From 1c8c601a8c0dc59fe64907dcd9d512a3d181ddc7 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 21 Jun 2013 08:58:15 -0400 Subject: locks: protect most of the file_lock handling with i_lock Having a global lock that protects all of this code is a clear scalability problem. Instead of doing that, move most of the code to be protected by the i_lock instead. The exceptions are the global lists that the ->fl_link sits on, and the ->fl_block list. ->fl_link is what connects these structures to the global lists, so we must ensure that we hold those locks when iterating over or updating these lists. Furthermore, sound deadlock detection requires that we hold the blocked_list state steady while checking for loops. We also must ensure that the search and update to the list are atomic. For the checking and insertion side of the blocked_list, push the acquisition of the global lock into __posix_lock_file and ensure that checking and update of the blocked_list is done without dropping the lock in between. On the removal side, when waking up blocked lock waiters, take the global lock before walking the blocked list and dequeue the waiters from the global list prior to removal from the fl_block list. With this, deadlock detection should be race free while we minimize excessive file_lock_lock thrashing. Finally, in order to avoid a lock inversion problem when handling /proc/locks output we must ensure that manipulations of the fl_block list are also protected by the file_lock_lock. Signed-off-by: Jeff Layton Signed-off-by: Al Viro --- fs/ceph/locks.c | 2 +- fs/ceph/mds_client.c | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c index ebbf680378e2..690f73f42425 100644 --- a/fs/ceph/locks.c +++ b/fs/ceph/locks.c @@ -192,7 +192,7 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) /** * Encode the flock and fcntl locks for the given inode into the ceph_filelock - * array. Must be called with lock_flocks() already held. + * array. Must be called with inode->i_lock already held. * If we encounter more of a specific lock type than expected, return -ENOSPC. */ int ceph_encode_locks_to_buffer(struct inode *inode, diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 4d2920304be8..74fd2898b2ab 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -2481,20 +2481,20 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap, struct ceph_filelock *flocks; encode_again: - lock_flocks(); + spin_lock(&inode->i_lock); ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks); - unlock_flocks(); + spin_unlock(&inode->i_lock); flocks = kmalloc((num_fcntl_locks+num_flock_locks) * sizeof(struct ceph_filelock), GFP_NOFS); if (!flocks) { err = -ENOMEM; goto out_free; } - lock_flocks(); + spin_lock(&inode->i_lock); err = ceph_encode_locks_to_buffer(inode, flocks, num_fcntl_locks, num_flock_locks); - unlock_flocks(); + spin_unlock(&inode->i_lock); if (err) { kfree(flocks); if (err == -ENOSPC) -- cgit v1.2.2 From 46a1c2c7ae53de2a5676754b54a73c591a3951d2 Mon Sep 17 00:00:00 2001 From: Jie Liu Date: Tue, 25 Jun 2013 12:02:13 +0800 Subject: vfs: export lseek_execute() to modules For those file systems(btrfs/ext4/ocfs2/tmpfs) that support SEEK_DATA/SEEK_HOLE functions, we end up handling the similar matter in lseek_execute() to update the current file offset to the desired offset if it is valid, ceph also does the simliar things at ceph_llseek(). To reduce the duplications, this patch make lseek_execute() public accessible so that we can call it directly from the underlying file systems. Thanks Dave Chinner for this suggestion. [AV: call it vfs_setpos(), don't bring the removed 'inode' argument back] v2->v1: - Add kernel-doc comments for lseek_execute() - Call lseek_execute() in ceph->llseek() Signed-off-by: Jie Liu Cc: Dave Chinner Cc: Al Viro Cc: Andi Kleen Cc: Andrew Morton Cc: Christoph Hellwig Cc: Chris Mason Cc: Josef Bacik Cc: Ben Myers Cc: Ted Tso Cc: Hugh Dickins Cc: Mark Fasheh Cc: Joel Becker Cc: Sage Weil Signed-off-by: Al Viro --- fs/ceph/file.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'fs/ceph') diff --git a/fs/ceph/file.c b/fs/ceph/file.c index 656e16907430..16c989d3e23c 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -866,16 +866,7 @@ static loff_t ceph_llseek(struct file *file, loff_t offset, int whence) break; } - if (offset < 0 || offset > inode->i_sb->s_maxbytes) { - offset = -EINVAL; - goto out; - } - - /* Special lock needed here? */ - if (offset != file->f_pos) { - file->f_pos = offset; - file->f_version = 0; - } + offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes); out: mutex_unlock(&inode->i_mutex); -- cgit v1.2.2