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: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Jeff Layton 2020-12-10 14:39:26 -05:00 committed by Ilya Dryomov
parent 64f28c627a
commit a8810cdc00
4 changed files with 48 additions and 8 deletions

View File

@ -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);

View File

@ -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);
}
/*

View File

@ -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);
}

View File

@ -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,