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authorGreg Farnum <gregf@hq.newdream.net>2010-09-17 10:24:02 -0700
committerSage Weil <sage@newdream.net>2010-10-20 15:38:17 -0700
commitfca4451acfdcf894154e4809529ca28a09db88ff (patch)
tree446381c8e8c7b592b47c2e50c32b1e40817fcfe1 /fs/ceph
parentac0b74d8a1ced8ea86147467daf06b15b130dd94 (diff)
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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 <gregf@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph')
-rw-r--r--fs/ceph/locks.c17
-rw-r--r--fs/ceph/mds_client.c42
2 files changed, 44 insertions, 15 deletions
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
index 087afe9..40abde9 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 3356823..fbfc298 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);
}