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Message-ID: <20130301022816.GA10692@gmail.com>
Date: Fri, 1 Mar 2013 10:28:16 +0800
From: Zheng Liu <gnehzuil.liu@...il.com>
To: Dmitry Monakhov <dmonakhov@...nvz.org>
Cc: linux-ext4@...r.kernel.org, Zheng Liu <wenqing.lz@...bao.com>,
Theodore Ts'o <tytso@....edu>
Subject: Re: [PATCH 3/6] ext4: add self-testing infrastructure to do a sanity
check
On Thu, Feb 28, 2013 at 11:04:39PM +0400, Dmitry Monakhov wrote:
> On Fri, 1 Mar 2013 02:26:41 +0800, Zheng Liu <gnehzuil.liu@...il.com> wrote:
> > From: Dmitry Monakhov <dmonakhov@...nvz.org>
> >
> > 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 | 64 ++++++++++++++++++++++++++++++++
> > fs/ext4/extents_status.h | 6 +++
> > fs/ext4/inode.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 165 insertions(+)
> >
> > diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> > index a769485..02df536 100644
> > --- a/fs/ext4/extents_status.c
> > +++ b/fs/ext4/extents_status.c
> > @@ -401,6 +401,66 @@ 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_check(struct inode *inode,
> > + struct extent_status *es)
> Agree, this is very good place for sanity check.
> > +{
> > + 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, ex_status, es_status;
> > +
> > + /*
> > + * Delayed and hole haven't been allocated in disk. We
> > + * don't need to check it.
> > + */
> Why? We still can perform ext4_ext_find_extent and check that:
> /* If extent is delayed only if ex == NULL */
> if (!ex == ext4_es_is_written(es))
> WARN_ON();
>
> if (ext4_es_is_unwritten(es) != ext4_ext_is_uninitialized(ex))
> WARN_ON();
Yes, it will be fixed in next version.
>
> > + if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es))
> > + return;
> > +
> > + /*
> > + * We don't need to worry about the race condition because
> > + * caller takes i_data_sem locking.
> Yes, and it is good place to assertion that we hold it.
A BUG_ON(mutex_is_locked(&inode->i_mutex) will be added.
> > + */
> > + path = ext4_ext_find_extent(inode, es->es_lblk, NULL);
> > + if (IS_ERR(path))
> > + return;
> > +
> > + depth = ext_depth(inode);
> > +
> > + /* We should always find an extent at given logical block */
> > + ex = path[depth].p_ext;
> > + if ((ex != NULL ) ^ ext4_es_is_written(es) {
> > + printk("ES insert assertation failed to inode: %lu "
> > + "can not find the extent at block %d\n",
> > + inode->i_ino, es->es_lblk);
> > + goto out;
> > + }
> > +
> > +> +
> > + ee_block = le32_to_cpu(ex->ee_block);
> > + ee_start = ext4_ext_pblock(ex);
> > + ee_len = ext4_ext_get_actual_len(ex);
> > +
> > + ex_status = ext4_ext_is_uninitialized(ex) ? 1 : 0;
> > + es_status = ext4_es_is_unwritten(es) ? 1 : 0;
> > + if (ex_status ^ es_status) {
> Why status only? we can also check pblock, and lblk.
Yes, it will be fixed.
Thanks,
- Zheng
> > + 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, ex_status ? 'u' : 'w',
> > + es->es_lblk, es->es_len, ext4_es_pblock(es),
> > + es_status ? 'u' : 'w');
> > + }
> > +out:
> > + if (path) {
> > + ext4_ext_drop_refs(path);
> > + kfree(path);
> > + }
> > +
> > +}
> > +#endif
> > +
> > static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
> > {
> > struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
> > @@ -483,6 +543,10 @@ 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
> > +
> > 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..8d22170 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -482,6 +482,57 @@ 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 flag because it shouldn't be marked
> > + * in es_map->m_flags.
> > + */
> > + map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
> > +
> > + /*
> > + * 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]\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);
> > + }
> > +}
> > +#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 +560,11 @@ 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 +587,10 @@ 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 +611,15 @@ 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
> > +
> > status = map->m_flags & EXT4_MAP_UNWRITTEN ?
> > EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
> > if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
> > @@ -643,6 +712,15 @@ 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
> > +
> > status = map->m_flags & EXT4_MAP_UNWRITTEN ?
> > EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
> > if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
> > @@ -1768,6 +1846,11 @@ 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 +1892,9 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
> > else
> > BUG_ON(1);
> >
> > +#ifdef ES_AGRESSIVE_TEST
> > + ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, flags);
> > +#endif
> > return retval;
> > }
> >
> > @@ -1873,6 +1959,15 @@ 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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