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Date: Mon, 19 Jan 2009 17:03:55 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: "Theodore Ts'o" <tytso@....edu>
Cc: linux-ext4@...r.kernel.org
Subject: Re: Ext4 tree backports for 2.6.27.10 and 2.6.28
From: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH] ext4: Add blocks added during resize to bitmap
With this change new blocks added during resize
are marked as free in the block bitmap and the
group is flagged with EXT4_GROUP_INFO_NEED_INIT_BIT
flag. This make sure when mballoc tries to allocate
blocks from the new group we would reload the
buddy information using the bitmap present in the disk.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
fs/ext4/balloc.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/ext4.h | 6 ++-
fs/ext4/resize.c | 11 +----
3 files changed, 132 insertions(+), 11 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index e9fa960..1b375bb 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -20,6 +20,7 @@
#include "ext4.h"
#include "ext4_jbd2.h"
#include "group.h"
+#include "mballoc.h"
/*
* balloc.c contains the blocks allocation and deallocation routines
@@ -837,6 +838,131 @@ error_return:
}
/**
+ * ext4_add_groupblocks() -- Add given blocks to an existing group
+ * @handle: handle to this transaction
+ * @sb: super block
+ * @block: start physcial block to add to the block group
+ * @count: number of blocks to free
+ *
+ * This marks the blocks as free in the bitmap. We ask the
+ * mballoc to reload the buddy after this by setting group
+ * EXT4_GROUP_INFO_NEED_INIT_BIT flag
+ */
+void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
+ ext4_fsblk_t block, unsigned long count)
+{
+ struct buffer_head *bitmap_bh = NULL;
+ struct buffer_head *gd_bh;
+ ext4_group_t block_group;
+ ext4_grpblk_t bit;
+ unsigned long i;
+ struct ext4_group_desc * desc;
+ struct ext4_super_block * es;
+ struct ext4_sb_info *sbi;
+ int err = 0, ret;
+ ext4_grpblk_t blocks_freed;
+ struct ext4_group_info *grp;
+
+ sbi = EXT4_SB(sb);
+ es = sbi->s_es;
+ ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
+
+ ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+ /*
+ * Check to see if we are freeing blocks across a group
+ * boundary.
+ */
+ if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
+ goto error_return;
+ }
+ bitmap_bh = ext4_read_block_bitmap(sb, block_group);
+ if (!bitmap_bh)
+ goto error_return;
+ desc = ext4_get_group_desc (sb, block_group, &gd_bh);
+ if (!desc)
+ goto error_return;
+
+ if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
+ in_range(ext4_inode_bitmap(sb, desc), block, count) ||
+ in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
+ in_range(block + count - 1, ext4_inode_table(sb, desc),
+ sbi->s_itb_per_group)) {
+ ext4_error(sb, __func__,
+ "Adding blocks in system zones - "
+ "Block = %llu, count = %lu",
+ block, count);
+ goto error_return;
+ }
+
+ /*
+ * We are about to add blocks to the bitmap,
+ * so we need undo access.
+ */
+ BUFFER_TRACE(bitmap_bh, "getting undo access");
+ err = ext4_journal_get_undo_access(handle, bitmap_bh);
+ if (err)
+ goto error_return;
+
+ /*
+ * We are about to modify some metadata. Call the journal APIs
+ * to unshare ->b_data if a currently-committing transaction is
+ * using it
+ */
+ BUFFER_TRACE(gd_bh, "get_write_access");
+ err = ext4_journal_get_write_access(handle, gd_bh);
+ if (err)
+ goto error_return;
+
+ for (i = 0, blocks_freed = 0; i < count; i++) {
+ BUFFER_TRACE(bitmap_bh, "clear bit");
+ if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
+ bit + i, bitmap_bh->b_data)) {
+ ext4_error(sb, __func__,
+ "bit already cleared for block %llu",
+ (ext4_fsblk_t)(block + i));
+ BUFFER_TRACE(bitmap_bh, "bit already cleared");
+ } else {
+ blocks_freed++;
+ }
+ }
+ spin_lock(sb_bgl_lock(sbi, block_group));
+ le16_add_cpu(&desc->bg_free_blocks_count, blocks_freed);
+ desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
+ spin_unlock(sb_bgl_lock(sbi, block_group));
+ percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed);
+
+ if (sbi->s_log_groups_per_flex) {
+ ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
+ spin_lock(sb_bgl_lock(sbi, flex_group));
+ sbi->s_flex_groups[flex_group].free_blocks += blocks_freed;
+ spin_unlock(sb_bgl_lock(sbi, flex_group));
+ }
+
+ /* We dirtied the bitmap block */
+ BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
+ err = ext4_journal_dirty_metadata(handle, bitmap_bh);
+
+ /* And the group descriptor block */
+ BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
+ ret = ext4_journal_dirty_metadata(handle, gd_bh);
+ if (!err)
+ err = ret;
+ sb->s_dirt = 1;
+ /*
+ * request to reload the buddy with the
+ * new bitmap information
+ */
+ grp = ext4_get_group_info(sb, block_group);
+ set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
+ ext4_mb_update_group_info(grp, blocks_freed);
+
+error_return:
+ brelse(bitmap_bh);
+ ext4_std_error(sb, err);
+ return;
+}
+
+/**
* ext4_free_blocks() -- Free given blocks and update quota
* @handle: handle for this transaction
* @inode: inode
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b0483ce..98de963 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -992,8 +992,10 @@ extern ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
extern void ext4_free_blocks (handle_t *handle, struct inode *inode,
ext4_fsblk_t block, unsigned long count, int metadata);
extern void ext4_free_blocks_sb (handle_t *handle, struct super_block *sb,
- ext4_fsblk_t block, unsigned long count,
- unsigned long *pdquot_freed_blocks);
+ ext4_fsblk_t block, unsigned long count,
+ unsigned long *pdquot_freed_blocks);
+extern void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
+ ext4_fsblk_t block, unsigned long count);
extern ext4_fsblk_t ext4_count_free_blocks (struct super_block *);
extern void ext4_check_blocks_bitmap (struct super_block *);
extern struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 5726c5e..d7e9761 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -974,9 +974,7 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
struct buffer_head * bh;
handle_t *handle;
int err;
- unsigned long freed_blocks;
ext4_group_t group;
- struct ext4_group_info *grp;
/* We don't need to worry about locking wrt other resizers just
* yet: we're going to revalidate es->s_blocks_count after
@@ -1075,7 +1073,8 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
unlock_super(sb);
ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
o_blocks_count + add);
- ext4_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
+ /* We add the blocks to the bitmap and set the group need init bit */
+ ext4_add_groupblocks(handle, sb, o_blocks_count, add);
ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
o_blocks_count + add);
if ((err = ext4_journal_stop(handle)))
@@ -1111,12 +1110,6 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
ClearPageUptodate(page);
page_cache_release(page);
}
-
- /* Get the info on the last group */
- grp = ext4_get_group_info(sb, group);
-
- /* Update free blocks in group info */
- ext4_mb_update_group_info(grp, add);
}
if (test_opt(sb, DEBUG))
--
tg: (0c56383..) blocks-added-during-resize (depends on: for-2.6.27)
--
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