Attachment 202835 Details for Bug 369024

[patch] commit 6f23e3872cff238589f9bf39c71db2ea880c9a26

nfs-fix-race-between-umount-and-nfs_access_cache_shrinker (text/plain), 1.26 KB, created by Sven Dietrich on 2008-03-19 03:58:31 UTC

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Creator: Sven Dietrich

Created: 2008-03-19 03:58:31 UTC

Size: 1.26 KB

patch

obsolete

>commit 6f23e3872cff238589f9bf39c71db2ea880c9a26
>Author: Trond Myklebust <Trond.Myklebust@netapp.com>
>Date:   Fri Jan 25 16:38:17 2008 -0500
>
>    NFS: Fix a potential race between umount and nfs_access_cache_shrinker()
>    
>    Thanks to Yawei Niu for spotting the race.
>    
>    Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
>
>diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>index 5ca762d..476cb0f 100644
>--- a/fs/nfs/dir.c
>+++ b/fs/nfs/dir.c
>@@ -1694,13 +1694,19 @@ int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
> restart:
> 	spin_lock(&nfs_access_lru_lock);
> 	list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) {
>+		struct rw_semaphore *s_umount;
> 		struct inode *inode;
> 
> 		if (nr_to_scan-- == 0)
> 			break;
>+		s_umount = &nfsi->vfs_inode.i_sb->s_umount;
>+		if (!down_read_trylock(s_umount))
>+			continue;
> 		inode = igrab(&nfsi->vfs_inode);
>-		if (inode == NULL)
>+		if (inode == NULL) {
>+			up_read(s_umount);
> 			continue;
>+		}
> 		spin_lock(&inode->i_lock);
> 		if (list_empty(&nfsi->access_cache_entry_lru))
> 			goto remove_lru_entry;
>@@ -1719,6 +1725,7 @@ remove_lru_entry:
> 		spin_unlock(&inode->i_lock);
> 		spin_unlock(&nfs_access_lru_lock);
> 		iput(inode);
>+		up_read(s_umount);
> 		goto restart;
> 	}
> 	spin_unlock(&nfs_access_lru_lock);

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Attachments on bug 369024: 200131 | 202834 | 202835