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authorMikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>2011-05-08 20:42:54 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-09 09:04:23 -0700
commit7dd29d8d865efdb00c0542a5d2c87af8c52ea6c7 (patch)
tree71f404ed317e2d1b689af088ece1c32c3b1535c8 /fs/hpfs/hpfs_fn.h
parent637b424bf8747e50bab6648ab919632d6efd6c28 (diff)
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HPFS: Introduce a global mutex and lock it on every callback from VFS.
Introduce a global mutex and lock it on every callback from VFS. Performance doesn't matter, reviewing the whole code for locking correctness would be too complicated, so simply lock it all. Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/hpfs/hpfs_fn.h')
-rw-r--r--fs/hpfs/hpfs_fn.h24
1 files changed, 15 insertions, 9 deletions
diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h
index c15adbca07ff..89a4714b44c7 100644
--- a/fs/hpfs/hpfs_fn.h
+++ b/fs/hpfs/hpfs_fn.h
@@ -63,6 +63,7 @@ struct hpfs_inode_info {
};
struct hpfs_sb_info {
+ struct mutex hpfs_mutex; /* global hpfs lock */
ino_t sb_root; /* inode number of root dir */
unsigned sb_fs_size; /* file system size, sectors */
unsigned sb_bitmaps; /* sector number of bitmap list */
@@ -346,21 +347,26 @@ static inline time32_t gmt_to_local(struct super_block *s, time_t t)
/*
* Locking:
*
- * hpfs_lock() is a leftover from the big kernel lock.
- * Right now, these functions are empty and only left
- * for documentation purposes. The file system no longer
- * works on SMP systems, so the lock is not needed
- * any more.
+ * hpfs_lock() locks the whole filesystem. It must be taken
+ * on any method called by the VFS.
*
- * If someone is interested in making it work again, this
- * would be the place to start by adding a per-superblock
- * mutex and fixing all the bugs and performance issues
- * caused by that.
+ * We don't do any per-file locking anymore, it is hard to
+ * review and HPFS is not performance-sensitive anyway.
*/
static inline void hpfs_lock(struct super_block *s)
{
+ struct hpfs_sb_info *sbi = hpfs_sb(s);
+ mutex_lock(&sbi->hpfs_mutex);
}
static inline void hpfs_unlock(struct super_block *s)
{
+ struct hpfs_sb_info *sbi = hpfs_sb(s);
+ mutex_unlock(&sbi->hpfs_mutex);
+}
+
+static inline void hpfs_lock_assert(struct super_block *s)
+{
+ struct hpfs_sb_info *sbi = hpfs_sb(s);
+ WARN_ON(!mutex_is_locked(&sbi->hpfs_mutex));
}