6.6-stable review patch. If anyone has any objections, please let me know.
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From: "Steven Rostedt (Google)" rostedt@goodmis.org
commit bcae32c5632fc0a0dbce46fa731cd23403117e66 upstream.
The both create_file_dentry() and create_dir_dentry() takes a boolean parameter "lookup", as on lookup the inode_lock should already be taken, but for dcache_dir_open_wrapper() it is not taken.
There's no reason that the dcache_dir_open_wrapper() can't take the inode_lock before calling these functions. In fact, it's better if it does, as the lock can be held throughout both directory and file creations.
This also simplifies the code, and possibly prevents unexpected race conditions when the lock is released.
Link: https://lkml.kernel.org/r/20231121231112.528544825@goodmis.org
Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Andrew Morton akpm@linux-foundation.org Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode") Reviewed-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/tracefs/event_inode.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-)
--- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -347,15 +347,8 @@ create_file_dentry(struct eventfs_inode
mutex_unlock(&eventfs_mutex);
- /* The lookup already has the parent->d_inode locked */ - if (!lookup) - inode_lock(parent->d_inode); - dentry = create_file(name, mode, attr, parent, data, fops);
- if (!lookup) - inode_unlock(parent->d_inode); - mutex_lock(&eventfs_mutex);
if (IS_ERR_OR_NULL(dentry)) { @@ -453,15 +446,8 @@ create_dir_dentry(struct eventfs_inode * } mutex_unlock(&eventfs_mutex);
- /* The lookup already has the parent->d_inode locked */ - if (!lookup) - inode_lock(parent->d_inode); - dentry = create_dir(ei, parent);
- if (!lookup) - inode_unlock(parent->d_inode); - mutex_lock(&eventfs_mutex);
if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) { @@ -693,6 +679,7 @@ static int dcache_dir_open_wrapper(struc return -ENOMEM; }
+ inode_lock(parent->d_inode); list_for_each_entry_srcu(ei_child, &ei->children, list, srcu_read_lock_held(&eventfs_srcu)) { d = create_dir_dentry(ei, ei_child, parent, false); @@ -725,6 +712,7 @@ static int dcache_dir_open_wrapper(struc cnt++; } } + inode_unlock(parent->d_inode); srcu_read_unlock(&eventfs_srcu, idx); ret = dcache_dir_open(inode, file);