Since commit a528d35e8bfc ("statx: Add a system call to make enhanced
file info available") kernel has statx(2) system call. This patch
implements FUSE_STATX as a superset of FUSE_GETATTR, which enables
user-space file-systems to report statx information; in particular,
creation (birth) time.
The newly added struct fuse_statx_timestamp has same members as
struct statx_timestamp, where 'sec' is __s64 and padded with reserved
field. Likewise, layout of struct fuse_statx follows struct statx,
including trailing spare place-holders, making it 240 bytes in size,
and struct fuse_statx_out 256 bytes in size. Due to difference in size
(strcut fuse_attr is only 88 bytes), FUSE_GETATTR is preferred over
FUSE_STATX unless request_mask has STATX_BTIME active.
With this patch:
$ stat --format %w /path/to/fuse/fs/file
2021-03-19 10:42:07.284912429 +0200
Tested with glibc-2.32 and coreutils-8.32 over 'voluta' user-space
file-system.
Signed-off-by: Shachar Sharon <synarete@xxxxxxxxx>
---
fs/fuse/dir.c | 161 ++++++++++++++++++++++++++++++++++----
fs/fuse/fuse_i.h | 3 +
include/uapi/linux/fuse.h | 48 +++++++++++-
3 files changed, 194 insertions(+), 18 deletions(-)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 06a18700a845..aa33669b9fda 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -111,6 +111,11 @@ static u64 attr_timeout(struct fuse_attr_out *o)
return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
}
+static u64 statx_timeout(struct fuse_statx_out *o)
+{
+ return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
+}
+
u64 entry_attr_timeout(struct fuse_entry_out *o)
{
return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
@@ -1022,8 +1027,116 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
stat->blksize = 1 << blkbits;
}
-static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
- struct file *file)
+static void fuse_fillattr2(struct inode *inode, struct fuse_attr *attr,
+ struct fuse_statx *stx, struct kstat *stat)
+{
+ fuse_fillattr(inode, attr, stat);
+ stat->result_mask = stx->mask;
+ stat->attributes = stx->attributes;
+ stat->attributes_mask = stx->attributes_mask;
+ if (stx->mask & STATX_BTIME) {
+ stat->btime.tv_sec = stx->btime.sec;
+ stat->btime.tv_nsec = stx->btime.nsec;
+ }
+}
+
+static void fuse_statx_to_attr(struct fuse_statx *stx, struct fuse_attr *attr)
+{
+ attr->ino = stx->ino;
+ attr->size = stx->size;
+ attr->blocks = stx->blocks;
+ attr->atime = stx->atime.sec;
+ attr->mtime = stx->mtime.sec;
+ attr->ctime = stx->ctime.sec;
+ attr->atimensec = stx->atime.nsec;
+ attr->mtimensec = stx->mtime.nsec;
+ attr->ctimensec = stx->ctime.nsec;
+ attr->mode = stx->mode;
+ attr->nlink = stx->nlink;
+ attr->uid = stx->uid;
+ attr->gid = stx->gid;
+ attr->rdev = MKDEV(stx->rdev_major, stx->rdev_minor);
+ attr->blksize = stx->blksize;
+ attr->flags = stx->flags;
+}
+
+static int fuse_require_valid_attr(struct inode *inode, struct fuse_attr *attr)
+{
+ int ret = 0;
+
+ if (fuse_invalid_attr(attr) || (inode->i_mode ^ attr->mode) & S_IFMT) {
+ fuse_make_bad(inode);
+ ret = -EIO;
+ }
+ return ret;
+}
+
+static void fuse_getattr_inargs(struct inode *inode, struct file *file,
+ u32 *getattr_flags, u64 *fh)
+{
+ /* Directories have separate file-handle space */
+ if (file && S_ISREG(inode->i_mode)) {
+ struct fuse_file *ff = file->private_data;
+
+ *getattr_flags |= FUSE_GETATTR_FH;
+ *fh = ff->fh;
+ }
+}
+
+static int __fuse_do_statx(struct inode *inode, struct kstat *stat,
+ struct file *file, u32 request_mask)
+{
+ int err;
+ struct fuse_attr attr;
+ struct fuse_statx_in inarg;
+ struct fuse_statx_out outarg;
+ struct fuse_mount *fm = get_fuse_mount(inode);
+ FUSE_ARGS(args);
+ u64 attr_version;
+
+ attr_version = fuse_get_attr_version(fm->fc);
+
+ memset(&inarg, 0, sizeof(inarg));
+ memset(&outarg, 0, sizeof(outarg));
+ fuse_getattr_inargs(inode, file, &inarg.getattr_flags, &inarg.fh);
+ inarg.mask = request_mask | STATX_BASIC_STATS;
+ args.opcode = FUSE_STATX;
+ args.nodeid = get_node_id(inode);
+ args.in_numargs = 1;
+ args.in_args[0].size = sizeof(inarg);
+ args.in_args[0].value = &inarg;
+ args.out_numargs = 1;
+ args.out_args[0].size = sizeof(outarg);
+ args.out_args[0].value = &outarg;
+ err = fuse_simple_request(fm, &args);
+ if (err == -ENOSYS)
+ goto no_statx;
+
+ if (err)
+ return err;
+
+ if ((outarg.attr.mask & STATX_BASIC_STATS) != STATX_BASIC_STATS)
+ goto no_statx;
+
+ fuse_statx_to_attr(&outarg.attr, &attr);
+ err = fuse_require_valid_attr(inode, &attr);
+ if (err)
+ return err;
+
+ fuse_change_attributes(inode, &attr,
+ statx_timeout(&outarg), attr_version);
+ if (stat)
+ fuse_fillattr2(inode, &attr, &outarg.attr, stat);
+
+ return err;
+
+no_statx:
+ fm->fc->no_statx = 1;
+ return -EINVAL;
+}
+
+static int __fuse_do_getattr(struct inode *inode, struct kstat *stat,
+ struct file *file)
{
int err;
struct fuse_getattr_in inarg;
@@ -1036,13 +1149,7 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
memset(&inarg, 0, sizeof(inarg));
memset(&outarg, 0, sizeof(outarg));
- /* Directories have separate file-handle space */
- if (file && S_ISREG(inode->i_mode)) {
- struct fuse_file *ff = file->private_data;
-
- inarg.getattr_flags |= FUSE_GETATTR_FH;
- inarg.fh = ff->fh;
- }
+ fuse_getattr_inargs(inode, file, &inarg.getattr_flags, &inarg.fh);
args.opcode = FUSE_GETATTR;
args.nodeid = get_node_id(inode);
args.in_numargs = 1;
@@ -1053,11 +1160,8 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
args.out_args[0].value = &outarg;
err = fuse_simple_request(fm, &args);
if (!err) {
- if (fuse_invalid_attr(&outarg.attr) ||
- (inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
- fuse_make_bad(inode);
- err = -EIO;
- } else {
+ err = fuse_require_valid_attr(inode, &outarg.attr);
+ if (!err) {
fuse_change_attributes(inode, &outarg.attr,
attr_timeout(&outarg),
attr_version);
@@ -1068,11 +1172,31 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
return err;
}
+static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
+ struct file *file, u32 request_mask)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ int err;
+
+ if (fc->no_statx || fc->minor < 34 || !(request_mask & STATX_BTIME))
+ goto getattr;
+
+ err = __fuse_do_statx(inode, stat, file, request_mask);
+ if (err && fc->no_statx)
+ goto getattr;
+
+ return err;
+
+getattr:
+ return __fuse_do_getattr(inode, stat, file);
+}
+
static int fuse_update_get_attr(struct inode *inode, struct file *file,
struct kstat *stat, u32 request_mask,
unsigned int flags)
{
struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_conn *fc = get_fuse_conn(inode);
int err = 0;
bool sync;
@@ -1082,12 +1206,14 @@ static int fuse_update_get_attr(struct inode *inode, struct file *file,
sync = false;
else if (request_mask & READ_ONCE(fi->inval_mask))
sync = true;
+ else if (!fc->no_statx && (request_mask & STATX_BTIME))
+ sync = true;
else
sync = time_before64(fi->i_time, get_jiffies_64());
if (sync) {
forget_all_cached_acls(inode);
- err = fuse_do_getattr(inode, stat, file);
+ err = fuse_do_getattr(inode, stat, file, request_mask);
} else if (stat) {
generic_fillattr(&init_user_ns, inode, stat);
stat->mode = fi->orig_i_mode;
@@ -1235,7 +1361,7 @@ static int fuse_perm_getattr(struct inode *inode, int mask)
return -ECHILD;
forget_all_cached_acls(inode);
- return fuse_do_getattr(inode, NULL, NULL);
+ return fuse_do_getattr(inode, NULL, NULL, STATX_BASIC_STATS);
}
/*
@@ -1789,7 +1915,8 @@ static int fuse_setattr(struct user_namespace *mnt_userns, struct dentry *entry,
* ia_mode calculation may have used stale i_mode.
* Refresh and recalculate.
*/
- ret = fuse_do_getattr(inode, NULL, file);
+ ret = fuse_do_getattr(inode, NULL, file,
+ STATX_BASIC_STATS);
if (ret)
return ret;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 63d97a15ffde..15cd1968aac9 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -755,6 +755,9 @@ struct fuse_conn {
/* Auto-mount submounts announced by the server */
unsigned int auto_submounts:1;
+ /** Is statx not implemented by fs? */
+ unsigned int no_statx:1;
+
/** The number of requests waiting for completion */
atomic_t num_waiting;
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 54442612c48b..36ac3c40b922 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -179,6 +179,9 @@
* 7.33
* - add FUSE_HANDLE_KILLPRIV_V2, FUSE_WRITE_KILL_SUIDGID, FATTR_KILL_SUIDGID
* - add FUSE_OPEN_KILL_SUIDGID
+ *
+ * 7.34
+ * - add FUSE_STATX
*/
#ifndef _LINUX_FUSE_H
@@ -214,7 +217,7 @@
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 33
+#define FUSE_KERNEL_MINOR_VERSION 34
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
@@ -499,6 +502,7 @@ enum fuse_opcode {
FUSE_COPY_FILE_RANGE = 47,
FUSE_SETUPMAPPING = 48,
FUSE_REMOVEMAPPING = 49,
+ FUSE_STATX = 50,
/* CUSE specific operations */
CUSE_INIT = 4096,
@@ -957,4 +961,46 @@ struct fuse_removemapping_one {
#define FUSE_REMOVEMAPPING_MAX_ENTRY \
(PAGE_SIZE / sizeof(struct fuse_removemapping_one))
+struct fuse_statx_timestamp {
+ int64_t sec;
+ uint32_t nsec;
+ int32_t reserved;
+};
+
+struct fuse_statx {
+ uint32_t mask;
+ uint32_t blksize;
+ uint64_t attributes;
+ uint32_t nlink;
+ uint32_t uid;
+ uint32_t gid;
+ uint32_t mode;
+ uint64_t ino;
+ uint64_t size;
+ uint64_t blocks;
+ uint64_t attributes_mask;
+ struct fuse_statx_timestamp atime;
+ struct fuse_statx_timestamp btime;
+ struct fuse_statx_timestamp ctime;
+ struct fuse_statx_timestamp mtime;
+ uint32_t rdev_major;
+ uint32_t rdev_minor;
+ uint32_t flags;
+ uint32_t padding;
+ uint64_t spare[12];
+};
+
+struct fuse_statx_in {
+ uint32_t getattr_flags;
+ uint32_t mask;
+ uint64_t fh;
+};
+
+struct fuse_statx_out {
+ uint64_t attr_valid;
+ uint32_t attr_valid_nsec;
+ uint32_t dummy;
+ struct fuse_statx attr;
+};
+
#endif /* _LINUX_FUSE_H */
--
2.26.3
