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| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-03-25 14:15:11 -0400 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-03-27 17:48:07 +0200 |
| commit | 4d65c520fb4abed970069d18c119cfe85624f46d (patch) | |
| tree | 74671eb263380317f1e4a958a6a7f73749e98eec | |
| parent | 16c29dafcc86024048f1dbb8349d31cb22c7c55a (diff) | |
| download | lwn-4d65c520fb4abed970069d18c119cfe85624f46d.tar.gz lwn-4d65c520fb4abed970069d18c119cfe85624f46d.zip | |
NFS: Fix a hang in the writeback path
Now that the inode scalability patches have been merged, it is no longer
safe to call igrab() under the inode->i_lock.
Now that we no longer call nfs_clear_request() until the nfs_page is
being freed, we know that we are always holding a reference to the
nfs_open_context, which again holds a reference to the path, and so
the inode cannot be freed until the last nfs_page has been removed
from the radix tree and freed.
We can therefore skip the igrab()/iput() altogether.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| -rw-r--r-- | fs/nfs/pagelist.c | 4 | ||||
| -rw-r--r-- | fs/nfs/write.c | 13 | ||||
| -rw-r--r-- | include/linux/nfs_page.h | 1 |
3 files changed, 5 insertions, 13 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 87a593c2b055..c80add6e2213 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -135,14 +135,14 @@ void nfs_clear_page_tag_locked(struct nfs_page *req) nfs_unlock_request(req); } -/** +/* * nfs_clear_request - Free up all resources allocated to the request * @req: * * Release page and open context resources associated with a read/write * request after it has completed. */ -void nfs_clear_request(struct nfs_page *req) +static void nfs_clear_request(struct nfs_page *req) { struct page *page = req->wb_page; struct nfs_open_context *ctx = req->wb_context; diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 85d75254328e..af0c6279a4a7 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -389,11 +389,8 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req) spin_lock(&inode->i_lock); error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req); BUG_ON(error); - if (!nfsi->npages) { - igrab(inode); - if (nfs_have_delegation(inode, FMODE_WRITE)) - nfsi->change_attr++; - } + if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE)) + nfsi->change_attr++; set_bit(PG_MAPPED, &req->wb_flags); SetPagePrivate(req->wb_page); set_page_private(req->wb_page, (unsigned long)req); @@ -423,11 +420,7 @@ static void nfs_inode_remove_request(struct nfs_page *req) clear_bit(PG_MAPPED, &req->wb_flags); radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index); nfsi->npages--; - if (!nfsi->npages) { - spin_unlock(&inode->i_lock); - iput(inode); - } else - spin_unlock(&inode->i_lock); + spin_unlock(&inode->i_lock); nfs_release_request(req); } diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 8023e4e25133..91af2e49fa3a 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -78,7 +78,6 @@ extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx, struct page *page, unsigned int offset, unsigned int count); -extern void nfs_clear_request(struct nfs_page *req); extern void nfs_release_request(struct nfs_page *req); |