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Commit 89b52fe1 authored by Yan, Zheng's avatar Yan, Zheng Committed by Ilya Dryomov
Browse files

ceph: fix flushing caps 



Current ceph_fsync() only flushes dirty caps and wait for them to be
flushed. It doesn't wait for caps that has already been flushing.
This patch makes ceph_fsync() wait for pending flushing caps too.
Besides, this patch also makes caps_are_flushed() peroperly handle
tid wrapping.

Signed-off-by: default avatarYan, Zheng <zyan@redhat.com>
parent 41445999

fs/ceph/caps.c

+25 −24
Original line number Diff line number Diff line
@@ -1097,8 +1097,7 @@ void ceph_queue_caps_release(struct inode *inode) 
 * caller should hold snap_rwsem (read), s_mutex.

 */

static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,

		      int op, int used, int want, int retain, int flushing,

		      unsigned *pflush_tid)

		      int op, int used, int want, int retain, int flushing)

	__releases(cap->ci->i_ceph_lock)

{

	struct ceph_inode_info *ci = cap->ci;
@@ -1170,8 +1169,6 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap, 
		 * first ack clean Ax.

		 */

		flush_tid = ++ci->i_cap_flush_last_tid;

		if (pflush_tid)

			*pflush_tid = flush_tid;

		dout(" cap_flush_tid %d\n", (int)flush_tid);

		for (i = 0; i < CEPH_CAP_BITS; i++)

			if (flushing & (1 << i))
@@ -1724,7 +1721,7 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags, 


		/* __send_cap drops i_ceph_lock */

		delayed += __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, cap_used,

				      want, retain, flushing, NULL);

				      want, retain, flushing);

		goto retry; /* retake i_ceph_lock and restart our cap scan. */

	}
@@ -1753,12 +1750,12 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags, 
/*

 * Try to flush dirty caps back to the auth mds.

 */

static int try_flush_caps(struct inode *inode, unsigned *flush_tid)

static int try_flush_caps(struct inode *inode, u16 flush_tid[])

{

	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;

	struct ceph_inode_info *ci = ceph_inode(inode);

	int flushing = 0;

	struct ceph_mds_session *session = NULL;

	int flushing = 0;



retry:

	spin_lock(&ci->i_ceph_lock);
@@ -1787,17 +1784,19 @@ static int try_flush_caps(struct inode *inode, unsigned *flush_tid) 


		/* __send_cap drops i_ceph_lock */

		delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, used, want,

				     cap->issued | cap->implemented, flushing,

				     flush_tid);

		if (!delayed)

			goto out_unlocked;

				     cap->issued | cap->implemented, flushing);



		spin_lock(&ci->i_ceph_lock);

		if (delayed)

			__cap_delay_requeue(mdsc, ci);

	}



	flushing = ci->i_flushing_caps;

	if (flushing)

		memcpy(flush_tid, ci->i_cap_flush_tid,

		       sizeof(ci->i_cap_flush_tid));

out:

	spin_unlock(&ci->i_ceph_lock);

out_unlocked:

	if (session)

		mutex_unlock(&session->s_mutex);

	return flushing;
@@ -1806,19 +1805,22 @@ static int try_flush_caps(struct inode *inode, unsigned *flush_tid) 
/*

 * Return true if we've flushed caps through the given flush_tid.

 */

static int caps_are_flushed(struct inode *inode, unsigned tid)

static int caps_are_flushed(struct inode *inode, u16 flush_tid[])

{

	struct ceph_inode_info *ci = ceph_inode(inode);

	int i, ret = 1;



	spin_lock(&ci->i_ceph_lock);

	for (i = 0; i < CEPH_CAP_BITS; i++)

		if ((ci->i_flushing_caps & (1 << i)) &&

		    ci->i_cap_flush_tid[i] <= tid) {

	for (i = 0; i < CEPH_CAP_BITS; i++) {

		if (!(ci->i_flushing_caps & (1 << i)))

			continue;

		// tid only has 16 bits. we need to handle wrapping

		if ((s16)(ci->i_cap_flush_tid[i] - flush_tid[i]) <= 0) {

			/* still flushing this bit */

			ret = 0;

			break;

		}

	}

	spin_unlock(&ci->i_ceph_lock);

	return ret;

}
@@ -1871,7 +1873,7 @@ int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync) 
{

	struct inode *inode = file->f_mapping->host;

	struct ceph_inode_info *ci = ceph_inode(inode);

	unsigned flush_tid;

	u16 flush_tid[CEPH_CAP_BITS];

	int ret;

	int dirty;
@@ -1883,7 +1885,7 @@ int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync) 
		return ret;

	mutex_lock(&inode->i_mutex);



	dirty = try_flush_caps(inode, &flush_tid);

	dirty = try_flush_caps(inode, flush_tid);

	dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));



	/*
@@ -1892,7 +1894,6 @@ int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync) 
	 * wait for that)

	 */

	if (!datasync && (dirty & ~CEPH_CAP_ANY_FILE_WR)) {

		dout("fsync waiting for flush_tid %u\n", flush_tid);

		ret = wait_event_interruptible(ci->i_cap_wq,

				       caps_are_flushed(inode, flush_tid));

	}
@@ -1911,14 +1912,14 @@ int ceph_fsync(struct file *file, loff_t start, loff_t end, int datasync) 
int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)

{

	struct ceph_inode_info *ci = ceph_inode(inode);

	unsigned flush_tid;

	u16 flush_tid[CEPH_CAP_BITS];

	int err = 0;

	int dirty;

	int wait = wbc->sync_mode == WB_SYNC_ALL;



	dout("write_inode %p wait=%d\n", inode, wait);

	if (wait) {

		dirty = try_flush_caps(inode, &flush_tid);

		dirty = try_flush_caps(inode, flush_tid);

		if (dirty)

			err = wait_event_interruptible(ci->i_cap_wq,

				       caps_are_flushed(inode, flush_tid));
@@ -1988,7 +1989,7 @@ void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc, 
					     __ceph_caps_used(ci),

					     __ceph_caps_wanted(ci),

					     cap->issued | cap->implemented,

					     ci->i_flushing_caps, NULL);

					     ci->i_flushing_caps);

			if (delayed) {

				spin_lock(&ci->i_ceph_lock);

				__cap_delay_requeue(mdsc, ci);
@@ -2027,7 +2028,7 @@ static void kick_flushing_inode_caps(struct ceph_mds_client *mdsc, 
				     __ceph_caps_used(ci),

				     __ceph_caps_wanted(ci),

				     cap->issued | cap->implemented,

				     ci->i_flushing_caps, NULL);

				     ci->i_flushing_caps);

		if (delayed) {

			spin_lock(&ci->i_ceph_lock);

			__cap_delay_requeue(mdsc, ci);