Commit a8810cdc authored by Jeff Layton's avatar Jeff Layton Committed by Ilya Dryomov
Browse files

ceph: allow queueing cap/snap handling after putting cap references 



Testing with the fscache overhaul has triggered some lockdep warnings
about circular lock dependencies involving page_mkwrite and the
mmap_lock. It'd be better to do the "real work" without the mmap lock
being held.

Change the skip_checking_caps parameter in __ceph_put_cap_refs to an
enum, and use that to determine whether to queue check_caps, do it
synchronously or not at all. Change ceph_page_mkwrite to do a
ceph_put_cap_refs_async().

Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarIlya Dryomov <idryomov@gmail.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 64f28c62

fs/ceph/addr.c

+1 −1
Original line number Diff line number Diff line
@@ -1662,7 +1662,7 @@ static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf) 


	dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %x\n",

	     inode, off, len, ceph_cap_string(got), ret);

	ceph_put_cap_refs(ci, got);

	ceph_put_cap_refs_async(ci, got);

out_free:

	ceph_restore_sigs(&oldset);

	sb_end_pagefault(inode->i_sb);

fs/ceph/caps.c

+25 −4
Original line number Diff line number Diff line
@@ -3027,6 +3027,12 @@ static int ceph_try_drop_cap_snap(struct ceph_inode_info *ci, 
	return 0;

}



enum put_cap_refs_mode {

	PUT_CAP_REFS_SYNC = 0,

	PUT_CAP_REFS_NO_CHECK,

	PUT_CAP_REFS_ASYNC,

};



/*

 * Release cap refs.

 *
@@ -3037,7 +3043,7 @@ static int ceph_try_drop_cap_snap(struct ceph_inode_info *ci, 
 * cap_snap, and wake up any waiters.

 */

static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had,

				bool skip_checking_caps)

				enum put_cap_refs_mode mode)

{

	struct inode *inode = &ci->vfs_inode;

	int last = 0, put = 0, flushsnaps = 0, wake = 0;
@@ -3093,11 +3099,21 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, 
	dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had),

	     last ? " last" : "", put ? " put" : "");



	if (!skip_checking_caps) {

	switch (mode) {

	case PUT_CAP_REFS_SYNC:

		if (last)

			ceph_check_caps(ci, 0, NULL);

		else if (flushsnaps)

			ceph_flush_snaps(ci, NULL);

		break;

	case PUT_CAP_REFS_ASYNC:

		if (last)

			ceph_queue_check_caps(inode);

		else if (flushsnaps)

			ceph_queue_flush_snaps(inode);

		break;

	default:

		break;

	}

	if (wake)

		wake_up_all(&ci->i_cap_wq);
@@ -3107,12 +3123,17 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, 


void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)

{

	__ceph_put_cap_refs(ci, had, false);

	__ceph_put_cap_refs(ci, had, PUT_CAP_REFS_SYNC);

}



void ceph_put_cap_refs_async(struct ceph_inode_info *ci, int had)

{

	__ceph_put_cap_refs(ci, had, PUT_CAP_REFS_ASYNC);

}



void ceph_put_cap_refs_no_check_caps(struct ceph_inode_info *ci, int had)

{

	__ceph_put_cap_refs(ci, had, true);

	__ceph_put_cap_refs(ci, had, PUT_CAP_REFS_NO_CHECK);

}



/*

fs/ceph/inode.c

+6 −0
Original line number Diff line number Diff line
@@ -1965,6 +1965,12 @@ static void ceph_inode_work(struct work_struct *work) 
	if (test_and_clear_bit(CEPH_I_WORK_VMTRUNCATE, &ci->i_work_mask))

		__ceph_do_pending_vmtruncate(inode);



	if (test_and_clear_bit(CEPH_I_WORK_CHECK_CAPS, &ci->i_work_mask))

		ceph_check_caps(ci, 0, NULL);



	if (test_and_clear_bit(CEPH_I_WORK_FLUSH_SNAPS, &ci->i_work_mask))

		ceph_flush_snaps(ci, NULL);



	iput(inode);

}

fs/ceph/super.h

+16 −3
Original line number Diff line number Diff line
@@ -562,9 +562,11 @@ static inline struct inode *ceph_find_inode(struct super_block *sb, 
/*

 * Masks of ceph inode work.

 */

#define CEPH_I_WORK_WRITEBACK		0 /* writeback */

#define CEPH_I_WORK_INVALIDATE_PAGES	1 /* invalidate pages */

#define CEPH_I_WORK_VMTRUNCATE		2 /* vmtruncate */

#define CEPH_I_WORK_WRITEBACK		0

#define CEPH_I_WORK_INVALIDATE_PAGES	1

#define CEPH_I_WORK_VMTRUNCATE		2

#define CEPH_I_WORK_CHECK_CAPS		3

#define CEPH_I_WORK_FLUSH_SNAPS		4



/*

 * We set the ERROR_WRITE bit when we start seeing write errors on an inode
@@ -982,6 +984,16 @@ static inline void ceph_queue_writeback(struct inode *inode) 
	ceph_queue_inode_work(inode, CEPH_I_WORK_WRITEBACK);

}



static inline void ceph_queue_check_caps(struct inode *inode)

{

	ceph_queue_inode_work(inode, CEPH_I_WORK_CHECK_CAPS);

}



static inline void ceph_queue_flush_snaps(struct inode *inode)

{

	ceph_queue_inode_work(inode, CEPH_I_WORK_FLUSH_SNAPS);

}



extern int __ceph_do_getattr(struct inode *inode, struct page *locked_page,

			     int mask, bool force);

static inline int ceph_do_getattr(struct inode *inode, int mask, bool force)
@@ -1120,6 +1132,7 @@ extern void ceph_take_cap_refs(struct ceph_inode_info *ci, int caps, 
				bool snap_rwsem_locked);

extern void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps);

extern void ceph_put_cap_refs(struct ceph_inode_info *ci, int had);

extern void ceph_put_cap_refs_async(struct ceph_inode_info *ci, int had);

extern void ceph_put_cap_refs_no_check_caps(struct ceph_inode_info *ci,

					    int had);

extern void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,