[LogFS] Prevent memory corruption on large deletes
Removing sufficiently large files would create aliases for a large
number of segments. This in turn results in a large number of journal
entries and an overflow of s_je_array.
Cheap fix is to add a BUG_ON, turning memory corruption into something
annoying, but less dangerous. Real fix is to count the number of
affected segments and prevent the problem completely.
Signed-off-by: Joern Engel <joern@logfs.org>
diff --git a/fs/logfs/journal.c b/fs/logfs/journal.c
index d57c7b0..2c22a4a 100644
--- a/fs/logfs/journal.c
+++ b/fs/logfs/journal.c
@@ -493,6 +493,8 @@
btree_grim_visitor64(&tree->new, (unsigned long)sb, account_shadow);
btree_grim_visitor64(&tree->old, (unsigned long)sb, account_shadow);
+ btree_grim_visitor32(&tree->segment_map, 0, NULL);
+ tree->no_shadowed_segments = 0;
if (li->li_block) {
/*
@@ -660,6 +662,7 @@
if (ofs < 0)
return ofs;
logfs_buf_write(area, ofs, super->s_compressed_je, len);
+ BUG_ON(super->s_no_je >= MAX_JOURNAL_ENTRIES);
super->s_je_array[super->s_no_je++] = cpu_to_be64(ofs);
return 0;
}