[lustre-devel] [PATCH 01/15] lustre: sec: keep encryption context in xattr cache

[James Simmons <jsimmons@infradead.org>]

From: Sebastien Buisson <sbuisson@ddn.com>

When an inode is being cleared, its xattr cache must be completely
wiped. But in case of lock cancel, we want to keep the encryption
context, as further processing might need to check it.

Fixes: b5de088eb4 ("lustre: sec: access to enc file's xattrs")
WC-bug-id: https://jira.whamcloud.com/browse/LU-14989
Lustre-commit: 14b37c763c5751faf ("LU-14989 sec: keep encryption context in xattr cache")
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-on: https://review.whamcloud.com/45148
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
---
 fs/lustre/llite/llite_internal.h |  1 +
 fs/lustre/llite/namei.c          |  2 +-
 fs/lustre/llite/xattr_cache.c    | 36 +++++++++++++++++++++++++++++++++++-
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/fs/lustre/llite/llite_internal.h b/fs/lustre/llite/llite_internal.h
index bd49228..bed0443 100644
--- a/fs/lustre/llite/llite_internal.h
+++ b/fs/lustre/llite/llite_internal.h
@@ -416,6 +416,7 @@ static inline void ll_layout_version_set(struct ll_inode_info *lli, u32 gen)
 }
 
 int ll_xattr_cache_destroy(struct inode *inode);
+int ll_xattr_cache_empty(struct inode *inode);
 
 int ll_xattr_cache_get(struct inode *inode, const char *name,
 		       char *buffer, size_t size, u64 valid);
diff --git a/fs/lustre/llite/namei.c b/fs/lustre/llite/namei.c
index f942179..fe7fdbb 100644
--- a/fs/lustre/llite/namei.c
+++ b/fs/lustre/llite/namei.c
@@ -248,7 +248,7 @@ static void ll_lock_cancel_bits(struct ldlm_lock *lock, u64 to_cancel)
 	}
 
 	if (bits & MDS_INODELOCK_XATTR) {
-		ll_xattr_cache_destroy(inode);
+		ll_xattr_cache_empty(inode);
 		bits &= ~MDS_INODELOCK_XATTR;
 	}
 
diff --git a/fs/lustre/llite/xattr_cache.c b/fs/lustre/llite/xattr_cache.c
index 0641f73..b044c89 100644
--- a/fs/lustre/llite/xattr_cache.c
+++ b/fs/lustre/llite/xattr_cache.c
@@ -272,6 +272,40 @@ int ll_xattr_cache_destroy(struct inode *inode)
 }
 
 /**
+ * ll_xattr_cache_empty - empty xattr cache for @ino
+ *
+ * Similar to ll_xattr_cache_destroy(), but preserves encryption context.
+ * So only LLIF_XATTR_CACHE_FILLED flag is cleared, but not LLIF_XATTR_CACHE.
+ */
+int ll_xattr_cache_empty(struct inode *inode)
+{
+	struct ll_inode_info *lli = ll_i2info(inode);
+	struct ll_xattr_entry *entry, *n;
+
+	down_write(&lli->lli_xattrs_list_rwsem);
+	if (!ll_xattr_cache_valid(lli) ||
+	    !ll_xattr_cache_filled(lli))
+		goto out_empty;
+
+	list_for_each_entry_safe(entry, n, &lli->lli_xattrs, xe_list) {
+		if (strcmp(entry->xe_name,
+			   LL_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
+			continue;
+
+		CDEBUG(D_CACHE, "delete: %s\n", entry->xe_name);
+		list_del(&entry->xe_list);
+		kfree(entry->xe_name);
+		kfree(entry->xe_value);
+		kmem_cache_free(xattr_kmem, entry);
+	}
+	clear_bit(LLIF_XATTR_CACHE_FILLED, &lli->lli_flags);
+
+out_empty:
+	up_write(&lli->lli_xattrs_list_rwsem);
+	return 0;
+}
+
+/**
  * Match or enqueue a PR lock.
  *
  * Find or request an LDLM lock with xattr data.
@@ -495,7 +529,7 @@ int ll_xattr_cache_get(struct inode *inode, const char *name, char *buffer,
 	 */
 	if ((valid & OBD_MD_FLXATTRLS ||
 	     strcmp(name, LL_XATTR_NAME_ENCRYPTION_CONTEXT) != 0) &&
-	    !ll_xattr_cache_valid(lli)) {
+	    !ll_xattr_cache_filled(lli)) {
 		up_read(&lli->lli_xattrs_list_rwsem);
 		rc = ll_xattr_cache_refill(inode);
 		if (rc)
-- 
1.8.3.1

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