* David S. Miller (davem@caip.rutgers.edu), 1995
*/
-#include <linux/config.h>
#include "ext2.h"
#include <linux/quotaops.h>
+#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/buffer_head.h>
+#include <linux/capability.h>
/*
* balloc.c contains the blocks allocation and deallocation routines
* The file system contains group descriptors which are located after the
* super block. Each descriptor contains the number of the bitmap block and
* the free blocks count in the block. The descriptors are loaded in memory
- * when a file system is mounted (see ext2_read_super).
+ * when a file system is mounted (see ext2_fill_super).
*/
return desc + offset;
}
+static int ext2_valid_block_bitmap(struct super_block *sb,
+ struct ext2_group_desc *desc,
+ unsigned int block_group,
+ struct buffer_head *bh)
+{
+ ext2_grpblk_t offset;
+ ext2_grpblk_t next_zero_bit;
+ ext2_fsblk_t bitmap_blk;
+ ext2_fsblk_t group_first_block;
+
+ group_first_block = ext2_group_first_block_no(sb, block_group);
+
+ /* check whether block bitmap block number is set */
+ bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+ offset = bitmap_blk - group_first_block;
+ if (!ext2_test_bit(offset, bh->b_data))
+ /* bad block bitmap */
+ goto err_out;
+
+ /* check whether the inode bitmap block number is set */
+ bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
+ offset = bitmap_blk - group_first_block;
+ if (!ext2_test_bit(offset, bh->b_data))
+ /* bad block bitmap */
+ goto err_out;
+
+ /* check whether the inode table block number is set */
+ bitmap_blk = le32_to_cpu(desc->bg_inode_table);
+ offset = bitmap_blk - group_first_block;
+ next_zero_bit = ext2_find_next_zero_bit(bh->b_data,
+ offset + EXT2_SB(sb)->s_itb_per_group,
+ offset);
+ if (next_zero_bit >= offset + EXT2_SB(sb)->s_itb_per_group)
+ /* good bitmap for inode tables */
+ return 1;
+
+err_out:
+ ext2_error(sb, __func__,
+ "Invalid block bitmap - "
+ "block_group = %d, block = %lu",
+ block_group, bitmap_blk);
+ return 0;
+}
+
/*
- * Read the bitmap for a given block_group, reading into the specified
- * slot in the superblock's bitmap cache.
+ * Read the bitmap for a given block_group,and validate the
+ * bits for block/inode/inode tables are set in the bitmaps
*
* Return buffer_head on success or NULL in case of failure.
*/
{
struct ext2_group_desc * desc;
struct buffer_head * bh = NULL;
-
- desc = ext2_get_group_desc (sb, block_group, NULL);
+ ext2_fsblk_t bitmap_blk;
+
+ desc = ext2_get_group_desc(sb, block_group, NULL);
if (!desc)
- goto error_out;
- bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
- if (!bh)
- ext2_error (sb, "read_block_bitmap",
+ return NULL;
+ bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+ bh = sb_getblk(sb, bitmap_blk);
+ if (unlikely(!bh)) {
+ ext2_error(sb, __func__,
"Cannot read block bitmap - "
"block_group = %d, block_bitmap = %u",
block_group, le32_to_cpu(desc->bg_block_bitmap));
-error_out:
- return bh;
-}
-
-/*
- * 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;
+ return NULL;
+ }
+ if (likely(bh_uptodate_or_lock(bh)))
+ return bh;
- 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;
+ if (bh_submit_read(bh) < 0) {
+ brelse(bh);
+ ext2_error(sb, __func__,
+ "Cannot read block bitmap - "
+ "block_group = %d, block_bitmap = %u",
+ block_group, le32_to_cpu(desc->bg_block_bitmap));
+ return NULL;
}
- percpu_counter_mod(&sbi->s_freeblocks_counter, -count);
- sb->s_dirt = 1;
- return count;
+ ext2_valid_block_bitmap(sb, desc, block_group, bh);
+ /*
+ * file system mounted not to panic on error, continue with corrupt
+ * bitmap
+ */
+ return bh;
}
static void release_blocks(struct super_block *sb, int count)
if (count) {
struct ext2_sb_info *sbi = EXT2_SB(sb);
- percpu_counter_mod(&sbi->s_freeblocks_counter, count);
+ percpu_counter_add(&sbi->s_freeblocks_counter, count);
sb->s_dirt = 1;
}
}
-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");
+ 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 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)
{
in_range (block, le32_to_cpu(desc->bg_inode_table),
sbi->s_itb_per_group) ||
in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
- sbi->s_itb_per_group))
+ sbi->s_itb_per_group)) {
ext2_error (sb, "ext2_free_blocks",
"Freeing blocks in system zones - "
"Block = %lu, count = %lu",
block, count);
+ goto error_return;
+ }
for (i = 0, group_freed = 0; i < count; i++) {
if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
bit + i, bitmap_bh->b_data)) {
- ext2_error(sb, __FUNCTION__,
+ ext2_error(sb, __func__,
"bit already cleared for block %lu", block + i);
} else {
group_freed++;
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) {
error_return:
brelse(bitmap_bh);
release_blocks(sb, freed);
- DQUOT_FREE_BLOCK(inode, freed);
+ 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)) {
/*
- * Search in the remainder of the current group.
+ * 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;
+}
- 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.
+/**
+ * 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)...
*/
- for (goal = k; goal && !ext2_test_bit (goal - 1, map); goal--)
- ;
- goto got_it;
+ 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);
+
+ /*
+ * 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)
+ ext2_rsv_window_add(sb, my_rsv);
+
+ return 0;
+}
- k = ext2_find_next_zero_bit ((u32 *)map, size, goal);
- if (k < size) {
- goal = k;
- goto got_it;
+/**
+ * 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.
+ */
+
+ 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;
+ }
}
- return -1;
-got_it:
- if (ext2_set_bit_atomic(lock, goal, (void *) map))
- goto repeat;
- return goal;
+
+ 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.
+ *
+ * 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;
+ int ret;
+
+ *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.
+ */
+ ret = dquot_alloc_block(inode, num);
+ if (ret) {
+ *errp = ret;
+ 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)
+ && (free_blocks > 0)
+ && (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.
+ * Now search the rest of the groups. We assume that
+ * group_no 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 (and avoid loading bitmap) if there
+ * are no free blocks
*/
- 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)
+ continue;
+ /*
+ * 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 = 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);
+ /*
+ * ext2_try_to_allocate marked the blocks we allocated as in
+ * use. So we may want to selectively mark some of the blocks
+ * as free
+ */
+ goto retry_alloc;
+ }
- 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
+
+static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
+
+unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
+{
+ unsigned int i;
+ unsigned long sum = 0;
+
+ if (!map)
+ return (0);
+ for (i = 0; i < numchars; i++)
+ sum += nibblemap[map->b_data[i] & 0xf] +
+ nibblemap[(map->b_data[i] >> 4) & 0xf];
+ return (sum);
}
+#endif /* EXT2FS_DEBUG */
+
unsigned long ext2_count_free_blocks (struct super_block * sb)
{
struct ext2_group_desc * desc;
unsigned long bitmap_count, x;
struct ext2_super_block *es;
- lock_super (sb);
es = EXT2_SB(sb)->s_es;
desc_count = 0;
bitmap_count = 0;
printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n",
(long)le32_to_cpu(es->s_free_blocks_count),
desc_count, bitmap_count);
- unlock_super (sb);
return bitmap_count;
#else
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
#endif
}
-static inline int
-block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
-{
- return ext2_test_bit ((block -
- le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) %
- EXT2_BLOCKS_PER_GROUP(sb), map);
-}
-
static inline int test_root(int a, int b)
{
int num = b;
*/
unsigned long ext2_bg_num_gdb(struct super_block *sb, int group)
{
- if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
- !ext2_group_sparse(group))
- return 0;
- return EXT2_SB(sb)->s_gdb_count;
+ return ext2_bg_has_super(sb, group) ? EXT2_SB(sb)->s_gdb_count : 0;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff