On Fri, Dec 15, 2023 at 04:16:00PM -0500, Gabriel Krisman Bertazi wrote: > [Apologies for the quick spin of a v2. The only difference are a couple > fixes to the build when CONFIG_UNICODE=n caught by LKP and detailed in > each patch changelog.] > > When case-insensitive and fscrypt were adapted to work together, we moved the > code that sets the dentry operations for case-insensitive dentries(d_hash and > d_compare) to happen from a helper inside ->lookup. This is because fscrypt > wants to set d_revalidate only on some dentries, so it does it only for them in > d_revalidate. > > But, case-insensitive hooks are actually set on all dentries in the filesystem, > so the natural place to do it is through s_d_op and let d_alloc handle it [1]. > In addition, doing it inside the ->lookup is a problem for case-insensitive > dentries that are not created through ->lookup, like those coming > open-by-fhandle[2], which will not see the required d_ops. > > This patchset therefore reverts to using sb->s_d_op to set the dentry operations > for case-insensitive filesystems. In order to set case-insensitive hooks early > and not require every dentry to have d_revalidate in case-insensitive > filesystems, it introduces a patch suggested by Al Viro to disable d_revalidate > on some dentries on the fly. > > It survives fstests encrypt and quick groups without regressions. Based on > v6.7-rc1. > > [1] https://lore.kernel.org/linux-fsdevel/20231123195327.GP38156@ZenIV/ > [2] https://lore.kernel.org/linux-fsdevel/20231123171255.GN38156@ZenIV/ > > Gabriel Krisman Bertazi (8): > dcache: Add helper to disable d_revalidate for a specific dentry > fscrypt: Drop d_revalidate if key is available > libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops > libfs: Expose generic_ci_dentry_ops outside of libfs > ext4: Set the case-insensitive dentry operations through ->s_d_op > f2fs: Set the case-insensitive dentry operations through ->s_d_op > libfs: Don't support setting casefold operations during lookup > fscrypt: Move d_revalidate configuration back into fscrypt Thanks Gabriel, this series looks good. Sorry that we missed this when adding the support for encrypt+casefold. It's slightly awkward that some lines of code added by patches 5-6 are removed in patch 8. These changes look very hard to split up, though, so you've probably done about the best that can be done. One question/request: besides performance, the other reason we're so careful about minimizing when ->d_revalidate is set for fscrypt is so that overlayfs works on encrypted directories. This is because overlayfs is not compatible with ->d_revalidate. I think your solution still works for that, since DCACHE_OP_REVALIDATE will be cleared after the first call to fscrypt_d_revalidate(), and when checking for usupported dentries overlayfs does indeed check for DCACHE_OP_REVALIDATE instead of ->d_revalidate directly. However, that does rely on that very first call to ->d_revalidate actually happening before the check is done. It would be nice to verify that overlayfs+fscrypt indeed continues to work, and explicitly mention this somewhere (I don't see any mention of overlayfs+fscrypt in the series). - Eric
