This is to update attributes on open to achieve close-to-open coherency even if an inode has a attribute cache timeout. Signed-off-by: Bernd Schubert <bschubert@xxxxxxx> --- libfuse patch: https://github.com/libfuse/libfuse/pull/1020 (FUSE_OPENDIR_GETATTR still missing at time of writing) Note: This does not make use of existing atomic-open patches as these are more complex than two new opcodes for open-getattr. Note2: This is an alternative to Joannes patch that adds FOPEN_FETCH_ATTR, which would need to kernel/userspace transitions https://lore.kernel.org/all/20240813212149.1909627-1-joannelkoong@xxxxxxxxx/ Question for reviewers: - Should this better use statx fields? Probably not needed for coherency? - Should this introduce a new struct that contains struct fuse_open_out and struct fuse_attr_out, with additional padding between them to avoid incompat issues if either struct should be extended? --- fs/fuse/file.c | 94 ++++++++++++++++++++++++++++++++++++++- fs/fuse/fuse_i.h | 7 +++ fs/fuse/ioctl.c | 2 +- include/uapi/linux/fuse.h | 5 +++ 4 files changed, 105 insertions(+), 3 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index f39456c65ed7..d470e6a2b3d4 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -51,6 +51,78 @@ static int fuse_send_open(struct fuse_mount *fm, u64 nodeid, return fuse_simple_request(fm, &args); } +/* + * Open the file and update inode attributes + */ +static int fuse_file_open_getattr(struct fuse_mount *fm, u64 nodeid, + struct inode *inode, unsigned int open_flags, + int opcode, + struct fuse_open_out *open_outargp) +{ + struct fuse_conn *fc = fm->fc; + u64 attr_version = fuse_get_attr_version(fc); + struct fuse_open_in inarg; + struct fuse_attr_out attr_outarg; + FUSE_ARGS(args); + int err; + + /* convert the opcode from plain open to open-with-getattr */ + if (opcode == FUSE_OPEN) { + if (fc->no_open_getattr) + return -ENOSYS; + opcode = FUSE_OPEN_GETATTR; + } else { + if (fc->no_opendir_getattr) + return -ENOSYS; + opcode = FUSE_OPENDIR_GETATTR; + } + + memset(&inarg, 0, sizeof(inarg)); + inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY); + if (!fm->fc->atomic_o_trunc) + inarg.flags &= ~O_TRUNC; + + if (fm->fc->handle_killpriv_v2 && + (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) { + inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID; + } + + args.opcode = opcode; + args.nodeid = nodeid; + args.in_numargs = 1; + args.in_args[0].size = sizeof(inarg); + args.in_args[0].value = &inarg; + args.out_numargs = 2; + args.out_args[0].size = sizeof(*open_outargp); + args.out_args[0].value = open_outargp; + args.out_args[1].size = sizeof(attr_outarg); + args.out_args[1].value = &attr_outarg; + + err = fuse_simple_request(fm, &args); + if (err) { + if (err == -ENOSYS) { + if (opcode == FUSE_OPEN) + fc->no_open_getattr = 1; + else + fc->no_opendir_getattr = 1; + } + return err; + } + + err = -EIO; + if (fuse_invalid_attr(&attr_outarg.attr) || + inode_wrong_type(inode, attr_outarg.attr.mode)) { + fuse_make_bad(inode); + return err; + } + + fuse_change_attributes(inode, &attr_outarg.attr, NULL, + ATTR_TIMEOUT(&attr_outarg), attr_version); + + return 0; +} + + struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release) { struct fuse_file *ff; @@ -123,7 +195,12 @@ static void fuse_file_put(struct fuse_file *ff, bool sync) } } +/* + * @inode might be NULL, the caller indicates the attr updates are not + * needed on open + */ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, + struct inode *inode, unsigned int open_flags, bool isdir) { struct fuse_conn *fc = fm->fc; @@ -143,7 +220,19 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, struct fuse_open_out *outargp = &ff->args->open_outarg; int err; - err = fuse_send_open(fm, nodeid, open_flags, opcode, outargp); + err = -ENOSYS; + if (inode) { + /* + * open-with-getattr preferred for + * close-to-open coherency + */ + err = fuse_file_open_getattr(fm, nodeid, inode, + open_flags, opcode, + outargp); + } + if (err == -ENOSYS) + err = fuse_send_open(fm, nodeid, open_flags, opcode, + outargp); if (!err) { ff->fh = outargp->fh; ff->open_flags = outargp->open_flags; @@ -172,7 +261,8 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file, bool isdir) { - struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir); + struct fuse_file *ff = fuse_file_open(fm, nodeid, file_inode(file), + file->f_flags, isdir); if (!IS_ERR(ff)) file->private_data = ff; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index f23919610313..5c0ea7ce0b4a 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -731,9 +731,15 @@ struct fuse_conn { /** Is open/release not implemented by fs? */ unsigned no_open:1; + /** Is open-getattr not implemented by fs */ + unsigned no_open_getattr:1; + /** Is opendir/releasedir not implemented by fs? */ unsigned no_opendir:1; + /** Is opendir-getattr not implemented by fs? */ + unsigned no_opendir_getattr:1; + /** Is fsync not implemented by fs? */ unsigned no_fsync:1; @@ -1404,6 +1410,7 @@ void fuse_file_io_release(struct fuse_file *ff, struct inode *inode); /* file.c */ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, + struct inode *inode, unsigned int open_flags, bool isdir); void fuse_file_release(struct inode *inode, struct fuse_file *ff, unsigned int open_flags, fl_owner_t id, bool isdir); diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c index 572ce8a82ceb..d5322f6a904d 100644 --- a/fs/fuse/ioctl.c +++ b/fs/fuse/ioctl.c @@ -493,7 +493,7 @@ static struct fuse_file *fuse_priv_ioctl_prepare(struct inode *inode) if (!S_ISREG(inode->i_mode) && !isdir) return ERR_PTR(-ENOTTY); - return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir); + return fuse_file_open(fm, get_node_id(inode), NULL, O_RDONLY, isdir); } static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file *ff) diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index d08b99d60f6f..34b06cf62c16 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -217,6 +217,9 @@ * - add backing_id to fuse_open_out, add FOPEN_PASSTHROUGH open flag * - add FUSE_NO_EXPORT_SUPPORT init flag * - add FUSE_NOTIFY_RESEND, add FUSE_HAS_RESEND init flag + * + * 7.41 + * - add FUSE_OPEN_GETATTR/FUSE_OPENDIR_GETATTR */ #ifndef _LINUX_FUSE_H @@ -633,6 +636,8 @@ enum fuse_opcode { FUSE_SYNCFS = 50, FUSE_TMPFILE = 51, FUSE_STATX = 52, + FUSE_OPEN_GETATTR = 53, + FUSE_OPENDIR_GETATTR = 54, /* CUSE specific operations */ CUSE_INIT = 4096, -- 2.43.0
