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author | Nick Piggin <npiggin@kernel.dk> | 2011-01-07 17:49:27 +1100 |
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committer | Nick Piggin <npiggin@kernel.dk> | 2011-01-07 17:50:19 +1100 |
commit | 621e155a3591962420eacdd39f6f0aa29ceb221e (patch) | |
tree | 387a9fb396f1bf24514b712c294182e36ba51076 /Documentation/filesystems/porting | |
parent | fb2d5b86aff355a27ebfc132d3c99f4a940cc3fe (diff) |
fs: change d_compare for rcu-walk
Change d_compare so it may be called from lock-free RCU lookups. This
does put significant restrictions on what may be done from the callback,
however there don't seem to have been any problems with in-tree fses.
If some strange use case pops up that _really_ cannot cope with the
rcu-walk rules, we can just add new rcu-unaware callbacks, which would
cause name lookup to drop out of rcu-walk mode.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'Documentation/filesystems/porting')
-rw-r--r-- | Documentation/filesystems/porting | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 9e71c9ad310..d44511e2082 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -326,3 +326,10 @@ to it. unreferenced dentries, and is now only called when the dentry refcount goes to 0. Even on 0 refcount transition, it must be able to tolerate being called 0, 1, or more times (eg. constant, idempotent). + +--- +[mandatory] + + .d_compare() calling convention and locking rules are significantly +changed. Read updated documentation in Documentation/filesystems/vfs.txt (and +look at examples of other filesystems) for guidance. |