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@xxxxxxxxxx>
Index: linux-2.6/fs/hfsplus/extents.c
===================================================================
--- linux-2.6.orig/fs/hfsplus/extents.c 2010-10-01 05:43:30.875023614 +0200
+++ linux-2.6/fs/hfsplus/extents.c 2010-10-01 05:46:02.058023612 +0200
@@ -88,6 +88,8 @@ static void __hfsplus_ext_write_extent(s
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 @@ static void __hfsplus_ext_write_extent(s
}
}
-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 ino
}
}
+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 @@ static inline int __hfsplus_ext_cache_ex
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 @@ out:
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);
Index: linux-2.6/fs/hfsplus/hfsplus_fs.h
===================================================================
--- linux-2.6.orig/fs/hfsplus/hfsplus_fs.h 2010-10-01 05:45:19.920023613 +0200
+++ linux-2.6/fs/hfsplus/hfsplus_fs.h 2010-10-01 05:46:02.059023612 +0200
@@ -158,28 +158,36 @@ struct hfsplus_sb_info {
struct hfsplus_inode_info {
- struct mutex extents_lock;
- u32 clump_blocks, alloc_blocks;
- sector_t fs_blocks;
- /* Allocation extents from catalog record or volume header */
- hfsplus_extent_rec first_extents;
- u32 first_blocks;
- hfsplus_extent_rec cached_extents;
- u32 cached_start, cached_blocks;
atomic_t opencnt;
- struct inode *rsrc_inode;
+ /*
+ * Extent allocation information, protected by extents_lock.
+ */
+ u32 first_blocks;
+ u32 clump_blocks;
+ u32 alloc_blocks;
+ u32 cached_start;
+ u32 cached_blocks;
+ hfsplus_extent_rec first_extents;
+ hfsplus_extent_rec cached_extents;
unsigned long flags;
+ struct mutex extents_lock;
+ /*
+ * Immutable data.
+ */
+ struct inode *rsrc_inode;
__be32 create_date;
- /* Device number in hfsplus_permissions in catalog */
u32 dev;
- /* BSD system and user file flags */
- u8 rootflags;
- u8 userflags;
+ /*
+ * Protected by i_mutex.
+ */
+ sector_t fs_blocks;
+ u8 rootflags, userflags; /* BSD system and user file flags */
struct list_head open_dir_list;
loff_t phys_size;
+
struct inode vfs_inode;
};
--
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