libext2fs: add ext2fs_{read,write}_inode2()

Add new library interface which allows the caller to control whether
the inode checksum should be checked on inode read, or set on inode
write.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 041e8dee3f534981a34f24f40dc22a0133f918a2..9e76ffaaa8738020177fbc16f4a46e1229479e85 100644 (file)
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -577,6 +577,16 @@ typedef struct ext2_icount *ext2_icount_t;
  */
 #define BMAP_RET_UNINIT        0x0001
 
+/*
+ * Flags for ext2fs_read_inode2
+ */
+#define READ_INODE_NOCSUM      0x0001
+
+/*
+ * Flags for ext2fs_write_inode2
+ */
+#define WRITE_INODE_NOCSUM     0x0001
+
 /*
  * Flags for imager.c functions
  */
@@ -1530,13 +1540,19 @@ extern int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
 extern errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
                                        struct ext2_inode * inode,
                                        int bufsize);
-extern errcode_t ext2fs_read_inode (ext2_filsys fs, ext2_ino_t ino,
+extern errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
                            struct ext2_inode * inode);
+extern errcode_t ext2fs_read_inode2(ext2_filsys fs, ext2_ino_t ino,
+                                   struct ext2_inode * inode,
+                                   int bufsize, int flags);
 extern errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
                                         struct ext2_inode * inode,
                                         int bufsize);
 extern errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
                            struct ext2_inode * inode);
+extern errcode_t ext2fs_write_inode2(ext2_filsys fs, ext2_ino_t ino,
+                                    struct ext2_inode * inode,
+                                    int bufsize, int flags);
 extern errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
                            struct ext2_inode * inode);
 extern errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks);

diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
index 015cfe4b54dc34178fa5d2118ec2c673d225987b..6d0938a4b10cdc1ab8d620e4db81d3417ed0d634 100644 (file)
--- a/lib/ext2fs/inode.c
+++ b/lib/ext2fs/inode.c
@@ -728,8 +728,9 @@ errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
 /*
  * Functions to read and write a single inode.
  */
-errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
-                                struct ext2_inode * inode, int bufsize)
+errcode_t ext2fs_read_inode2(ext2_filsys fs, ext2_ino_t ino,
+                            struct ext2_inode * inode, int bufsize,
+                            int flags)
 {
        blk64_t         block_nr;
        unsigned long   group, block, offset;
@@ -833,21 +834,29 @@ errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
        }
        memcpy(inode, iptr, (bufsize > length) ? length : bufsize);
 
-       if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) && fail_csum)
+       if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
+           !(flags & READ_INODE_NOCSUM) && fail_csum)
                return EXT2_ET_INODE_CSUM_INVALID;
 
        return 0;
 }
 
+errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
+                                struct ext2_inode * inode, int bufsize)
+{
+       return ext2fs_read_inode2(fs, ino, inode, bufsize, 0);
+}
+
 errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
                            struct ext2_inode * inode)
 {
-       return ext2fs_read_inode_full(fs, ino, inode,
-                                       sizeof(struct ext2_inode));
+       return ext2fs_read_inode2(fs, ino, inode,
+                                 sizeof(struct ext2_inode), 0);
 }
 
-errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
-                                 struct ext2_inode * inode, int bufsize)
+errcode_t ext2fs_write_inode2(ext2_filsys fs, ext2_ino_t ino,
+                             struct ext2_inode * inode, int bufsize,
+                             int flags)
 {
        blk64_t block_nr;
        unsigned long group, block, offset;
@@ -877,12 +886,9 @@ errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
 
        if (bufsize < length) {
                int old_flags = fs->flags;
-               fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
-               retval = ext2fs_read_inode_full(fs, ino,
-                                               (struct ext2_inode *)w_inode,
-                                               length);
-               fs->flags = (old_flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) |
-                           (fs->flags & ~EXT2_FLAG_IGNORE_CSUM_ERRORS);
+               retval = ext2fs_read_inode2(fs, ino,
+                                           (struct ext2_inode *)w_inode,
+                                           length, READ_INODE_NOCSUM);
                if (retval)
                        goto errout;
        }
@@ -912,9 +918,11 @@ errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
        ext2fs_swap_inode_full(fs, w_inode, w_inode, 1, length);
 #endif
 
-       retval = ext2fs_inode_csum_set(fs, ino, w_inode);
-       if (retval)
-               goto errout;
+       if ((flags & WRITE_INODE_NOCSUM) == 0) {
+               retval = ext2fs_inode_csum_set(fs, ino, w_inode);
+               if (retval)
+                       goto errout;
+       }
 
        group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
        offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
@@ -964,11 +972,17 @@ errout:
        return retval;
 }
 
+errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
+                                 struct ext2_inode * inode, int bufsize)
+{
+       return ext2fs_write_inode2(fs, ino, inode, bufsize, 0);
+}
+
 errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
                             struct ext2_inode *inode)
 {
-       return ext2fs_write_inode_full(fs, ino, inode,
-                                      sizeof(struct ext2_inode));
+       return ext2fs_write_inode2(fs, ino, inode,
+                                  sizeof(struct ext2_inode), 0);
 }
 
 /*