int64_t off, uint64_t len, char* buf);
int ceph_ll_fsync(struct ceph_mount_info *cmount, struct Fh *fh,
int syncdataonly);
+int ceph_ll_sync_inode(struct ceph_mount_info *cmount, struct Inode *in,
+ int syncdataonly);
int ceph_ll_write(struct ceph_mount_info *cmount, struct Fh* filehandle,
int64_t off, uint64_t len, const char *data);
int64_t ceph_ll_readv(struct ceph_mount_info *cmount, struct Fh *fh,
int ceph_ll_setlk(struct ceph_mount_info *cmount,
Fh *fh, struct flock *fl, uint64_t owner, int sleep);
+/*
+ * Delegation support
+ *
+ * Delegations are way for an application to request exclusive or
+ * semi-exclusive access to an Inode. The client requests the delegation and
+ * if it's successful it can reliably cache file data and metadata until the
+ * delegation is recalled.
+ *
+ * Recalls are issued via a callback function, provided by the application.
+ * Callback functions should act something like signal handlers. You want to
+ * do as little as possible in the callback. Any major work should be deferred
+ * in some fashion as it's difficult to predict the context in which this
+ * function will be called.
+ *
+ * Once the delegation has been recalled, the application should return it as
+ * soon as possible. The application has client_deleg_timeout seconds to
+ * return it, after which the cmount structure is forcibly unmounted and
+ * further calls into it fail.
+ *
+ * The application can set the client_deleg_timeout config option to suit its
+ * needs, but it should take care to choose a value that allows it to avoid
+ * forcible eviction from the cluster in the event of an application bug.
+ */
+typedef void (*ceph_deleg_cb_t)(struct Fh *fh, void *priv);
+
+/* Commands for manipulating delegation state */
+#ifndef CEPH_DELEGATION_NONE
+# define CEPH_DELEGATION_NONE 0
+# define CEPH_DELEGATION_RD 1
+# define CEPH_DELEGATION_WR 2
+#endif
+
+/**
+ * Get the amount of time that the client has to return caps
+ * @param cmount the ceph mount handle to use.
+ *
+ * In the event that a client does not return its caps, the MDS may blacklist
+ * it after this timeout. Applications should check this value and ensure
+ * that they set the delegation timeout to a value lower than this.
+ *
+ * This call returns the cap return timeout (in seconds) for this cmount, or
+ * zero if it's not mounted.
+ */
+uint32_t ceph_get_cap_return_timeout(struct ceph_mount_info *cmount);
+
+/**
+ * Set the delegation timeout for the mount (thereby enabling delegations)
+ * @param cmount the ceph mount handle to use.
+ * @param timeout the delegation timeout (in seconds)
+ *
+ * Since the client could end up blacklisted if it doesn't return delegations
+ * in time, we mandate that any application wanting to use delegations
+ * explicitly set the timeout beforehand. Until this call is done on the
+ * mount, attempts to set a delegation will return -ETIME.
+ *
+ * Once a delegation is recalled, if it is not returned in this amount of
+ * time, the cmount will be forcibly unmounted and further access attempts
+ * will fail (usually with -ENOTCONN errors).
+ *
+ * This value is further vetted against the cap return timeout, and this call
+ * can fail with -EINVAL if the timeout value is too long. Delegations can be
+ * disabled again by setting the timeout to 0.
+ */
+int ceph_set_deleg_timeout(struct ceph_mount_info *cmount, uint32_t timeout);
+
+/**
+ * Request a delegation on an open Fh
+ * @param cmount the ceph mount handle to use.
+ * @param fh file handle
+ * @param cmd CEPH_DELEGATION_* command
+ * @param cb callback function for recalling delegation
+ * @param priv opaque token passed back during recalls
+ *
+ * Returns 0 if the delegation was granted, -EAGAIN if there was a conflict
+ * and other error codes if there is a fatal error of some sort (e.g. -ENOMEM,
+ * -ETIME)
+ */
+int ceph_ll_delegation(struct ceph_mount_info *cmount, Fh *fh,
+ unsigned int cmd, ceph_deleg_cb_t cb, void *priv);
#ifdef __cplusplus
}
#endif
projects / ceph.git / blobdiff