diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 7d7f6f91d555..0c7e247f714c 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1052,7 +1052,8 @@ static void ext4_mb_release_desc(struct ext4_buddy *e4b) if (e4b->bd_buddy_page) page_cache_release(e4b->bd_buddy_page); /* Done with the buddy cache */ - up_read(e4b->alloc_semp); + if (e4b->alloc_semp) + up_read(e4b->alloc_semp); } @@ -1371,7 +1372,9 @@ static void ext4_mb_use_best_found(struct ext4_allocation_context *ac, get_page(ac->ac_bitmap_page); ac->ac_buddy_page = e4b->bd_buddy_page; get_page(ac->ac_buddy_page); - + /* on allocation we use ac to track the held semaphore */ + ac->alloc_semp = e4b->alloc_semp; + e4b->alloc_semp = NULL; /* store last allocated for subsequent stream allocation */ if ((ac->ac_flags & EXT4_MB_HINT_DATA)) { spin_lock(&sbi->s_md_lock); @@ -4289,6 +4292,7 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac, ac->ac_pa = NULL; ac->ac_bitmap_page = NULL; ac->ac_buddy_page = NULL; + ac->alloc_semp = NULL; ac->ac_lg = NULL; /* we have to define context: we'll we work with a file or @@ -4469,6 +4473,8 @@ static int ext4_mb_release_context(struct ext4_allocation_context *ac) } ext4_mb_put_pa(ac, ac->ac_sb, pa); } + if (ac->alloc_semp) + up_read(ac->alloc_semp); if (ac->ac_bitmap_page) page_cache_release(ac->ac_bitmap_page); if (ac->ac_buddy_page) @@ -4569,10 +4575,14 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len) ext4_mb_new_preallocation(ac); } - if (likely(ac->ac_status == AC_STATUS_FOUND)) { *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks); if (*errp == -EAGAIN) { + /* + * drop the reference that we took + * in ext4_mb_use_best_found + */ + ext4_mb_release_context(ac); ac->ac_b_ex.fe_group = 0; ac->ac_b_ex.fe_start = 0; ac->ac_b_ex.fe_len = 0; diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h index 95d4c7f29a8a..10a2921baf14 100644 --- a/fs/ext4/mballoc.h +++ b/fs/ext4/mballoc.h @@ -195,6 +195,11 @@ struct ext4_allocation_context { __u8 ac_op; /* operation, for history only */ struct page *ac_bitmap_page; struct page *ac_buddy_page; + /* + * pointer to the held semaphore upon successful + * block allocation + */ + struct rw_semaphore *alloc_semp; struct ext4_prealloc_space *ac_pa; struct ext4_locality_group *ac_lg; };