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-rw-r--r--arch/um/drivers/ubd_kern.c28
1 files changed, 15 insertions, 13 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 7696f8d2d89c..c171d0aa5e9d 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1103,31 +1103,33 @@ static int ubd_ioctl(struct inode * inode, struct file * file,
1103 return(-EINVAL); 1103 return(-EINVAL);
1104} 1104}
1105 1105
1106static int same_backing_files(char *from_cmdline, char *from_cow, char *cow) 1106static int path_requires_switch(char *from_cmdline, char *from_cow, char *cow)
1107{ 1107{
1108 struct uml_stat buf1, buf2; 1108 struct uml_stat buf1, buf2;
1109 int err; 1109 int err;
1110 1110
1111 if(from_cmdline == NULL) return(1); 1111 if(from_cmdline == NULL)
1112 if(!strcmp(from_cmdline, from_cow)) return(1); 1112 return 0;
1113 if(!strcmp(from_cmdline, from_cow))
1114 return 0;
1113 1115
1114 err = os_stat_file(from_cmdline, &buf1); 1116 err = os_stat_file(from_cmdline, &buf1);
1115 if(err < 0){ 1117 if(err < 0){
1116 printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err); 1118 printk("Couldn't stat '%s', err = %d\n", from_cmdline, -err);
1117 return(1); 1119 return 0;
1118 } 1120 }
1119 err = os_stat_file(from_cow, &buf2); 1121 err = os_stat_file(from_cow, &buf2);
1120 if(err < 0){ 1122 if(err < 0){
1121 printk("Couldn't stat '%s', err = %d\n", from_cow, -err); 1123 printk("Couldn't stat '%s', err = %d\n", from_cow, -err);
1122 return(1); 1124 return 1;
1123 } 1125 }
1124 if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino)) 1126 if((buf1.ust_dev == buf2.ust_dev) && (buf1.ust_ino == buf2.ust_ino))
1125 return(1); 1127 return 0;
1126 1128
1127 printk("Backing file mismatch - \"%s\" requested,\n" 1129 printk("Backing file mismatch - \"%s\" requested,\n"
1128 "\"%s\" specified in COW header of \"%s\"\n", 1130 "\"%s\" specified in COW header of \"%s\"\n",
1129 from_cmdline, from_cow, cow); 1131 from_cmdline, from_cow, cow);
1130 return(0); 1132 return 1;
1131} 1133}
1132 1134
1133static int backing_file_mismatch(char *file, __u64 size, time_t mtime) 1135static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
@@ -1189,7 +1191,7 @@ int open_ubd_file(char *file, struct openflags *openflags,
1189 unsigned long long size; 1191 unsigned long long size;
1190 __u32 version, align; 1192 __u32 version, align;
1191 char *backing_file; 1193 char *backing_file;
1192 int fd, err, sectorsize, same, mode = 0644; 1194 int fd, err, sectorsize, asked_switch, mode = 0644;
1193 1195
1194 fd = os_open_file(file, *openflags, mode); 1196 fd = os_open_file(file, *openflags, mode);
1195 if(fd < 0){ 1197 if(fd < 0){
@@ -1209,6 +1211,7 @@ int open_ubd_file(char *file, struct openflags *openflags,
1209 goto out_close; 1211 goto out_close;
1210 } 1212 }
1211 1213
1214 /* Succesful return case! */
1212 if(backing_file_out == NULL) return(fd); 1215 if(backing_file_out == NULL) return(fd);
1213 1216
1214 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime, 1217 err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
@@ -1220,17 +1223,16 @@ int open_ubd_file(char *file, struct openflags *openflags,
1220 } 1223 }
1221 if(err) return(fd); 1224 if(err) return(fd);
1222 1225
1223 if(backing_file_out == NULL) return(fd); 1226 asked_switch = path_requires_switch(*backing_file_out, backing_file, file);
1224
1225 same = same_backing_files(*backing_file_out, backing_file, file);
1226 1227
1227 if(!same && !backing_file_mismatch(*backing_file_out, size, mtime)){ 1228 /* Allow switching only if no mismatch. */
1229 if (asked_switch && !backing_file_mismatch(*backing_file_out, size, mtime)) {
1228 printk("Switching backing file to '%s'\n", *backing_file_out); 1230 printk("Switching backing file to '%s'\n", *backing_file_out);
1229 err = write_cow_header(file, fd, *backing_file_out, 1231 err = write_cow_header(file, fd, *backing_file_out,
1230 sectorsize, align, &size); 1232 sectorsize, align, &size);
1231 if(err){ 1233 if(err){
1232 printk("Switch failed, errno = %d\n", -err); 1234 printk("Switch failed, errno = %d\n", -err);
1233 return(err); 1235 goto out_close;
1234 } 1236 }
1235 } 1237 }
1236 else { 1238 else {