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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 07:48:52 +0200 |
| commit | 03bb7588942a38623f108b3302c2d1aebb525696 (patch) | |
| tree | 7221b546da232e805a3a91fc57ba090789ccd1c9 /fs/jffs2 | |
| parent | 1a54258e10b23c6877d699ef6cf3f2b02b17b87f (diff) | |
| download | linux-stable-03bb7588942a38623f108b3302c2d1aebb525696.tar.gz linux-stable-03bb7588942a38623f108b3302c2d1aebb525696.tar.bz2 linux-stable-03bb7588942a38623f108b3302c2d1aebb525696.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 'fs/jffs2')
| -rw-r--r-- | fs/jffs2/dir.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c index 30c4c9ebb693..e27317169697 100644 --- a/fs/jffs2/dir.c +++ b/fs/jffs2/dir.c @@ -207,8 +207,7 @@ static int jffs2_create(struct inode *dir_i, struct dentry *dentry, __func__, inode->i_ino, inode->i_mode, inode->i_nlink, f->inocache->pino_nlink, inode->i_mapping->nrpages); - unlock_new_inode(inode); - d_instantiate(dentry, inode); + d_instantiate_new(dentry, inode); return 0; fail: @@ -428,8 +427,7 @@ static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char mutex_unlock(&dir_f->sem); jffs2_complete_reservation(c); - unlock_new_inode(inode); - d_instantiate(dentry, inode); + d_instantiate_new(dentry, inode); return 0; fail: @@ -573,8 +571,7 @@ static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode mutex_unlock(&dir_f->sem); jffs2_complete_reservation(c); - unlock_new_inode(inode); - d_instantiate(dentry, inode); + d_instantiate_new(dentry, inode); return 0; fail: @@ -745,8 +742,7 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode mutex_unlock(&dir_f->sem); jffs2_complete_reservation(c); - unlock_new_inode(inode); - d_instantiate(dentry, inode); + d_instantiate_new(dentry, inode); return 0; fail: |