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HPFS: Introduce a global mutex and lock it on every callback from VFS.

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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>
This commit is contained in:
Mikulas Patocka
2011-05-08 20:42:54 +02:00
committed by Linus Torvalds
parent 637b424bf8
commit 7dd29d8d86
4 changed files with 51 additions and 18 deletions
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24
fs/hpfs/hpfs_fn.h
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@@ -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));
}