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authorSteven Whitehouse <swhiteho@redhat.com>2011-09-08 10:21:13 +0100
committerSteven Whitehouse <swhiteho@redhat.com>2011-10-21 12:39:46 +0100
commitf75bbfb4dda68c86eb33cde7e2b5c1343c6d5812 (patch)
tree42d5f7a3637061cddc3170aac8e57c4933007898 /fs/gfs2
parent13d921e37174e3d1042deeb303537c1d935da553 (diff)
GFS2: Fix off-by-one in gfs2_blk2rgrpd
Bob reported: I found an off-by-one problem with how I coded this section: It should be: + else if (blk >= cur->rd_data0 + cur->rd_data) In fact, cur->rd_data0 + cur->rd_data is the start of the next rgrp (the next ri_addr), so without the "=" check it can land on the wrong rgrp. In all normal cases, this won't be a problem: you're searching for a block _within_ the rgrp, which will pass the test properly. Where it gets into trouble is if you search the rgrps for the block exactly equal to ri_addr. I don't think anything in the kernel does this, but I found a place in gfs2-utils gfs2_edit where it does. So I definitely need to fix it in libgfs2. I'd like to suggest we fix it in the kernel as well for the sake of keeping the functions similar. So this patch fixes the above mentioned off by one error as well as removing the unused parent pointer. Reported-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/rgrp.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 8ec41744594b..1daf8a78c733 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -329,17 +329,16 @@ static inline int rgrp_contains_block(struct gfs2_rgrpd *rgd, u64 block)
struct gfs2_rgrpd *gfs2_blk2rgrpd(struct gfs2_sbd *sdp, u64 blk)
{
- struct rb_node **newn, *parent = NULL;
+ struct rb_node **newn;
+ struct gfs2_rgrpd *cur;
spin_lock(&sdp->sd_rindex_spin);
newn = &sdp->sd_rindex_tree.rb_node;
while (*newn) {
- struct gfs2_rgrpd *cur = rb_entry(*newn, struct gfs2_rgrpd,
- rd_node);
- parent = *newn;
+ cur = rb_entry(*newn, struct gfs2_rgrpd, rd_node);
if (blk < cur->rd_addr)
newn = &((*newn)->rb_left);
- else if (blk > cur->rd_data0 + cur->rd_data)
+ else if (blk >= cur->rd_data0 + cur->rd_data)
newn = &((*newn)->rb_right);
else {
spin_unlock(&sdp->sd_rindex_spin);