ceph: fix __dcache_readdir() (4d5f5df6) · Commits · 戴 / test

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 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@intel.com>

fs/ceph/dir.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -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 (int)(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,

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