On 03/20/2013 07:39 PM, Trond Myklebust wrote:
> In order to be able to safely return the layout in nfs4_proc_setattr,
> we need to block new uses of the layout, wait for all outstanding
> users of the layout to complete, commit the layout and then return it.
>
> This patch adds a helper in order to do all this safely.
>
Hi Trond
It looks like this patchset might actually fix my problem as well.
I've been super swamped with internal work at Panasas, and never got
a chance to cleanup and review my experimental fixes. So it looks like
you bit me to it. Your work looks much better, and deeper then what I
had. Though one concern I have is that I need those for @stable so my
change was as minimal as possible, single patch.
I have just arrived back to Israel today, and will only have time to test
all this Next week. I have just the right setup for this. I understand that
for you it might be harder because Files-layout does not support segments and
my deadlock can only happen with two segments and up.
[BTW: I did not even reviewed the code yet will do ASAP]
Thanks
Boaz
> Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> Cc: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
> ---
> fs/nfs/nfs4proc.c | 2 +-
> fs/nfs/pnfs.c | 22 ++++++++++++++++++++++
> fs/nfs/pnfs.h | 6 ++++++
> 3 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 5122753..c560c8f 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -2695,7 +2695,7 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
> int status;
>
> if (pnfs_ld_layoutret_on_setattr(inode))
> - pnfs_return_layout(inode);
> + pnfs_commit_and_return_layout(inode);
>
> nfs_fattr_init(fattr);
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 45badca..5a5e14d 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -868,6 +868,28 @@ out:
> }
> EXPORT_SYMBOL_GPL(_pnfs_return_layout);
>
> +int
> +pnfs_commit_and_return_layout(struct inode *inode)
> +{
> + struct pnfs_layout_hdr *lo;
> + int ret;
> +
> + spin_lock(&inode->i_lock);
> + lo = NFS_I(inode)->layout;
> + if (lo == NULL) {
> + spin_unlock(&inode->i_lock);
> + return 0;
> + }
> + /* Block new layoutgets and read/write to ds */
> + lo->plh_block_lgets++;
> + spin_unlock(&inode->i_lock);
> + filemap_fdatawait(inode->i_mapping);
> + ret = pnfs_layoutcommit_inode(inode, true);
> + if (ret == 0)
> + ret = _pnfs_return_layout(inode);
> + return ret;
> +}
> +
> bool pnfs_roc(struct inode *ino)
> {
> struct pnfs_layout_hdr *lo;
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 94ba804..f5f8a47 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -219,6 +219,7 @@ void pnfs_set_layoutcommit(struct nfs_write_data *wdata);
> void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data);
> int pnfs_layoutcommit_inode(struct inode *inode, bool sync);
> int _pnfs_return_layout(struct inode *);
> +int pnfs_commit_and_return_layout(struct inode *);
> void pnfs_ld_write_done(struct nfs_write_data *);
> void pnfs_ld_read_done(struct nfs_read_data *);
> struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
> @@ -407,6 +408,11 @@ static inline int pnfs_return_layout(struct inode *ino)
> return 0;
> }
>
> +static inline int pnfs_commit_and_return_layout(struct inode *inode)
> +{
> + return 0;
> +}
> +
> static inline bool
> pnfs_ld_layoutret_on_setattr(struct inode *inode)
> {
>
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