From: Bob Peterson rpeterso@redhat.com
[ Upstream commit d3add1a9519dcacd6e644ecac741c56cf18b67f5 ]
When a file is opened for writing, the vfs code (do_dentry_open) calls get_write_access for the inode, thus incrementing the inode's write count. That writer normally then creates a multi-block reservation for the inode (i_res) that can be re-used by other writers, which speeds up writes for applications that stupidly loop on open/write/close. When the writes are all done, the multi-block reservation should be deleted when the file is closed by the last "writer."
Commit 0ec9b9ea4f83 broke that concept when it moved the call to gfs2_rs_delete before the check for FMODE_WRITE. Non-writers have no business removing the multi-block reservations of writers. In fact, if someone opens and closes the file for RO while a writer has a multi-block reservation, the RO closer will delete the reservation midway through the write, and this results in:
kernel BUG at fs/gfs2/rgrp.c:677! (or thereabouts) which is: BUG_ON(rs->rs_requested); from function gfs2_rs_deltree.
This patch moves the check back inside the check for FMODE_WRITE.
Fixes: 0ec9b9ea4f83 ("gfs2: Check for active reservation in gfs2_release") Cc: stable@vger.kernel.org # v5.12+ Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/file.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 59318b1eaa60..7bd7581aa682 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -716,10 +716,11 @@ static int gfs2_release(struct inode *inode, struct file *file) kfree(file->private_data); file->private_data = NULL;
- if (gfs2_rs_active(&ip->i_res)) - gfs2_rs_delete(ip, &inode->i_writecount); - if (file->f_mode & FMODE_WRITE) + if (file->f_mode & FMODE_WRITE) { + if (gfs2_rs_active(&ip->i_res)) + gfs2_rs_delete(ip, &inode->i_writecount); gfs2_qa_put(ip); + } return 0; }