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| author | Benjamin Marzinski <bmarzins@redhat.com> | 2009-06-30 20:51:11 +0200 |
|---|---|---|
| committer | Steven Whitehouse <swhiteho@redhat.com> | 2009-07-30 11:59:28 +0200 |
| commit | a51b56fff3f04fc5aa66b21a2a6d693ee9862d66 (patch) | |
| tree | e93c25ebe818e7a157f2b878a9512ada0f2f2bd1 /fs/gfs2 | |
| parent | GFS2: keep statfs info in sync on grows (diff) | |
| download | linux-a51b56fff3f04fc5aa66b21a2a6d693ee9862d66.tar.xz linux-a51b56fff3f04fc5aa66b21a2a6d693ee9862d66.zip | |
GFS2: Fix panic in glock memory shrinker
It is possible for gfs2_shrink_glock_memory() to check a glock for
demotion
that's in the process of being freed by gfs2_glock_put(). In this case,
gfs2_shrink_glock_memory() will acquire a new reference to this glock,
and
then try to free the glock itself when it drops the refernce. To solve
this, gfs2_shrink_glock_memory() just needs to check if the glock is in
the process of being freed, and if so skip it without ever unlocking the
lru_lock.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2')
| -rw-r--r-- | fs/gfs2/glock.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index fdb796c4f940..827136ee794c 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1314,6 +1314,10 @@ static int gfs2_shrink_glock_memory(int nr, gfp_t gfp_mask) list_del_init(&gl->gl_lru); atomic_dec(&lru_count); + /* Check if glock is about to be freed */ + if (atomic_read(&gl->gl_ref) == 0) + continue; + /* Test for being demotable */ if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { gfs2_glock_hold(gl); |