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authorBob Peterson <rpeterso@redhat.com>2013-12-13 08:31:06 -0500
committerSteven Whitehouse <swhiteho@redhat.com>2013-12-13 21:42:40 +0000
commit502be2a32f09f388e4ff34ef2e3ebcabbbb261da (patch)
treeea89d072b44346858e3fa5eb06652675e7e1b6ff
parent9290a9a7c0bcf5400e8dbfbf9707fa68ea3fb338 (diff)
downloadop-kernel-dev-502be2a32f09f388e4ff34ef2e3ebcabbbb261da.zip
op-kernel-dev-502be2a32f09f388e4ff34ef2e3ebcabbbb261da.tar.gz
GFS2: Fix slab memory leak in gfs2_bufdata
This patch fixes a slab memory leak that sometimes can occur for files with a very short lifespan. The problem occurs when a dinode is deleted before it has gotten to the journal properly. In the leak scenario, the bd object is pinned for journal committment (queued to the metadata buffers queue: sd_log_le_buf) but is subsequently unpinned and dequeued before it finds its way to the ail or the revoke queue. In this rare circumstance, the bd object needs to be freed from slab memory, or it is forgotten. We have to be very careful how we do it, though, because multiple processes can call gfs2_remove_from_journal. In order to avoid double-frees, only the process that does the unpinning is allowed to free the bd. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/meta_io.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 9324150..52f177b 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -258,6 +258,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
struct address_space *mapping = bh->b_page->mapping;
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
struct gfs2_bufdata *bd = bh->b_private;
+ int was_pinned = 0;
if (test_clear_buffer_pinned(bh)) {
trace_gfs2_pin(bd, 0);
@@ -273,12 +274,16 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
tr->tr_num_databuf_rm++;
}
tr->tr_touched = 1;
+ was_pinned = 1;
brelse(bh);
}
if (bd) {
spin_lock(&sdp->sd_ail_lock);
if (bd->bd_tr) {
gfs2_trans_add_revoke(sdp, bd);
+ } else if (was_pinned) {
+ bh->b_private = NULL;
+ kmem_cache_free(gfs2_bufdata_cachep, bd);
}
spin_unlock(&sdp->sd_ail_lock);
}
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