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Date: Thu, 07 Mar 2013 19:41:05 +0400
From: Dmitry Monakhov <dmonakhov@...nvz.org>
To: Zheng Liu <gnehzuil.liu@...il.com>, linux-ext4@...r.kernel.org
Cc: Zheng Liu <wenqing.lz@...bao.com>, Theodore Ts'o <tytso@....edu>
Subject: Re: [PATCH v2 2/5] ext4: add self-testing infrastructure to do a sanity check
On Wed, 6 Mar 2013 22:17:12 +0800, Zheng Liu <gnehzuil.liu@...il.com> wrote:
> From: Dmitry Monakhov <dmonakhov@...nvz.org>
Looks good with small comments (see below)
>
> This commit adds a self-testing infrastructure like extent tree does to
> do a sanity check for extent status tree. After status tree is as a
> extent cache, we'd better to make sure that it caches right result.
>
> After applied this commit, we will get a lot of messages when we run
> xfstests as below.
>
> ...
> kernel: ES len assertation failed for inode: 230 retval 1 != map->m_len
> 3 in ext4_map_blocks (allocation)
> ...
> kernel: ES cache assertation failed for inode: 230 es_cached ex
> [974/2/4781/20] != found ex [974/1/4781/1000]
> ...
> kernel: ES insert assertation failed for inode: 635 ex_status
> [0/45/21388/w] != es_status [44/1/21432/u]
> ...
>
> Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
> Signed-off-by: Zheng Liu <wenqing.lz@...bao.com>
> Cc: "Theodore Ts'o" <tytso@....edu>
> ---
> fs/ext4/extents_status.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++
> fs/ext4/extents_status.h | 6 ++
> fs/ext4/inode.c | 96 +++++++++++++++++++++++++++
> 3 files changed, 271 insertions(+)
>
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index dc4e4c5..a434f81 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -405,6 +405,171 @@ ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es)
> return es;
> }
>
> +#ifdef ES_AGGRESSIVE_TEST
> +static void ext4_es_insert_extent_ext_check(struct inode *inode,
> + struct extent_status *es)
> +{
> + struct ext4_ext_path *path = NULL;
> + struct ext4_extent *ex;
> + ext4_lblk_t ee_block;
> + ext4_fsblk_t ee_start;
> + unsigned short ee_len;
> + int depth, ee_status, es_status;
> +
> + path = ext4_ext_find_extent(inode, es->es_lblk, NULL);
> + if (IS_ERR(path))
> + return;
> +
> + depth = ext_depth(inode);
> + ex = path[depth].p_ext;
> +
> + if (ex) {
> +
> + ee_block = le32_to_cpu(ex->ee_block);
> + ee_start = ext4_ext_pblock(ex);
> + ee_len = ext4_ext_get_actual_len(ex);
> +
> + ee_status = ext4_ext_is_uninitialized(ex) ? 1 : 0;
> + es_status = ext4_es_is_unwritten(es) ? 1 : 0;
> +
> + /*
> + * Make sure ex and es are not overlap when we try to insert
> + * a delayed/hole extent.
> + */
> + if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es)) {
> + if (in_range(es->es_lblk, ee_block, ee_len)) {
> + printk("ES insert assertation failed for inode: %lu "
> + "we can find an extent at block "
> + "[%d/%d/%llu/%c], but we want to add an "
> + "delayed/hole extent [%d/%d/%llu/%llx]\n",
> + inode->i_ino, ee_block, ee_len, ee_start,
> + ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
> + ext4_es_pblock(es), ext4_es_status(es));
> + }
> + goto out;
> + }
> +
> + /*
> + * We don't check ee_block == es->es_lblk, etc. because es
> + * might be a part of whole extent, vice versa.
> + */
> + if (es->es_lblk < ee_block ||
> + ext4_es_pblock(es) != ee_start + es->es_lblk - ee_block) {
> + printk("ES insert assertation failed for inode: %lu "
> + "ex_status [%d/%d/%llu/%c] != "
> + "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
> + ee_block, ee_len, ee_start, ee_status ? 'u' : 'w',
> + es->es_lblk, es->es_len, ext4_es_pblock(es),
> + es_status ? 'u' : 'w');
> + goto out;
> + }
> +
> + if (ee_status ^ es_status) {
> + printk("ES insert assertation failed for inode: %lu "
> + "ex_status [%d/%d/%llu/%c] != "
> + "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
> + ee_block, ee_len, ee_start, ee_status ? 'u' : 'w',
> + es->es_lblk, es->es_len, ext4_es_pblock(es),
> + es_status ? 'u' : 'w');
> + }
> + } else {
> + /*
> + * We can't find an extent on disk. So we need to make sure
> + * that we don't want to add an written/unwritten extent.
> + */
> + if (!ext4_es_is_delayed(es) && !ext4_es_is_hole(es)) {
> + printk("ES insert assertation failed for inode: %lu "
> + "can't find an extent at block %d but we want "
> + "to add an written/unwritten extent "
> + "[%d/%d/%llu/%llx]\n", inode->i_ino,
> + es->es_lblk, es->es_lblk, es->es_len,
> + ext4_es_pblock(es), ext4_es_status(es));
> + }
> + }
> +out:
> + if (path) {
> + ext4_ext_drop_refs(path);
> + kfree(path);
> + }
> +}
> +
> +static void ext4_es_insert_extent_ind_check(struct inode *inode,
> + struct extent_status *es)
> +{
> + struct ext4_map_blocks map;
> + int retval;
> +
> + /*
> + * Here we call ext4_ind_map_blocks to lookup a block mapping because
> + * 'Indirect' structure is defined in indirect.c. So we couldn't
> + * access direct/indirect tree from outside. It is too dirty to define
> + * this function in indirect.c file.
> + */
> +
> + map.m_lblk = es->es_lblk;
> + map.m_len = es->es_len;
> +
> + retval = ext4_ind_map_blocks(NULL, inode, &map, 0);
> + if (retval > 0) {
> + if (ext4_es_is_delayed(es) || ext4_es_is_hole(es)) {
> + /*
> + * We want to add a delayed/hole extent but this
> + * block has been allocated.
> + */
> + printk("ES insert assertation failed for inode: %lu "
> + "We can find blocks but we want to add a "
> + "delayed/hole extent [%d/%d/%llu/%llx]\n",
> + inode->i_ino, es->es_lblk, es->es_len,
> + ext4_es_pblock(es), ext4_es_status(es));
> + return;
> + } else if (ext4_es_is_written(es)) {
> + if (retval != es->es_len) {
> + printk("ES insert assertation failed for inode: "
> + "%lu retval %d != es_len %d\n",
> + inode->i_ino, retval, es->es_len);
> + return;
> + }
> + if (map.m_pblk != ext4_es_pblock(es)) {
> + printk("ES insert assertation failed for inode: "
> + "%lu m_pblk %llu != es_pblk %llu\n",
> + inode->i_ino, map.m_pblk,
> + ext4_es_pblock(es));
> + return;
> + }
> + } else {
> + /*
> + * We don't need to check unwritten extent because
> + * indirect-based file doesn't have it.
> + */
> + BUG_ON(1);
> + }
> + } else if (retval == 0) {
> + if (ext4_es_is_written(es)) {
> + printk("ES insert assertation failed for inode: %lu "
> + "We can't find the block but we want to add "
> + "an written extent [%d/%d/%llu/%llx]\n",
> + inode->i_ino, es->es_lblk, es->es_len,
> + ext4_es_pblock(es), ext4_es_status(es));
> + return;
> + }
> + }
> +}
> +
> +static inline void ext4_es_insert_extent_check(struct inode *inode,
> + struct extent_status *es)
> +{
> + /*
> + * We don't need to worry about the race condition because
> + * caller takes i_data_sem locking.
> + */
> + BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
> + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
> + ext4_es_insert_extent_ext_check(inode, es);
> + else
> + ext4_es_insert_extent_ind_check(inode, es);
> +}
> +#endif
> +
> static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
> {
> struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
> @@ -487,6 +652,10 @@ int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
> ext4_es_store_status(&newes, status);
> trace_ext4_es_insert_extent(inode, &newes);
>
> +#ifdef ES_AGGRESSIVE_TEST
> + ext4_es_insert_extent_check(inode, &newes);
> +#endif
We can avoid #ifdef here simply by defining ext4_es_insert_extent_check
like follows:
#ifdef ES_AGGRESSIVE_TEST
void ext4_es_insert_extent_check(inode, &newes) {
... our stuff here
}
#elseif
#define ext4_es_insert_extent_check(a, b) do {} while(0)
#endif
> +#endif
> +
> write_lock(&EXT4_I(inode)->i_es_lock);
> err = __es_remove_extent(inode, lblk, end);
> if (err != 0)
> diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
> index f190dfe..56140ad 100644
> --- a/fs/ext4/extents_status.h
> +++ b/fs/ext4/extents_status.h
> @@ -21,6 +21,12 @@
> #endif
>
> /*
> + * With ES_AGGRESSIVE_TEST defined, the result of es caching will be
> + * checked with old map_block's result.
> + */
> +#define ES_AGGRESSIVE_TEST__
> +
> +/*
> * These flags live in the high bits of extent_status.es_pblk
> */
> #define EXTENT_STATUS_WRITTEN (1ULL << 63)
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 95a0c62..3186a43 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -482,6 +482,58 @@ static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
> return num;
> }
>
> +#ifdef ES_AGGRESSIVE_TEST
> +static void ext4_map_blocks_es_recheck(handle_t *handle,
> + struct inode *inode,
> + struct ext4_map_blocks *es_map,
> + struct ext4_map_blocks *map,
> + int flags)
> +{
> + int retval;
> +
> + map->m_flags = 0;
> + /*
> + * There is a race window that the result is not the same.
> + * e.g. xfstests #223 when dioread_nolock enables. The reason
> + * is that we lookup a block mapping in extent status tree with
> + * out taking i_data_sem. So at the time the unwritten extent
> + * could be converted.
> + */
> + if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
> + down_read((&EXT4_I(inode)->i_data_sem));
> + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
> + retval = ext4_ext_map_blocks(handle, inode, map, flags &
> + EXT4_GET_BLOCKS_KEEP_SIZE);
> + } else {
> + retval = ext4_ind_map_blocks(handle, inode, map, flags &
> + EXT4_GET_BLOCKS_KEEP_SIZE);
> + }
> + if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
> + up_read((&EXT4_I(inode)->i_data_sem));
> + /*
> + * Clear EXT4_MAP_FROM_CLUSTER and EXT4_MAP_BOUNDARY flag
> + * because it shouldn't be marked in es_map->m_flags.
> + */
> + map->m_flags &= ~(EXT4_MAP_FROM_CLUSTER | EXT4_MAP_BOUNDARY);
> +
> + /*
> + * We don't check m_len because extent will be collpased in status
> + * tree. So the m_len might not equal.
> + */
> + if (es_map->m_lblk != map->m_lblk ||
> + es_map->m_flags != map->m_flags ||
> + es_map->m_pblk != map->m_pblk) {
> + printk("ES cache assertation failed for inode: %lu "
> + "es_cached ex [%d/%d/%llu/%x] != "
> + "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
> + inode->i_ino, es_map->m_lblk, es_map->m_len,
> + es_map->m_pblk, es_map->m_flags, map->m_lblk,
> + map->m_len, map->m_pblk, map->m_flags,
> + retval, flags);
> + }
> +}
> +#endif /* ES_AGGRESSIVE_TEST */
> +
> /*
> * The ext4_map_blocks() function tries to look up the requested blocks,
> * and returns if the blocks are already mapped.
> @@ -509,6 +561,11 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
> {
> struct extent_status es;
> int retval;
> +#ifdef ES_AGGRESSIVE_TEST
> + struct ext4_map_blocks orig_map;
> +
> + memcpy(&orig_map, map, sizeof(*map));
> +#endif
>
> map->m_flags = 0;
> ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
> @@ -531,6 +588,10 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
> } else {
> BUG_ON(1);
> }
> +#ifdef ES_AGGRESSIVE_TEST
> + ext4_map_blocks_es_recheck(handle, inode, map,
> + &orig_map, flags);
> +#endif
> goto found;
> }
>
> @@ -551,6 +612,15 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
> int ret;
> unsigned long long status;
>
> +#ifdef ES_AGGRESSIVE_TEST
> + if (retval != map->m_len) {
> + printk("ES len assertation failed for inode: %lu "
> + "retval %d != map->m_len %d "
> + "in %s (lookup)\n", inode->i_ino, retval,
> + map->m_len, __func__);
> + }
> +#endif
It is reasonable to replace this by one-line check
BUG_ON(retval != map->m_len)
> +
> status = map->m_flags & EXT4_MAP_UNWRITTEN ?
> EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
> if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
> @@ -643,6 +713,15 @@ found:
> int ret;
> unsigned long long status;
>
> +#ifdef ES_AGGRESSIVE_TEST
> + if (retval != map->m_len) {
> + printk("ES len assertation failed for inode: %lu "
> + "retval %d != map->m_len %d "
> + "in %s (allocation)\n", inode->i_ino, retval,
> + map->m_len, __func__);
> + }
> +#endif
Also one line check BUG_ON(retval != map->m_len)
> +
> status = map->m_flags & EXT4_MAP_UNWRITTEN ?
> EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
> if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
> @@ -1768,6 +1847,11 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
> struct extent_status es;
> int retval;
> sector_t invalid_block = ~((sector_t) 0xffff);
> +#ifdef ES_AGGRESSIVE_TEST
> + struct ext4_map_blocks orig_map;
> +
> + memcpy(&orig_map, map, sizeof(*map));
> +#endif
>
> if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
> invalid_block = ~0;
> @@ -1809,6 +1893,9 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
> else
> BUG_ON(1);
>
> +#ifdef ES_AGGRESSIVE_TEST
> + ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
> +#endif
> return retval;
> }
>
> @@ -1873,6 +1960,15 @@ add_delayed:
> int ret;
> unsigned long long status;
>
> +#ifdef ES_AGGRESSIVE_TEST
> + if (retval != map->m_len) {
> + printk("ES len assertation failed for inode: %lu "
> + "retval %d != map->m_len %d "
> + "in %s (lookup)\n", inode->i_ino, retval,
> + map->m_len, __func__);
> + }
> +#endif
> +
> status = map->m_flags & EXT4_MAP_UNWRITTEN ?
> EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
> ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
> --
> 1.7.12.rc2.18.g61b472e
>
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