[v0,4/4] Btrfs sysfs support documentation.

Commit Message

Goffredo Baroncelli Aug. 23, 2012, 12:13 p.m. UTC

Update of the Documentation/filesystes/btrfs.txt file.
---
 0 files changed


--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
index 7671352..35840ab 100644
--- a/Documentation/filesystems/btrfs.txt
+++ b/Documentation/filesystems/btrfs.txt
@@ -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.
+