Remove zpl_revalidate: fix snapshot rollback

Open files, which aren't present in the snapshot, which is being
roll-backed to, need to disappear from the visible VFS image of
the dataset.

Kernel provides d_drop function to drop invalid entry from
the dcache, but inode can be referenced by dentry multiple dentries.

The introduced zpl_d_drop_aliases function walks and invalidates
all aliases of an inode.

Reviewed-by: Ryan Moeller <[email protected]>
Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Pavel Snajdr <[email protected]>
Closes #9600
Closes #14070

4 files changed, 26 insertions, 8 deletions

diff --git a/include/os/linux/kernel/linux/dcache_compat.h b/include/os/linux/kernel/linux/dcache_compat.h
index 0fbd92458..4de1118da 100644
--- a/include/os/linux/kernel/linux/dcache_compat.h
+++ b/include/os/linux/kernel/linux/dcache_compat.h
@@ -61,4 +61,25 @@ d_clear_d_op(struct dentry *dentry)
 	    DCACHE_OP_REVALIDATE | DCACHE_OP_DELETE);
 }
 
+/*
+ * Walk and invalidate all dentry aliases of an inode
+ * unless it's a mountpoint
+ */
+static inline void
+zpl_d_drop_aliases(struct inode *inode)
+{
+	struct dentry *dentry;
+	spin_lock(&inode->i_lock);
+#ifdef HAVE_DENTRY_D_U_ALIASES
+	hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
+#else
+	hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+#endif
+		if (!IS_ROOT(dentry) && !d_mountpoint(dentry) &&
+		    (dentry->d_inode == inode)) {
+			d_drop(dentry);
+		}
+	}
+	spin_unlock(&inode->i_lock);
+}
 #endif /* _ZFS_DCACHE_H */
diff --git a/include/os/linux/zfs/sys/trace_acl.h b/include/os/linux/zfs/sys/trace_acl.h
index 6a73545fe..2c7343222 100644
--- a/include/os/linux/zfs/sys/trace_acl.h
+++ b/include/os/linux/zfs/sys/trace_acl.h
@@ -64,7 +64,6 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
 	    __field(boolean_t,		z_is_sa)
 	    __field(boolean_t,		z_is_mapped)
 	    __field(boolean_t,		z_is_ctldir)
-	    __field(boolean_t,		z_is_stale)
 
 	    __field(uint32_t,		i_uid)
 	    __field(uint32_t,		i_gid)
@@ -99,7 +98,6 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
 	    __entry->z_is_sa		= zn->z_is_sa;
 	    __entry->z_is_mapped	= zn->z_is_mapped;
 	    __entry->z_is_ctldir	= zn->z_is_ctldir;
-	    __entry->z_is_stale		= zn->z_is_stale;
 
 	    __entry->i_uid		= KUID_TO_SUID(ZTOI(zn)->i_uid);
 	    __entry->i_gid		= KGID_TO_SGID(ZTOI(zn)->i_gid);
@@ -121,9 +119,8 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
 	    "zn_prefetch %u blksz %u seq %u "
 	    "mapcnt %llu size %llu pflags %llu "
 	    "sync_cnt %u sync_writes_cnt %u async_writes_cnt %u "
-	    "mode 0x%x is_sa %d is_mapped %d "
-	    "is_ctldir %d is_stale %d inode { "
-	    "uid %u gid %u ino %lu nlink %u size %lli "
+	    "mode 0x%x is_sa %d is_mapped %d is_ctldir %d "
+	    "inode { uid %u gid %u ino %lu nlink %u size %lli "
 	    "blkbits %u bytes %u mode 0x%x generation %x } } "
 	    "ace { type %u flags %u access_mask %u } mask_matched %u",
 	    __entry->z_id, __entry->z_unlinked, __entry->z_atime_dirty,
@@ -132,7 +129,7 @@ DECLARE_EVENT_CLASS(zfs_ace_class,
 	    __entry->z_pflags, __entry->z_sync_cnt,
 	    __entry->z_sync_writes_cnt, __entry->z_async_writes_cnt,
 	    __entry->z_mode, __entry->z_is_sa, __entry->z_is_mapped,
-	    __entry->z_is_ctldir, __entry->z_is_stale, __entry->i_uid,
+	    __entry->z_is_ctldir, __entry->i_uid,
 	    __entry->i_gid, __entry->i_ino, __entry->i_nlink,
 	    __entry->i_size, __entry->i_blkbits,
 	    __entry->i_bytes, __entry->i_mode, __entry->i_generation,
diff --git a/include/os/linux/zfs/sys/zpl.h b/include/os/linux/zfs/sys/zpl.h
index 30d73db6b..83416d647 100644
--- a/include/os/linux/zfs/sys/zpl.h
+++ b/include/os/linux/zfs/sys/zpl.h
@@ -45,7 +45,8 @@ extern const struct inode_operations zpl_inode_operations;
 extern const struct inode_operations zpl_dir_inode_operations;
 extern const struct inode_operations zpl_symlink_inode_operations;
 extern const struct inode_operations zpl_special_inode_operations;
-extern dentry_operations_t zpl_dentry_operations;
+
+/* zpl_file.c */
 extern const struct address_space_operations zpl_address_space_operations;
 extern const struct file_operations zpl_file_operations;
 extern const struct file_operations zpl_dir_file_operations;
diff --git a/include/sys/zfs_znode.h b/include/sys/zfs_znode.h
index 7c906050b..c8656b3f6 100644
--- a/include/sys/zfs_znode.h
+++ b/include/sys/zfs_znode.h
@@ -190,7 +190,6 @@ typedef struct znode {
 	boolean_t	z_is_sa;	/* are we native sa? */
 	boolean_t	z_is_mapped;	/* are we mmap'ed */
 	boolean_t	z_is_ctldir;	/* are we .zfs entry */
-	boolean_t	z_is_stale;	/* are we stale due to rollback? */
 	boolean_t	z_suspended;	/* extra ref from a suspend? */
 	uint_t		z_blksz;	/* block size in bytes */
 	uint_t		z_seq;		/* modification sequence number */