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| author |   Nick Piggin <npiggin@kernel.dk> | 2011-01-14 02:35:53 +0000 |
|---|---|---|
| committer |   Nick Piggin <npiggin@hera.kernel.org> | 2011-01-14 02:35:53 +0000 |
| commit | bb20c18db6fbb5e6ba499c76473a487d35073467 (patch) | |
| tree | ca0426f86e5c2a331bd5006d7f16795711b7ade2 /fs | |
| parent | fs: small rcu-walk documentation fixes (diff) | |
| download | linux-dev-bb20c18db6fbb5e6ba499c76473a487d35073467.tar.xz linux-dev-bb20c18db6fbb5e6ba499c76473a487d35073467.zip | |
fs: force_reval_path drop rcu-walk before d_invalidate
d_revalidate can return in rcu-walk mode even when it returns 0. We can't just
call any old dcache function on rcu-walk dentry (the dentry is unstable, so
even through d_lock can safely be taken, the result may no longer be what we
expect -- careful re-checks would be required). So just drop rcu in this case.
(I missed this conversion when switching to the rcu-walk convention that Linus
suggested)
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/namei.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/namei.c b/fs/namei.c index 19433cdba011..0f02359ce685 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -583,6 +583,13 @@ void release_open_intent(struct nameidata *nd) fput(nd->intent.open.file); } +/* + * Call d_revalidate and handle filesystems that request rcu-walk + * to be dropped. This may be called and return in rcu-walk mode, + * regardless of success or error. If -ECHILD is returned, the caller + * must return -ECHILD back up the path walk stack so path walk may + * be restarted in ref-walk mode. + */ static int d_revalidate(struct dentry *dentry, struct nameidata *nd) { int status; @@ -673,6 +680,9 @@ force_reval_path(struct path *path, struct nameidata *nd) return 0; if (!status) { + /* Don't d_invalidate in rcu-walk mode */ + if (nameidata_drop_rcu(nd)) + return -ECHILD; d_invalidate(dentry); status = -ESTALE; } |