Merge tag 'filelock-v5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux

Pull file locking updates from Jeff Layton:
 "Just a couple of minor bugfixes, a revision to a tracepoint to account
  for some earlier changes to the internals, and a patch to add a
  pr_warn message when someone tries to mount a filesystem with '-o
  mand' on a kernel that has that support disabled"

* tag 'filelock-v5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
  locks: fix a memory leak bug in __break_lease()
  locks: print a warning when mount fails due to lack of "mand" support
  locks: Fix procfs output for file leases
  locks: revise generic_add_lease tracepoint
This commit is contained in:
Linus Torvalds
2019-09-18 13:41:01 -07:00
4 changed files with 31 additions and 15 deletions

View File

@@ -169,3 +169,13 @@ havoc if they lock crucial files. The way around it is to change the file
permissions (remove the setgid bit) before trying to read or write to it.
Of course, that might be a bit tricky if the system is hung :-(
7. The "mand" mount option
--------------------------
Mandatory locking is disabled on all filesystems by default, and must be
administratively enabled by mounting with "-o mand". That mount option
is only allowed if the mounting task has the CAP_SYS_ADMIN capability.
Since kernel v4.5, it is possible to disable mandatory locking
altogether by setting CONFIG_MANDATORY_FILE_LOCKING to "n". A kernel
with this disabled will reject attempts to mount filesystems with the
"mand" mount option with the error status EPERM.