diff options
| author | Max Reitz <mreitz@redhat.com> | 2018-02-28 14:13:14 +0100 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2018-04-03 17:39:37 +0200 |
| commit | 82b45e0a0b824787bd79ce3f6453eaa2afddd138 (patch) | |
| tree | c4ee6e328b99659949226314bbf6cdbbee1ed361 | |
| parent | 627f607e3dddb23cef69374c8bfb09a33d19926a (diff) | |
block/file-posix: Fix fully preallocated truncate
Storing the lseek() result in an int results in it overflowing when the
file is at least 2 GB big. Then, we have a 50 % chance of the result
being "negative" and thus thinking an error occurred when actually
everything went just fine.
So we should use the correct type for storing the result: off_t.
Reported-by: Daniel P. Berrange <berrange@redhat.com>
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1549231
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180228131315.30194-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
| -rw-r--r-- | block/file-posix.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/block/file-posix.c b/block/file-posix.c index a2f6d8a8c8..3794c0007a 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1701,6 +1701,7 @@ static int raw_regular_truncate(int fd, int64_t offset, PreallocMode prealloc, case PREALLOC_MODE_FULL: { int64_t num = 0, left = offset - current_length; + off_t seek_result; /* * Knowing the final size from the beginning could allow the file @@ -1715,8 +1716,8 @@ static int raw_regular_truncate(int fd, int64_t offset, PreallocMode prealloc, buf = g_malloc0(65536); - result = lseek(fd, current_length, SEEK_SET); - if (result < 0) { + seek_result = lseek(fd, current_length, SEEK_SET); + if (seek_result < 0) { result = -errno; error_setg_errno(errp, -result, "Failed to seek to the old end of file"); |