From b415bf4f9fe25f39934f5c464125e4a2dffb6d08 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Tue, 2 Jul 2013 12:40:19 +0800 Subject: [PATCH] ceph: fix pending vmtruncate race The locking order for pending vmtruncate is wrong, it can lead to following race: write wmtruncate work ------------------------ ---------------------- lock i_mutex check i_truncate_pending check i_truncate_pending truncate_inode_pages() lock i_mutex (blocked) copy data to page cache unlock i_mutex truncate_inode_pages() The fix is take i_mutex before calling __ceph_do_pending_vmtruncate() Fixes: http://tracker.ceph.com/issues/5453 Signed-off-by: Yan, Zheng Reviewed-by: Sage Weil --- fs/ceph/caps.c | 6 +++++- fs/ceph/file.c | 2 +- fs/ceph/inode.c | 14 ++++++-------- fs/ceph/super.h | 2 +- 4 files changed, 13 insertions(+), 11 deletions(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 8ec27b1..16266f3 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -2057,7 +2057,11 @@ static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want, /* finish pending truncate */ while (ci->i_truncate_pending) { spin_unlock(&ci->i_ceph_lock); - __ceph_do_pending_vmtruncate(inode, !(need & CEPH_CAP_FILE_WR)); + if (!(need & CEPH_CAP_FILE_WR)) + mutex_lock(&inode->i_mutex); + __ceph_do_pending_vmtruncate(inode); + if (!(need & CEPH_CAP_FILE_WR)) + mutex_unlock(&inode->i_mutex); spin_lock(&ci->i_ceph_lock); } diff --git a/fs/ceph/file.c b/fs/ceph/file.c index 7c69f4f..a44d515 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -822,7 +822,7 @@ static loff_t ceph_llseek(struct file *file, loff_t offset, int whence) int ret; mutex_lock(&inode->i_mutex); - __ceph_do_pending_vmtruncate(inode, false); + __ceph_do_pending_vmtruncate(inode); if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) { ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE); diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index be0f7e2..4906ada 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1465,7 +1465,9 @@ static void ceph_vmtruncate_work(struct work_struct *work) struct inode *inode = &ci->vfs_inode; dout("vmtruncate_work %p\n", inode); - __ceph_do_pending_vmtruncate(inode, true); + mutex_lock(&inode->i_mutex); + __ceph_do_pending_vmtruncate(inode); + mutex_unlock(&inode->i_mutex); iput(inode); } @@ -1492,7 +1494,7 @@ void ceph_queue_vmtruncate(struct inode *inode) * Make sure any pending truncation is applied before doing anything * that may depend on it. */ -void __ceph_do_pending_vmtruncate(struct inode *inode, bool needlock) +void __ceph_do_pending_vmtruncate(struct inode *inode) { struct ceph_inode_info *ci = ceph_inode(inode); u64 to; @@ -1525,11 +1527,7 @@ retry: ci->i_truncate_pending, to); spin_unlock(&ci->i_ceph_lock); - if (needlock) - mutex_lock(&inode->i_mutex); truncate_inode_pages(inode->i_mapping, to); - if (needlock) - mutex_unlock(&inode->i_mutex); spin_lock(&ci->i_ceph_lock); if (to == ci->i_truncate_size) { @@ -1588,7 +1586,7 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr) if (ceph_snap(inode) != CEPH_NOSNAP) return -EROFS; - __ceph_do_pending_vmtruncate(inode, false); + __ceph_do_pending_vmtruncate(inode); err = inode_change_ok(inode, attr); if (err != 0) @@ -1770,7 +1768,7 @@ int ceph_setattr(struct dentry *dentry, struct iattr *attr) ceph_cap_string(dirtied), mask); ceph_mdsc_put_request(req); - __ceph_do_pending_vmtruncate(inode, false); + __ceph_do_pending_vmtruncate(inode); return err; out: spin_unlock(&ci->i_ceph_lock); diff --git a/fs/ceph/super.h b/fs/ceph/super.h index dfbb729..cbded57 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -692,7 +692,7 @@ extern int ceph_readdir_prepopulate(struct ceph_mds_request *req, extern int ceph_inode_holds_cap(struct inode *inode, int mask); extern int ceph_inode_set_size(struct inode *inode, loff_t size); -extern void __ceph_do_pending_vmtruncate(struct inode *inode, bool needlock); +extern void __ceph_do_pending_vmtruncate(struct inode *inode); extern void ceph_queue_vmtruncate(struct inode *inode); extern void ceph_queue_invalidate(struct inode *inode); -- 2.7.4