On Tue, Aug 17, 2021 at 01:26:39AM +0300, Kari Argillander wrote: > Reorganize classes so that it is easier to read. Before number 4 was > written in one lenghty paragraph. It is as long as number 6 and it is > basically same kind of class (rename()). Also old number 5 was list and > it is as short as 1, 2, 3 so it can be converted non list. > > This makes file now much readible. Gently ping for this one. > > Signed-off-by: Kari Argillander <kari.argillander@xxxxxxxxx> > --- > .../filesystems/directory-locking.rst | 31 +++++++++---------- > 1 file changed, 15 insertions(+), 16 deletions(-) > > diff --git a/Documentation/filesystems/directory-locking.rst b/Documentation/filesystems/directory-locking.rst > index 504ba940c36c..33921dff7af4 100644 > --- a/Documentation/filesystems/directory-locking.rst > +++ b/Documentation/filesystems/directory-locking.rst > @@ -11,7 +11,7 @@ When taking the i_rwsem on multiple non-directory objects, we > always acquire the locks in order by increasing address. We'll call > that "inode pointer" order in the following. > > -For our purposes all operations fall in 5 classes: > +For our purposes all operations fall in 6 classes: > > 1) read access. Locking rules: caller locks directory we are accessing. > The lock is taken shared. > @@ -22,26 +22,25 @@ exclusive. > 3) object removal. Locking rules: caller locks parent, finds victim, > locks victim and calls the method. Locks are exclusive. > > -4) rename() that is _not_ cross-directory. Locking rules: caller locks > -the parent and finds source and target. In case of exchange (with > -RENAME_EXCHANGE in flags argument) lock both. In any case, > -if the target already exists, lock it. If the source is a non-directory, > -lock it. If we need to lock both, lock them in inode pointer order. > -Then call the method. All locks are exclusive. > -NB: we might get away with locking the source (and target in exchange > -case) shared. > +4) link creation. Locking rules: lock parent, check that source is not > +a directory, lock source and call the method. Locks are exclusive. > > -5) link creation. Locking rules: > +5) rename() that is _not_ cross-directory. > +Locking rules: > > - * lock parent > - * check that source is not a directory > - * lock source > - * call the method. > + * Caller locks the parent and finds source and target. > + * In case of exchange (with RENAME_EXCHANGE in flags argument) > + lock both the source and the target. > + * If the target exists, lock it, If the source is a non-directory, > + lock it. If we need to lock both, do so in inode pointer order. > + * Call the method. > > All locks are exclusive. > +NB: we might get away with locking the source (and target in exchange > +case) shared. > > -6) cross-directory rename. The trickiest in the whole bunch. Locking > -rules: > +6) rename() that _is_ cross-directory. The trickiest in the whole bunch. > +Locking rules: > > * lock the filesystem > * lock parents in "ancestors first" order. > -- > 2.30.2 >
