hfsplus: add missing extent locking in hfsplus_write_inode
Most of the extent handling code already does proper SMP locking, but
hfsplus_write_inode was calling into hfsplus_ext_write_extent without
taking the extents_lock. Fix this by splitting hfsplus_ext_write_extent
into an internal helper that expects the lock, and a public interface
that first acquires it.
Also add a few locking asserts and document the locking rules in
hfsplus_fs.h.
Signed-off-by: Christoph Hellwig <hch@tuxera.com>
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index b1017ea..0c9cb18 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -88,6 +88,8 @@
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
int res;
+ WARN_ON(!mutex_is_locked(&hip->extents_lock));
+
hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
HFSPLUS_IS_RSRC(inode) ?
HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
@@ -108,7 +110,7 @@
}
}
-void hfsplus_ext_write_extent(struct inode *inode)
+static void hfsplus_ext_write_extent_locked(struct inode *inode)
{
if (HFSPLUS_I(inode)->flags & HFSPLUS_FLG_EXT_DIRTY) {
struct hfs_find_data fd;
@@ -119,6 +121,13 @@
}
}
+void hfsplus_ext_write_extent(struct inode *inode)
+{
+ mutex_lock(&HFSPLUS_I(inode)->extents_lock);
+ hfsplus_ext_write_extent_locked(inode);
+ mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
+}
+
static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
struct hfsplus_extent *extent,
u32 cnid, u32 block, u8 type)
@@ -144,6 +153,8 @@
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
int res;
+ WARN_ON(!mutex_is_locked(&hip->extents_lock));
+
if (hip->flags & HFSPLUS_FLG_EXT_DIRTY)
__hfsplus_ext_write_extent(inode, fd);
@@ -433,7 +444,7 @@
insert_extent:
dprint(DBG_EXTENT, "insert new extent\n");
- hfsplus_ext_write_extent(inode);
+ hfsplus_ext_write_extent_locked(inode);
memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
hip->cached_extents[0].start_block = cpu_to_be32(start);