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authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-07-26 15:51:27 +0300
committerJonathan Corbet <corbet@lwn.net>2019-07-31 22:31:05 +0300
commitec23eb54fbc7a07405d416d77e8115e575ce3adc (patch)
tree8cfd014d305628f35f42f75e24b8f5db46537ad5 /Documentation/filesystems/nfs
parent5a5e045bb3b839405e3a58b02a3333d33812214c (diff)
downloadlinux-ec23eb54fbc7a07405d416d77e8115e575ce3adc.tar.xz
docs: fs: convert docs without extension to ReST
There are 3 remaining files without an extension inside the fs docs dir. Manually convert them to ReST. In the case of the nfs/exporting.rst file, as the nfs docs aren't ported yet, I opted to convert and add a :orphan: there, with should be removed when it gets added into a nfs-specific part of the fs documentation. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/filesystems/nfs')
-rw-r--r--Documentation/filesystems/nfs/exporting.rst (renamed from Documentation/filesystems/nfs/Exporting)31
1 files changed, 18 insertions, 13 deletions
diff --git a/Documentation/filesystems/nfs/Exporting b/Documentation/filesystems/nfs/exporting.rst
index 63889149f532..33d588a01ace 100644
--- a/Documentation/filesystems/nfs/Exporting
+++ b/Documentation/filesystems/nfs/exporting.rst
@@ -1,3 +1,4 @@
+:orphan:
Making Filesystems Exportable
=============================
@@ -42,9 +43,9 @@ filehandle fragment, there is no automatic creation of a path prefix
for the object. This leads to two related but distinct features of
the dcache that are not needed for normal filesystem access.
-1/ The dcache must sometimes contain objects that are not part of the
+1. The dcache must sometimes contain objects that are not part of the
proper prefix. i.e that are not connected to the root.
-2/ The dcache must be prepared for a newly found (via ->lookup) directory
+2. The dcache must be prepared for a newly found (via ->lookup) directory
to already have a (non-connected) dentry, and must be able to move
that dentry into place (based on the parent and name in the
->lookup). This is particularly needed for directories as
@@ -52,7 +53,7 @@ the dcache that are not needed for normal filesystem access.
To implement these features, the dcache has:
-a/ A dentry flag DCACHE_DISCONNECTED which is set on
+a. A dentry flag DCACHE_DISCONNECTED which is set on
any dentry that might not be part of the proper prefix.
This is set when anonymous dentries are created, and cleared when a
dentry is noticed to be a child of a dentry which is in the proper
@@ -71,48 +72,52 @@ a/ A dentry flag DCACHE_DISCONNECTED which is set on
dentries. That guarantees that we won't need to hunt them down upon
umount.
-b/ A primitive for creation of secondary roots - d_obtain_root(inode).
+b. A primitive for creation of secondary roots - d_obtain_root(inode).
Those do _not_ bear DCACHE_DISCONNECTED. They are placed on the
per-superblock list (->s_roots), so they can be located at umount
time for eviction purposes.
-c/ Helper routines to allocate anonymous dentries, and to help attach
+c. Helper routines to allocate anonymous dentries, and to help attach
loose directory dentries at lookup time. They are:
+
d_obtain_alias(inode) will return a dentry for the given inode.
If the inode already has a dentry, one of those is returned.
+
If it doesn't, a new anonymous (IS_ROOT and
- DCACHE_DISCONNECTED) dentry is allocated and attached.
+ DCACHE_DISCONNECTED) dentry is allocated and attached.
+
In the case of a directory, care is taken that only one dentry
can ever be attached.
+
d_splice_alias(inode, dentry) will introduce a new dentry into the tree;
either the passed-in dentry or a preexisting alias for the given inode
(such as an anonymous one created by d_obtain_alias), if appropriate.
It returns NULL when the passed-in dentry is used, following the calling
convention of ->lookup.
-
+
Filesystem Issues
-----------------
For a filesystem to be exportable it must:
-
- 1/ provide the filehandle fragment routines described below.
- 2/ make sure that d_splice_alias is used rather than d_add
+
+ 1. provide the filehandle fragment routines described below.
+ 2. make sure that d_splice_alias is used rather than d_add
when ->lookup finds an inode for a given parent and name.
- If inode is NULL, d_splice_alias(inode, dentry) is equivalent to
+ If inode is NULL, d_splice_alias(inode, dentry) is equivalent to::
d_add(dentry, inode), NULL
Similarly, d_splice_alias(ERR_PTR(err), dentry) = ERR_PTR(err)
- Typically the ->lookup routine will simply end with a:
+ Typically the ->lookup routine will simply end with a::
return d_splice_alias(inode, dentry);
}
- A file system implementation declares that instances of the filesystem
+A file system implementation declares that instances of the filesystem
are exportable by setting the s_export_op field in the struct
super_block. This field must point to a "struct export_operations"
struct which has the following members: