When using `fsck.erofs` to extract some image have a very large file
inside, for example 2G, my fsck.erofs report some thing like this:
<E> erofs_io: Failed to read data from device - erofs.image:[4096,
2147483648].
<E> erofs: failed to read data of m_pa 4096, m_plen 2147483648 @ nid 40: -17
<E> erofs: Failed to extract filesystem
You can use this script to reproduce this issue.
mkdir tmp extract
dd if=/dev/urandom of=tmp/big_file bs=1M count=2048
mkfs.erofs erofs.image tmp
fsck.erofs erofs.image --extract=extract
I found that dev_open will failed if we can not get all data we want
with one pread call.
I write this little patch try to fix this issue.
Signed-off-by: Chen Linxuan <chenlinx...@uniontech.com>
---
lib/io.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/lib/io.c b/lib/io.c
index 524cfb4..ccd433f 100644
--- a/lib/io.c
+++ b/lib/io.c
@@ -256,7 +256,7 @@ int dev_resize(unsigned int blocks)
int dev_read(int device_id, void *buf, u64 offset, size_t len)
{
- int ret, fd;
+ int read_count, fd;
if (cfg.c_dry_run)
return 0;
@@ -278,15 +278,27 @@ int dev_read(int device_id, void *buf, u64 offset, size_t
len)
fd = erofs_blobfd[device_id - 1];
}
+ while (len > 0) {
#ifdef HAVE_PREAD64
- ret = pread64(fd, buf, len, (off64_t)offset);
+ read_count = pread64(fd, buf, len, (off64_t)offset);
#else
- ret = pread(fd, buf, len, (off_t)offset);
+ read_count = pread(fd, buf, len, (off_t)offset);
#endif
- if (ret != (int)len) {
- erofs_err("Failed to read data from device - %s:[%" PRIu64 ",
%zd].",
- erofs_devname, offset, len);
- return -errno;
+ if (read_count == -1 || read_count == 0) {
+ if (errno) {
+ erofs_err("Failed to read data from device -
%s:[%" PRIu64 ", %zd].",
+ erofs_devname, offset, len);
+ return -errno;
+ } else {
+ erofs_err("Reach EOF of device - %s:[%" PRIu64
", %zd].",
+ erofs_devname, offset, len);
+ return -EINVAL;
+ }
+ }
+
+ offset += read_count;
+ len -= read_count;
+ buf += read_count;
}
return 0;
}
--
2.37.3
