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Subject[211/244] btrfs: fix d_off in the first dirent
3.0-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

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 <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Cc: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/btrfs/inode.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4124,7 +4124,8 @@ static int btrfs_real_readdir(struct fil

/* 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 fil
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;



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