From fca4451acfdcf894154e4809529ca28a09db88ff Mon Sep 17 00:00:00 2001 From: Greg Farnum Date: Fri, 17 Sep 2010 10:24:02 -0700 Subject: ceph: preallocate flock state without locks held When the lock_kernel() turns into lock_flocks() and a spinlock, we won't be able to do allocations with the lock held. Preallocate space without the lock, and retry if the lock state changes out from underneath us. Signed-off-by: Greg Farnum Signed-off-by: Sage Weil --- fs/ceph/locks.c | 17 +++++++++++++++-- fs/ceph/mds_client.c | 42 +++++++++++++++++++++++++++++------------- 2 files changed, 44 insertions(+), 15 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c index 087afe9ca367..40abde93c345 100644 --- a/fs/ceph/locks.c +++ b/fs/ceph/locks.c @@ -181,8 +181,9 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) * Encode the flock and fcntl locks for the given inode into the pagelist. * Format is: #fcntl locks, sequential fcntl locks, #flock locks, * sequential flock locks. - * Must be called with BLK already held, and the lock numbers should have - * been gathered under the same lock holding window. + * Must be called with lock_flocks() already held. + * If we encounter more of a specific lock type than expected, + * we return the value 1. */ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, int num_fcntl_locks, int num_flock_locks) @@ -190,6 +191,8 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, struct file_lock *lock; struct ceph_filelock cephlock; int err = 0; + int seen_fcntl = 0; + int seen_flock = 0; dout("encoding %d flock and %d fcntl locks", num_flock_locks, num_fcntl_locks); @@ -198,6 +201,11 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, goto fail; for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { if (lock->fl_flags & FL_POSIX) { + ++seen_fcntl; + if (seen_fcntl > num_fcntl_locks) { + err = -ENOSPC; + goto fail; + } err = lock_to_ceph_filelock(lock, &cephlock); if (err) goto fail; @@ -213,6 +221,11 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, goto fail; for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { if (lock->fl_flags & FL_FLOCK) { + ++seen_flock; + if (seen_flock > num_flock_locks) { + err = -ENOSPC; + goto fail; + } err = lock_to_ceph_filelock(lock, &cephlock); if (err) goto fail; diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 33568239a08e..fbfc298ac55b 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -2365,19 +2365,35 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap, if (recon_state->flock) { int num_fcntl_locks, num_flock_locks; - - lock_kernel(); - ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks); - rec.v2.flock_len = (2*sizeof(u32) + - (num_fcntl_locks+num_flock_locks) * - sizeof(struct ceph_filelock)); - - err = ceph_pagelist_append(pagelist, &rec, reclen); - if (!err) - err = ceph_encode_locks(inode, pagelist, - num_fcntl_locks, - num_flock_locks); - unlock_kernel(); + struct ceph_pagelist_cursor trunc_point; + + ceph_pagelist_set_cursor(pagelist, &trunc_point); + do { + lock_kernel(); + ceph_count_locks(inode, &num_fcntl_locks, + &num_flock_locks); + rec.v2.flock_len = (2*sizeof(u32) + + (num_fcntl_locks+num_flock_locks) * + sizeof(struct ceph_filelock)); + unlock_kernel(); + + /* pre-alloc pagelist */ + ceph_pagelist_truncate(pagelist, &trunc_point); + err = ceph_pagelist_append(pagelist, &rec, reclen); + if (!err) + err = ceph_pagelist_reserve(pagelist, + rec.v2.flock_len); + + /* encode locks */ + if (!err) { + lock_kernel(); + err = ceph_encode_locks(inode, + pagelist, + num_fcntl_locks, + num_flock_locks); + unlock_kernel(); + } + } while (err == -ENOSPC); } else { err = ceph_pagelist_append(pagelist, &rec, reclen); } -- cgit v1.2.3-59-g8ed1b