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Message-Id: <1271244184-8693-2-git-send-email-dmonakhov@openvz.org>
Date: Wed, 14 Apr 2010 15:23:04 +0400
From: Dmitry Monakhov <dmonakhov@...nvz.org>
To: linux-ext4@...r.kernel.org
Cc: jack@...e.cz, Dmitry Monakhov <dmonakhov@...nvz.org>
Subject: [PATCH 2/2] ext4: fix inode bitmaps manipulation in free_inode
- Reorganize locking scheme to batch two atomic operation in to one.
This also allow us to state what healthy group must obey following rule
ext4_free_inodes_count(sb, gdp) == ext4_count_free(inode_bitmap, NUM);
- Fix possible undefined pointer deference.
- Even if group descriptor stats aren't assessable we have to update
inode bitmaps.
- Move non group members update out of group_lock.
Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
---
fs/ext4/ialloc.c | 91 +++++++++++++++++++++++++++--------------------------
1 files changed, 46 insertions(+), 45 deletions(-)
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 57f6eef..78ceab5 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -240,59 +240,60 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
if (fatal)
goto error_return;
- /* Ok, now we can actually update the inode bitmaps.. */
- cleared = ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group),
- bit, bitmap_bh->b_data);
- if (!cleared)
- ext4_error(sb, "bit already cleared for inode %lu", ino);
- else {
- gdp = ext4_get_group_desc(sb, block_group, &bh2);
-
+ fatal = -ESRCH;
+ gdp = ext4_get_group_desc(sb, block_group, &bh2);
+ if (gdp) {
BUFFER_TRACE(bh2, "get_write_access");
fatal = ext4_journal_get_write_access(handle, bh2);
- if (fatal) goto error_return;
-
- if (gdp) {
- ext4_lock_group(sb, block_group);
- count = ext4_free_inodes_count(sb, gdp) + 1;
- ext4_free_inodes_set(sb, gdp, count);
- if (is_directory) {
- count = ext4_used_dirs_count(sb, gdp) - 1;
- ext4_used_dirs_set(sb, gdp, count);
- if (sbi->s_log_groups_per_flex) {
- ext4_group_t f;
-
- f = ext4_flex_group(sbi, block_group);
- atomic_dec(&sbi->s_flex_groups[f].used_dirs);
- }
+ }
+ ext4_lock_group(sb, block_group);
+ if (fatal) {
+ /* Skip group descriptor update, update only inode bitmaps */
+ cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
+ ext4_unlock_group(sb, block_group);
+ goto out;
+ }
- }
- gdp->bg_checksum = ext4_group_desc_csum(sbi,
- block_group, gdp);
- ext4_unlock_group(sb, block_group);
- percpu_counter_inc(&sbi->s_freeinodes_counter);
- if (is_directory)
- percpu_counter_dec(&sbi->s_dirs_counter);
-
- if (sbi->s_log_groups_per_flex) {
- ext4_group_t f;
-
- f = ext4_flex_group(sbi, block_group);
- atomic_inc(&sbi->s_flex_groups[f].free_inodes);
- }
- }
- BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, NULL, bh2);
- if (!fatal) fatal = err;
+ /* Ok, now we can actually update the inode bitmaps.. */
+ cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
+ if (!cleared) {
+ ext4_unlock_group(sb, block_group);
+ goto out;
}
- BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
- if (!fatal)
- fatal = err;
- sb->s_dirt = 1;
+ count = ext4_free_inodes_count(sb, gdp) + 1;
+ ext4_free_inodes_set(sb, gdp, count);
+ if (is_directory) {
+ count = ext4_used_dirs_count(sb, gdp) - 1;
+ ext4_used_dirs_set(sb, gdp, count);
+ }
+ gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
+ ext4_unlock_group(sb, block_group);
+
+ percpu_counter_inc(&sbi->s_freeinodes_counter);
+ if (is_directory)
+ percpu_counter_dec(&sbi->s_dirs_counter);
+ if (sbi->s_log_groups_per_flex) {
+ ext4_group_t f = ext4_flex_group(sbi, block_group);
+ atomic_inc(&sbi->s_flex_groups[f].free_inodes);
+ if (is_directory)
+ atomic_dec(&sbi->s_flex_groups[f].used_dirs);
+ }
+ BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
+ fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
+out:
+ if (cleared) {
+ BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
+ if (!fatal)
+ fatal = err;
+ sb->s_dirt = 1;
+ } else
+ ext4_error(sb, "bit already cleared for inode %lu", ino);
+
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, fatal);
+ return;
}
/*
--
1.6.6.1
--
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