per-filesystem reservation rb tree
- * @verbose: verbose mode
- * @fn: function which wishes to dump the reservation map
- *
- * If verbose is turned on, it will print the whole block reservation
- * windows(start, end). Otherwise, it will only print out the "bad" windows,
- * those windows that overlap with their immediate neighbors.
- */
-#if 1
-static void __rsv_window_dump(struct rb_root *root, int verbose,
- const char *fn)
-{
- struct rb_node *n;
- struct ext4_reserve_window_node *rsv, *prev;
- int bad;
-
-restart:
- n = rb_first(root);
- bad = 0;
- prev = NULL;
-
- printk(KERN_DEBUG "Block Allocation Reservation "
- "Windows Map (%s):\n", fn);
- while (n) {
- rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node);
- if (verbose)
- printk(KERN_DEBUG "reservation window 0x%p "
- "start: %llu, end: %llu\n",
- rsv, rsv->rsv_start, rsv->rsv_end);
- if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
- printk(KERN_DEBUG "Bad reservation %p (start >= end)\n",
- rsv);
- bad = 1;
- }
- if (prev && prev->rsv_end >= rsv->rsv_start) {
- printk(KERN_DEBUG "Bad reservation %p "
- "(prev->end >= start)\n", rsv);
- bad = 1;
- }
- if (bad) {
- if (!verbose) {
- printk(KERN_DEBUG "Restarting reservation "
- "walk in verbose mode\n");
- verbose = 1;
- goto restart;
- }
- }
- n = rb_next(n);
- prev = rsv;
- }
- printk(KERN_DEBUG "Window map complete.\n");
- BUG_ON(bad);
-}
-#define rsv_window_dump(root, verbose) \
- __rsv_window_dump((root), (verbose), __func__)
-#else
-#define rsv_window_dump(root, verbose) do {} while (0)
-#endif
-
-/**
- * goal_in_my_reservation()
- * @rsv: inode's reservation window
- * @grp_goal: given goal block relative to the allocation block group
- * @group: the current allocation block group
- * @sb: filesystem super block
- *
- * Test if the given goal block (group relative) is within the file's
- * own block reservation window range.
- *
- * If the reservation window is outside the goal allocation group, return 0;
- * grp_goal (given goal block) could be -1, which means no specific
- * goal block. In this case, always return 1.
- * If the goal block is within the reservation window, return 1;
- * otherwise, return 0;
- */
-static int
-goal_in_my_reservation(struct ext4_reserve_window *rsv, ext4_grpblk_t grp_goal,
- ext4_group_t group, struct super_block *sb)
-{
- ext4_fsblk_t group_first_block, group_last_block;
-
- group_first_block = ext4_group_first_block_no(sb, group);
- group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1);
-
- if ((rsv->_rsv_start > group_last_block) ||
- (rsv->_rsv_end < group_first_block))
- return 0;
- if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
- || (grp_goal + group_first_block > rsv->_rsv_end)))
- return 0;
- return 1;
-}
-
-/**
- * search_reserve_window()
- * @rb_root: root of reservation tree
- * @goal: target allocation block
- *
- * 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 ext4_reserve_window_node *
-search_reserve_window(struct rb_root *root, ext4_fsblk_t goal)
-{
- struct rb_node *n = root->rb_node;
- struct ext4_reserve_window_node *rsv;
-
- if (!n)
- return NULL;
-
- do {
- rsv = rb_entry(n, struct ext4_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 ext4_reserve_window_node, rsv_node);
- }
- return rsv;
-}
-
-/**
- * ext4_rsv_window_add() -- Insert a window to the block reservation rb tree.
- * @sb: super block
- * @rsv: reservation window to add
- *
- * Must be called with rsv_lock hold.
- */
-void ext4_rsv_window_add(struct super_block *sb,
- struct ext4_reserve_window_node *rsv)
-{
- struct rb_root *root = &EXT4_SB(sb)->s_rsv_window_root;
- struct rb_node *node = &rsv->rsv_node;
- ext4_fsblk_t start = rsv->rsv_start;
-
- struct rb_node **p = &root->rb_node;
- struct rb_node *parent = NULL;
- struct ext4_reserve_window_node *this;
-
- while (*p)
- {
- parent = *p;
- this = rb_entry(parent, struct ext4_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 {
- rsv_window_dump(root, 1);
- BUG();
- }
- }
-
- rb_link_node(node, parent, p);
- rb_insert_color(node, root);
-}
-
-/**
- * ext4_rsv_window_remove() -- unlink a window from the reservation rb tree
- * @sb: super block
- * @rsv: reservation window to remove
- *
- * Mark the block reservation window as not allocated, and unlink it
- * from the filesystem reservation window rb tree. Must be called with
- * rsv_lock hold.
- */
-static void rsv_window_remove(struct super_block *sb,
- struct ext4_reserve_window_node *rsv)
-{
- rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
- rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
- rsv->rsv_alloc_hit = 0;
- rb_erase(&rsv->rsv_node, &EXT4_SB(sb)->s_rsv_window_root);
-}
-
-/*
- * rsv_is_empty() -- Check if the reservation window is allocated.
- * @rsv: given reservation window to check
- *
- * returns 1 if the end block is EXT4_RESERVE_WINDOW_NOT_ALLOCATED.
- */
-static inline int rsv_is_empty(struct ext4_reserve_window *rsv)
-{
- /* a valid reservation end block could not be 0 */
- return rsv->_rsv_end == EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
-}
-
-/**
- * ext4_init_block_alloc_info()
- * @inode: file inode structure
- *
- * Allocate and initialize the reservation window structure, and
- * link the window to the ext4 inode structure at last
- *
- * The reservation window structure is only dynamically allocated
- * and linked to ext4 inode the first time the open file
- * needs a new block. So, before every ext4_new_block(s) call, for
- * regular files, we should check whether the reservation window
- * structure exists or not. In the latter case, this function is called.
- * Fail to do so will result in block reservation being turned off for that
- * open file.
- *
- * This function is called from ext4_get_blocks_handle(), also called
- * when setting the reservation window size through ioctl before the file
- * is open for write (needs block allocation).
- *
- * Needs down_write(i_data_sem) protection prior to call this function.
- */
-void ext4_init_block_alloc_info(struct inode *inode)
-{
- struct ext4_inode_info *ei = EXT4_I(inode);
- struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info;
- struct super_block *sb = inode->i_sb;
-
- block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
- if (block_i) {
- struct ext4_reserve_window_node *rsv = &block_i->rsv_window_node;
-
- rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
- rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED;
-
- /*
- * if filesystem is mounted with NORESERVATION, the goal
- * reservation window size is set to zero to indicate
- * block reservation is off
- */
- if (!test_opt(sb, RESERVATION))
- rsv->rsv_goal_size = 0;
- else
- rsv->rsv_goal_size = EXT4_DEFAULT_RESERVE_BLOCKS;
- rsv->rsv_alloc_hit = 0;
- block_i->last_alloc_logical_block = 0;
- block_i->last_alloc_physical_block = 0;
- }
- ei->i_block_alloc_info = block_i;
-}
-
-/**
- * ext4_discard_reservation()
- * @inode: inode
- *
- * Discard(free) block reservation window on last file close, or truncate
- * or at last iput().
- *
- * It is being called in three cases:
- * ext4_release_file(): last writer close the file
- * ext4_clear_inode(): last iput(), when nobody link to this file.
- * ext4_truncate(): when the block indirect map is about to change.
- *
- */
-void ext4_discard_reservation(struct inode *inode)
-{
- struct ext4_inode_info *ei = EXT4_I(inode);
- struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info;
- struct ext4_reserve_window_node *rsv;
- spinlock_t *rsv_lock = &EXT4_SB(inode->i_sb)->s_rsv_window_lock;
-
- ext4_mb_discard_inode_preallocations(inode);
-
- if (!block_i)
- return;
-
- rsv = &block_i->rsv_window_node;
- if (!rsv_is_empty(&rsv->rsv_window)) {
- spin_lock(rsv_lock);
- if (!rsv_is_empty(&rsv->rsv_window))
- rsv_window_remove(inode->i_sb, rsv);
- spin_unlock(rsv_lock);
- }
-}
/**
* ext4_free_blocks_sb() -- Free given blocks and update quota
* @block: start physcial block to free
* @count: number of blocks to free
* @pdquot_freed_blocks: pointer to quota
+ *
+ * XXX This function is only used by the on-line resizing code, which
+ * should probably be fixed up to call the mballoc variant. There
+ * this needs to be cleaned up later; in fact, I'm not convinced this
+ * is 100% correct in the face of the mballoc code. The online resizing
+ * code needs to be fixed up to more tightly (and correctly) interlock
+ * with the mballoc code.
*/
void ext4_free_blocks_sb(handle_t *handle, struct super_block *sb,
ext4_fsblk_t block, unsigned long count,
sb = inode->i_sb;
- if (!test_opt(sb, MBALLOC) || !EXT4_SB(sb)->s_group_info)
- ext4_free_blocks_sb(handle, sb, block, count,
- &dquot_freed_blocks);
- else
- ext4_mb_free_blocks(handle, inode, block, count,
- metadata, &dquot_freed_blocks);
+ ext4_mb_free_blocks(handle, inode, block, count,
+ metadata, &dquot_freed_blocks);
if (dquot_freed_blocks)
DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
return;
}
-/**
- * ext4_test_allocatable()
- * @nr: given allocation block group
- * @bh: bufferhead contains the bitmap of the given block group
- *
- * For ext4 allocations, we must not reuse any blocks which are
- * allocated in the bitmap buffer's "last committed data" copy. This
- * prevents deletes from freeing up the page for reuse until we have
- * committed the delete transaction.
- *
- * If we didn't do this, then deleting something and reallocating it as
- * data would allow the old block to be overwritten before the
- * transaction committed (because we force data to disk before commit).
- * This would lead to corruption if we crashed between overwriting the
- * data and committing the delete.
- *
- * @@@ We may want to make this allocation behaviour conditional on
- * data-writes at some point, and disable it for metadata allocations or
- * sync-data inodes.
- */
-static int ext4_test_allocatable(ext4_grpblk_t nr, struct buffer_head *bh)
-{
- int ret;
- struct journal_head *jh = bh2jh(bh);
-
- if (ext4_test_bit(nr, bh->b_data))
- return 0;
-
- jbd_lock_bh_state(bh);
- if (!jh->b_committed_data)
- ret = 1;
- else
- ret = !ext4_test_bit(nr, jh->b_committed_data);
- jbd_unlock_bh_state(bh);
- return ret;
-}
-
-/**
- * bitmap_search_next_usable_block()
- * @start: the starting block (group relative) of the search
- * @bh: bufferhead contains the block group bitmap
- * @maxblocks: the ending block (group relative) of the reservation
- *
- * The bitmap search --- search forward alternately through the actual
- * bitmap on disk and the last-committed copy in journal, until we find a
- * bit free in both bitmaps.
- */
-static ext4_grpblk_t
-bitmap_search_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh,
- ext4_grpblk_t maxblocks)
-{
- ext4_grpblk_t next;
- struct journal_head *jh = bh2jh(bh);
-
- while (start < maxblocks) {
- next = ext4_find_next_zero_bit(bh->b_data, maxblocks, start);
- if (next >= maxblocks)
- return -1;
- if (ext4_test_allocatable(next, bh))
- return next;
- jbd_lock_bh_state(bh);
- if (jh->b_committed_data)
- start = ext4_find_next_zero_bit(jh->b_committed_data,
- maxblocks, next);
- jbd_unlock_bh_state(bh);
- }
- return -1;
-}
-
-/**
- * find_next_usable_block()
- * @start: the starting block (group relative) to find next
- * allocatable block in bitmap.
- * @bh: bufferhead contains the block group bitmap
- * @maxblocks: the ending block (group relative) for the search
- *
- * Find an allocatable block in a bitmap. We honor both the bitmap and
- * its last-committed copy (if that exists), and perform the "most
- * appropriate allocation" algorithm of looking for a free block near
- * the initial goal; then for a free byte somewhere in the bitmap; then
- * for any free bit in the bitmap.
- */
-static ext4_grpblk_t
-find_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh,
- ext4_grpblk_t maxblocks)
-{
- ext4_grpblk_t here, next;
- char *p, *r;
-
- if (start > 0) {
- /*
- * The goal was occupied; search forward for a free
- * block within the next XX blocks.
- *
- * end_goal is more or less random, but it has to be
- * less than EXT4_BLOCKS_PER_GROUP. Aligning up to the
- * next 64-bit boundary is simple..
- */
- ext4_grpblk_t end_goal = (start + 63) & ~63;
- if (end_goal > maxblocks)
- end_goal = maxblocks;
- here = ext4_find_next_zero_bit(bh->b_data, end_goal, start);
- if (here < end_goal && ext4_test_allocatable(here, bh))
- return here;
- ext4_debug("Bit not found near goal\n");
- }
-
- here = start;
- if (here < 0)
- here = 0;
-
- p = ((char *)bh->b_data) + (here >> 3);
- r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3));
- next = (r - ((char *)bh->b_data)) << 3;
-
- if (next < maxblocks && next >= start && ext4_test_allocatable(next, bh))
- return next;
-
- /*
- * The bitmap search --- search forward alternately through the actual
- * bitmap and the last-committed copy until we find a bit free in
- * both
- */
- here = bitmap_search_next_usable_block(here, bh, maxblocks);
- return here;
-}
-
-/**
- * claim_block()
- * @block: the free block (group relative) to allocate
- * @bh: the bufferhead containts the block group bitmap
- *
- * We think we can allocate this block in this bitmap. Try to set the bit.
- * If that succeeds then check that nobody has allocated and then freed the
- * block since we saw that is was not marked in b_committed_data. If it _was_
- * allocated and freed then clear the bit in the bitmap again and return
- * zero (failure).
- */
-static inline int
-claim_block(spinlock_t *lock, ext4_grpblk_t block, struct buffer_head *bh)
-{
- struct journal_head *jh = bh2jh(bh);
- int ret;
-
- if (ext4_set_bit_atomic(lock, block, bh->b_data))
- return 0;
- jbd_lock_bh_state(bh);
- if (jh->b_committed_data && ext4_test_bit(block, jh->b_committed_data)) {
- ext4_clear_bit_atomic(lock, block, bh->b_data);
- ret = 0;
- } else {
- ret = 1;
- }
- jbd_unlock_bh_state(bh);
- return ret;
-}
-
-/**
- * ext4_try_to_allocate()
- * @sb: superblock
- * @handle: handle to this transaction
- * @group: given allocation block group
- * @bitmap_bh: bufferhead holds the block bitmap
- * @grp_goal: given target block within the group
- * @count: target number of blocks to allocate
- * @my_rsv: reservation window
- *
- * Attempt to allocate blocks within a give range. Set the range of allocation
- * first, then find the first free bit(s) from the bitmap (within the range),
- * and at last, allocate the blocks by claiming the found free bit as allocated.
- *
- * To set the range of this allocation:
- * if there is a reservation window, only try to allocate block(s) from the
- * file's own reservation window;
- * Otherwise, the allocation range starts from the give goal block, ends at
- * the block group's last block.
- *
- * If we failed to allocate the desired block then we may end up crossing to a
- * new bitmap. In that case we must release write access to the old one via
- * ext4_journal_release_buffer(), else we'll run out of credits.
- */
-static ext4_grpblk_t
-ext4_try_to_allocate(struct super_block *sb, handle_t *handle,
- ext4_group_t group, struct buffer_head *bitmap_bh,
- ext4_grpblk_t grp_goal, unsigned long *count,
- struct ext4_reserve_window *my_rsv)
-{
- ext4_fsblk_t group_first_block;
- ext4_grpblk_t start, end;
- unsigned long num = 0;
-
- /* we do allocation within the reservation window if we have a window */
- if (my_rsv) {
- group_first_block = ext4_group_first_block_no(sb, group);
- 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 > EXT4_BLOCKS_PER_GROUP(sb))
- /* reservation window crosses group boundary */
- end = EXT4_BLOCKS_PER_GROUP(sb);
- if ((start <= grp_goal) && (grp_goal < end))
- start = grp_goal;
- else
- grp_goal = -1;
- } else {
- if (grp_goal > 0)
- start = grp_goal;
- else
- start = 0;
- end = EXT4_BLOCKS_PER_GROUP(sb);
- }
-
- BUG_ON(start > EXT4_BLOCKS_PER_GROUP(sb));
-
-repeat:
- if (grp_goal < 0 || !ext4_test_allocatable(grp_goal, bitmap_bh)) {
- grp_goal = find_next_usable_block(start, bitmap_bh, end);
- if (grp_goal < 0)
- goto fail_access;
- if (!my_rsv) {
- int i;
-
- for (i = 0; i < 7 && grp_goal > start &&
- ext4_test_allocatable(grp_goal - 1,
- bitmap_bh);
- i++, grp_goal--)
- ;
- }
- }
- start = grp_goal;
-
- if (!claim_block(sb_bgl_lock(EXT4_SB(sb), group),
- grp_goal, bitmap_bh)) {
- /*
- * The block was allocated by another thread, or it was
- * allocated and then freed by another thread
- */
- start++;
- grp_goal++;
- if (start >= end)
- goto fail_access;
- goto repeat;
- }
- num++;
- grp_goal++;
- while (num < *count && grp_goal < end
- && ext4_test_allocatable(grp_goal, bitmap_bh)
- && claim_block(sb_bgl_lock(EXT4_SB(sb), group),
- grp_goal, bitmap_bh)) {
- num++;
- grp_goal++;
- }
- *count = num;
- return grp_goal - num;
-fail_access:
- *count = num;
- return -1;
-}
-
-/**
- * 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.
- *
- */
-static int find_next_reservable_window(
- struct ext4_reserve_window_node *search_head,
- struct ext4_reserve_window_node *my_rsv,
- struct super_block *sb,
- ext4_fsblk_t start_block,
- ext4_fsblk_t last_block)
-{
- struct rb_node *next;
- struct ext4_reserve_window_node *rsv, *prev;
- ext4_fsblk_t cur;
- int size = my_rsv->rsv_goal_size;
-
- /* TODO: make the start of the reservation window byte-aligned */
- /* cur = *start_block & ~7;*/
- cur = start_block;
- rsv = search_head;
- if (!rsv)
- return -1;
-
- 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 -1; /* fail */
-
- prev = rsv;
- next = rb_next(&rsv->rsv_node);
- rsv = rb_entry(next, struct ext4_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.
- */
-
- if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
- rsv_window_remove(sb, my_rsv);
-
- /*
- * Let's book the whole avaliable window for now. We will check the
- * disk bitmap later and then, if there are free blocks then we adjust
- * the window size if it's larger than requested.
- * Otherwise, we will remove this node from the tree next time
- * call find_next_reservable_window.
- */
- my_rsv->rsv_start = cur;
- my_rsv->rsv_end = cur + size - 1;
- my_rsv->rsv_alloc_hit = 0;
-
- if (prev != my_rsv)
- ext4_rsv_window_add(sb, my_rsv);
-
- return 0;
-}
-
-/**
- * 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
- *
- * @grp_goal: The goal (group-relative). It is where the search for a
- * free reservable space should start from.
- * if we have a grp_goal(grp_goal >0 ), then start from there,
- * no grp_goal(grp_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 ext4_reserve_window_node *my_rsv,
- ext4_grpblk_t grp_goal, struct super_block *sb,
- ext4_group_t group, struct buffer_head *bitmap_bh)
-{
- struct ext4_reserve_window_node *search_head;
- ext4_fsblk_t group_first_block, group_end_block, start_block;
- ext4_grpblk_t first_free_block;
- struct rb_root *fs_rsv_root = &EXT4_SB(sb)->s_rsv_window_root;
- unsigned long size;
- int ret;
- spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock;
-
- group_first_block = ext4_group_first_block_no(sb, group);
- group_end_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1);
-
- if (grp_goal < 0)
- start_block = group_first_block;
- else
- start_block = grp_goal + group_first_block;
-
- size = 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 ((my_rsv->rsv_alloc_hit >
- (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
- /*
- * if the previously allocation hit ratio is
- * greater than 1/2, then we double the size of
- * the reservation window the next time,
- * otherwise we keep the same size window
- */
- size = size * 2;
- if (size > EXT4_MAX_RESERVE_BLOCKS)
- size = EXT4_MAX_RESERVE_BLOCKS;
- my_rsv->rsv_goal_size = size;
- }
- }
-
- spin_lock(rsv_lock);
- /*
- * 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:
- ret = find_next_reservable_window(search_head, my_rsv, sb,
- start_block, group_end_block);
-
- if (ret == -1) {
- if (!rsv_is_empty(&my_rsv->rsv_window))
- rsv_window_remove(sb, my_rsv);
- spin_unlock(rsv_lock);
- return -1;
- }
-
- /*
- * 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.
- */
- spin_unlock(rsv_lock);
- first_free_block = bitmap_search_next_usable_block(
- my_rsv->rsv_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.
- */
- spin_lock(rsv_lock);
- if (!rsv_is_empty(&my_rsv->rsv_window))
- rsv_window_remove(sb, my_rsv);
- spin_unlock(rsv_lock);
- return -1; /* failed */
- }
-
- start_block = first_free_block + group_first_block;
- /*
- * check if the first free block is within the
- * free space we just reserved
- */
- if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end)
- return 0; /* success */
- /*
- * if the first free bit we found is out of the reservable space
- * 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 = my_rsv;
- spin_lock(rsv_lock);
- goto retry;
-}
-
-/**
- * try_to_extend_reservation()
- * @my_rsv: given reservation window
- * @sb: super block
- * @size: the delta to extend
- *
- * Attempt to expand the reservation window large enough to have
- * required number of free blocks
- *
- * Since ext4_try_to_allocate() will always allocate blocks within
- * the reservation window range, if the window size is too small,
- * multiple blocks allocation has to stop at the end of the reservation
- * window. To make this more efficient, given the total number of
- * blocks needed and the current size of the window, we try to
- * expand the reservation window size if necessary on a best-effort
- * basis before ext4_new_blocks() tries to allocate blocks,
- */
-static void try_to_extend_reservation(struct ext4_reserve_window_node *my_rsv,
- struct super_block *sb, int size)
-{
- struct ext4_reserve_window_node *next_rsv;
- struct rb_node *next;
- spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock;
-
- if (!spin_trylock(rsv_lock))
- return;
-
- next = rb_next(&my_rsv->rsv_node);
-
- if (!next)
- my_rsv->rsv_end += size;
- else {
- next_rsv = rb_entry(next, struct ext4_reserve_window_node, rsv_node);
-
- if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
- my_rsv->rsv_end += size;
- else
- my_rsv->rsv_end = next_rsv->rsv_start - 1;
- }
- spin_unlock(rsv_lock);
-}
-
-/**
- * ext4_try_to_allocate_with_rsv()
- * @sb: superblock
- * @handle: handle to this transaction
- * @group: given allocation block group
- * @bitmap_bh: bufferhead holds the block bitmap
- * @grp_goal: given target block within the group
- * @count: target number of blocks to allocate
- * @my_rsv: reservation window
- * @errp: pointer to store the error code
- *
- * 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 somebody is looking for a free block (without
- * reservation), and there are lots of free blocks, but they are all
- * being reserved.
- *
- * We use a red-black tree for the per-filesystem reservation list.
- *
- */
-static ext4_grpblk_t
-ext4_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
- ext4_group_t group, struct buffer_head *bitmap_bh,
- ext4_grpblk_t grp_goal,
- struct ext4_reserve_window_node *my_rsv,
- unsigned long *count, int *errp)
-{
- ext4_fsblk_t group_first_block, group_last_block;
- ext4_grpblk_t ret = 0;
- int fatal;
- unsigned long num = *count;
-
- *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 = ext4_journal_get_undo_access(handle, bitmap_bh);
- if (fatal) {
- *errp = fatal;
- 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 = ext4_try_to_allocate(sb, handle, group, bitmap_bh,
- grp_goal, count, NULL);
- goto out;
- }
- /*
- * grp_goal is a group relative block number (if there is a goal)
- * 0 <= grp_goal < EXT4_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 = ext4_group_first_block_no(sb, group);
- group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1);
-
- /*
- * 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) {
- if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
- !goal_in_my_reservation(&my_rsv->rsv_window,
- grp_goal, group, sb)) {
- if (my_rsv->rsv_goal_size < *count)
- my_rsv->rsv_goal_size = *count;
- ret = alloc_new_reservation(my_rsv, grp_goal, sb,
- group, bitmap_bh);
- if (ret < 0)
- break; /* failed */
-
- if (!goal_in_my_reservation(&my_rsv->rsv_window,
- grp_goal, group, sb))
- grp_goal = -1;
- } else if (grp_goal >= 0) {
- int curr = my_rsv->rsv_end -
- (grp_goal + group_first_block) + 1;
-
- if (curr < *count)
- try_to_extend_reservation(my_rsv, sb,
- *count - curr);
- }
-
- if ((my_rsv->rsv_start > group_last_block) ||
- (my_rsv->rsv_end < group_first_block)) {
- rsv_window_dump(&EXT4_SB(sb)->s_rsv_window_root, 1);
- BUG();
- }
- ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh,
- grp_goal, &num, &my_rsv->rsv_window);
- if (ret >= 0) {
- my_rsv->rsv_alloc_hit += num;
- *count = num;
- break; /* succeed */
- }
- num = *count;
- }
-out:
- if (ret >= 0) {
- BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
- "bitmap block");
- fatal = ext4_journal_dirty_metadata(handle, bitmap_bh);
- if (fatal) {
- *errp = fatal;
- return -1;
- }
- return ret;
- }
-
- BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
- ext4_journal_release_buffer(handle, bitmap_bh);
- return ret;
-}
-
int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
s64 nblocks)
{
return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
}
-/**
- * ext4_old_new_blocks() -- core block bitmap based block allocation function
- *
- * @handle: handle to this transaction
- * @inode: file inode
- * @goal: given target block(filesystem wide)
- * @count: target number of blocks to allocate
- * @errp: error code
- *
- * ext4_old_new_blocks uses a goal block to assist allocation and look up
- * the block bitmap directly to do block allocation. It tries to
- * allocate block(s) from the block group contains the goal block first. If
- * that fails, it will try to allocate block(s) from other block groups
- * without any specific goal block.
- *
- * This function is called when -o nomballoc mount option is enabled
- *
- */
-ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
- ext4_fsblk_t goal, unsigned long *count, int *errp)
-{
- struct buffer_head *bitmap_bh = NULL;
- struct buffer_head *gdp_bh;
- ext4_group_t group_no;
- ext4_group_t goal_group;
- ext4_grpblk_t grp_target_blk; /* blockgroup relative goal block */
- ext4_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/
- ext4_fsblk_t ret_block; /* filesyetem-wide allocated block */
- ext4_group_t bgi; /* blockgroup iteration index */
- int fatal = 0, err;
- int performed_allocation = 0;
- ext4_grpblk_t free_blocks; /* number of free blocks in a group */
- struct super_block *sb;
- struct ext4_group_desc *gdp;
- struct ext4_super_block *es;
- struct ext4_sb_info *sbi;
- struct ext4_reserve_window_node *my_rsv = NULL;
- struct ext4_block_alloc_info *block_i;
- unsigned short windowsz = 0;
- ext4_group_t ngroups;
- unsigned long num = *count;
-
- sb = inode->i_sb;
- if (!sb) {
- *errp = -ENODEV;
- printk(KERN_ERR "ext4_new_block: nonexistent superblock");
- return 0;
- }
-
- sbi = EXT4_SB(sb);
- if (!EXT4_I(inode)->i_delalloc_reserved_flag) {
- /*
- * With delalloc we already reserved the blocks
- */
- while (*count && ext4_claim_free_blocks(sbi, *count)) {
- /* let others to free the space */
- yield();
- *count = *count >> 1;
- }
- if (!*count) {
- *errp = -ENOSPC;
- return 0; /*return with ENOSPC error */
- }
- num = *count;
- }
- /*
- * Check quota for allocation of this block.
- */
- if (DQUOT_ALLOC_BLOCK(inode, num)) {
- *errp = -EDQUOT;
- return 0;
- }
-
- sbi = EXT4_SB(sb);
- es = EXT4_SB(sb)->s_es;
- ext4_debug("goal=%llu.\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 EXT4_IOC_SETRSVSZ to set the window size to 0 to turn off
- * reservation on that particular file)
- */
- block_i = EXT4_I(inode)->i_block_alloc_info;
- if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
- my_rsv = &block_i->rsv_window_node;
-
- /*
- * First, test whether the goal block is free.
- */
- if (goal < le32_to_cpu(es->s_first_data_block) ||
- goal >= ext4_blocks_count(es))
- goal = le32_to_cpu(es->s_first_data_block);
- ext4_get_group_no_and_offset(sb, goal, &group_no, &grp_target_blk);
- goal_group = group_no;
-retry_alloc:
- gdp = ext4_get_group_desc(sb, group_no, &gdp_bh);
- if (!gdp)
- goto io_error;
-
- free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
-
- if (free_blocks > 0) {
- /*
- * try to allocate with group target block
- * in the goal group. If we have low free_blocks
- * count turn off reservation
- */
- if (my_rsv && (free_blocks < windowsz)
- && (rsv_is_empty(&my_rsv->rsv_window)))
- my_rsv = NULL;
-
- bitmap_bh = ext4_read_block_bitmap(sb, group_no);
- if (!bitmap_bh)
- goto io_error;
- grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle,
- group_no, bitmap_bh, grp_target_blk,
- my_rsv, &num, &fatal);
- if (fatal)
- goto out;
- if (grp_alloc_blk >= 0)
- goto allocated;
- }
-
- ngroups = EXT4_SB(sb)->s_groups_count;
- smp_rmb();
-
- /*
- * Now search the rest of the groups. We assume that
- * group_no and gdp correctly point to the last group visited.
- */
- for (bgi = 0; bgi < ngroups; bgi++) {
- group_no++;
- if (group_no >= ngroups)
- group_no = 0;
- gdp = ext4_get_group_desc(sb, group_no, &gdp_bh);
- if (!gdp)
- goto io_error;
- free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
- /*
- * skip this group if the number of
- * free blocks is less than half of the reservation
- * window size.
- */
- if (my_rsv && (free_blocks <= (windowsz/2)))
- continue;
-
- brelse(bitmap_bh);
- bitmap_bh = ext4_read_block_bitmap(sb, group_no);
- if (!bitmap_bh)
- goto io_error;
- /*
- * try to allocate block(s) from this group, without a goal(-1).
- */
- grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle,
- group_no, bitmap_bh, -1, my_rsv,
- &num, &fatal);
- if (fatal)
- goto out;
- if (grp_alloc_blk >= 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;
- windowsz = 0;
- group_no = goal_group;
- goto retry_alloc;
- }
- /* No space left on the device */
- *errp = -ENOSPC;
- goto out;
-
-allocated:
-
- ext4_debug("using block group %lu(%d)\n",
- group_no, gdp->bg_free_blocks_count);
-
- BUFFER_TRACE(gdp_bh, "get_write_access");
- fatal = ext4_journal_get_write_access(handle, gdp_bh);
- if (fatal)
- goto out;
-
- ret_block = grp_alloc_blk + ext4_group_first_block_no(sb, group_no);
-
- if (in_range(ext4_block_bitmap(sb, gdp), ret_block, num) ||
- in_range(ext4_inode_bitmap(sb, gdp), ret_block, num) ||
- in_range(ret_block, ext4_inode_table(sb, gdp),
- EXT4_SB(sb)->s_itb_per_group) ||
- in_range(ret_block + num - 1, ext4_inode_table(sb, gdp),
- EXT4_SB(sb)->s_itb_per_group)) {
- ext4_error(sb, "ext4_new_block",
- "Allocating block in system zone - "
- "blocks from %llu, length %lu",
- ret_block, num);
- /*
- * claim_block marked the blocks we allocated
- * as in use. So we may want to selectively
- * mark some of the blocks as free
- */
- goto retry_alloc;
- }
-
- performed_allocation = 1;
-
-#ifdef CONFIG_JBD2_DEBUG
- {
- struct buffer_head *debug_bh;
-
- /* Record bitmap buffer state in the newly allocated block */
- debug_bh = sb_find_get_block(sb, ret_block);
- if (debug_bh) {
- BUFFER_TRACE(debug_bh, "state when allocated");
- BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
- brelse(debug_bh);
- }
- }
- jbd_lock_bh_state(bitmap_bh);
- spin_lock(sb_bgl_lock(sbi, group_no));
- if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
- int i;
-
- for (i = 0; i < num; i++) {
- if (ext4_test_bit(grp_alloc_blk+i,
- bh2jh(bitmap_bh)->b_committed_data)) {
- printk(KERN_ERR "%s: block was unexpectedly "
- "set in b_committed_data\n", __func__);
- }
- }
- }
- ext4_debug("found bit %d\n", grp_alloc_blk);
- spin_unlock(sb_bgl_lock(sbi, group_no));
- jbd_unlock_bh_state(bitmap_bh);
-#endif
-
- if (ret_block + num - 1 >= ext4_blocks_count(es)) {
- ext4_error(sb, "ext4_new_block",
- "block(%llu) >= blocks count(%llu) - "
- "block_group = %lu, es == %p ", ret_block,
- ext4_blocks_count(es), group_no, es);
- goto out;
- }
-
- /*
- * It is up to the caller to add the new buffer to a journal
- * list of some description. We don't know in advance whether
- * the caller wants to use it as metadata or data.
- */
- spin_lock(sb_bgl_lock(sbi, group_no));
- if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))
- gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
- le16_add_cpu(&gdp->bg_free_blocks_count, -num);
- gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
- spin_unlock(sb_bgl_lock(sbi, group_no));
- percpu_counter_sub(&sbi->s_freeblocks_counter, num);
- /*
- * Now reduce the dirty block count also. Should not go negative
- */
- if (!EXT4_I(inode)->i_delalloc_reserved_flag)
- percpu_counter_sub(&sbi->s_dirtyblocks_counter, *count);
- else
- percpu_counter_sub(&sbi->s_dirtyblocks_counter, num);
- if (sbi->s_log_groups_per_flex) {
- ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
- spin_lock(sb_bgl_lock(sbi, flex_group));
- sbi->s_flex_groups[flex_group].free_blocks -= num;
- spin_unlock(sb_bgl_lock(sbi, flex_group));
- }
-
- BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
- err = ext4_journal_dirty_metadata(handle, gdp_bh);
- if (!fatal)
- fatal = err;
-
- sb->s_dirt = 1;
- if (fatal)
- goto out;
-
- *errp = 0;
- brelse(bitmap_bh);
- DQUOT_FREE_BLOCK(inode, *count-num);
- *count = num;
- return ret_block;
-
-io_error:
- *errp = -EIO;
-out:
- if (fatal) {
- *errp = fatal;
- ext4_std_error(sb, fatal);
- }
- /*
- * Undo the block allocation
- */
- if (!performed_allocation)
- DQUOT_FREE_BLOCK(inode, *count);
- brelse(bitmap_bh);
- return 0;
-}
-
#define EXT4_META_BLOCK 0x1
static ext4_fsblk_t do_blk_alloc(handle_t *handle, struct inode *inode,
struct ext4_allocation_request ar;
ext4_fsblk_t ret;
- if (!test_opt(inode->i_sb, MBALLOC)) {
- return ext4_old_new_blocks(handle, inode, goal, count, errp);
- }
-
memset(&ar, 0, sizeof(ar));
/* Fill with neighbour allocated blocks */
return ext4_bg_num_gdb_meta(sb,group);
}
+
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff