On Fri, Mar 29, 2024 at 01:44:51PM -0700, Darrick J. Wong wrote: > On Wed, Mar 27, 2024 at 09:53:38AM -0700, Christoph Hellwig wrote: > > > /* Write the symlink target into the inode. */ > > > int > > > -xfs_symlink_write_target( > > > +__xfs_symlink_write_target( > > > struct xfs_trans *tp, > > > struct xfs_inode *ip, > > > + xfs_ino_t owner, > > > > The xfs_symlink_write_target/__xfs_symlink_write_target split seems > > a bit pointless with just a single real caller for either variant. > > Why not just pass the owner to xfs_symlink_write_target and do away > > with __xfs_symlink_write_target? Oops, I forgot to respond to this -- yeah, I'll get rid of this trivial helper. --D > > > +/* > > > + * Symbolic Link Repair > > > + * ==================== > > > + * > > > + * We repair symbolic links by reading whatever target data we can find, up to > > > + * the first NULL byte. Zero length symlinks are turned into links to the > > > + * current directory. > > > > Are we actually doing that? xrep_setup_symlink sets up a link with > > the "." target (and could use a comment on why), but we're always > > writing the long dummy target below now, or am I missing something? > > If the target that we salvage has the same strlen as i_size, then we'll > rewrite what we found into the symlink. In all other cases, yes, we > write out the DUMMY_TARGET string. > > IOWs, the comment is out of date. Here's what I have now: > > /* > * Symbolic Link Repair > * ==================== > * > * We repair symbolic links by reading whatever target data we can find, up to > * the first NULL byte. If the recovered target strlen matches i_size, then > * we rewrite the target. In all other cases, we replace the target with an > * overly long string that cannot possibly resolve. The new target is written > * into a private hidden temporary file, and then a file contents exchange > * commits the new symlink target to the file being repaired. > */ > > > > +/* Set us up to repair the rtsummary file. */ > > > > I don't think that's what it does :) > > > > > + * We cannot use xfs_exchmaps_estimate because we have not yet > > > + * constructed the replacement rtsummary and therefore do not know how > > > + * many extents it will use. By the time we do, we will have a dirty > > > + * transaction (which we cannot drop because we cannot drop the > > > + * rtsummary ILOCK) and cannot ask for more reservation. > > > > No rtsummary here either.. > > Oops. Fixed both of those things. :( > > > > + > > > +#define DUMMY_TARGET \ > > > + "The target of this symbolic link could not be recovered at all and " \ > > > + "has been replaced with this explanatory message. To avoid " \ > > > + "accidentally pointing to an existing file path, this message is " \ > > > + "longer than the maximum supported file name length. That is an " \ > > > + "acceptable length for a symlink target on XFS but will produce " \ > > > + "File Name Too Long errors if resolved." > > > > Haha. Can this cause the repair to run into ENOSPC if the previous > > corrupted symlink was way shorter? > > Yes. In that case, xrep_symlink_rebuild will fail to write DUMMY_TARGET > into sc->tempip, we ifree the tempfile (with its '.' target), and return > the error to userspace. > > --D >
