From: Greg Kurz <groug@kaod.org> To: Miklos Szeredi <miklos@szeredi.hu> Cc: linux-kernel@vger.kernel.org, Max Reitz <mreitz@redhat.com>, linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com, Vivek Goyal <vgoyal@redhat.com>, Greg Kurz <groug@kaod.org> Subject: [PATCH v2 5/7] fuse: Call vfs_get_tree() for submounts Date: Fri, 4 Jun 2021 18:11:54 +0200 [thread overview] Message-ID: <20210604161156.408496-6-groug@kaod.org> (raw) In-Reply-To: <20210604161156.408496-1-groug@kaod.org> We recently fixed an infinite loop by setting the SB_BORN flag on submounts along with the write barrier needed by super_cache_count(). This is the job of vfs_get_tree() and FUSE shouldn't have to care about the barrier at all. Split out some code from fuse_dentry_automount() to the dedicated fuse_get_tree_submount() handler for submounts and call vfs_get_tree(). Signed-off-by: Greg Kurz <groug@kaod.org> --- fs/fuse/dir.c | 53 +++++-------------------------------------------- fs/fuse/inode.c | 36 +++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+), 48 deletions(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 3fa8604c21d5..b88e5785a3dd 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -309,12 +309,8 @@ static int fuse_dentry_delete(const struct dentry *dentry) static struct vfsmount *fuse_dentry_automount(struct path *path) { struct fs_context *fsc; - struct fuse_mount *parent_fm = get_fuse_mount_super(path->mnt->mnt_sb); - struct fuse_conn *fc = parent_fm->fc; - struct fuse_mount *fm; struct vfsmount *mnt; struct fuse_inode *mp_fi = get_fuse_inode(d_inode(path->dentry)); - struct super_block *sb; int err; fsc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry); @@ -323,48 +319,15 @@ static struct vfsmount *fuse_dentry_automount(struct path *path) goto out; } - err = -ENOMEM; - fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); - if (!fm) - goto out_put_fsc; + /* Pass the FUSE inode of the mount for fuse_get_tree_submount() */ + fsc->fs_private = mp_fi; - fsc->s_fs_info = fm; - sb = sget_fc(fsc, NULL, set_anon_super_fc); - if (IS_ERR(sb)) { - err = PTR_ERR(sb); - kfree(fm); + err = vfs_get_tree(fsc); + if (err) goto out_put_fsc; - } - fm->fc = fuse_conn_get(fc); - - /* Initialize superblock, making @mp_fi its root */ - err = fuse_fill_super_submount(sb, mp_fi); - if (err) { - fuse_conn_put(fc); - kfree(fm); - sb->s_fs_info = NULL; - goto out_put_sb; - } - - down_write(&fc->killsb); - list_add_tail(&fm->fc_entry, &fc->mounts); - up_write(&fc->killsb); - - sb->s_flags |= SB_ACTIVE; - fsc->root = dget(sb->s_root); - - /* - * FIXME: setting SB_BORN requires a write barrier for - * super_cache_count(). We should actually come - * up with a proper ->get_tree() implementation - * for submounts and call vfs_get_tree() to take - * care of the write barrier. - */ - smp_wmb(); - sb->s_flags |= SB_BORN; /* We are done configuring the superblock, so unlock it */ - up_write(&sb->s_umount); + up_write(&fsc->root->d_sb->s_umount); /* Create the submount */ mnt = vfs_create_mount(fsc); @@ -376,12 +339,6 @@ static struct vfsmount *fuse_dentry_automount(struct path *path) put_fs_context(fsc); return mnt; -out_put_sb: - /* - * Only jump here when fsc->root is NULL and sb is still locked - * (otherwise put_fs_context() will put the superblock) - */ - deactivate_locked_super(sb); out_put_fsc: put_fs_context(fsc); out: diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index fa96a3762ea2..bec1676811d4 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1313,8 +1313,44 @@ int fuse_fill_super_submount(struct super_block *sb, return 0; } +/* Filesystem context private data holds the FUSE inode of the mount point */ static int fuse_get_tree_submount(struct fs_context *fsc) { + struct fuse_mount *fm; + struct fuse_inode *mp_fi = fsc->fs_private; + struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); + struct super_block *sb; + int err; + + fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); + if (!fm) + return -ENOMEM; + + fsc->s_fs_info = fm; + sb = sget_fc(fsc, NULL, set_anon_super_fc); + if (IS_ERR(sb)) { + kfree(fm); + return PTR_ERR(sb); + } + fm->fc = fuse_conn_get(fc); + + /* Initialize superblock, making @mp_fi its root */ + err = fuse_fill_super_submount(sb, mp_fi); + if (err) { + fuse_conn_put(fc); + kfree(fm); + sb->s_fs_info = NULL; + deactivate_locked_super(sb); + return err; + } + + down_write(&fc->killsb); + list_add_tail(&fm->fc_entry, &fc->mounts); + up_write(&fc->killsb); + + sb->s_flags |= SB_ACTIVE; + fsc->root = dget(sb->s_root); + return 0; } -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Greg Kurz <groug@kaod.org> To: Miklos Szeredi <miklos@szeredi.hu> Cc: linux-kernel@vger.kernel.org, virtio-fs@redhat.com, linux-fsdevel@vger.kernel.org, Max Reitz <mreitz@redhat.com>, Vivek Goyal <vgoyal@redhat.com> Subject: [Virtio-fs] [PATCH v2 5/7] fuse: Call vfs_get_tree() for submounts Date: Fri, 4 Jun 2021 18:11:54 +0200 [thread overview] Message-ID: <20210604161156.408496-6-groug@kaod.org> (raw) In-Reply-To: <20210604161156.408496-1-groug@kaod.org> We recently fixed an infinite loop by setting the SB_BORN flag on submounts along with the write barrier needed by super_cache_count(). This is the job of vfs_get_tree() and FUSE shouldn't have to care about the barrier at all. Split out some code from fuse_dentry_automount() to the dedicated fuse_get_tree_submount() handler for submounts and call vfs_get_tree(). Signed-off-by: Greg Kurz <groug@kaod.org> --- fs/fuse/dir.c | 53 +++++-------------------------------------------- fs/fuse/inode.c | 36 +++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+), 48 deletions(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 3fa8604c21d5..b88e5785a3dd 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -309,12 +309,8 @@ static int fuse_dentry_delete(const struct dentry *dentry) static struct vfsmount *fuse_dentry_automount(struct path *path) { struct fs_context *fsc; - struct fuse_mount *parent_fm = get_fuse_mount_super(path->mnt->mnt_sb); - struct fuse_conn *fc = parent_fm->fc; - struct fuse_mount *fm; struct vfsmount *mnt; struct fuse_inode *mp_fi = get_fuse_inode(d_inode(path->dentry)); - struct super_block *sb; int err; fsc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry); @@ -323,48 +319,15 @@ static struct vfsmount *fuse_dentry_automount(struct path *path) goto out; } - err = -ENOMEM; - fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); - if (!fm) - goto out_put_fsc; + /* Pass the FUSE inode of the mount for fuse_get_tree_submount() */ + fsc->fs_private = mp_fi; - fsc->s_fs_info = fm; - sb = sget_fc(fsc, NULL, set_anon_super_fc); - if (IS_ERR(sb)) { - err = PTR_ERR(sb); - kfree(fm); + err = vfs_get_tree(fsc); + if (err) goto out_put_fsc; - } - fm->fc = fuse_conn_get(fc); - - /* Initialize superblock, making @mp_fi its root */ - err = fuse_fill_super_submount(sb, mp_fi); - if (err) { - fuse_conn_put(fc); - kfree(fm); - sb->s_fs_info = NULL; - goto out_put_sb; - } - - down_write(&fc->killsb); - list_add_tail(&fm->fc_entry, &fc->mounts); - up_write(&fc->killsb); - - sb->s_flags |= SB_ACTIVE; - fsc->root = dget(sb->s_root); - - /* - * FIXME: setting SB_BORN requires a write barrier for - * super_cache_count(). We should actually come - * up with a proper ->get_tree() implementation - * for submounts and call vfs_get_tree() to take - * care of the write barrier. - */ - smp_wmb(); - sb->s_flags |= SB_BORN; /* We are done configuring the superblock, so unlock it */ - up_write(&sb->s_umount); + up_write(&fsc->root->d_sb->s_umount); /* Create the submount */ mnt = vfs_create_mount(fsc); @@ -376,12 +339,6 @@ static struct vfsmount *fuse_dentry_automount(struct path *path) put_fs_context(fsc); return mnt; -out_put_sb: - /* - * Only jump here when fsc->root is NULL and sb is still locked - * (otherwise put_fs_context() will put the superblock) - */ - deactivate_locked_super(sb); out_put_fsc: put_fs_context(fsc); out: diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index fa96a3762ea2..bec1676811d4 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1313,8 +1313,44 @@ int fuse_fill_super_submount(struct super_block *sb, return 0; } +/* Filesystem context private data holds the FUSE inode of the mount point */ static int fuse_get_tree_submount(struct fs_context *fsc) { + struct fuse_mount *fm; + struct fuse_inode *mp_fi = fsc->fs_private; + struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); + struct super_block *sb; + int err; + + fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); + if (!fm) + return -ENOMEM; + + fsc->s_fs_info = fm; + sb = sget_fc(fsc, NULL, set_anon_super_fc); + if (IS_ERR(sb)) { + kfree(fm); + return PTR_ERR(sb); + } + fm->fc = fuse_conn_get(fc); + + /* Initialize superblock, making @mp_fi its root */ + err = fuse_fill_super_submount(sb, mp_fi); + if (err) { + fuse_conn_put(fc); + kfree(fm); + sb->s_fs_info = NULL; + deactivate_locked_super(sb); + return err; + } + + down_write(&fc->killsb); + list_add_tail(&fm->fc_entry, &fc->mounts); + up_write(&fc->killsb); + + sb->s_flags |= SB_ACTIVE; + fsc->root = dget(sb->s_root); + return 0; } -- 2.31.1
next prev parent reply other threads:[~2021-06-04 16:12 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-04 16:11 [PATCH v2 0/7] fuse: Some fixes for submounts Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-04 16:11 ` [PATCH v2 1/7] fuse: Fix crash in fuse_dentry_automount() error path Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-04 16:11 ` [PATCH v2 2/7] fuse: Fix crash if superblock of submount gets killed early Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-08 15:08 ` Max Reitz 2021-06-08 15:08 ` [Virtio-fs] " Max Reitz 2021-06-04 16:11 ` [PATCH v2 3/7] fuse: Fix infinite loop in sget_fc() Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-08 15:12 ` Max Reitz 2021-06-08 15:12 ` [Virtio-fs] " Max Reitz 2021-06-04 16:11 ` [PATCH v2 4/7] fuse: Add dedicated filesystem context ops for submounts Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-08 15:25 ` Max Reitz 2021-06-08 15:25 ` [Virtio-fs] " Max Reitz 2021-06-04 16:11 ` Greg Kurz [this message] 2021-06-04 16:11 ` [Virtio-fs] [PATCH v2 5/7] fuse: Call vfs_get_tree() " Greg Kurz 2021-06-08 15:40 ` Max Reitz 2021-06-08 15:40 ` [Virtio-fs] " Max Reitz 2021-06-04 16:11 ` [PATCH v2 6/7] fuse: Switch to fc_mount() " Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-08 15:51 ` Max Reitz 2021-06-08 15:51 ` [Virtio-fs] " Max Reitz 2021-06-09 7:45 ` Greg Kurz 2021-06-09 7:45 ` [Virtio-fs] " Greg Kurz 2021-06-11 14:44 ` Miklos Szeredi 2021-06-11 14:44 ` [Virtio-fs] " Miklos Szeredi 2021-06-04 16:11 ` [PATCH v2 7/7] fuse: Make fuse_fill_super_submount() static Greg Kurz 2021-06-04 16:11 ` [Virtio-fs] " Greg Kurz 2021-06-08 15:52 ` [PATCH v2 0/7] fuse: Some fixes for submounts Max Reitz 2021-06-08 15:52 ` [Virtio-fs] " Max Reitz 2021-06-09 7:46 ` Greg Kurz 2021-06-09 7:46 ` [Virtio-fs] " Greg Kurz
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