When device is missing, read_extent_data() (function exported from old
btrfs check code) has the following problems:
1) Modify @len parameter if device is missing
If device returned in @multi is missing, @len can be larger than
@max_len (originl length).
This could confusing caller and underflow the read loop.
2) Still return 0 for missing device
It only handles read error, missing device is not handled and 0 is
returned.
3) Wrong check for device->fd
In fact, 0 is also a valid fd.
Although not possible under most case, it's still need fix.
Fix them all.
Fixes: 1bad2f2f2dfe ("Btrfs-progs: fsck: add an option to check data csums")
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
disk-io.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/disk-io.c b/disk-io.c
index 610963357675..310ab19cf099 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -395,10 +395,12 @@ int read_extent_data(struct btrfs_fs_info *fs_info, char *data, u64 logical,
}
device = multi->stripes[0].dev;
- if (device->fd <= 0)
- goto err;
if (*len > max_len)
*len = max_len;
+ if (device->fd < 0) {
+ ret = -EIO;
+ goto err;
+ }
ret = pread64(device->fd, data, *len, multi->stripes[0].physical);
if (ret != *len)
--
2.16.3
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