From 860b69a9d77160d21ca00357fd6c5217f9d41fb1 Mon Sep 17 00:00:00 2001 From: Rohith Surabattula Date: Wed, 5 May 2021 10:56:47 +0000 Subject: [PATCH] Fix kernel oops when CONFIG_DEBUG_ATOMIC_SLEEP is enabled. Removed oplock_break_received flag which was added to achieve synchronization between oplock handler and open handler by earlier commit. It is not needed because there is an existing lock open_file_lock to achieve the same. find_readable_file takes open_file_lock and then traverses the openFileList. Similarly, cifs_oplock_break while closing the deferred handle (i.e cifsFileInfo_put) takes open_file_lock and then sends close to the server. Added comments for better readability. Signed-off-by: Rohith Surabattula Signed-off-by: Steve French --- fs/cifs/cifsfs.c | 2 +- fs/cifs/cifsglob.h | 3 +-- fs/cifs/file.c | 27 ++++++++++++--------------- fs/cifs/misc.c | 9 +++++++++ 4 files changed, 23 insertions(+), 18 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index d7ea9c5fe0f8..2ffcb29d5c8f 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -133,7 +133,7 @@ struct workqueue_struct *cifsiod_wq; struct workqueue_struct *decrypt_wq; struct workqueue_struct *fileinfo_put_wq; struct workqueue_struct *cifsoplockd_wq; -struct workqueue_struct *deferredclose_wq; +struct workqueue_struct *deferredclose_wq; __u32 cifs_lock_secret; /* diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index d88b4b523dcc..ea90c53386b8 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1257,8 +1257,7 @@ struct cifsFileInfo { struct work_struct oplock_break; /* work for oplock breaks */ struct work_struct put; /* work for the final part of _put */ struct delayed_work deferred; - bool oplock_break_received; /* Flag to indicate oplock break */ - bool deferred_scheduled; + bool deferred_close_scheduled; /* Flag to indicate close is scheduled */ }; struct cifs_io_parms { diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 6caad100c3f3..304d9d3783c6 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -323,8 +323,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file, cfile->dentry = dget(dentry); cfile->f_flags = file->f_flags; cfile->invalidHandle = false; - cfile->oplock_break_received = false; - cfile->deferred_scheduled = false; + cfile->deferred_close_scheduled = false; cfile->tlink = cifs_get_tlink(tlink); INIT_WORK(&cfile->oplock_break, cifs_oplock_break); INIT_WORK(&cfile->put, cifsFileInfo_put_work); @@ -574,21 +573,18 @@ int cifs_open(struct inode *inode, struct file *file) file->f_op = &cifs_file_direct_ops; } - spin_lock(&CIFS_I(inode)->deferred_lock); /* Get the cached handle as SMB2 close is deferred */ rc = cifs_get_readable_path(tcon, full_path, &cfile); if (rc == 0) { if (file->f_flags == cfile->f_flags) { file->private_data = cfile; + spin_lock(&CIFS_I(inode)->deferred_lock); cifs_del_deferred_close(cfile); spin_unlock(&CIFS_I(inode)->deferred_lock); goto out; } else { - spin_unlock(&CIFS_I(inode)->deferred_lock); _cifsFileInfo_put(cfile, true, false); } - } else { - spin_unlock(&CIFS_I(inode)->deferred_lock); } if (server->oplocks) @@ -878,12 +874,12 @@ void smb2_deferred_work_close(struct work_struct *work) struct cifsFileInfo, deferred.work); spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock); - if (!cfile->deferred_scheduled) { + if (!cfile->deferred_close_scheduled) { spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock); return; } cifs_del_deferred_close(cfile); - cfile->deferred_scheduled = false; + cfile->deferred_close_scheduled = false; spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock); _cifsFileInfo_put(cfile, true, false); } @@ -905,14 +901,15 @@ int cifs_close(struct inode *inode, struct file *file) inode->i_ctime = inode->i_mtime = current_time(inode); spin_lock(&cinode->deferred_lock); cifs_add_deferred_close(cfile, dclose); - if (cfile->deferred_scheduled) { + if (cfile->deferred_close_scheduled && + delayed_work_pending(&cfile->deferred)) { mod_delayed_work(deferredclose_wq, &cfile->deferred, cifs_sb->ctx->acregmax); } else { /* Deferred close for files */ queue_delayed_work(deferredclose_wq, &cfile->deferred, cifs_sb->ctx->acregmax); - cfile->deferred_scheduled = true; + cfile->deferred_close_scheduled = true; spin_unlock(&cinode->deferred_lock); return 0; } @@ -2020,8 +2017,7 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode, if (fsuid_only && !uid_eq(open_file->uid, current_fsuid())) continue; if (OPEN_FMODE(open_file->f_flags) & FMODE_READ) { - if ((!open_file->invalidHandle) && - (!open_file->oplock_break_received)) { + if ((!open_file->invalidHandle)) { /* found a good file */ /* lock it so it will not be closed on us */ cifsFileInfo_get(open_file); @@ -4874,13 +4870,14 @@ oplock_break_ack: } /* * When oplock break is received and there are no active - * file handles but cached, then set the flag oplock_break_received. + * file handles but cached, then schedule deferred close immediately. * So, new open will not use cached handle. */ spin_lock(&CIFS_I(inode)->deferred_lock); is_deferred = cifs_is_deferred_close(cfile, &dclose); - if (is_deferred && cfile->deferred_scheduled) { - cfile->oplock_break_received = true; + if (is_deferred && + cfile->deferred_close_scheduled && + delayed_work_pending(&cfile->deferred)) { mod_delayed_work(deferredclose_wq, &cfile->deferred, 0); } spin_unlock(&CIFS_I(inode)->deferred_lock); diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 801a5300f765..34f2a7e80c58 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -672,6 +672,9 @@ cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink, spin_unlock(&tlink_tcon(open->tlink)->open_file_lock); } +/* + * Critical section which runs after acquiring deferred_lock. + */ bool cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose) { @@ -688,6 +691,9 @@ cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close ** return false; } +/* + * Critical section which runs after acquiring deferred_lock. + */ void cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose) { @@ -707,6 +713,9 @@ cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close * list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes); } +/* + * Critical section which runs after acquiring deferred_lock. + */ void cifs_del_deferred_close(struct cifsFileInfo *cfile) {