From c806e68f5647109350ec546fee5b526962970fd2 Mon Sep 17 00:00:00 2001 From: Frederic Bohe Date: Fri, 10 Oct 2008 08:09:18 -0400 Subject: ext4: fix initialization of UNINIT bitmap blocks This fixes a bug which caused on-line resizing of filesystems with a 1k blocksize to fail. The root cause of this bug was the fact that if an uninitalized bitmap block gets read in by userspace (which e2fsprogs does try to avoid, but can happen when the blocksize is less than the pagesize and an adjacent blocks is read into memory) ext4_read_block_bitmap() was erroneously depending on the buffer uptodate flag to decide whether it needed to initialize the bitmap block in memory --- i.e., to set the standard set of blocks in use by a block group (superblock, bitmaps, inode table, etc.). Essentially, ext4_read_block_bitmap() assumed it was the only routine that might try to read a block containing a block bitmap, which is simply not true. To fix this, ext4_read_block_bitmap() and ext4_read_inode_bitmap() must always initialize uninitialized bitmap blocks. Once a block or inode is allocated out of that bitmap, it will be marked as initialized in the block group descriptor, so in general this won't result any extra unnecessary work. Signed-off-by: Frederic Bohe Signed-off-by: "Theodore Ts'o" --- fs/ext4/ialloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'fs/ext4/ialloc.c') diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 1343bf18825b..fe34d74cfb19 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -115,9 +115,11 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) block_group, bitmap_blk); return NULL; } - if (bh_uptodate_or_lock(bh)) + if (buffer_uptodate(bh) && + !(desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) return bh; + lock_buffer(bh); spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group)); if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) { ext4_init_inode_bitmap(sb, bh, block_group, desc); -- cgit v1.2.3