Merge tag 'afs-fixes-20201029' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull AFS fixes from David Howells:
- Fix copy_file_range() to an afs file now returning EINVAL if the
splice_write file op isn't supplied.
- Fix a deref-before-check in afs_unuse_cell().
- Fix a use-after-free in afs_xattr_get_acl().
- Fix afs to not try to clear PG_writeback when laundering a page.
- Fix afs to take a ref on a page that it sets PG_private on and to
drop that ref when clearing PG_private. This is done through recently
added helpers.
- Fix a page leak if write_begin() fails.
- Fix afs_write_begin() to not alter the dirty region info stored in
page->private, but rather do this in afs_write_end() instead when we
know what we actually changed.
- Fix afs_invalidatepage() to alter the dirty region info on a page
when partial page invalidation occurs so that we don't inadvertantly
include a span of zeros that will get written back if a page gets
laundered due to a remote 3rd-party induced invalidation.
We mustn't, however, reduce the dirty region if the page has been
seen to be mapped (ie. we got called through the page_mkwrite vector)
as the page might still be mapped and we might lose data if the file
is extended again.
- Fix the dirty region info to have a lower resolution if the size of
the page is too large for this to be encoded (e.g. powerpc32 with 64K
pages).
Note that this might not be the ideal way to handle this, since it
may allow some leakage of undirtied zero bytes to the server's copy
in the case of a 3rd-party conflict.
To aid the last two fixes, two additional changes:
- Wrap the manipulations of the dirty region info stored in
page->private into helper functions.
- Alter the encoding of the dirty region so that the region bounds can
be stored with one fewer bit, making a bit available for the
indication of mappedness.
* tag 'afs-fixes-20201029' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
afs: Fix dirty-region encoding on ppc32 with 64K pages
afs: Fix afs_invalidatepage to adjust the dirty region
afs: Alter dirty range encoding in page->private
afs: Wrap page->private manipulations in inline functions
afs: Fix where page->private is set during write
afs: Fix page leak on afs_write_begin() failure
afs: Fix to take ref on page when PG_private is set
afs: Fix afs_launder_page to not clear PG_writeback
afs: Fix a use after free in afs_xattr_get_acl()
afs: Fix tracing deref-before-check
afs: Fix copy_file_range()
