Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 15/30] ext4: fix race in ext4_mb_add_n_trim() | Date | Fri, 1 Mar 2013 11:45:36 -0800 |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Niu Yawei <yawei.niu@gmail.com>
commit f1167009711032b0d747ec89a632a626c901a1ad upstream.
In ext4_mb_add_n_trim(), lg_prealloc_lock should be taken when changing the lg_prealloc_list.
Signed-off-by: Niu Yawei <yawei.niu@intel.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext4/mballoc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4111,7 +4111,7 @@ static void ext4_mb_add_n_trim(struct ex /* The max size of hash table is PREALLOC_TB_SIZE */ order = PREALLOC_TB_SIZE - 1; /* Add the prealloc space to lg */ - rcu_read_lock(); + spin_lock(&lg->lg_prealloc_lock); list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order], pa_inode_list) { spin_lock(&tmp_pa->pa_lock); @@ -4135,12 +4135,12 @@ static void ext4_mb_add_n_trim(struct ex if (!added) list_add_tail_rcu(&pa->pa_inode_list, &lg->lg_prealloc_list[order]); - rcu_read_unlock(); + spin_unlock(&lg->lg_prealloc_lock); /* Now trim the list to be not more than 8 elements */ if (lg_prealloc_count > 8) { ext4_mb_discard_lg_preallocations(sb, lg, - order, lg_prealloc_count); + order, lg_prealloc_count); return; } return ;
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