5 files changed, 41 insertions, 27 deletions

diff --git a/arch/um/drivers/cow.h b/arch/um/drivers/cow.h
index dc36b222100b..04e3958266e0 100644
--- a/arch/um/drivers/cow.h
+++ b/arch/um/drivers/cow.h
@@ -46,7 +46,7 @@ extern int file_reader(__u64 offset, char *buf, int len, void *arg);
 extern int read_cow_header(int (*reader)(__u64, char *, int, void *),
                            void *arg, __u32 *version_out,
                            char **backing_file_out, time_t *mtime_out,
-                           unsigned long long *size_out, int *sectorsize_out,
+                           __u64 *size_out, int *sectorsize_out,
                            __u32 *align_out, int *bitmap_offset_out);
 
 extern int write_cow_header(char *cow_file, int fd, char *backing_file,
diff --git a/arch/um/drivers/cow_sys.h b/arch/um/drivers/cow_sys.h
index c83fc5d68936..94de4ead4f7a 100644
--- a/arch/um/drivers/cow_sys.h
+++ b/arch/um/drivers/cow_sys.h
@@ -23,17 +23,17 @@ static inline char *cow_strdup(char *str)
         return(uml_strdup(str));
 }
 
-static inline int cow_seek_file(int fd, unsigned long long offset)
+static inline int cow_seek_file(int fd, __u64 offset)
 {
         return(os_seek_file(fd, offset));
 }
 
-static inline int cow_file_size(char *file, unsigned long long *size_out)
+static inline int cow_file_size(char *file, __u64 *size_out)
 {
         return(os_file_size(file, size_out));
 }
 
-static inline int cow_write_file(int fd, char *buf, int size)
+static inline int cow_write_file(int fd, void *buf, int size)
 {
         return(os_write_file(fd, buf, size));
 }
diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c
index fbe2217db5dd..61951b721268 100644
--- a/arch/um/drivers/cow_user.c
+++ b/arch/um/drivers/cow_user.c
@@ -176,7 +176,7 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
         err = -ENOMEM;
         header = cow_malloc(sizeof(*header));
         if(header == NULL){
-                cow_printf("Failed to allocate COW V3 header\n");
+                cow_printf("write_cow_header - failed to allocate COW V3 header\n");
                 goto out;
         }
         header->magic = htonl(COW_MAGIC);
@@ -196,15 +196,17 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
 
         err = os_file_modtime(header->backing_file, &modtime);
         if(err < 0){
-                cow_printf("Backing file '%s' mtime request failed, "
-                           "err = %d\n", header->backing_file, -err);
+                cow_printf("write_cow_header - backing file '%s' mtime "
+                           "request failed, err = %d\n", header->backing_file,
+                           -err);
                 goto out_free;
         }
 
         err = cow_file_size(header->backing_file, size);
         if(err < 0){
-                cow_printf("Couldn't get size of backing file '%s', "
-                           "err = %d\n", header->backing_file, -err);
+                cow_printf("write_cow_header - couldn't get size of "
+                           "backing file '%s', err = %d\n",
+                           header->backing_file, -err);
                 goto out_free;
         }
 
@@ -214,10 +216,11 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
         header->alignment = htonl(alignment);
         header->cow_format = COW_BITMAP;
 
-        err = os_write_file(fd, header, sizeof(*header));
+        err = cow_write_file(fd, header, sizeof(*header));
         if(err != sizeof(*header)){
-                cow_printf("Write of header to new COW file '%s' failed, "
-                           "err = %d\n", cow_file, -err);
+                cow_printf("write_cow_header - write of header to "
+                           "new COW file '%s' failed, err = %d\n", cow_file,
+                           -err);
                 goto out_free;
         }
         err = 0;
@@ -299,7 +302,7 @@ int read_cow_header(int (*reader)(__u64, char *, int, void *), void *arg,
         }
         else if(version == 3){
                 if(n < sizeof(header->v3)){
-                        cow_printf("read_cow_header - failed to read V2 "
+                        cow_printf("read_cow_header - failed to read V3 "
                                    "header\n");
                         goto out;
                 }
@@ -359,7 +362,8 @@ int init_cow_file(int fd, char *cow_file, char *backing_file, int sectorsize,
         if(err != sizeof(zero)){
                 cow_printf("Write of bitmap to new COW file '%s' failed, "
                            "err = %d\n", cow_file, -err);
-                err = -EINVAL;
+                if (err >= 0)
+                        err = -EINVAL;
                 goto out;
         }
 
diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c
index 098fa65981ab..0e2f06187ea7 100644
--- a/arch/um/drivers/net_user.c
+++ b/arch/um/drivers/net_user.c
@@ -47,10 +47,12 @@ void tap_check_ips(char *gate_addr, unsigned char *eth_addr)
         }
 }
 
+/* Do reliable error handling as this fails frequently enough. */
 void read_output(int fd, char *output, int len)
 {
-        int remain, n, actual;
+        int remain, ret, expected;
         char c;
+        char *str;
 
         if(output == NULL){
                 output = &c;
@@ -58,23 +60,31 @@ void read_output(int fd, char *output, int len)
         }
                 
         *output = '\0';
-        n = os_read_file(fd, &remain, sizeof(remain));
-        if(n != sizeof(remain)){
-                printk("read_output - read of length failed, err = %d\n", -n);
-                return;
+        ret = os_read_file(fd, &remain, sizeof(remain));
+
+        if (ret != sizeof(remain)) {
+                expected = sizeof(remain);
+                str = "length";
+                goto err;
         }
 
         while(remain != 0){
-                n = (remain < len) ? remain : len;
-                actual = os_read_file(fd, output, n);
-                if(actual != n){
-                        printk("read_output - read of data failed, "
-                               "err = %d\n", -actual);
-                        return;
+                expected = (remain < len) ? remain : len;
+                ret = os_read_file(fd, output, expected);
+                if (ret != expected) {
+                        str = "data";
+                        goto err;
                 }
-                remain -= actual;
+                remain -= ret;
         }
+
         return;
+
+err:
+        if (ret < 0)
+                printk("read_output - read of %s failed, errno = %d\n", str, -ret);
+        else
+                printk("read_output - read of %s failed, read only %d of %d bytes\n", str, ret, expected);
 }
 
 int net_read(int fd, void *buf, int len)
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 101efd26d467..fa617e0719ab 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1135,7 +1135,7 @@ static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
 static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
 {
         unsigned long modtime;
-        long long actual;
+        unsigned long long actual;
         int err;
 
         err = os_file_modtime(file, &modtime);