On Tue, Jan 02, 2018 at 02:26:49PM +0200, Amir Goldstein wrote:
> Instead of looking for all the places that update inode's m_time,
> update overlay inode i_mtime just before nfsd needs to read it.
>
> The non uptodate mtime issue was found and verified with the
> nfstest_posix test when run over NFS exported overlayfs:
>
> $ nfstest_posix --runtest=link,write
> ...
> FAIL: link - parent directory st_mtime should be updated
> FAIL: write - file st_mtime should be updated
Grepping for users of i_mtime in fs/nfsd/....
Looks like we might need something similar for fill_pre_wcc() ? (And
maybe nfsd4_block_commit_blocks() ?)
I don't think it's necessary for do_nfsd_create(), but it should be
harmless if we want to just make it a rule that nfsd shouldn't be
accessing i_mtime directly.
--b.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/inode.c | 10 ++++++++--
> fs/internal.h | 1 +
> fs/locks.c | 12 +++++++++++-
> 3 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index a252256f4e51..ceb5f5cb9c79 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1595,6 +1595,14 @@ static void update_ovl_d_inode_times(struct dentry *dentry, bool rcu)
> }
> }
>
> +void update_ovl_inode_times(struct inode *inode)
> +{
> + struct dentry *alias = d_find_any_alias(inode);
> +
> + if (alias)
> + update_ovl_d_inode_times(alias, false);
> +}
> +
> /*
> * With relative atime, only update atime if the previous atime is
> * earlier than either the ctime or mtime or if at least a day has
> @@ -1877,8 +1885,6 @@ int file_update_time(struct file *file)
> ret = update_time(inode, &now, sync_it);
> __mnt_drop_write_file(file);
>
> - update_ovl_d_inode_times(file->f_path.dentry, false);
> -
> return ret;
> }
> EXPORT_SYMBOL(file_update_time);
> diff --git a/fs/internal.h b/fs/internal.h
> index df262f41a0ef..a631fd49a1ee 100644
> --- a/fs/internal.h
> +++ b/fs/internal.h
> @@ -122,6 +122,7 @@ extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
> extern void inode_add_lru(struct inode *inode);
> extern int dentry_needs_remove_privs(struct dentry *dentry);
>
> +extern void update_ovl_inode_times(struct inode *inode);
> extern bool __atime_needs_update(const struct path *, struct inode *, bool);
> static inline bool atime_needs_update_rcu(const struct path *path,
> struct inode *inode)
> diff --git a/fs/locks.c b/fs/locks.c
> index 21b4dfa289ee..e2f604839aaf 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -127,6 +127,7 @@
> #include <linux/pid_namespace.h>
> #include <linux/hashtable.h>
> #include <linux/percpu.h>
> +#include "internal.h"
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/filelock.h>
> @@ -1553,6 +1554,15 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
>
> EXPORT_SYMBOL(__break_lease);
>
> +static struct timespec inode_mtime(struct inode *inode)
> +{
> + /* TODO: use another SB_ flag and/or pass dentry to lease_get_mtime() */
> + if (unlikely(inode->i_sb->s_flags & MS_NOREMOTELOCK))
> + update_ovl_inode_times(inode);
> +
> + return inode->i_mtime;
> +}
> +
> /**
> * lease_get_mtime - get the last modified time of an inode
> * @inode: the inode
> @@ -1581,7 +1591,7 @@ void lease_get_mtime(struct inode *inode, struct timespec *time)
> if (has_lease)
> *time = current_time(inode);
> else
> - *time = inode->i_mtime;
> + *time = inode_mtime(inode);
> }
>
> EXPORT_SYMBOL(lease_get_mtime);
> --
> 2.7.4
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