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| author | Al Viro <viro@zeniv.linux.org.uk> | 2018-05-04 08:23:01 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-30 07:47:29 +0200 |
| commit | b90b64116b1136c9c965e019283daf6100a6d1ac (patch) | |
| tree | 3cbc2f60d23d0a37967e8dbf5ab8eeccfb7ca81e /include | |
| parent | fac7c7ecdec9bd1fbe18ae30f9026e301666c7a7 (diff) | |
| download | linux-b90b64116b1136c9c965e019283daf6100a6d1ac.tar.gz linux-b90b64116b1136c9c965e019283daf6100a6d1ac.tar.bz2 linux-b90b64116b1136c9c965e019283daf6100a6d1ac.zip | |
do d_instantiate/unlock_new_inode combinations safely
commit 1e2e547a93a00ebc21582c06ca3c6cfea2a309ee upstream.
For anything NFS-exported we do _not_ want to unlock new inode
before it has grown an alias; original set of fixes got the
ordering right, but missed the nasty complication in case of
lockdep being enabled - unlock_new_inode() does
lockdep_annotate_inode_mutex_key(inode)
which can only be done before anyone gets a chance to touch
->i_mutex. Unfortunately, flipping the order and doing
unlock_new_inode() before d_instantiate() opens a window when
mkdir can race with open-by-fhandle on a guessed fhandle, leading
to multiple aliases for a directory inode and all the breakage
that follows from that.
Correct solution: a new primitive (d_instantiate_new())
combining these two in the right order - lockdep annotate, then
d_instantiate(), then the rest of unlock_new_inode(). All
combinations of d_instantiate() with unlock_new_inode() should
be converted to that.
Cc: stable@kernel.org # 2.6.29 and later
Tested-by: Mike Marshall <hubcap@omnibond.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/dcache.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 493926ff1717..c33793eab131 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -231,6 +231,7 @@ extern seqlock_t rename_lock; * These are the low-level FS interfaces to the dcache.. */ extern void d_instantiate(struct dentry *, struct inode *); +extern void d_instantiate_new(struct dentry *, struct inode *); extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); extern struct dentry * d_materialise_unique(struct dentry *, struct inode *); extern int d_instantiate_no_diralias(struct dentry *, struct inode *); |