From: Zhang Yi When querying extents in the extent status tree, we should hold the data_sem if we want to obtain the sequence number as a valid cookie simultaneously. However, currently, ext4_map_blocks() calls ext4_es_lookup_extent() without holding data_sem. Therefore, we should acquire i_es_lock instead, which also ensures that the sequence cookie and the extent remain consistent. Consequently, make ext4_es_lookup_extent() to pass out the sequence number when necessary. Signed-off-by: Zhang Yi --- fs/ext4/extents.c | 2 +- fs/ext4/extents_status.c | 6 ++++-- fs/ext4/extents_status.h | 2 +- fs/ext4/inode.c | 8 ++++---- 4 files changed, 10 insertions(+), 8 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index ca5499e9412b..c7d219e6c6d8 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2213,7 +2213,7 @@ static int ext4_fill_es_cache_info(struct inode *inode, while (block <= end) { next = 0; flags = 0; - if (!ext4_es_lookup_extent(inode, block, &next, &es)) + if (!ext4_es_lookup_extent(inode, block, &next, &es, NULL)) break; if (ext4_es_is_unwritten(&es)) flags |= FIEMAP_EXTENT_UNWRITTEN; diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index 62886e18e2a3..9bf2f48d8ffe 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -1035,8 +1035,8 @@ void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk, * Return: 1 on found, 0 on not */ int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, - ext4_lblk_t *next_lblk, - struct extent_status *es) + ext4_lblk_t *next_lblk, struct extent_status *es, + u64 *pseq) { struct ext4_es_tree *tree; struct ext4_es_stats *stats; @@ -1095,6 +1095,8 @@ int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, } else *next_lblk = 0; } + if (pseq) + *pseq = EXT4_I(inode)->i_es_seq; } else { percpu_counter_inc(&stats->es_stats_cache_misses); } diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h index 8f9c008d11e8..f3396cf32b44 100644 --- a/fs/ext4/extents_status.h +++ b/fs/ext4/extents_status.h @@ -148,7 +148,7 @@ extern void ext4_es_find_extent_range(struct inode *inode, struct extent_status *es); extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t *next_lblk, - struct extent_status *es); + struct extent_status *es, u64 *pseq); extern bool ext4_es_scan_range(struct inode *inode, int (*matching_fn)(struct extent_status *es), ext4_lblk_t lblk, ext4_lblk_t end); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5b7a15db4953..c7fac4b89c88 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -649,7 +649,7 @@ static int ext4_map_create_blocks(handle_t *handle, struct inode *inode, * extent status tree. */ if (flags & EXT4_GET_BLOCKS_PRE_IO && - ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) { + ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, NULL)) { if (ext4_es_is_written(&es)) return retval; } @@ -723,7 +723,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, ext4_check_map_extents_env(inode); /* Lookup extent status tree firstly */ - if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) { + if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, NULL)) { if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) { map->m_pblk = ext4_es_pblock(&es) + map->m_lblk - es.es_lblk; @@ -1908,7 +1908,7 @@ static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map) ext4_check_map_extents_env(inode); /* Lookup extent status tree firstly */ - if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) { + if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, NULL)) { map->m_len = min_t(unsigned int, map->m_len, es.es_len - (map->m_lblk - es.es_lblk)); @@ -1961,7 +1961,7 @@ static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map) * is held in write mode, before inserting a new da entry in * the extent status tree. */ - if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) { + if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es, NULL)) { map->m_len = min_t(unsigned int, map->m_len, es.es_len - (map->m_lblk - es.es_lblk)); -- 2.46.1