docs: filesystems: convert quota.txt to ReST

- Add a SPDX header;
- Adjust document title;
- Some whitespace fixes and new line breaks;
- Add it to filesystems/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/10a707377475bb252f454af2b8f58a038527933f.1588021877.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/index.rst

@@ -31,6 +31,7 @@ algorithms work.
    locks
    mandatory-locking
    mount_api
+   quota
 
    automount-support
 

Documentation/filesystems/quota.rst

@@ -1,4 +1,6 @@
+.. SPDX-License-Identifier: GPL-2.0
 
+===============
 Quota subsystem
 ===============
 
@@ -39,6 +41,7 @@ Currently, the interface supports only one message type QUOTA_NL_C_WARNING.
 This command is used to send a notification about any of the above mentioned
 events. Each message has six attributes. These are (type of the argument is
 in parentheses):
+
         QUOTA_NL_A_QTYPE (u32)
 	  - type of quota being exceeded (one of USRQUOTA, GRPQUOTA)
         QUOTA_NL_A_EXCESS_ID (u64)
@@ -48,20 +51,34 @@ in parentheses):
 	  - UID of a user who caused the event
         QUOTA_NL_A_WARNING (u32)
 	  - what kind of limit is exceeded:
-		QUOTA_NL_IHARDWARN - inode hardlimit
+
-		QUOTA_NL_ISOFTLONGWARN - inode softlimit is exceeded longer
+		QUOTA_NL_IHARDWARN
-		  than given grace period
+		    inode hardlimit
-		QUOTA_NL_ISOFTWARN - inode softlimit
+		QUOTA_NL_ISOFTLONGWARN
-		QUOTA_NL_BHARDWARN - space (block) hardlimit
+		    inode softlimit is exceeded longer
-		QUOTA_NL_BSOFTLONGWARN - space (block) softlimit is exceeded
+		    than given grace period
-		  longer than given grace period.
+		QUOTA_NL_ISOFTWARN
-		QUOTA_NL_BSOFTWARN - space (block) softlimit
+		    inode softlimit
+		QUOTA_NL_BHARDWARN
+		    space (block) hardlimit
+		QUOTA_NL_BSOFTLONGWARN
+		    space (block) softlimit is exceeded
+		    longer than given grace period.
+		QUOTA_NL_BSOFTWARN
+		    space (block) softlimit
+
 	  - four warnings are also defined for the event when user stops
 	    exceeding some limit:
-		QUOTA_NL_IHARDBELOW - inode hardlimit
+
-		QUOTA_NL_ISOFTBELOW - inode softlimit
+		QUOTA_NL_IHARDBELOW
-		QUOTA_NL_BHARDBELOW - space (block) hardlimit
+		    inode hardlimit
-		QUOTA_NL_BSOFTBELOW - space (block) softlimit
+		QUOTA_NL_ISOFTBELOW
+		    inode softlimit
+		QUOTA_NL_BHARDBELOW
+		    space (block) hardlimit
+		QUOTA_NL_BSOFTBELOW
+		    space (block) softlimit
+
         QUOTA_NL_A_DEV_MAJOR (u32)
 	  - major number of a device with the affected filesystem
         QUOTA_NL_A_DEV_MINOR (u32)

MAINTAINERS

@@ -5010,7 +5010,7 @@ W:	http://www.win.tue.nl/~aeb/partitions/partition_types-1.html
 DISKQUOTA
 M:	Jan Kara <jack@suse.com>
 S:	Maintained
-F:	Documentation/filesystems/quota.txt
+F:	Documentation/filesystems/quota.rst
 F:	fs/quota/
 F:	include/linux/quota*.h
 F:	include/uapi/linux/quota*.h