On Wed, Mar 04, 2009 at 05:11:28PM -0600, Eric Sandeen wrote:
> Eric Sandeen wrote:
>
> Index: linux-2.6/fs/ext4/ialloc.c
> ===================================================================
> --- linux-2.6.orig/fs/ext4/ialloc.c
> +++ linux-2.6/fs/ext4/ialloc.c
> @@ -609,26 +609,33 @@ static int ext4_claim_inode(struct super
> struct buffer_head *inode_bitmap_bh,
> unsigned long ino, ext4_group_t group, int mode)
> {
> - int free = 0, retval = 0, count;
> + int free = 0, bitset, count;
> struct ext4_sb_info *sbi = EXT4_SB(sb);
> struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
>
> - spin_lock(sb_bgl_lock(sbi, group));
> - if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
> - /* not a free inode */
> - retval = 1;
> - goto err_ret;
> + /* if uninit, protect against ext4_read_inode_bitmap initialization */
> + bitset = -1;
> + if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
> + spin_lock(sb_bgl_lock(sbi, group));
> + if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))
> + bitset = ext4_set_bit(ino, inode_bitmap_bh->b_data);
> + spin_unlock(sb_bgl_lock(sbi, group));
> }
That won't work. We need set the bit and clear the INODE_UNINIT flag
by holding the spin_lock. In ext4_read_inode_bitmap we check the
INODE_UNINIT flag and re-init the inode bitmap. So we may end up
re-initing the bitmap if we don't clear the INODE_UNINIT flag holding
the spin lock
> + if (bitset < 0) /* we didn't set it above, so not uninit */
> + bitset = ext4_set_bit_atomic(sb_bgl_lock(sbi, group),
> + ino, inode_bitmap_bh->b_data);
> + if (bitset) /* this is not a free inode */
> + return 1;
> ino++;
> if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
> ino > EXT4_INODES_PER_GROUP(sb)) {
> - spin_unlock(sb_bgl_lock(sbi, group));
> ext4_error(sb, __func__,
> "reserved inode or inode > inodes count - "
> "block_group = %u, inode=%lu", group,
> ino + group * EXT4_INODES_PER_GROUP(sb));
> return 1;
> }
> + spin_lock(sb_bgl_lock(sbi, group));
> /* If we didn't allocate from within the initialized part of the inode
> * table then we need to initialize up to this inode. */
> if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
> @@ -665,9 +672,8 @@ static int ext4_claim_inode(struct super
> ext4_used_dirs_set(sb, gdp, count);
> }
> gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
> -err_ret:
> spin_unlock(sb_bgl_lock(sbi, group));
> - return retval;
> + return 0;
> }
>
-aneesh
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