On Aug 30, 2017, at 9:13 AM, Theodore Ts'o <tytso@xxxxxxx> wrote: > > On Wed, Aug 30, 2017 at 01:43:30AM -0600, Andreas Dilger wrote: >> On a related note, I was trying to implement the optimization for >> more efficient ext2fs_link() insertion, but this has proven to be >> much more complex than I expected. I was thinking I would just >> call the link_proc() function directly to handle insertion of the >> new name, using block number of the previous caller. However, this >> function depends on the directory leaf buffers having been read >> from disk, and being passed a dirent pointer to the free space after >> being called through a series of callback indirections. > > I think it's more trouble than it's worth to preseve the existing > link_proc() function. I'd recommend out to be just what is necessary > to do the directory entry insert, and make that a helper function > which is called by link_proc() and the shortcut handling code in > ext2fs_link(). I looked at implementing it this way, but unfortunately that doesn't appear workable since ext2fs_link() never gets the block numbers to be able to do this. I'd essentially have to reimplement all of the block and directory leaf processing in ext2fs_dir_iterate2() to get figure out where to store the first entries in the directory. What I'm looking at now is add a new ext2fs_dir_iterate3() function that passes *blocknr and blockcnt to the link_proc() and unlink_proc() callback functions so they can be stored in struct_ext2_filsys, and used to shortcut the iteration in ext2fs_link() for multiple inserts. It is added to unlink_proc() so that we can reset the saved state if entries are being deleted. Cheers, Andreas
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