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| author | Steven Whitehouse <swhiteho@redhat.com> | 2012-01-16 15:46:21 +0000 |
|---|---|---|
| committer | Steven Whitehouse <swhiteho@redhat.com> | 2012-02-28 09:43:07 +0000 |
| commit | 4043b886b0740ded65f633fc4b7225d624c7e658 (patch) | |
| tree | 532dc280a44a051b6a93d23702f8b847b07e5ff6 | |
| parent | 586c6e7013c8cbb8c91aaa6568ec349b1dc2c691 (diff) | |
| download | linux-4043b886b0740ded65f633fc4b7225d624c7e658.tar.bz2 | |
GFS2: Fix race between lru_list and glock ref count
This patch fixes a narrow race window between the glock ref count
hitting zero and glocks being removed from the lru_list.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
| -rw-r--r-- | fs/gfs2/glock.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 376816fcd040..351a3e797789 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -167,14 +167,19 @@ void gfs2_glock_add_to_lru(struct gfs2_glock *gl) spin_unlock(&lru_lock); } -static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl) +static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl) { - spin_lock(&lru_lock); if (!list_empty(&gl->gl_lru)) { list_del_init(&gl->gl_lru); atomic_dec(&lru_count); clear_bit(GLF_LRU, &gl->gl_flags); } +} + +static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl) +{ + spin_lock(&lru_lock); + __gfs2_glock_remove_from_lru(gl); spin_unlock(&lru_lock); } @@ -217,11 +222,12 @@ void gfs2_glock_put(struct gfs2_glock *gl) struct gfs2_sbd *sdp = gl->gl_sbd; struct address_space *mapping = gfs2_glock2aspace(gl); - if (atomic_dec_and_test(&gl->gl_ref)) { + if (atomic_dec_and_lock(&gl->gl_ref, &lru_lock)) { + __gfs2_glock_remove_from_lru(gl); + spin_unlock(&lru_lock); spin_lock_bucket(gl->gl_hash); hlist_bl_del_rcu(&gl->gl_list); spin_unlock_bucket(gl->gl_hash); - gfs2_glock_remove_from_lru(gl); GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders)); GLOCK_BUG_ON(gl, mapping && mapping->nrpages); trace_gfs2_glock_put(gl); |