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authorSrinivasa Ds <srinivasa@in.ibm.com>2006-11-02 22:07:12 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-11-03 12:27:57 -0800
commit7ef55b8a05c02db7c07d81827c69fe8f124e8654 (patch)
treef588e5256e88595d04662c1faf105f9b95656c6b /fs/nfsd
parent77d6e1397a004c9376fed855e4164ca2b1dba2ed (diff)
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[PATCH] NFS4: fix for recursive locking problem
When I was performing some operations on NFS, I got below error on server side. ============================================= [ INFO: possible recursive locking detected ] 2.6.19-prep #1 --------------------------------------------- nfsd4/3525 is trying to acquire lock: (&inode->i_mutex){--..}, at: [<c0611e5a>] mutex_lock+0x21/0x24 but task is already holding lock: (&inode->i_mutex){--..}, at: [<c0611e5a>] mutex_lock+0x21/0x24 other info that might help us debug this: 2 locks held by nfsd4/3525: #0: (client_mutex){--..}, at: [<c0611e5a>] mutex_lock+0x21/0x24 #1: (&inode->i_mutex){--..}, at: [<c0611e5a>] mutex_lock+0x21/0x24 stack backtrace: [<c04051ed>] show_trace_log_lvl+0x58/0x16a [<c04057fa>] show_trace+0xd/0x10 [<c0405913>] dump_stack+0x19/0x1b [<c043b6f1>] __lock_acquire+0x778/0x99c [<c043be86>] lock_acquire+0x4b/0x6d [<c0611ceb>] __mutex_lock_slowpath+0xbc/0x20a [<c0611e5a>] mutex_lock+0x21/0x24 [<c047fd7e>] vfs_rmdir+0x76/0xf8 [<f94b7ce9>] nfsd4_clear_clid_dir+0x2c/0x41 [nfsd] [<f94b7de9>] nfsd4_remove_clid_dir+0xb1/0xe8 [nfsd] [<f94b307b>] laundromat_main+0x9b/0x1c3 [nfsd] [<c04333d6>] run_workqueue+0x7a/0xbb [<c0433d0b>] worker_thread+0xd2/0x107 [<c0436285>] kthread+0xc3/0xf2 [<c0402005>] kernel_thread_helper+0x5/0xb =================================================================== Cause for this problem was,2 successive mutex_lock calls on 2 diffrent inodes ,as shown below static int nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry) { int status; /* For now this directory should already be empty, but we empty it of * any regular files anyway, just in case the directory was created by * a kernel from the future.... */ nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file); mutex_lock(&dir->d_inode->i_mutex); status = vfs_rmdir(dir->d_inode, dentry); ... int vfs_rmdir(struct inode *dir, struct dentry *dentry) { int error = may_delete(dir, dentry, 1); if (error) return error; if (!dir->i_op || !dir->i_op->rmdir) return -EPERM; DQUOT_INIT(dir); mutex_lock(&dentry->d_inode->i_mutex); ... So I have developed the patch to overcome this problem. Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs4recover.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index e9d07704680e..81b8565d3837 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -274,7 +274,7 @@ nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
* any regular files anyway, just in case the directory was created by
* a kernel from the future.... */
nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
- mutex_lock(&dir->d_inode->i_mutex);
+ mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
status = vfs_rmdir(dir->d_inode, dentry);
mutex_unlock(&dir->d_inode->i_mutex);
return status;