From d405498e377754e5465c5c8e849b9df4deb65c49 Mon Sep 17 00:00:00 2001 From: Xavi Hernandez Date: Tue, 12 May 2020 23:54:54 +0200 Subject: open-behind: rewrite of internal logic There was a critical flaw in the previous implementation of open-behind. When an open is done in the background, it's necessary to take a reference on the fd_t object because once we "fake" the open answer, the fd could be destroyed. However as long as there's a reference, the release function won't be called. So, if the application closes the file descriptor without having actually opened it, there will always remain at least 1 reference, causing a leak. To avoid this problem, the previous implementation didn't take a reference on the fd_t, so there were races where the fd could be destroyed while it was still in use. To fix this, I've implemented a new xlator cbk that gets called from fuse when the application closes a file descriptor. The whole logic of handling background opens have been simplified and it's more efficient now. Only if the fop needs to be delayed until an open completes, a stub is created. Otherwise no memory allocations are needed. Correctly handling the close request while the open is still pending has added a bit of complexity, but overall normal operation is simpler. Change-Id: I6376a5491368e0e1c283cc452849032636261592 Fixes: #1225 Signed-off-by: Xavi Hernandez --- libglusterfs/src/glusterfs/fd.h | 3 +++ libglusterfs/src/glusterfs/xlator.h | 4 ++++ 2 files changed, 7 insertions(+) (limited to 'libglusterfs/src/glusterfs') diff --git a/libglusterfs/src/glusterfs/fd.h b/libglusterfs/src/glusterfs/fd.h index 28906d34e4d..3ffaaa60504 100644 --- a/libglusterfs/src/glusterfs/fd.h +++ b/libglusterfs/src/glusterfs/fd.h @@ -106,6 +106,9 @@ fd_ref(fd_t *fd); void fd_unref(fd_t *fd); +void +fd_close(fd_t *fd); + fd_t * fd_create(struct _inode *inode, pid_t pid); diff --git a/libglusterfs/src/glusterfs/xlator.h b/libglusterfs/src/glusterfs/xlator.h index c94bd75cf1c..23004ab2245 100644 --- a/libglusterfs/src/glusterfs/xlator.h +++ b/libglusterfs/src/glusterfs/xlator.h @@ -702,6 +702,8 @@ typedef size_t (*cbk_inodectx_size_t)(xlator_t *this, inode_t *inode); typedef size_t (*cbk_fdctx_size_t)(xlator_t *this, fd_t *fd); +typedef void (*cbk_fdclose_t)(xlator_t *this, fd_t *fd); + struct xlator_cbks { cbk_forget_t forget; cbk_release_t release; @@ -712,6 +714,8 @@ struct xlator_cbks { cbk_ictxmerge_t ictxmerge; cbk_inodectx_size_t ictxsize; cbk_fdctx_size_t fdctxsize; + cbk_fdclose_t fdclose; + cbk_fdclose_t fdclosedir; }; typedef int32_t (*dumpop_priv_t)(xlator_t *this); -- cgit