From 890ecd3d30e0ba8b1b676eaf6c925f65483f5f0d Mon Sep 17 00:00:00 2001 From: Hidetoshi Seto Date: Sun, 18 Sep 2011 10:20:46 -0400 Subject: [PATCH] btrfs: fix d_off in the first dirent commit 3765fefaee2da83f10829fa64a74e6b7360350cb upstream. Since the d_off in the first dirent for "." (that originates from the 4th argument "offset" of filldir() for the 2nd dirent for "..") is wrongly assigned in btrfs_real_readdir(), telldir returns same offset for different locations. | # mkfs.btrfs /dev/sdb1 | # mount /dev/sdb1 fs0 | # cd fs0 | # touch file0 file1 | # ../test | telldir: 0 | readdir: d_off = 2, d_name = "." | telldir: 2 | readdir: d_off = 2, d_name = ".." | telldir: 2 | readdir: d_off = 3, d_name = "file0" | telldir: 3 | readdir: d_off = 2147483647, d_name = "file1" | telldir: 2147483647 To fix this problem, pass filp->f_pos (which is loff_t) instead. | # ../test | telldir: 0 | readdir: d_off = 1, d_name = "." | telldir: 1 | readdir: d_off = 2, d_name = ".." | telldir: 2 | readdir: d_off = 3, d_name = "file0" : At the moment the "offset" for "." is unused because there is no preceding dirent, however it is better to pass filp->f_pos to follow grammatical usage. Signed-off-by: Hidetoshi Seto Signed-off-by: Chris Mason Cc: Grazvydas Ignotas Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/inode.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 3601f0a..d42e6bf 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4124,7 +4124,8 @@ static int btrfs_real_readdir(struct file *filp, void *dirent, /* special case for "." */ if (filp->f_pos == 0) { - over = filldir(dirent, ".", 1, 1, btrfs_ino(inode), DT_DIR); + over = filldir(dirent, ".", 1, + filp->f_pos, btrfs_ino(inode), DT_DIR); if (over) return 0; filp->f_pos = 1; @@ -4133,7 +4134,7 @@ static int btrfs_real_readdir(struct file *filp, void *dirent, if (filp->f_pos == 1) { u64 pino = parent_ino(filp->f_path.dentry); over = filldir(dirent, "..", 2, - 2, pino, DT_DIR); + filp->f_pos, pino, DT_DIR); if (over) return 0; filp->f_pos = 2; -- 2.7.4