xfs_io: fix pwrite/pread length truncation on 32-bit systems

The pwrite and pread commands in xfs_io accept an operation length that
can be any quantity that fits in a long long int; and loops to handle
the cases where the operation length is larger than the IO buffer.

Weirdly, the do_ functions contain code to shorten the operation to the
IO buffer size but the @count parameter is size_t, which means that for
a large argument on a 32-bit system, we rip off the upper bits of the
length, turning your 8GB write into a 0 byte write, which does nothing.

This was found by running generic/175 and observing that the 8G test
file it creates has zero length after the operation:

wrote 0/8589934592 bytes at offset 0
0.000000 bytes, 0 ops; 0.0001 sec (0.000000 bytes/sec and 0.0000 ops/sec)

Fix this by pushing long long count all the way through the call stack.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/io/pread.c b/io/pread.c
index 1b4352be1978598e23e90d17177e130de59585eb..d52e21d965f0803e506c5b6742c5e09f91c13230 100644 (file)
--- a/io/pread.c
+++ b/io/pread.c
@@ -164,7 +164,7 @@ static ssize_t
 do_preadv(
        int             fd,
        off64_t         offset,
-       size_t          count)
+       long long       count)
 {
        int             vecs = 0;
        ssize_t         oldlen = 0;
@@ -199,7 +199,7 @@ static ssize_t
 do_pread(
        int             fd,
        off64_t         offset,
-       size_t          count,
+       long long       count,
        size_t          buffer_size)
 {
        if (!vectors)

diff --git a/io/pwrite.c b/io/pwrite.c
index ccf14be928c8e706c52d39ca49c5a73296dcd40f..1c28612f3bd6a2849e2b3fae9663e8e23290eece 100644 (file)
--- a/io/pwrite.c
+++ b/io/pwrite.c
@@ -54,8 +54,8 @@ static ssize_t
 do_pwritev(
        int             fd,
        off64_t         offset,
-       size_t          count,
-       int             pwritev2_flags)
+       long long       count,
+       int             pwritev2_flags)
 {
        int vecs = 0;
        ssize_t oldlen = 0;
@@ -97,7 +97,7 @@ static ssize_t
 do_pwrite(
        int             fd,
        off64_t         offset,
-       size_t          count,
+       long long       count,
        size_t          buffer_size,
        int             pwritev2_flags)
 {