return NULL;
}
-/*
- * Set sb->s_dirt here because the superblock was "logically" altered. We
- * need to recalculate its free blocks count and flush it out.
- */
-static int reserve_blocks(struct super_block *sb, int count)
-{
- struct ext2_sb_info *sbi = EXT2_SB(sb);
- struct ext2_super_block *es = sbi->s_es;
- unsigned free_blocks;
- unsigned root_blocks;
-
- free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
- root_blocks = le32_to_cpu(es->s_r_blocks_count);
-
- if (free_blocks < count)
- count = free_blocks;
-
- if (free_blocks < root_blocks + count && !capable(CAP_SYS_RESOURCE) &&
- sbi->s_resuid != current->fsuid &&
- (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
- /*
- * We are too close to reserve and we are not privileged.
- * Can we allocate anything at all?
- */
- if (free_blocks > root_blocks)
- count = free_blocks - root_blocks;
- else
- return 0;
- }
-
- percpu_counter_sub(&sbi->s_freeblocks_counter, count);
- sb->s_dirt = 1;
- return count;
-}
-
static void release_blocks(struct super_block *sb, int count)
{
if (count) {
}
}
-static int group_reserve_blocks(struct ext2_sb_info *sbi, int group_no,
- struct ext2_group_desc *desc, struct buffer_head *bh, int count)
-{
- unsigned free_blocks;
-
- if (!desc->bg_free_blocks_count)
- return 0;
-
- spin_lock(sb_bgl_lock(sbi, group_no));
- free_blocks = le16_to_cpu(desc->bg_free_blocks_count);
- if (free_blocks < count)
- count = free_blocks;
- desc->bg_free_blocks_count = cpu_to_le16(free_blocks - count);
- spin_unlock(sb_bgl_lock(sbi, group_no));
- mark_buffer_dirty(bh);
- return count;
-}
-
-static void group_release_blocks(struct super_block *sb, int group_no,
+static void group_adjust_blocks(struct super_block *sb, int group_no,
struct ext2_group_desc *desc, struct buffer_head *bh, int count)
{
if (count) {
}
}
-/* Free given blocks, update quota and i_blocks field */
+/*
+ * 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 ext2_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 = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
+ if (verbose)
+ printk("reservation window 0x%p "
+ "start: %lu, end: %lu\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
+
+/**
+ * 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 ext2_reserve_window *rsv, ext2_grpblk_t grp_goal,
+ unsigned int group, struct super_block * sb)
+{
+ ext2_fsblk_t group_first_block, group_last_block;
+
+ group_first_block = ext2_group_first_block_no(sb, group);
+ group_last_block = group_first_block + EXT2_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 ext2_reserve_window_node *
+search_reserve_window(struct rb_root *root, ext2_fsblk_t goal)
+{
+ struct rb_node *n = root->rb_node;
+ struct ext2_reserve_window_node *rsv;
+
+ if (!n)
+ return NULL;
+
+ do {
+ rsv = rb_entry(n, struct ext2_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 ext2_reserve_window_node, rsv_node);
+ }
+ return rsv;
+}
+
+/*
+ * ext2_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 held.
+ */
+void ext2_rsv_window_add(struct super_block *sb,
+ struct ext2_reserve_window_node *rsv)
+{
+ struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root;
+ struct rb_node *node = &rsv->rsv_node;
+ ext2_fsblk_t start = rsv->rsv_start;
+
+ struct rb_node ** p = &root->rb_node;
+ struct rb_node * parent = NULL;
+ struct ext2_reserve_window_node *this;
+
+ while (*p)
+ {
+ parent = *p;
+ this = rb_entry(parent, struct ext2_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);
+}
+
+/**
+ * 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 held.
+ */
+static void rsv_window_remove(struct super_block *sb,
+ struct ext2_reserve_window_node *rsv)
+{
+ rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+ rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+ rsv->rsv_alloc_hit = 0;
+ rb_erase(&rsv->rsv_node, &EXT2_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 EXT2_RESERVE_WINDOW_NOT_ALLOCATED.
+ */
+static inline int rsv_is_empty(struct ext2_reserve_window *rsv)
+{
+ /* a valid reservation end block could not be 0 */
+ return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED);
+}
+
+/**
+ * ext2_init_block_alloc_info()
+ * @inode: file inode structure
+ *
+ * Allocate and initialize the reservation window structure, and
+ * link the window to the ext2 inode structure at last
+ *
+ * The reservation window structure is only dynamically allocated
+ * and linked to ext2 inode the first time the open file
+ * needs a new block. So, before every ext2_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 ext2_get_blocks_handle(), also called
+ * when setting the reservation window size through ioctl before the file
+ * is open for write (needs block allocation).
+ *
+ * Needs truncate_mutex protection prior to calling this function.
+ */
+void ext2_init_block_alloc_info(struct inode *inode)
+{
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ struct ext2_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 ext2_reserve_window_node *rsv = &block_i->rsv_window_node;
+
+ rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+ rsv->rsv_end = EXT2_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 = EXT2_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;
+}
+
+/**
+ * ext2_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:
+ * ext2_release_file(): last writer closes the file
+ * ext2_clear_inode(): last iput(), when nobody links to this file.
+ * ext2_truncate(): when the block indirect map is about to change.
+ */
+void ext2_discard_reservation(struct inode *inode)
+{
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info;
+ struct ext2_reserve_window_node *rsv;
+ spinlock_t *rsv_lock = &EXT2_SB(inode->i_sb)->s_rsv_window_lock;
+
+ 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);
+ }
+}
+
+/**
+ * ext2_free_blocks_sb() -- Free given blocks and update quota and i_blocks
+ * @inode: inode
+ * @block: start physcial block to free
+ * @count: number of blocks to free
+ */
void ext2_free_blocks (struct inode * inode, unsigned long block,
unsigned long count)
{
if (sb->s_flags & MS_SYNCHRONOUS)
sync_dirty_buffer(bitmap_bh);
- group_release_blocks(sb, block_group, desc, bh2, group_freed);
+ group_adjust_blocks(sb, block_group, desc, bh2, group_freed);
freed += group_freed;
if (overflow) {
DQUOT_FREE_BLOCK(inode, freed);
}
-static int grab_block(spinlock_t *lock, char *map, unsigned size, int goal)
+/**
+ * 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 through the actual bitmap on disk until
+ * we find a bit free.
+ */
+static ext2_grpblk_t
+bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh,
+ ext2_grpblk_t maxblocks)
{
- int k;
- char *p, *r;
+ ext2_grpblk_t next;
- if (!ext2_test_bit(goal, map))
- goto got_it;
+ next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start);
+ if (next >= maxblocks)
+ return -1;
+ return next;
+}
-repeat:
- if (goal) {
+/**
+ * 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 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 ext2_grpblk_t
+find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
+{
+ ext2_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.
* less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
* next 64-bit boundary is simple..
*/
- k = (goal + 63) & ~63;
- goal = ext2_find_next_zero_bit(map, k, goal);
- if (goal < k)
- goto got_it;
+ ext2_grpblk_t end_goal = (start + 63) & ~63;
+ if (end_goal > maxblocks)
+ end_goal = maxblocks;
+ here = ext2_find_next_zero_bit(bh->b_data, end_goal, start);
+ if (here < end_goal)
+ return here;
+ ext2_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 >= here)
+ return next;
+
+ here = bitmap_search_next_usable_block(here, bh, maxblocks);
+ return here;
+}
+
+/*
+ * ext2_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.
+ */
+static int
+ext2_try_to_allocate(struct super_block *sb, int group,
+ struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
+ unsigned long *count,
+ struct ext2_reserve_window *my_rsv)
+{
+ ext2_fsblk_t group_first_block;
+ ext2_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 = ext2_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 > EXT2_BLOCKS_PER_GROUP(sb))
+ /* reservation window crosses group boundary */
+ end = EXT2_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 = EXT2_BLOCKS_PER_GROUP(sb);
+ }
+
+ BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb));
+
+repeat:
+ if (grp_goal < 0) {
+ 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 &&
+ !ext2_test_bit(grp_goal - 1,
+ bitmap_bh->b_data);
+ i++, grp_goal--)
+ ;
+ }
+ }
+ start = grp_goal;
+
+ if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), grp_goal,
+ bitmap_bh->b_data)) {
+ /*
+ * 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
+ && !ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group),
+ grp_goal, bitmap_bh->b_data)) {
+ 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 ext2_reserve_window_node *search_head,
+ struct ext2_reserve_window_node *my_rsv,
+ struct super_block * sb,
+ ext2_fsblk_t start_block,
+ ext2_fsblk_t last_block)
+{
+ struct rb_node *next;
+ struct ext2_reserve_window_node *rsv, *prev;
+ ext2_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 ext2_reserve_window_node,rsv_node);
+
/*
- * Search in the remainder of the current group.
+ * 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.
+ */
- p = map + (goal >> 3);
- r = memscan(p, 0, (size - goal + 7) >> 3);
- k = (r - map) << 3;
- if (k < size) {
- /*
- * We have succeeded in finding a free byte in the block
- * bitmap. Now search backwards to find the start of this
- * group of free blocks - won't take more than 7 iterations.
+ 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)
+ ext2_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 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 ext2_reserve_window_node *my_rsv,
+ ext2_grpblk_t grp_goal, struct super_block *sb,
+ unsigned int group, struct buffer_head *bitmap_bh)
+{
+ struct ext2_reserve_window_node *search_head;
+ ext2_fsblk_t group_first_block, group_end_block, start_block;
+ ext2_grpblk_t first_free_block;
+ struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root;
+ unsigned long size;
+ int ret;
+ spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock;
+
+ group_first_block = ext2_group_first_block_no(sb, group);
+ group_end_block = group_first_block + (EXT2_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.
*/
- for (goal = k; goal && !ext2_test_bit (goal - 1, map); goal--)
- ;
- goto got_it;
+
+ 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 > EXT2_MAX_RESERVE_BLOCKS)
+ size = EXT2_MAX_RESERVE_BLOCKS;
+ my_rsv->rsv_goal_size= size;
+ }
}
- k = ext2_find_next_zero_bit ((u32 *)map, size, goal);
- if (k < size) {
- goal = k;
- goto got_it;
+ 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;
}
- return -1;
-got_it:
- if (ext2_set_bit_atomic(lock, goal, (void *) map))
- goto repeat;
- return goal;
+
+ /*
+ * 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.
+ *
+ * Search the first free bit on the block bitmap. Search starts 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 ext2_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 ext2_new_blocks() tries to allocate blocks.
+ */
+static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv,
+ struct super_block *sb, int size)
+{
+ struct ext2_reserve_window_node *next_rsv;
+ struct rb_node *next;
+ spinlock_t *rsv_lock = &EXT2_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 ext2_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);
+}
+
+/**
+ * ext2_try_to_allocate_with_rsv()
+ * @sb: superblock
+ * @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
+ *
+ * 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 ext2_grpblk_t
+ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group,
+ struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
+ struct ext2_reserve_window_node * my_rsv,
+ unsigned long *count)
+{
+ ext2_fsblk_t group_first_block, group_last_block;
+ ext2_grpblk_t ret = 0;
+ unsigned long num = *count;
+
+ /*
+ * 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) {
+ return ext2_try_to_allocate(sb, group, bitmap_bh,
+ grp_goal, count, NULL);
+ }
+ /*
+ * grp_goal is a group relative block number (if there is a goal)
+ * 0 <= grp_goal < EXT2_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 = ext2_group_first_block_no(sb, group);
+ group_last_block = group_first_block + (EXT2_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(&EXT2_SB(sb)->s_rsv_window_root, 1);
+ BUG();
+ }
+ ret = ext2_try_to_allocate(sb, 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;
+ }
+ return ret;
+}
+
+/**
+ * ext2_has_free_blocks()
+ * @sbi: in-core super block structure.
+ *
+ * Check if filesystem has at least 1 free block available for allocation.
+ */
+static int ext2_has_free_blocks(struct ext2_sb_info *sbi)
+{
+ ext2_fsblk_t free_blocks, root_blocks;
+
+ free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+ root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
+ if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
+ sbi->s_resuid != current->fsuid &&
+ (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
+ return 0;
+ }
+ return 1;
}
/*
- * ext2_new_block uses a goal block to assist allocation. If the goal is
+ * ext2_new_blocks() -- core block(s) allocation function
+ * @inode: file inode
+ * @goal: given target block(filesystem wide)
+ * @count: target number of blocks to allocate
+ * @errp: error code
+ *
+ * ext2_new_blocks uses a goal block to assist allocation. If the goal is
* free, or there is a free block within 32 blocks of the goal, that block
* is allocated. Otherwise a forward search is made for a free block; within
* each block group the search first looks for an entire free byte in the block
* bitmap, and then for any free bit if that fails.
* This function also updates quota and i_blocks field.
*/
-int ext2_new_block(struct inode *inode, unsigned long goal,
- u32 *prealloc_count, u32 *prealloc_block, int *err)
+ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
+ unsigned long *count, int *errp)
{
struct buffer_head *bitmap_bh = NULL;
- struct buffer_head *gdp_bh; /* bh2 */
- struct ext2_group_desc *desc;
- int group_no; /* i */
- int ret_block; /* j */
- int group_idx; /* k */
- int target_block; /* tmp */
- int block = 0;
- struct super_block *sb = inode->i_sb;
- struct ext2_sb_info *sbi = EXT2_SB(sb);
- struct ext2_super_block *es = sbi->s_es;
- unsigned group_size = EXT2_BLOCKS_PER_GROUP(sb);
- unsigned prealloc_goal = es->s_prealloc_blocks;
- unsigned group_alloc = 0, es_alloc, dq_alloc;
- int nr_scanned_groups;
-
- if (!prealloc_goal--)
- prealloc_goal = EXT2_DEFAULT_PREALLOC_BLOCKS - 1;
- if (!prealloc_count || *prealloc_count)
- prealloc_goal = 0;
-
- if (DQUOT_ALLOC_BLOCK(inode, 1)) {
- *err = -EDQUOT;
- goto out;
+ struct buffer_head *gdp_bh;
+ int group_no;
+ int goal_group;
+ ext2_grpblk_t grp_target_blk; /* blockgroup relative goal block */
+ ext2_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/
+ ext2_fsblk_t ret_block; /* filesyetem-wide allocated block */
+ int bgi; /* blockgroup iteration index */
+ int performed_allocation = 0;
+ ext2_grpblk_t free_blocks; /* number of free blocks in a group */
+ struct super_block *sb;
+ struct ext2_group_desc *gdp;
+ struct ext2_super_block *es;
+ struct ext2_sb_info *sbi;
+ struct ext2_reserve_window_node *my_rsv = NULL;
+ struct ext2_block_alloc_info *block_i;
+ unsigned short windowsz = 0;
+ unsigned long ngroups;
+ unsigned long num = *count;
+
+ *errp = -ENOSPC;
+ sb = inode->i_sb;
+ if (!sb) {
+ printk("ext2_new_blocks: nonexistent device");
+ return 0;
}
- while (prealloc_goal && DQUOT_PREALLOC_BLOCK(inode, prealloc_goal))
- prealloc_goal--;
+ /*
+ * Check quota for allocation of this block.
+ */
+ if (DQUOT_ALLOC_BLOCK(inode, num)) {
+ *errp = -EDQUOT;
+ return 0;
+ }
- dq_alloc = prealloc_goal + 1;
- es_alloc = reserve_blocks(sb, dq_alloc);
- if (!es_alloc) {
- *err = -ENOSPC;
- goto out_dquot;
+ sbi = EXT2_SB(sb);
+ es = EXT2_SB(sb)->s_es;
+ ext2_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 EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off
+ * reservation on that particular file)
+ */
+ block_i = EXT2_I(inode)->i_block_alloc_info;
+ if (block_i) {
+ windowsz = block_i->rsv_window_node.rsv_goal_size;
+ if (windowsz > 0)
+ my_rsv = &block_i->rsv_window_node;
}
- ext2_debug ("goal=%lu.\n", goal);
+ if (!ext2_has_free_blocks(sbi)) {
+ *errp = -ENOSPC;
+ goto out;
+ }
+ /*
+ * First, test whether the goal block is free.
+ */
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= le32_to_cpu(es->s_blocks_count))
goal = le32_to_cpu(es->s_first_data_block);
- group_no = (goal - le32_to_cpu(es->s_first_data_block)) / group_size;
- desc = ext2_get_group_desc (sb, group_no, &gdp_bh);
- if (!desc) {
- /*
- * gdp_bh may still be uninitialised. But group_release_blocks
- * will not touch it because group_alloc is zero.
- */
+ group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
+ EXT2_BLOCKS_PER_GROUP(sb);
+ goal_group = group_no;
+retry_alloc:
+ gdp = ext2_get_group_desc(sb, group_no, &gdp_bh);
+ if (!gdp)
goto io_error;
- }
- group_alloc = group_reserve_blocks(sbi, group_no, desc,
- gdp_bh, es_alloc);
- if (group_alloc) {
- ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) %
- group_size);
- brelse(bitmap_bh);
+ free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+ /*
+ * if there is not enough free blocks to make a new resevation
+ * turn off reservation for this allocation
+ */
+ if (my_rsv && (free_blocks < windowsz)
+ && (rsv_is_empty(&my_rsv->rsv_window)))
+ my_rsv = NULL;
+
+ if (free_blocks > 0) {
+ grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
+ EXT2_BLOCKS_PER_GROUP(sb));
bitmap_bh = read_block_bitmap(sb, group_no);
if (!bitmap_bh)
goto io_error;
-
- ext2_debug("goal is at %d:%d.\n", group_no, ret_block);
-
- ret_block = grab_block(sb_bgl_lock(sbi, group_no),
- bitmap_bh->b_data, group_size, ret_block);
- if (ret_block >= 0)
- goto got_block;
- group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc);
- group_alloc = 0;
+ grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
+ bitmap_bh, grp_target_blk,
+ my_rsv, &num);
+ if (grp_alloc_blk >= 0)
+ goto allocated;
}
- ext2_debug ("Bit not found in block group %d.\n", group_no);
+ ngroups = EXT2_SB(sb)->s_groups_count;
+ smp_rmb();
/*
* Now search the rest of the groups. We assume that
- * i and desc correctly point to the last group visited.
+ * i and gdp correctly point to the last group visited.
*/
- nr_scanned_groups = 0;
-retry:
- for (group_idx = 0; !group_alloc &&
- group_idx < sbi->s_groups_count; group_idx++) {
+ for (bgi = 0; bgi < ngroups; bgi++) {
group_no++;
- if (group_no >= sbi->s_groups_count)
+ if (group_no >= ngroups)
group_no = 0;
- desc = ext2_get_group_desc(sb, group_no, &gdp_bh);
- if (!desc)
+ gdp = ext2_get_group_desc(sb, group_no, &gdp_bh);
+ if (!gdp)
goto io_error;
- group_alloc = group_reserve_blocks(sbi, group_no, desc,
- gdp_bh, es_alloc);
- }
- if (!group_alloc) {
- *err = -ENOSPC;
- goto out_release;
- }
- brelse(bitmap_bh);
- bitmap_bh = read_block_bitmap(sb, group_no);
- if (!bitmap_bh)
- goto io_error;
- ret_block = grab_block(sb_bgl_lock(sbi, group_no), bitmap_bh->b_data,
- group_size, 0);
- if (ret_block < 0) {
+ free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
/*
- * If a free block counter is corrupted we can loop inifintely.
- * Detect that here.
+ * skip this group if the number of
+ * free blocks is less than half of the reservation
+ * window size.
*/
- nr_scanned_groups++;
- if (nr_scanned_groups > 2 * sbi->s_groups_count) {
- ext2_error(sb, "ext2_new_block",
- "corrupted free blocks counters");
+ if (free_blocks <= (windowsz/2))
+ continue;
+
+ brelse(bitmap_bh);
+ bitmap_bh = read_block_bitmap(sb, group_no);
+ if (!bitmap_bh)
goto io_error;
- }
/*
- * Someone else grabbed the last free block in this blockgroup
- * before us. Retry the scan.
+ * try to allocate block(s) from this group, without a goal(-1).
*/
- group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc);
- group_alloc = 0;
- goto retry;
+ grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
+ bitmap_bh, -1, my_rsv, &num);
+ 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:
-got_block:
ext2_debug("using block group %d(%d)\n",
- group_no, desc->bg_free_blocks_count);
+ group_no, gdp->bg_free_blocks_count);
- target_block = ret_block + group_no * group_size +
- le32_to_cpu(es->s_first_data_block);
+ ret_block = grp_alloc_blk + ext2_group_first_block_no(sb, group_no);
- if (target_block == le32_to_cpu(desc->bg_block_bitmap) ||
- target_block == le32_to_cpu(desc->bg_inode_bitmap) ||
- in_range(target_block, le32_to_cpu(desc->bg_inode_table),
- sbi->s_itb_per_group))
- ext2_error (sb, "ext2_new_block",
+ if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
+ in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
+ in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
+ EXT2_SB(sb)->s_itb_per_group) ||
+ in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
+ EXT2_SB(sb)->s_itb_per_group))
+ ext2_error(sb, "ext2_new_blocks",
"Allocating block in system zone - "
- "block = %u", target_block);
+ "blocks from "E2FSBLK", length %lu",
+ ret_block, num);
- if (target_block >= le32_to_cpu(es->s_blocks_count)) {
- ext2_error (sb, "ext2_new_block",
- "block(%d) >= blocks count(%d) - "
+ performed_allocation = 1;
+
+ if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
+ ext2_error(sb, "ext2_new_blocks",
+ "block("E2FSBLK") >= blocks count(%d) - "
"block_group = %d, es == %p ", ret_block,
le32_to_cpu(es->s_blocks_count), group_no, es);
- goto io_error;
+ goto out;
}
- block = target_block;
-
- /* OK, we _had_ allocated something */
- ext2_debug("found bit %d\n", ret_block);
-
- dq_alloc--;
- es_alloc--;
- group_alloc--;
- /*
- * Do block preallocation now if required.
- */
- write_lock(&EXT2_I(inode)->i_meta_lock);
- if (group_alloc && !*prealloc_count) {
- unsigned n;
-
- for (n = 0; n < group_alloc && ++ret_block < group_size; n++) {
- if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group_no),
- ret_block,
- (void*) bitmap_bh->b_data))
- break;
- }
- *prealloc_block = block + 1;
- *prealloc_count = n;
- es_alloc -= n;
- dq_alloc -= n;
- group_alloc -= n;
- }
- write_unlock(&EXT2_I(inode)->i_meta_lock);
+ group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num);
+ percpu_counter_sub(&sbi->s_freeblocks_counter, num);
mark_buffer_dirty(bitmap_bh);
if (sb->s_flags & MS_SYNCHRONOUS)
sync_dirty_buffer(bitmap_bh);
- ext2_debug ("allocating block %d. ", block);
+ *errp = 0;
+ brelse(bitmap_bh);
+ DQUOT_FREE_BLOCK(inode, *count-num);
+ *count = num;
+ return ret_block;
- *err = 0;
-out_release:
- group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc);
- release_blocks(sb, es_alloc);
-out_dquot:
- DQUOT_FREE_BLOCK(inode, dq_alloc);
+io_error:
+ *errp = -EIO;
out:
+ /*
+ * Undo the block allocation
+ */
+ if (!performed_allocation)
+ DQUOT_FREE_BLOCK(inode, *count);
brelse(bitmap_bh);
- return block;
+ return 0;
+}
-io_error:
- *err = -EIO;
- goto out_release;
+ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp)
+{
+ unsigned long count = 1;
+
+ return ext2_new_blocks(inode, goal, &count, errp);
}
#ifdef EXT2FS_DEBUG
inode->i_blocks - ea_blocks == 0);
}
-/*
- * Called at each iput().
- *
- * The inode may be "bad" if ext2_read_inode() saw an error from
- * ext2_get_inode(), so we need to check that to avoid freeing random disk
- * blocks.
- */
-void ext2_put_inode(struct inode *inode)
-{
- if (!is_bad_inode(inode))
- ext2_discard_prealloc(inode);
-}
-
/*
* Called at the last iput() if i_nlink is zero.
*/
clear_inode(inode); /* We must guarantee clearing of inode... */
}
-void ext2_discard_prealloc (struct inode * inode)
-{
-#ifdef EXT2_PREALLOCATE
- struct ext2_inode_info *ei = EXT2_I(inode);
- write_lock(&ei->i_meta_lock);
- if (ei->i_prealloc_count) {
- unsigned short total = ei->i_prealloc_count;
- unsigned long block = ei->i_prealloc_block;
- ei->i_prealloc_count = 0;
- ei->i_prealloc_block = 0;
- write_unlock(&ei->i_meta_lock);
- ext2_free_blocks (inode, block, total);
- return;
- } else
- write_unlock(&ei->i_meta_lock);
-#endif
-}
-
-static int ext2_alloc_block (struct inode * inode, unsigned long goal, int *err)
-{
-#ifdef EXT2FS_DEBUG
- static unsigned long alloc_hits, alloc_attempts;
-#endif
- unsigned long result;
-
-
-#ifdef EXT2_PREALLOCATE
- struct ext2_inode_info *ei = EXT2_I(inode);
- write_lock(&ei->i_meta_lock);
- if (ei->i_prealloc_count &&
- (goal == ei->i_prealloc_block || goal + 1 == ei->i_prealloc_block))
- {
- result = ei->i_prealloc_block++;
- ei->i_prealloc_count--;
- write_unlock(&ei->i_meta_lock);
- ext2_debug ("preallocation hit (%lu/%lu).\n",
- ++alloc_hits, ++alloc_attempts);
- } else {
- write_unlock(&ei->i_meta_lock);
- ext2_discard_prealloc (inode);
- ext2_debug ("preallocation miss (%lu/%lu).\n",
- alloc_hits, ++alloc_attempts);
- if (S_ISREG(inode->i_mode))
- result = ext2_new_block (inode, goal,
- &ei->i_prealloc_count,
- &ei->i_prealloc_block, err);
- else
- result = ext2_new_block(inode, goal, NULL, NULL, err);
- }
-#else
- result = ext2_new_block (inode, goal, 0, 0, err);
-#endif
- return result;
-}
-
typedef struct {
__le32 *p;
__le32 key;
ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
}
if (boundary)
- *boundary = (i_block & (ptrs - 1)) == (final - 1);
+ *boundary = final - 1 - (i_block & (ptrs - 1));
+
return n;
}
* @block: block we want
* @chain: chain of indirect blocks
* @partial: pointer to the last triple within a chain
- * @goal: place to store the result.
*
- * Normally this function find the prefered place for block allocation,
- * stores it in *@goal and returns zero. If the branch had been changed
- * under us we return -EAGAIN.
+ * Returns preferred place for a block (the goal).
*/
static inline int ext2_find_goal(struct inode *inode,
long block,
Indirect chain[4],
- Indirect *partial,
- unsigned long *goal)
+ Indirect *partial)
{
- struct ext2_inode_info *ei = EXT2_I(inode);
- write_lock(&ei->i_meta_lock);
- if ((block == ei->i_next_alloc_block + 1) && ei->i_next_alloc_goal) {
- ei->i_next_alloc_block++;
- ei->i_next_alloc_goal++;
- }
- if (verify_chain(chain, partial)) {
- /*
- * try the heuristic for sequential allocation,
- * failing that at least try to get decent locality.
- */
- if (block == ei->i_next_alloc_block)
- *goal = ei->i_next_alloc_goal;
- if (!*goal)
- *goal = ext2_find_near(inode, partial);
- write_unlock(&ei->i_meta_lock);
- return 0;
+ struct ext2_block_alloc_info *block_i;
+
+ block_i = EXT2_I(inode)->i_block_alloc_info;
+
+ /*
+ * try the heuristic for sequential allocation,
+ * failing that at least try to get decent locality.
+ */
+ if (block_i && (block == block_i->last_alloc_logical_block + 1)
+ && (block_i->last_alloc_physical_block != 0)) {
+ return block_i->last_alloc_physical_block + 1;
}
- write_unlock(&ei->i_meta_lock);
- return -EAGAIN;
+
+ return ext2_find_near(inode, partial);
+}
+
+/**
+ * ext2_blks_to_allocate: Look up the block map and count the number
+ * of direct blocks need to be allocated for the given branch.
+ *
+ * @branch: chain of indirect blocks
+ * @k: number of blocks need for indirect blocks
+ * @blks: number of data blocks to be mapped.
+ * @blocks_to_boundary: the offset in the indirect block
+ *
+ * return the total number of blocks to be allocate, including the
+ * direct and indirect blocks.
+ */
+static int
+ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
+ int blocks_to_boundary)
+{
+ unsigned long count = 0;
+
+ /*
+ * Simple case, [t,d]Indirect block(s) has not allocated yet
+ * then it's clear blocks on that path have not allocated
+ */
+ if (k > 0) {
+ /* right now don't hanel cross boundary allocation */
+ if (blks < blocks_to_boundary + 1)
+ count += blks;
+ else
+ count += blocks_to_boundary + 1;
+ return count;
+ }
+
+ count++;
+ while (count < blks && count <= blocks_to_boundary
+ && le32_to_cpu(*(branch[0].p + count)) == 0) {
+ count++;
+ }
+ return count;
+}
+
+/**
+ * ext2_alloc_blocks: multiple allocate blocks needed for a branch
+ * @indirect_blks: the number of blocks need to allocate for indirect
+ * blocks
+ *
+ * @new_blocks: on return it will store the new block numbers for
+ * the indirect blocks(if needed) and the first direct block,
+ * @blks: on return it will store the total number of allocated
+ * direct blocks
+ */
+static int ext2_alloc_blocks(struct inode *inode,
+ ext2_fsblk_t goal, int indirect_blks, int blks,
+ ext2_fsblk_t new_blocks[4], int *err)
+{
+ int target, i;
+ unsigned long count = 0;
+ int index = 0;
+ ext2_fsblk_t current_block = 0;
+ int ret = 0;
+
+ /*
+ * Here we try to allocate the requested multiple blocks at once,
+ * on a best-effort basis.
+ * To build a branch, we should allocate blocks for
+ * the indirect blocks(if not allocated yet), and at least
+ * the first direct block of this branch. That's the
+ * minimum number of blocks need to allocate(required)
+ */
+ target = blks + indirect_blks;
+
+ while (1) {
+ count = target;
+ /* allocating blocks for indirect blocks and direct blocks */
+ current_block = ext2_new_blocks(inode,goal,&count,err);
+ if (*err)
+ goto failed_out;
+
+ target -= count;
+ /* allocate blocks for indirect blocks */
+ while (index < indirect_blks && count) {
+ new_blocks[index++] = current_block++;
+ count--;
+ }
+
+ if (count > 0)
+ break;
+ }
+
+ /* save the new block number for the first direct block */
+ new_blocks[index] = current_block;
+
+ /* total number of blocks allocated for direct blocks */
+ ret = count;
+ *err = 0;
+ return ret;
+failed_out:
+ for (i = 0; i <index; i++)
+ ext2_free_blocks(inode, new_blocks[i], 1);
+ return ret;
}
/**
*/
static int ext2_alloc_branch(struct inode *inode,
- int num,
- unsigned long goal,
- int *offsets,
- Indirect *branch)
+ int indirect_blks, int *blks, ext2_fsblk_t goal,
+ int *offsets, Indirect *branch)
{
int blocksize = inode->i_sb->s_blocksize;
- int n = 0;
- int err;
- int i;
- int parent = ext2_alloc_block(inode, goal, &err);
-
- branch[0].key = cpu_to_le32(parent);
- if (parent) for (n = 1; n < num; n++) {
- struct buffer_head *bh;
- /* Allocate the next block */
- int nr = ext2_alloc_block(inode, parent, &err);
- if (!nr)
- break;
- branch[n].key = cpu_to_le32(nr);
+ int i, n = 0;
+ int err = 0;
+ struct buffer_head *bh;
+ int num;
+ ext2_fsblk_t new_blocks[4];
+ ext2_fsblk_t current_block;
+
+ num = ext2_alloc_blocks(inode, goal, indirect_blks,
+ *blks, new_blocks, &err);
+ if (err)
+ return err;
+
+ branch[0].key = cpu_to_le32(new_blocks[0]);
+ /*
+ * metadata blocks and data blocks are allocated.
+ */
+ for (n = 1; n <= indirect_blks; n++) {
/*
- * Get buffer_head for parent block, zero it out and set
- * the pointer to new one, then send parent to disk.
+ * Get buffer_head for parent block, zero it out
+ * and set the pointer to new one, then send
+ * parent to disk.
*/
- bh = sb_getblk(inode->i_sb, parent);
- if (!bh) {
- err = -EIO;
- break;
- }
+ bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
+ branch[n].bh = bh;
lock_buffer(bh);
memset(bh->b_data, 0, blocksize);
- branch[n].bh = bh;
branch[n].p = (__le32 *) bh->b_data + offsets[n];
+ branch[n].key = cpu_to_le32(new_blocks[n]);
*branch[n].p = branch[n].key;
+ if ( n == indirect_blks) {
+ current_block = new_blocks[n];
+ /*
+ * End of chain, update the last new metablock of
+ * the chain to point to the new allocated
+ * data blocks numbers
+ */
+ for (i=1; i < num; i++)
+ *(branch[n].p + i) = cpu_to_le32(++current_block);
+ }
set_buffer_uptodate(bh);
unlock_buffer(bh);
mark_buffer_dirty_inode(bh, inode);
*/
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
sync_dirty_buffer(bh);
- parent = nr;
}
- if (n == num)
- return 0;
-
- /* Allocation failed, free what we already allocated */
- for (i = 1; i < n; i++)
- bforget(branch[i].bh);
- for (i = 0; i < n; i++)
- ext2_free_blocks(inode, le32_to_cpu(branch[i].key), 1);
+ *blks = num;
return err;
}
/**
- * ext2_splice_branch - splice the allocated branch onto inode.
- * @inode: owner
- * @block: (logical) number of block we are adding
- * @chain: chain of indirect blocks (with a missing link - see
- * ext2_alloc_branch)
- * @where: location of missing link
- * @num: number of blocks we are adding
+ * ext2_splice_branch - splice the allocated branch onto inode.
+ * @inode: owner
+ * @block: (logical) number of block we are adding
+ * @chain: chain of indirect blocks (with a missing link - see
+ * ext2_alloc_branch)
+ * @where: location of missing link
+ * @num: number of indirect blocks we are adding
+ * @blks: number of direct blocks we are adding
*
- * This function verifies that chain (up to the missing link) had not
- * changed, fills the missing link and does all housekeeping needed in
- * inode (->i_blocks, etc.). In case of success we end up with the full
- * chain to new block and return 0. Otherwise (== chain had been changed)
- * we free the new blocks (forgetting their buffer_heads, indeed) and
- * return -EAGAIN.
+ * This function fills the missing link and does all housekeeping needed in
+ * inode (->i_blocks, etc.). In case of success we end up with the full
+ * chain to new block and return 0.
*/
-
-static inline int ext2_splice_branch(struct inode *inode,
- long block,
- Indirect chain[4],
- Indirect *where,
- int num)
+static void ext2_splice_branch(struct inode *inode,
+ long block, Indirect *where, int num, int blks)
{
- struct ext2_inode_info *ei = EXT2_I(inode);
int i;
+ struct ext2_block_alloc_info *block_i;
+ ext2_fsblk_t current_block;
- /* Verify that place we are splicing to is still there and vacant */
-
- write_lock(&ei->i_meta_lock);
- if (!verify_chain(chain, where-1) || *where->p)
- goto changed;
+ block_i = EXT2_I(inode)->i_block_alloc_info;
+ /* XXX LOCKING probably should have i_meta_lock ?*/
/* That's it */
*where->p = where->key;
- ei->i_next_alloc_block = block;
- ei->i_next_alloc_goal = le32_to_cpu(where[num-1].key);
- write_unlock(&ei->i_meta_lock);
+ /*
+ * Update the host buffer_head or inode to point to more just allocated
+ * direct blocks blocks
+ */
+ if (num == 0 && blks > 1) {
+ current_block = le32_to_cpu(where->key) + 1;
+ for (i = 1; i < blks; i++)
+ *(where->p + i ) = cpu_to_le32(current_block++);
+ }
- /* We are done with atomic stuff, now do the rest of housekeeping */
+ /*
+ * update the most recently allocated logical & physical block
+ * in i_block_alloc_info, to assist find the proper goal block for next
+ * allocation
+ */
+ if (block_i) {
+ block_i->last_alloc_logical_block = block + blks - 1;
+ block_i->last_alloc_physical_block =
+ le32_to_cpu(where[num].key) + blks - 1;
+ }
- inode->i_ctime = CURRENT_TIME_SEC;
+ /* We are done with atomic stuff, now do the rest of housekeeping */
/* had we spliced it onto indirect block? */
if (where->bh)
mark_buffer_dirty_inode(where->bh, inode);
+ inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
- return 0;
-
-changed:
- write_unlock(&ei->i_meta_lock);
- for (i = 1; i < num; i++)
- bforget(where[i].bh);
- for (i = 0; i < num; i++)
- ext2_free_blocks(inode, le32_to_cpu(where[i].key), 1);
- return -EAGAIN;
}
/*
* That has a nice additional property: no special recovery from the failed
* allocations is needed - we simply release blocks and do not touch anything
* reachable from inode.
+ *
+ * `handle' can be NULL if create == 0.
+ *
+ * The BKL may not be held on entry here. Be sure to take it early.
+ * return > 0, # of blocks mapped or allocated.
+ * return = 0, if plain lookup failed.
+ * return < 0, error case.
*/
-
-int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
+static int ext2_get_blocks(struct inode *inode,
+ sector_t iblock, unsigned long maxblocks,
+ struct buffer_head *bh_result,
+ int create)
{
int err = -EIO;
int offsets[4];
Indirect chain[4];
Indirect *partial;
- unsigned long goal;
- int left;
- int boundary = 0;
- int depth = ext2_block_to_path(inode, iblock, offsets, &boundary);
+ ext2_fsblk_t goal;
+ int indirect_blks;
+ int blocks_to_boundary = 0;
+ int depth;
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ int count = 0;
+ ext2_fsblk_t first_block = 0;
- if (depth == 0)
- goto out;
+ depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
+ if (depth == 0)
+ return (err);
reread:
partial = ext2_get_branch(inode, depth, offsets, chain, &err);
/* Simplest case - block found, no allocation needed */
if (!partial) {
-got_it:
- map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
- if (boundary)
- set_buffer_boundary(bh_result);
- /* Clean up and exit */
- partial = chain+depth-1; /* the whole chain */
- goto cleanup;
+ first_block = le32_to_cpu(chain[depth - 1].key);
+ clear_buffer_new(bh_result); /* What's this do? */
+ count++;
+ /*map more blocks*/
+ while (count < maxblocks && count <= blocks_to_boundary) {
+ ext2_fsblk_t blk;
+
+ if (!verify_chain(chain, partial)) {
+ /*
+ * Indirect block might be removed by
+ * truncate while we were reading it.
+ * Handling of that case: forget what we've
+ * got now, go to reread.
+ */
+ count = 0;
+ goto changed;
+ }
+ blk = le32_to_cpu(*(chain[depth-1].p + count));
+ if (blk == first_block + count)
+ count++;
+ else
+ break;
+ }
+ goto got_it;
}
/* Next simple case - plain lookup or failed read of indirect block */
- if (!create || err == -EIO) {
-cleanup:
- while (partial > chain) {
- brelse(partial->bh);
- partial--;
- }
-out:
- return err;
- }
+ if (!create || err == -EIO)
+ goto cleanup;
+
+ mutex_lock(&ei->truncate_mutex);
/*
- * Indirect block might be removed by truncate while we were
- * reading it. Handling of that case (forget what we've got and
- * reread) is taken out of the main path.
- */
- if (err == -EAGAIN)
- goto changed;
+ * Okay, we need to do block allocation. Lazily initialize the block
+ * allocation info here if necessary
+ */
+ if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
+ ext2_init_block_alloc_info(inode);
- goal = 0;
- if (ext2_find_goal(inode, iblock, chain, partial, &goal) < 0)
- goto changed;
+ goal = ext2_find_goal(inode, iblock, chain, partial);
- left = (chain + depth) - partial;
- err = ext2_alloc_branch(inode, left, goal,
- offsets+(partial-chain), partial);
- if (err)
+ /* the number of blocks need to allocate for [d,t]indirect blocks */
+ indirect_blks = (chain + depth) - partial - 1;
+ /*
+ * Next look up the indirect map to count the totoal number of
+ * direct blocks to allocate for this branch.
+ */
+ count = ext2_blks_to_allocate(partial, indirect_blks,
+ maxblocks, blocks_to_boundary);
+ /*
+ * XXX ???? Block out ext2_truncate while we alter the tree
+ */
+ err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
+ offsets + (partial - chain), partial);
+
+ if (err) {
+ mutex_unlock(&ei->truncate_mutex);
goto cleanup;
+ }
if (ext2_use_xip(inode->i_sb)) {
/*
*/
err = ext2_clear_xip_target (inode,
le32_to_cpu(chain[depth-1].key));
- if (err)
+ if (err) {
+ mutex_unlock(&ei->truncate_mutex);
goto cleanup;
+ }
}
- if (ext2_splice_branch(inode, iblock, chain, partial, left) < 0)
- goto changed;
-
+ ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
+ mutex_unlock(&ei->truncate_mutex);
set_buffer_new(bh_result);
- goto got_it;
-
+got_it:
+ map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
+ if (count > blocks_to_boundary)
+ set_buffer_boundary(bh_result);
+ err = count;
+ /* Clean up and exit */
+ partial = chain + depth - 1; /* the whole chain */
+cleanup:
+ while (partial > chain) {
+ brelse(partial->bh);
+ partial--;
+ }
+ return err;
changed:
while (partial > chain) {
brelse(partial->bh);
goto reread;
}
+int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
+{
+ unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+ int ret = ext2_get_blocks(inode, iblock, max_blocks,
+ bh_result, create);
+ if (ret > 0) {
+ bh_result->b_size = (ret << inode->i_blkbits);
+ ret = 0;
+ }
+ return ret;
+
+}
+
static int ext2_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, ext2_get_block, wbc);
ext2_free_data(inode, p, q);
}
-void ext2_truncate (struct inode * inode)
+void ext2_truncate(struct inode *inode)
{
__le32 *i_data = EXT2_I(inode)->i_data;
+ struct ext2_inode_info *ei = EXT2_I(inode);
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
int offsets[4];
Indirect chain[4];
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return;
- ext2_discard_prealloc(inode);
-
blocksize = inode->i_sb->s_blocksize;
iblock = (inode->i_size + blocksize-1)
>> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
if (n == 0)
return;
+ /*
+ * From here we block out all ext2_get_block() callers who want to
+ * modify the block allocation tree.
+ */
+ mutex_lock(&ei->truncate_mutex);
+
if (n == 1) {
ext2_free_data(inode, i_data+offsets[0],
i_data + EXT2_NDIR_BLOCKS);
case EXT2_TIND_BLOCK:
;
}
+
+ ext2_discard_reservation(inode);
+
+ mutex_unlock(&ei->truncate_mutex);
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
if (inode_needs_sync(inode)) {
sync_mapping_buffers(inode->i_mapping);
ei->i_acl = EXT2_ACL_NOT_CACHED;
ei->i_default_acl = EXT2_ACL_NOT_CACHED;
#endif
+ ei->i_block_alloc_info = NULL;
+
if (IS_ERR(raw_inode))
goto bad_inode;
ei->i_dtime = 0;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
ei->i_state = 0;
- ei->i_next_alloc_block = 0;
- ei->i_next_alloc_goal = 0;
- ei->i_prealloc_count = 0;
ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
ei->i_dir_start_lookup = 0;
projects / linux-2.6 / commitdiff