If directory is fragmented, readdir() read its dirfrags one by one.
After reading all dirfrags, the corresponding dentries are sorted in
(frag_t, off) order in the dcache. If dentries of a directory are all
cached, __dcache_readdir() can use the cached dentries to satisfy
readdir syscall. But when checking if a given dentry is after the
the position of readdir, __dcache_readdir() compares numerical value
of frag_t directly. This is wrong, it should use ceph_frag_compare().
Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
---
fs/ceph/dir.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 3bbd0eb..42edab9 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -100,6 +100,14 @@ static unsigned fpos_off(loff_t p)
return p & 0xffffffff;
}
+static int fpos_cmp(loff_t l, loff_t r)
+{
+ int v = ceph_frag_compare(fpos_frag(l), fpos_frag(r));
+ if (v)
+ return v;
+ return fpos_off(l) > fpos_off(r);
+}
+
/*
* When possible, we try to satisfy a readdir by peeking at the
* dcache. We make this work by carefully ordering dentries on
@@ -156,7 +164,7 @@ more:
if (!d_unhashed(dentry) && dentry->d_inode &&
ceph_snap(dentry->d_inode) != CEPH_SNAPDIR &&
ceph_ino(dentry->d_inode) != CEPH_INO_CEPH &&
- ctx->pos <= di->offset)
+ fpos_cmp(ctx->pos, di->offset) <= 0)
break;
dout(" skipping %p %.*s at %llu (%llu)%s%s\n", dentry,
dentry->d_name.len, dentry->d_name.name, di->offset,
--
1.8.5.3
--
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