From 58590b06d79f7ce5ab64ff3b6d537180fa50dc84 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 27 Oct 2010 21:23:12 -0400 Subject: [PATCH] ext4: fix EOFBLOCKS_FL handling It turns out we have several problems with how EOFBLOCKS_FL is handled. First of all, there was a fencepost error where we were not clearing the EOFBLOCKS_FL when fill in the last uninitialized block, but rather when we allocate the next block _after_ the uninitalized block. Secondly we were not testing to see if we needed to clear the EOFBLOCKS_FL when writing to the file O_DIRECT or when were converting an uninitialized block (which is the most common case). Google-Bug-Id: 2928259 Signed-off-by: "Theodore Ts'o" --- fs/ext4/extents.c | 98 +++++++++++++++++++++++++++++++++-------------- 1 file changed, 69 insertions(+), 29 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 06328d3e5717..820278410220 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3180,6 +3180,57 @@ static void unmap_underlying_metadata_blocks(struct block_device *bdev, unmap_underlying_metadata(bdev, block + i); } +/* + * Handle EOFBLOCKS_FL flag, clearing it if necessary + */ +static int check_eofblocks_fl(handle_t *handle, struct inode *inode, + struct ext4_map_blocks *map, + struct ext4_ext_path *path, + unsigned int len) +{ + int i, depth; + struct ext4_extent_header *eh; + struct ext4_extent *ex, *last_ex; + + if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)) + return 0; + + depth = ext_depth(inode); + eh = path[depth].p_hdr; + ex = path[depth].p_ext; + + if (unlikely(!eh->eh_entries)) { + EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and " + "EOFBLOCKS_FL set"); + return -EIO; + } + last_ex = EXT_LAST_EXTENT(eh); + /* + * We should clear the EOFBLOCKS_FL flag if we are writing the + * last block in the last extent in the file. We test this by + * first checking to see if the caller to + * ext4_ext_get_blocks() was interested in the last block (or + * a block beyond the last block) in the current extent. If + * this turns out to be false, we can bail out from this + * function immediately. + */ + if (map->m_lblk + len < le32_to_cpu(last_ex->ee_block) + + ext4_ext_get_actual_len(last_ex)) + return 0; + /* + * If the caller does appear to be planning to write at or + * beyond the end of the current extent, we then test to see + * if the current extent is the last extent in the file, by + * checking to make sure it was reached via the rightmost node + * at each level of the tree. + */ + for (i = depth-1; i >= 0; i--) + if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr)) + return 0; + ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); + return ext4_mark_inode_dirty(handle, inode); +} + static int ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, struct ext4_map_blocks *map, @@ -3217,8 +3268,12 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, if ((flags & EXT4_GET_BLOCKS_CONVERT)) { ret = ext4_convert_unwritten_extents_endio(handle, inode, path); - if (ret >= 0) + if (ret >= 0) { ext4_update_inode_fsync_trans(handle, inode, 1); + err = check_eofblocks_fl(handle, inode, map, path, + map->m_len); + } else + err = ret; goto out2; } /* buffered IO case */ @@ -3244,8 +3299,13 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, /* buffered write, writepage time, convert*/ ret = ext4_ext_convert_to_initialized(handle, inode, map, path); - if (ret >= 0) + if (ret >= 0) { ext4_update_inode_fsync_trans(handle, inode, 1); + err = check_eofblocks_fl(handle, inode, map, path, map->m_len); + if (err < 0) + goto out2; + } + out: if (ret <= 0) { err = ret; @@ -3292,6 +3352,7 @@ out2: } return err ? err : allocated; } + /* * Block allocation/map/preallocation routine for extents based files * @@ -3315,9 +3376,9 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, { struct ext4_ext_path *path = NULL; struct ext4_extent_header *eh; - struct ext4_extent newex, *ex, *last_ex; + struct ext4_extent newex, *ex; ext4_fsblk_t newblock; - int i, err = 0, depth, ret, cache_type; + int err = 0, depth, ret, cache_type; unsigned int allocated = 0; struct ext4_allocation_request ar; ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio; @@ -3497,31 +3558,10 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, map->m_flags |= EXT4_MAP_UNINIT; } - if (unlikely(ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))) { - if (unlikely(!eh->eh_entries)) { - EXT4_ERROR_INODE(inode, - "eh->eh_entries == 0 and " - "EOFBLOCKS_FL set"); - err = -EIO; - goto out2; - } - last_ex = EXT_LAST_EXTENT(eh); - /* - * If the current leaf block was reached by looking at - * the last index block all the way down the tree, and - * we are extending the inode beyond the last extent - * in the current leaf block, then clear the - * EOFBLOCKS_FL flag. - */ - for (i = depth-1; i >= 0; i--) { - if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr)) - break; - } - if ((i < 0) && - (map->m_lblk + ar.len > le32_to_cpu(last_ex->ee_block) + - ext4_ext_get_actual_len(last_ex))) - ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); - } + err = check_eofblocks_fl(handle, inode, map, path, ar.len); + if (err) + goto out2; + err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); if (err) { /* free data blocks we just allocated */ -- 2.39.5