ceph: quota: update MDS when max_bytes is approaching

When we're reaching the ceph.quota.max_bytes limit, i.e., when writing
more than 1/16th of the space left in a quota realm, update the MDS with
the new file size.

This mirrors the fuse-client approach with commit 122c50315ed1 ("client:
Inform mds file size when approaching quota limit"), in the ceph git tree.

Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

3 files changed, 45 insertions, 1 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 0a2843fdebbd..f85040d73e3d 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1464,6 +1464,7 @@ retry_snap:
 
         if (written >= 0) {
                 int dirty;
+
                 spin_lock(&ci->i_ceph_lock);
                 ci->i_inline_version = CEPH_INLINE_NONE;
                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
@@ -1471,6 +1472,8 @@ retry_snap:
                 spin_unlock(&ci->i_ceph_lock);
                 if (dirty)
                         __mark_inode_dirty(inode, dirty);
+                if (ceph_quota_is_max_bytes_approaching(inode, iocb->ki_pos))
+                        ceph_check_caps(ci, CHECK_CAPS_NODELAY, NULL);
         }
 
         dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
@@ -1767,6 +1770,9 @@ static long ceph_fallocate(struct file *file, int mode,
                 spin_unlock(&ci->i_ceph_lock);
                 if (dirty)
                         __mark_inode_dirty(inode, dirty);
+                if ((endoff > size) &&
+                    ceph_quota_is_max_bytes_approaching(inode, endoff))
+                        ceph_check_caps(ci, CHECK_CAPS_NODELAY, NULL);
         }
 
         ceph_put_cap_refs(ci, got);
diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
index 745f9f47027b..7d1e18e2249f 100644
--- a/fs/ceph/quota.c
+++ b/fs/ceph/quota.c
@@ -135,7 +135,9 @@ bool ceph_quota_is_same_realm(struct inode *old, struct inode *new)
 
 enum quota_check_op {
         QUOTA_CHECK_MAX_FILES_OP,       /* check quota max_files limit */
-        QUOTA_CHECK_MAX_BYTES_OP        /* check quota max_files limit */
+        QUOTA_CHECK_MAX_BYTES_OP,       /* check quota max_files limit */
+        QUOTA_CHECK_MAX_BYTES_APPROACHING_OP    /* check if quota max_files
+                                                   limit is approaching */
 };
 
 /*
@@ -185,6 +187,20 @@ static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op,
                 case QUOTA_CHECK_MAX_BYTES_OP:
                         exceeded = (max && (rvalue + delta > max));
                         break;
+                case QUOTA_CHECK_MAX_BYTES_APPROACHING_OP:
+                        if (max) {
+                                if (rvalue >= max)
+                                        exceeded = true;
+                                else {
+                                        /*
+                                         * when we're writing more that 1/16th
+                                         * of the available space
+                                         */
+                                        exceeded =
+                                                (((max - rvalue) >> 4) < delta);
+                                }
+                        }
+                        break;
                 default:
                         /* Shouldn't happen */
                         pr_warn("Invalid quota check op (%d)\n", op);
@@ -238,3 +254,23 @@ bool ceph_quota_is_max_bytes_exceeded(struct inode *inode, loff_t newsize)
 
         return check_quota_exceeded(inode, QUOTA_CHECK_MAX_BYTES_OP, (newsize - size));
 }
+
+/*
+ * ceph_quota_is_max_bytes_approaching - check if we're reaching max_bytes
+ * @inode:      inode being written
+ * @newsize:    new size if write succeeds
+ *
+ * This function returns true if the new file size @newsize will be consuming
+ * more than 1/16th of the available quota space; it returns false otherwise.
+ */
+bool ceph_quota_is_max_bytes_approaching(struct inode *inode, loff_t newsize)
+{
+        loff_t size = ceph_inode(inode)->i_reported_size;
+
+        /* return immediately if we're decreasing file size */
+        if (newsize <= size)
+                return false;
+
+        return check_quota_exceeded(inode, QUOTA_CHECK_MAX_BYTES_APPROACHING_OP,
+                                    (newsize - size));
+}
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 5870c225c2fc..e4ff485d24c7 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1081,5 +1081,7 @@ extern bool ceph_quota_is_max_files_exceeded(struct inode *inode);
 extern bool ceph_quota_is_same_realm(struct inode *old, struct inode *new);
 extern bool ceph_quota_is_max_bytes_exceeded(struct inode *inode,
                                              loff_t newlen);
+extern bool ceph_quota_is_max_bytes_approaching(struct inode *inode,
+                                                loff_t newlen);
 
 #endif /* _FS_CEPH_SUPER_H */