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(libext2fs.info)Opening an ext2 filesystem

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Opening an ext2 filesystem
--------------------------

   Most libext2fs functions take a filesystem handle of type
`ext2_filsys'.  A filesystem handle is created either by opening an
existing function using `ext2fs_open', or by initializing a new
filesystem using `ext2fs_initialize'.

 - Function: errcode_t ext2fs_open (const char *NAME, int FLAGS, int
          SUPERBLOCK, int BLOCK_SIZE, io_manager MANAGER, ext2_filsys
          *RET_FS)
     Opens a filesystem named NAME, using the the io_manager MANAGER to
     define the input/output routines needed to read and write the
     filesystem.  In the case of the `unix_io' io_manager, NAME is
     interpreted as the Unix filename of the filesystem image.  This is
     often a device file, such as `/dev/hda1'.

     The SUPERBLOCK parameter specifies the block number of the
     superblock which should be used when opening the filesystem.  If
     SUPERBLOCK is zero, `ext2fs_open' will use the primary superblock
     located at offset 1024 bytes from the start of the filesystem
     image.

     The BLOCK_SIZE parameter specifies the block size used by the
     filesystem.  Normally this is determined automatically from the
     filesystem uperblock.  If BLOCK_SIZE is non-zero, it must match
     the block size found in the superblock, or the error
     `EXT2_ET_UNEXPECTED_BLOCK_SIZE' will be returned.  The BLOCK_SIZE
     parameter is also used to help fund the superblock when SUPERBLOCK
     is non-zero.

     The FLAGS argument contains a bitmask of flags which control how
     the filesystem open should be handled.

    `EXT2_FLAG_RW'
          Open the filesystem for reading and writing.  Without this
          flag, the filesystem is opened for reading only.

    `EXT2_FLAG_FORCE'
          Open the filesystem regardless of the feature sets listed in
          the superblock.