@@ -89,3 +89,78 @@ btrfsck: do a limited check of the FS extent trees.
btrfs-debug-tree: print all of the FS metadata in text form. Example:
btrfs-debug-tree /dev/sda2 >& big_output_file
+
+
+
+ SYSFS SUPPORT
+ =============
+
+If the option CONFIG_BTRFS_FS_SYSFS is enabled, BTRFS exports some
+information via the sysfs filesystem.
+Todate these information are read-only.
+
+The information exported are related to both the devices and the filesystems.
+When a devices is registred (for example via the btrfs filesystem scan
+command), BTRFS creates the following entries under /sys/fs/btrfs:
+
+/sys/fs/btrfs:
+
+ - devices -> information per device basis
+ - filesystem -> information per filesystem basis
+
+/sys/fs/btrfs/devices/<device-UUID>:
+
+ - bytes_used
+ - devid
+ - disk_total_bytes
+ - fsid -> fielsystem UUID
+ - generation
+ - major [*]
+ - minor [*]
+ - missing
+ - name -> device name (eg: /dev/sda)
+ - total_bytes
+ - write_errors -> error info
+ - corruption_errors -> error info
+ - read_errors -> error info
+ - generation_errors -> error info
+ - flush_errors -> error info
+ - writeable
+
+[*] These information are available only after the mounting of the
+filesystem.
+
+/sys/fs/btrfs/filesystem/<filesystem-UUID>/fs_info:
+
+ - balance_cancel_req -> balance status information
+ - balance_pause_req -> balance status information
+ - balance_running -> balance status information
+ - fs_state
+ - generation
+ - label -> label of the filesystem
+ - last_trans_committed
+ - scrub_cancel_req -> scrub status information
+ - scrub_pause_req -> scrub status information
+ - scrubs_paused -> scrub status information
+ - scrubs_running -> scrub status information
+
+/sys/fs/btrfs/filesystem/<filesystem-UUID>/fs_devices:
+
+ - latest_devid
+ - latest_trans
+ - missing_devices
+ - num_can_discard
+ - open_devices
+ - opened
+ - rw_devices
+ - seeding
+ - total_rw_bytes
+
+The filesystems information are split in two section (fs_info and fs_devices)
+because the fs_devices entries are available after the scan of the device(s),
+but the fs_info entries are available only after the mount of the
+filesystem.
+
+The link between the filesystem and the device(s) is the fsid ==
+filesystem-UUID.
+
Update of the Documentation/filesystes/btrfs.txt file. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> --- 0 files changed -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html