Limit the n_unaligned argument of gfs2_unaligned_extlen to the number of
blocks to scan so that the len argument can never underrun.
Slightly simplify the unaligned block logic in gfs2_free_extlen.
Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
---
fs/gfs2/rgrp.c | 30 +++++++++++++-----------------
1 file changed, 13 insertions(+), 17 deletions(-)
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 2ce46e372b020..f06755dae951e 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -335,8 +335,6 @@ static bool gfs2_unaligned_extlen(struct gfs2_rbm *rbm, u32
n_unaligned, u32 *le
if (res != GFS2_BLKST_FREE)
return true;
(*len)--;
- if (*len == 0)
- return true;
if (gfs2_rbm_incr(rbm))
return true;
}
@@ -362,7 +360,6 @@ static bool gfs2_unaligned_extlen(struct gfs2_rbm *rbm, u32
n_unaligned, u32 *le
static u32 gfs2_free_extlen(const struct gfs2_rbm *rrbm, u32 len)
{
struct gfs2_rbm rbm = *rrbm;
- u32 n_unaligned = rbm.offset & 3;
u32 size = len;
u32 bytes;
u32 chunk_size;
@@ -370,11 +367,14 @@ static u32 gfs2_free_extlen(const struct gfs2_rbm *rrbm,
u32 len)
u64 block;
struct gfs2_bitmap *bi;
- if (n_unaligned &&
- gfs2_unaligned_extlen(&rbm, 4 - n_unaligned, &len))
- goto out;
+ /* Deal with unaligned bits at the front */
+ if (rbm.offset & 3) {
+ u32 n_unaligned = min(4 - (rbm.offset & 3), len);
+
+ if (gfs2_unaligned_extlen(&rbm, n_unaligned, &len))
+ goto out;
+ }
- n_unaligned = len & 3;
/* Start is now byte aligned */
while (len > 3) {
bi = rbm_bi(&rbm);
@@ -392,20 +392,16 @@ static u32 gfs2_free_extlen(const struct gfs2_rbm *rrbm,
u32 len)
BUG_ON(len < chunk_size);
len -= chunk_size;
block = gfs2_rbm_to_block(&rbm);
- if (gfs2_rbm_from_block(&rbm, block + chunk_size)) {
- n_unaligned = 0;
- break;
- }
- if (ptr) {
- n_unaligned = 3;
+ if (gfs2_rbm_from_block(&rbm, block + chunk_size))
+ goto out;
+ if (ptr)
break;
- }
- n_unaligned = len & 3;
}
/* Deal with any bits left over at the end */
- if (n_unaligned)
- gfs2_unaligned_extlen(&rbm, n_unaligned, &len);
+ if (len)
+ gfs2_unaligned_extlen(&rbm, len, &len);
+
out:
return size - len;
}
--
2.20.1
