1 files changed, 74 insertions, 73 deletions

diff --git a/extlinux/main.c b/extlinux/main.c
index 6ba16e1e..a7ebd49a 100644
--- a/extlinux/main.c
+++ b/extlinux/main.c
@@ -14,7 +14,7 @@
 /*
  * extlinux.c
  *
- * Install the syslinux boot block on an fat, ntfs, ext2/3/4, btrfs, xfs,
+ * Install the syslinux boot block on a fat, ntfs, ext2/3/4, btrfs, xfs,
  * and ufs1/2 filesystem.
  */
 
@@ -56,6 +56,7 @@
 #include "version.h"
 #include "syslxint.h"
 #include "syslxcom.h" /* common functions shared with extlinux and syslinux */
+#include "syslxrw.h"
 #include "syslxfs.h"
 #include "setadv.h"
 #include "syslxopt.h" /* unified options */
@@ -337,6 +338,59 @@ static int patch_file_and_bootblock(int fd, const char *dir, int devfd)
     return rv;
 }
 
+static int ext_read_adv_offset(int devfd, off_t offset)
+{
+    const size_t adv_size = 2 * ADV_SIZE;
+
+    if (xpread(devfd, syslinux_adv, adv_size, offset) != adv_size)
+      return -1;
+
+    return syslinux_validate_adv(syslinux_adv) ? 1 : 0;
+}
+
+static int ext_read_adv(const char *path, int devfd, const char **namep)
+{
+    int err;
+    const char *name;
+
+    if (fs_type == BTRFS) {
+	/* btrfs "ldlinux.sys" is in 64k blank area */
+	return ext_read_adv_offset(devfd, BTRFS_ADV_OFFSET);
+    } else if (fs_type == XFS) {
+	/* XFS "ldlinux.sys" is in the first 2048 bytes of the primary AG */
+	return ext_read_adv_offset(devfd, boot_image_len);
+    } else {
+	err = read_adv(path, name = "ldlinux.sys");
+	if (err == 2)		/* ldlinux.sys does not exist */
+	    err = read_adv(path, name = "extlinux.sys");
+	if (namep)
+	    *namep = name;
+	return err;
+    }
+}
+
+static int ext_write_adv_offset(int devfd, off_t offset)
+{
+    const size_t adv_size = 2 * ADV_SIZE;
+
+    if (xpwrite(devfd, syslinux_adv, adv_size, offset) != adv_size) {
+	perror("writing adv");
+	return 1;
+    }
+
+    return 0;
+}
+
+static int ext_write_adv(const char *path, const char *cfg, int devfd)
+{
+    if (fs_type == BTRFS) {
+	/* btrfs "ldlinux.sys" is in 64k blank area */
+	return ext_write_adv_offset(devfd, BTRFS_ADV_OFFSET);
+    } else {
+	return write_adv(path, cfg);
+    }
+}
+
 /*
  * Install the boot block on the specified device.
  * Must be run AFTER install_file()!
@@ -392,11 +446,11 @@ int install_bootblock(int fd, const char *device)
 	if (sb5.sb_magicnum == *(u32 *)XFS_SB_MAGIC) {
 	    if (be32_to_cpu(sb5.sb_blocksize) != XFS_SUPPORTED_BLOCKSIZE) {
 		fprintf(stderr,
-			"You need to have 4 KiB filesystem block size for "
-			" being able to install Syslinux in your XFS "
-			"partition (because there is no enough space in MBR to "
-			"determine where Syslinux bootsector can be installed "
-			"regardless the filesystem block size)\n");
+			"You need to have 4 KiB filesystem block size for"
+			" being able to install Syslinux in your XFS"
+			" partition (because there is not enough space in MBR to"
+			" determine where Syslinux bootsector can be installed"
+			" regardless of the filesystem block size)\n");
 		return 1;
 	    }
 
@@ -419,8 +473,8 @@ int install_bootblock(int fd, const char *device)
 
     if (!ok) {
 	fprintf(stderr,
-		"no fat, ntfs, ext2/3/4, btrfs, xfs "
-		"or ufs1/2 superblock found on %s\n",
+		"no fat, ntfs, ext2/3/4, btrfs, xfs"
+		" or ufs1/2 superblock found on %s\n",
 		device);
 	return 1;
     }
@@ -483,8 +537,7 @@ static int rewrite_boot_image(int devfd, const char *path, const char *filename)
     }
 
     /* Write ADV */
-    ret = xpwrite(fd, syslinux_adv, 2 * ADV_SIZE, boot_image_len);
-    if (ret != 2 * ADV_SIZE) {
+    if (ext_write_adv_offset(fd, boot_image_len)) {
 	fprintf(stderr, "%s: write failure on %s\n", program, filename);
 	goto error;
     }
@@ -597,9 +650,12 @@ bail:
     return 1;
 }
 
-/* btrfs has to install the ldlinux.sys in the first 64K blank area, which
-   is not managered by btrfs tree, so actually this is not installed as files.
-   since the cow feature of btrfs will move the ldlinux.sys every where */
+/* btrfs has to install ldlinux.sys to a boot area, which is not managed by
+   btrfs tree, so actually this is not installed as a file, since the cow
+   feature of btrfs would move the ldlinux.sys file everywhere. Older
+   versions installed it to the first 64kiB (aka Boot Area A) but as of
+   commit ID 37eef640 (before 6.03-pre12, before 6.03), it is now in Boot
+   Area B (a 768kiB blank space at offset 256kiB). */
 int btrfs_install_file(const char *path, int devfd, struct stat *rst)
 {
     char *file;
@@ -613,9 +669,7 @@ int btrfs_install_file(const char *path, int devfd, struct stat *rst)
 	return 1;
     }
     dprintf("write boot_image to 0x%x\n", BTRFS_EXTLINUX_OFFSET);
-    if (xpwrite(devfd, syslinux_adv, 2 * ADV_SIZE, BTRFS_ADV_OFFSET)
-	!= 2 * ADV_SIZE) {
-	perror("writing adv");
+    if (ext_write_adv_offset(devfd, BTRFS_ADV_OFFSET)) {
 	return 1;
     }
     dprintf("write adv to 0x%x\n", BTRFS_ADV_OFFSET);
@@ -661,7 +715,7 @@ int btrfs_install_file(const char *path, int devfd, struct stat *rst)
  * Due to historical reasons (SGI IRIX's design of disk layouts), the first
  * sector in the primary AG on XFS filesystems contains the superblock, which is
  * a problem with bootloaders that rely on BIOSes (that load VBRs which are
- * (located in the first sector of the partition).
+ * located in the first sector of the partition).
  *
  * Thus, we need to handle this issue, otherwise Syslinux will damage the XFS's
  * superblock.
@@ -750,7 +804,7 @@ bail:
  *  * test if path is a subvolume:
  *   * this function return
  *    * 0-> path exists but it is not a subvolume
- *     * 1-> path exists and it is  a subvolume
+ *     * 1-> path exists and it is a subvolume
  *      * -1 -> path is unaccessible
  *       */
 static int test_issubvolume(char *path)
@@ -1384,8 +1438,8 @@ static int open_device(const char *path, struct stat *st, char **_devname)
 
     if (!fs_type) {
 	fprintf(stderr,
-		"%s: not a fat, ntfs, ext2/3/4, btrfs, xfs or"
-		"ufs1/2 filesystem: %s\n",
+		"%s: not a fat, ntfs, ext2/3/4, btrfs, xfs"
+		" or ufs1/2 filesystem: %s\n",
 		program, path);
 	return -1;
     }
@@ -1414,59 +1468,6 @@ static int open_device(const char *path, struct stat *st, char **_devname)
     return devfd;
 }
 
-static int btrfs_read_adv(int devfd)
-{
-    if (xpread(devfd, syslinux_adv, 2 * ADV_SIZE, BTRFS_ADV_OFFSET)
-	!= 2 * ADV_SIZE)
-	return -1;
-
-    return syslinux_validate_adv(syslinux_adv) ? 1 : 0;
-}
-
-static inline int xfs_read_adv(int devfd)
-{
-    const size_t adv_size = 2 * ADV_SIZE;
-
-    if (xpread(devfd, syslinux_adv, adv_size, boot_image_len) != adv_size)
-	return -1;
-
-    return syslinux_validate_adv(syslinux_adv) ? 1 : 0;
-}
-
-static int ext_read_adv(const char *path, int devfd, const char **namep)
-{
-    int err;
-    const char *name;
-
-    if (fs_type == BTRFS) {
-	/* btrfs "ldlinux.sys" is in 64k blank area */
-	return btrfs_read_adv(devfd);
-    } else if (fs_type == XFS) {
-	/* XFS "ldlinux.sys" is in the first 2048 bytes of the primary AG */
-	return xfs_read_adv(devfd);
-    } else {
-	err = read_adv(path, name = "ldlinux.sys");
-	if (err == 2)		/* ldlinux.sys does not exist */
-	    err = read_adv(path, name = "extlinux.sys");
-	if (namep)
-	    *namep = name;
-	return err;
-    }
-}
-
-static int ext_write_adv(const char *path, const char *cfg, int devfd)
-{
-    if (fs_type == BTRFS) { /* btrfs "ldlinux.sys" is in 64k blank area */
-	if (xpwrite(devfd, syslinux_adv, 2 * ADV_SIZE,
-		BTRFS_ADV_OFFSET) != 2 * ADV_SIZE) {
-		perror("writing adv");
-		return 1;
-	}
-	return 0;
-    }
-    return write_adv(path, cfg);
-}
-
 static int install_loader(const char *path, int update_only)
 {
     struct stat st, fst;