6 Commits

Author	SHA1	Message	Date
Bryn M. Reeves	77a7ed065f	dmfilemapd: ensure path argument is absolute ... Require that the path argument to dmfilemapd be an absolute path and document this in tool output, libdevmapper.h and dmfilemapd.8. The check is also enforced by dm_stats_start_filemapd() to avoid forking a new process with an invalid path argument.	2017-03-13 11:44:05 +00:00
Bryn M. Reeves	9b0aba5fe9	dmfilemapd: return error for wrong number of args ... The initial check on argc incorrectly returns 1 when the wrong number of arguments are present, causing a segfault in main() when no arguments are given: # dmfilemapd Wrong number of arguments. usage: dmfilemapd <fd> <group_id> <path> <mode> [<foreground>[<log_level>]] Segmentation fault (core dumped)	2017-03-13 11:09:11 +00:00
Bryn M. Reeves	a9341b18ef	daemons: use DEFAULT_PROC_DIR in dmfilemapd ... Include defaults.h and use it to obtain the default procfs mount point in dmfilemapd.	2017-03-10 17:26:47 +00:00
Bryn M. Reeves	b17eb054cd	daemons: cleanup dmeventd references from dmfilemapd/Makefile.in	2017-03-10 17:26:47 +00:00
Bryn M. Reeves	1ba11aa7ee	dmfilemapd: always set the program_id after listing regions ... The filemap daemon takes its program_id from the regions it is managing: use DM_STATS_ALL_PROGRAMS when retrieving an initial listing and then obtain the correct program_id from the group leader.	2017-03-09 21:20:27 +00:00
Bryn M. Reeves	8b78982297	daemons: add dmfilemapd ... Add a daemon that can be launched to monitor a group of regions corresponding to the extents of a file, and to update the regions as the file's allocation changes. The daemon is intended to be started from a library interface, but can also be run from the command line: dmfilemapd <fd> <group_id> <path> <mode> [<foreground>[<log_level>]] Where fd is a file descriptor open on the mapped file, group_id is the group identifier of the mapped group and mode is either "inode" or "path". E.g.: # dmfilemapd 3 0 vm.img inode 1 3 3<vm.img ... If foreground is non-zero, the daemon will not fork to run in the background. If verbose is non-zero, libdm and daemon log messages will be printed. It is possible for the group identifier to change when regions are re-mapped: this occurs when the group leader is deleted (regroup=1 in dm_stats_update_regions_from_fd()), and another region is created before the daemon has a chance to recreate the leader region. The operation is inherently racey since there is currently no way to atomically move or resize a dm_stats region while retaining its region_id. Detect this condition and update the group_id value stored in the filemap monitor. A function is also provided in the the stats API to launch the filemap monitoring daemon: int dm_stats_start_filemapd(int fd, uint64_t group_id, const char *path, dm_filemapd_mode_t mode, unsigned foreground, unsigned verbose); This carries out the first fork and execs dmfilemapd with the arguments specified. A dm_filemapd_mode_t value is specified by the mode argument: either DM_FILEMAPD_FOLLOW_INODE, or DM_FILEMAPD_FOLLOW_PATH. A helper function, dm_filemapd_mode_from_string(), is provided to parse a string containing a valid mode name into the appropriate dm_filemapd_mode_t value.	2017-03-09 18:50:15 +00:00