return error;
if (ia_valid & ATTR_SIZE)
- down_write(&dentry->d_inode->i_alloc_sem);
+ inode_dio_wait(inode);
if (inode->i_op->setattr)
error = inode->i_op->setattr(dentry, attr);
else
error = simple_setattr(dentry, attr);
- if (ia_valid & ATTR_SIZE)
- up_write(&dentry->d_inode->i_alloc_sem);
-
if (!error)
fsnotify_change(dentry, ia_valid);
struct page *pages[DIO_PAGES]; /* page buffer */
};
+static void __inode_dio_wait(struct inode *inode)
+{
+ wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
+ DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
+
+ do {
+ prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&inode->i_dio_count))
+ schedule();
+ } while (atomic_read(&inode->i_dio_count));
+ finish_wait(wq, &q.wait);
+}
+
+/**
+ * inode_dio_wait - wait for outstanding DIO requests to finish
+ * @inode: inode to wait for
+ *
+ * Waits for all pending direct I/O requests to finish so that we can
+ * proceed with a truncate or equivalent operation.
+ *
+ * Must be called under a lock that serializes taking new references
+ * to i_dio_count, usually by inode->i_mutex.
+ */
+void inode_dio_wait(struct inode *inode)
+{
+ if (atomic_read(&inode->i_dio_count))
+ __inode_dio_wait(inode);
+}
+EXPORT_SYMBOL_GPL(inode_dio_wait);
+
+/*
+ * inode_dio_done - signal finish of a direct I/O requests
+ * @inode: inode the direct I/O happens on
+ *
+ * This is called once we've finished processing a direct I/O request,
+ * and is used to wake up callers waiting for direct I/O to be quiesced.
+ */
+void inode_dio_done(struct inode *inode)
+{
+ if (atomic_dec_and_test(&inode->i_dio_count))
+ wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
+}
+EXPORT_SYMBOL_GPL(inode_dio_done);
+
/*
* How many pages are in the queue?
*/
}
if (dio->flags & DIO_LOCKING)
- /* lockdep: non-owner release */
- up_read_non_owner(&dio->inode->i_alloc_sem);
-
+ inode_dio_done(dio->inode);
return ret;
}
return ret;
}
-/*
- * Releases both i_mutex and i_alloc_sem
- */
static ssize_t
direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
const struct iovec *iov, loff_t offset, unsigned long nr_segs,
* For writes this function is called under i_mutex and returns with
* i_mutex held, for reads, i_mutex is not held on entry, but it is
* taken and dropped again before returning.
- * For reads and writes i_alloc_sem is taken in shared mode and released
- * on I/O completion (which may happen asynchronously after returning to
- * the caller).
+ * The i_dio_count counter keeps track of the number of outstanding
+ * direct I/O requests, and truncate waits for it to reach zero.
+ * New references to i_dio_count must only be grabbed with i_mutex
+ * held.
*
* - if the flags value does NOT contain DIO_LOCKING we don't use any
* internal locking but rather rely on the filesystem to synchronize
* direct I/O reads/writes versus each other and truncate.
- * For reads and writes both i_mutex and i_alloc_sem are not held on
- * entry and are never taken.
*/
ssize_t
__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
}
/*
- * Will be released at I/O completion, possibly in a
- * different thread.
+ * Will be decremented at I/O completion time.
*/
- down_read_non_owner(&inode->i_alloc_sem);
+ atomic_inc(&inode->i_dio_count);
}
/*
mutex_init(&inode->i_mutex);
lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
- init_rwsem(&inode->i_alloc_sem);
- lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
+ atomic_set(&inode->i_dio_count, 0);
mapping->a_ops = &empty_aops;
mapping->host = inode;
* fails again.
*/
if (unlikely(NInoTruncateFailed(ni))) {
- down_write(&vi->i_alloc_sem);
+ inode_dio_wait(vi);
err = ntfs_truncate(vi);
- up_write(&vi->i_alloc_sem);
if (err || NInoTruncateFailed(ni)) {
if (!err)
err = -EIO;
*
* Returns 0 on success or -errno on error.
*
- * Called with ->i_mutex held. In all but one case ->i_alloc_sem is held for
- * writing. The only case in the kernel where ->i_alloc_sem is not held is
- * mm/filemap.c::generic_file_buffered_write() where vmtruncate() is called
- * with the current i_size as the offset. The analogous place in NTFS is in
- * fs/ntfs/file.c::ntfs_file_buffered_write() where we call vmtruncate() again
- * without holding ->i_alloc_sem.
+ * Called with ->i_mutex held.
*/
int ntfs_truncate(struct inode *vi)
{
* We also abort all changes of user, group, and mode as we do not implement
* the NTFS ACLs yet.
*
- * Called with ->i_mutex held. For the ATTR_SIZE (i.e. ->truncate) case, also
- * called with ->i_alloc_sem held for writing.
+ * Called with ->i_mutex held.
*/
int ntfs_setattr(struct dentry *dentry, struct iattr *attr)
{
/*
* ocfs2_dio_end_io is called by the dio core when a dio is finished. We're
- * particularly interested in the aio/dio case. Like the core uses
- * i_alloc_sem, we use the rw_lock DLM lock to protect io on one node from
- * truncation on another.
+ * particularly interested in the aio/dio case. We use the rw_lock DLM lock
+ * to protect io on one node from truncation on another.
*/
static void ocfs2_dio_end_io(struct kiocb *iocb,
loff_t offset,
BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
if (ocfs2_iocb_is_sem_locked(iocb)) {
- up_read(&inode->i_alloc_sem);
+ inode_dio_done(inode);
ocfs2_iocb_clear_sem_locked(iocb);
}
ocfs2_iocb_clear_sem_locked(iocb);
relock:
- /* to match setattr's i_mutex -> i_alloc_sem -> rw_lock ordering */
+ /* to match setattr's i_mutex -> rw_lock ordering */
if (direct_io) {
- down_read(&inode->i_alloc_sem);
+ atomic_inc(&inode->i_dio_count);
have_alloc_sem = 1;
/* communicate with ocfs2_dio_end_io */
ocfs2_iocb_set_sem_locked(iocb);
*/
if (direct_io && !can_do_direct) {
ocfs2_rw_unlock(inode, rw_level);
- up_read(&inode->i_alloc_sem);
+ inode_dio_done(inode);
have_alloc_sem = 0;
rw_level = -1;
/*
* deep in g_f_a_w_n()->ocfs2_direct_IO we pass in a ocfs2_dio_end_io
* function pointer which is called when o_direct io completes so that
- * it can unlock our rw lock. (it's the clustered equivalent of
- * i_alloc_sem; protects truncate from racing with pending ios).
+ * it can unlock our rw lock.
* Unfortunately there are error cases which call end_io and others
* that don't. so we don't have to unlock the rw_lock if either an
* async dio is going to do it in the future or an end_io after an
out_sems:
if (have_alloc_sem) {
- up_read(&inode->i_alloc_sem);
+ inode_dio_done(inode);
ocfs2_iocb_clear_sem_locked(iocb);
}
* need locks to protect pending reads from racing with truncate.
*/
if (filp->f_flags & O_DIRECT) {
- down_read(&inode->i_alloc_sem);
have_alloc_sem = 1;
+ atomic_inc(&inode->i_dio_count);
ocfs2_iocb_set_sem_locked(iocb);
ret = ocfs2_rw_lock(inode, 0);
bail:
if (have_alloc_sem) {
- up_read(&inode->i_alloc_sem);
+ inode_dio_done(inode);
ocfs2_iocb_clear_sem_locked(iocb);
}
if (rw_level != -1)
reiserfs_write_unlock(inode->i_sb);
mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR);
- down_write(&dentry->d_inode->i_alloc_sem);
+ inode_dio_wait(dentry->d_inode);
reiserfs_write_lock(inode->i_sb);
err = reiserfs_setattr(dentry, &newattrs);
- up_write(&dentry->d_inode->i_alloc_sem);
mutex_unlock(&dentry->d_inode->i_mutex);
} else
update_ctime(inode);
struct timespec i_ctime;
blkcnt_t i_blocks;
unsigned short i_bytes;
- struct rw_semaphore i_alloc_sem;
+ atomic_t i_dio_count;
const struct file_operations *i_fop; /* former ->i_op->default_file_ops */
struct file_lock *i_flock;
struct address_space *i_mapping;
* set during data writeback, and cleared with a wakeup
* on the bit address once it is done.
*
+ * I_REFERENCED Marks the inode as recently references on the LRU list.
+ *
+ * I_DIO_WAKEUP Never set. Only used as a key for wait_on_bit().
+ *
* Q: What is the difference between I_WILL_FREE and I_FREEING?
*/
#define I_DIRTY_SYNC (1 << 0)
#define __I_SYNC 7
#define I_SYNC (1 << __I_SYNC)
#define I_REFERENCED (1 << 8)
+#define __I_DIO_WAKEUP 9
+#define I_DIO_WAKEUP (1 << I_DIO_WAKEUP)
#define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
struct lock_class_key i_lock_key;
struct lock_class_key i_mutex_key;
struct lock_class_key i_mutex_dir_key;
- struct lock_class_key i_alloc_sem_key;
};
extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
};
void dio_end_io(struct bio *bio, int error);
+void inode_dio_wait(struct inode *inode);
+void inode_dio_done(struct inode *inode);
ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
struct block_device *bdev, const struct iovec *iov, loff_t offset,
* ->i_mutex (generic_file_buffered_write)
* ->mmap_sem (fault_in_pages_readable->do_page_fault)
*
- * ->i_mutex
- * ->i_alloc_sem (various)
- *
* inode_wb_list_lock
* sb_lock (fs/fs-writeback.c)
* ->mapping->tree_lock (__sync_single_inode)
endoff = (loff_t)(end - vma->vm_start - 1)
+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
- /* vmtruncate_range needs to take i_mutex and i_alloc_sem */
+ /* vmtruncate_range needs to take i_mutex */
up_read(¤t->mm->mmap_sem);
error = vmtruncate_range(mapping->host, offset, endoff);
down_read(¤t->mm->mmap_sem);
* Lock ordering in mm:
*
* inode->i_mutex (while writing or truncating, not reading or faulting)
- * inode->i_alloc_sem (vmtruncate_range)
* mm->mmap_sem
* page->flags PG_locked (lock_page)
* mapping->i_mmap_mutex
return -ENOSYS;
mutex_lock(&inode->i_mutex);
- down_write(&inode->i_alloc_sem);
+ inode_dio_wait(inode);
unmap_mapping_range(mapping, offset, (end - offset), 1);
inode->i_op->truncate_range(inode, offset, end);
/* unmap again to remove racily COWed private pages */
unmap_mapping_range(mapping, offset, (end - offset), 1);
- up_write(&inode->i_alloc_sem);
mutex_unlock(&inode->i_mutex);
return 0;
git.openpandora.org / pandora-kernel.git / commitdiff