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authorAl Viro <viro@zeniv.linux.org.uk>2019-04-10 21:43:44 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2019-05-02 05:37:39 +0300
commitfdb0da89f4ba0c74d7d3b9e6f471e96a5766820b (patch)
tree3c82eb1fe04568315a76d03ec86617e206b12a41 /Documentation/filesystems/Locking
parentad7999cd701e4e058765d35cf5274ee16801e986 (diff)
downloadlinux-fdb0da89f4ba0c74d7d3b9e6f471e96a5766820b.tar.xz
new inode method: ->free_inode()
A lot of ->destroy_inode() instances end with call_rcu() of a callback that does RCU-delayed part of freeing. Introduce a new method for doing just that, with saner signature. Rules: ->destroy_inode ->free_inode f g immediate call of f(), RCU-delayed call of g() f NULL immediate call of f(), no RCU-delayed calls NULL g RCU-delayed call of g() NULL NULL RCU-delayed default freeing IOW, NULL ->free_inode gives the same behaviour as now. Note that NULL, NULL is equivalent to NULL, free_inode_nonrcu; we could mandate the latter form, but that would have very little benefit beyond making rules a bit more symmetric. It would break backwards compatibility, require extra boilerplate and expected semantics for (NULL, NULL) pair would have no use whatsoever... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems/Locking')
-rw-r--r--Documentation/filesystems/Locking2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index efea228ccd8a..7b20c385cc02 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -118,6 +118,7 @@ set: exclusive
--------------------------- super_operations ---------------------------
prototypes:
struct inode *(*alloc_inode)(struct super_block *sb);
+ void (*free_inode)(struct inode *);
void (*destroy_inode)(struct inode *);
void (*dirty_inode) (struct inode *, int flags);
int (*write_inode) (struct inode *, struct writeback_control *wbc);
@@ -139,6 +140,7 @@ locking rules:
All may block [not true, see below]
s_umount
alloc_inode:
+free_inode: called from RCU callback
destroy_inode:
dirty_inode:
write_inode: