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authorArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2014-07-16 15:22:29 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-14 08:47:54 -0800
commit6f1aec53eded9399e6b44cab8c9aa36c65a8f402 (patch)
tree3b9f70938dcc21c9a292d81934d77d979421e0b5
parent918ecf66a11bb3bdc818a264319dcaf984c11a3f (diff)
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UBIFS: fix free log space calculation
commit ba29e721eb2df6df8f33c1f248388bb037a47914 upstream. Hu (hujianyang <hujianyang@huawei.com>) 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 <hujianyang@huawei.com> Reported-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ubifs/log.c8
1 files 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;
}
/**