ext4: fix BUG when calling ext4_error with locked block group
The mballoc code likes to call ext4_error while it is holding locked
block groups. This can causes a scheduling in atomic context BUG. We
can't just unlock the block group and relock it after/if ext4_error
returns since that might result in race conditions in the case where
the filesystem is set to continue after finding errors.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8152b56..f0b1db6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1126,6 +1126,9 @@
__attribute__ ((format (printf, 3, 4)));
extern void ext4_warning(struct super_block *, const char *, const char *, ...)
__attribute__ ((format (printf, 3, 4)));
+extern void ext4_grp_locked_error(struct super_block *, ext4_group_t,
+ const char *, const char *, ...)
+ __attribute__ ((format (printf, 4, 5)));
extern void ext4_update_dynamic_rev(struct super_block *sb);
extern int ext4_update_compat_feature(handle_t *handle, struct super_block *sb,
__u32 compat);
@@ -1249,6 +1252,50 @@
return ;
}
+struct ext4_group_info {
+ unsigned long bb_state;
+ struct rb_root bb_free_root;
+ unsigned short bb_first_free;
+ unsigned short bb_free;
+ unsigned short bb_fragments;
+ struct list_head bb_prealloc_list;
+#ifdef DOUBLE_CHECK
+ void *bb_bitmap;
+#endif
+ struct rw_semaphore alloc_sem;
+ unsigned short bb_counters[];
+};
+
+#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
+#define EXT4_GROUP_INFO_LOCKED_BIT 1
+
+#define EXT4_MB_GRP_NEED_INIT(grp) \
+ (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
+
+static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
+{
+ struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
+
+ bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
+}
+
+static inline void ext4_unlock_group(struct super_block *sb,
+ ext4_group_t group)
+{
+ struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
+
+ bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
+}
+
+static inline int ext4_is_group_locked(struct super_block *sb,
+ ext4_group_t group)
+{
+ struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
+
+ return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT,
+ &(grinfo->bb_state));
+}
+
/*
* Inodes and files operations
*/
