Previously, io path option changes on a file would be picked up
automatically and applied to existing data - but not for reflinked data,
as we had no way of doing this safely. A user may have had permission to
copy (and reflink) a given file, but not write to it, and if so they
shouldn't be allowed to change e.g. nr_replicas or other options.
This uses the incompat feature mechanism in the previous patch to add a
new incompatible flag to bch_reflink_p, indicating whether a given
reflink pointer may propagate io path option changes back to the
indirect extent.
In this initial patch we're only setting it for the source extents.
We'd like to set it for the destination in a reflink copy, when the user
has write access to the source, but that requires mnt_idmap which is not
curretly plumbed up to remap_file_range.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
To avoid tragic loss in the event of transient errors (i.e., a btree
node topology error that was later corrected by btree node scan), we
can't delete reflink pointers to correct errors.
This adds a new error bit to bch_reflink_p, indicating that it is known
to point to a missing indirect extent, and the error has already been
reported.
Indirect extent lookups now use bch2_lookup_indirect_extent(), which on
error reports it as a fsck_err() and sets the error bit, and clears it
if necessary on succesful lookup.
This also gets rid of the bch2_inconsistent_error() call in
__bch2_read_indirect_extent, and in the reflink_p trigger: part of the
online self healing project.
An on disk format change isn't necessary here: setting the error bit
will be interpreted by older versions as pointing to a different index,
which will also be missing - which is fine.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Better repair for reflink pointers, as well as propagating new inode
options to indirect extents, are going to require a few extra bits
bch_reflink_p: so claim a few from the high end of the destination
index.
Also add some missing bounds checking.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
