| From 7c2dad99d60c86ec686b3bfdcb787c450a7ea89f Mon Sep 17 00:00:00 2001 |
| From: Trond Myklebust <trond.myklebust@primarydata.com> |
| Date: Thu, 6 Aug 2015 12:06:30 -0400 |
| Subject: NFS: Don't let the ctime override attribute barriers. |
| |
| From: Trond Myklebust <trond.myklebust@primarydata.com> |
| |
| commit 7c2dad99d60c86ec686b3bfdcb787c450a7ea89f upstream. |
| |
| Chuck reports seeing cases where a GETATTR that happens to race |
| with an asynchronous WRITE is overriding the file size, despite |
| the attribute barrier being set by the writeback code. |
| |
| The culprit turns out to be the check in nfs_ctime_need_update(), |
| which sees that the ctime is newer than the cached ctime, and |
| assumes that it is safe to override the attribute barrier. |
| This patch removes that override, and ensures that attribute |
| barriers are always respected. |
| |
| Reported-by: Chuck Lever <chuck.lever@oracle.com> |
| Fixes: a08a8cd375db9 ("NFS: Add attribute update barriers to NFS writebacks") |
| Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/nfs/inode.c | 8 -------- |
| 1 file changed, 8 deletions(-) |
| |
| --- a/fs/nfs/inode.c |
| +++ b/fs/nfs/inode.c |
| @@ -1270,13 +1270,6 @@ static int nfs_check_inode_attributes(st |
| return 0; |
| } |
| |
| -static int nfs_ctime_need_update(const struct inode *inode, const struct nfs_fattr *fattr) |
| -{ |
| - if (!(fattr->valid & NFS_ATTR_FATTR_CTIME)) |
| - return 0; |
| - return timespec_compare(&fattr->ctime, &inode->i_ctime) > 0; |
| -} |
| - |
| static atomic_long_t nfs_attr_generation_counter; |
| |
| static unsigned long nfs_read_attr_generation_counter(void) |
| @@ -1425,7 +1418,6 @@ static int nfs_inode_attrs_need_update(c |
| const struct nfs_inode *nfsi = NFS_I(inode); |
| |
| return ((long)fattr->gencount - (long)nfsi->attr_gencount) > 0 || |
| - nfs_ctime_need_update(inode, fattr) || |
| ((long)nfsi->attr_gencount - (long)nfs_read_attr_generation_counter() > 0); |
| } |
| |
