From 6f1aec53eded9399e6b44cab8c9aa36c65a8f402 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Wed, 16 Jul 2014 15:22:29 +0300 Subject: [PATCH] UBIFS: fix free log space calculation commit ba29e721eb2df6df8f33c1f248388bb037a47914 upstream. Hu (hujianyang ) discovered an issue in the 'empty_log_bytes()' function, which calculates how many bytes are left in the log: " If 'c->lhead_lnum + 1 == c->ltail_lnum' and 'c->lhead_offs == c->leb_size', 'h' would equalent to 't' and 'empty_log_bytes()' would return 'c->log_bytes' instead of 0. " At this point it is not clear what would be the consequences of this, and whether this may lead to any problems, but this patch addresses the issue just in case. Tested-by: hujianyang Reported-by: hujianyang Signed-off-by: Artem Bityutskiy Signed-off-by: Greg Kroah-Hartman --- fs/ubifs/log.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/ubifs/log.c b/fs/ubifs/log.c index be67120fb919..06649d21b056 100644 --- a/fs/ubifs/log.c +++ b/fs/ubifs/log.c @@ -106,10 +106,14 @@ static inline long long empty_log_bytes(const struct ubifs_info *c) h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs; t = (long long)c->ltail_lnum * c->leb_size; - if (h >= t) + if (h > t) return c->log_bytes - h + t; - else + else if (h != t) return t - h; + else if (c->lhead_lnum != c->ltail_lnum) + return 0; + else + return c->log_bytes; } /** -- 2.34.1