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| author | NeilBrown <neilb@suse.de> | 2014-09-11 16:19:37 +1000 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-09-12 13:10:53 -0400 |
| commit | f39c01047994e66e7f3d89ddb4c6141f23349d8d (patch) | |
| tree | f529a1bcb1a4c63d0396049e9444859dd3424fde /fs | |
| parent | 224ecbf5a674ec7da3a3b3ea21ca62e2853653fa (diff) | |
| download | linux-f39c01047994e66e7f3d89ddb4c6141f23349d8d.tar.gz linux-f39c01047994e66e7f3d89ddb4c6141f23349d8d.tar.xz | |
NFS: remove BUG possibility in nfs4_open_and_get_state
commit 4fa2c54b5198d09607a534e2fd436581064587ed
NFS: nfs4_do_open should add negative results to the dcache.
used "d_drop(); d_add();" to ensure that a dentry was hashed
as a negative cached entry.
This is not safe if the dentry has an non-NULL ->d_inode.
It will trigger a BUG_ON in d_instantiate().
In that case, d_delete() is needed.
Also, only d_add if the dentry is currently unhashed, it seems
pointless removed and re-adding it unchanged.
Reported-by: Christoph Hellwig <hch@infradead.org>
Fixes: 4fa2c54b5198d09607a534e2fd436581064587ed
Cc: Jeff Layton <jeff.layton@primarydata.com>
Link: http://lkml.kernel.org/r/20140908144525.GB19811@infradead.org
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/nfs4proc.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 7dd8aca31c29..ac2dd953fc18 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -2226,9 +2226,13 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata, ret = _nfs4_proc_open(opendata); if (ret != 0) { if (ret == -ENOENT) { - d_drop(opendata->dentry); - d_add(opendata->dentry, NULL); - nfs_set_verifier(opendata->dentry, + dentry = opendata->dentry; + if (dentry->d_inode) + d_delete(dentry); + else if (d_unhashed(dentry)) + d_add(dentry, NULL); + + nfs_set_verifier(dentry, nfs_save_change_attribute(opendata->dir->d_inode)); } goto out; |