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authorAmir Goldstein <amir73il@gmail.com>2024-04-07 18:57:57 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2024-04-15 10:12:44 +0200
commit7cc911262835419fe469ebfae89891c0e97c62ef (patch)
tree8100455dddb40fbca0bf73b84136088469e4a779
parent4864a6dd8320ad856698f93009c89f66ccb1653f (diff)
downloadlinux-7cc911262835419fe469ebfae89891c0e97c62ef.tar.gz
fuse: fix parallel dio write on file open in passthrough mode
Parallel dio write takes a negative refcount of fi->iocachectr and so does open of file in passthrough mode. The refcount of passthrough mode is associated with attach/detach of a fuse_backing object to fuse inode. For parallel dio write, the backing file is irrelevant, so the call to fuse_inode_uncached_io_start() passes a NULL fuse_backing object. Passing a NULL fuse_backing will result in false -EBUSY error if the file is already open in passthrough mode. Allow taking negative fi->iocachectr refcount with NULL fuse_backing, because it does not conflict with an already attached fuse_backing object. Fixes: 4a90451bbc7f ("fuse: implement open in passthrough mode") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--fs/fuse/iomode.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c
index 98f1fd523dae63..c99e285f3183ef 100644
--- a/fs/fuse/iomode.c
+++ b/fs/fuse/iomode.c
@@ -90,7 +90,7 @@ int fuse_inode_uncached_io_start(struct fuse_inode *fi, struct fuse_backing *fb)
spin_lock(&fi->lock);
/* deny conflicting backing files on same fuse inode */
oldfb = fuse_inode_backing(fi);
- if (oldfb && oldfb != fb) {
+ if (fb && oldfb && oldfb != fb) {
err = -EBUSY;
goto unlock;
}
@@ -101,7 +101,7 @@ int fuse_inode_uncached_io_start(struct fuse_inode *fi, struct fuse_backing *fb)
fi->iocachectr--;
/* fuse inode holds a single refcount of backing file */
- if (!oldfb) {
+ if (fb && !oldfb) {
oldfb = fuse_inode_backing_set(fi, fb);
WARN_ON_ONCE(oldfb != NULL);
} else {