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| author | Niu Yawei <yawei.niu@gmail.com> | 2013-02-01 21:31:27 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-04 06:06:42 +0800 |
| commit | 51e26006d1c9d5a2609d1bb6b7899cd86f92eed9 (patch) | |
| tree | 84ad55a0a9b0046cf184ca655a63df796f1052e3 /fs/ext4 | |
| parent | ced2decfe31ba7b7b97cce2de010f75e8a90b412 (diff) | |
| download | lwn-51e26006d1c9d5a2609d1bb6b7899cd86f92eed9.tar.gz lwn-51e26006d1c9d5a2609d1bb6b7899cd86f92eed9.zip | |
ext4: fix race in ext4_mb_add_n_trim()
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>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/mballoc.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index e77c4fe665a0..3122ece15147 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4126,7 +4126,7 @@ static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac) /* 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); @@ -4150,12 +4150,12 @@ static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac) 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 ; |