On 8/10/23 12:55, Miklos Szeredi wrote:
Allow querying btime. When btime is requested in mask, then FUSE_STATX
request is sent. Otherwise keep using FUSE_GETATTR.
The userspace interface for statx matches that of the statx(2) API.
However there are limitations on how this interface is used:
- returned basic stats and btime are used, stx_attributes, etc. are
ignored
- always query basic stats and btime, regardless of what was requested
- requested sync type is ignored, the default is passed to the server
- if server returns with some attributes missing from the result_mask,
then no attributes will be cached
- btime is not cached yet (next patch will fix that)
For new inodes initialize fi->inval_mask to "all invalid", instead of "all
valid" as previously. Also only clear basic stats from inval_mask when
caching attributes. This will result in the caching logic not thinking
that btime is cached.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/fuse/dir.c | 106 ++++++++++++++++++++++++++++++++++++++++++++---
fs/fuse/fuse_i.h | 3 ++
fs/fuse/inode.c | 5 ++-
3 files changed, 107 insertions(+), 7 deletions(-)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 04006db6e173..552157bd6a4d 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -350,10 +350,14 @@ int fuse_valid_type(int m)
S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
}
+bool fuse_valid_size(u64 size)
+{
+ return size <= LLONG_MAX;
+}
+
bool fuse_invalid_attr(struct fuse_attr *attr)
{
- return !fuse_valid_type(attr->mode) ||
- attr->size > LLONG_MAX;
+ return !fuse_valid_type(attr->mode) || !fuse_valid_size(attr->size);
}
int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
@@ -1143,6 +1147,84 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
stat->blksize = 1 << blkbits;
}
+static void fuse_statx_to_attr(struct fuse_statx *sx, struct fuse_attr *attr)
+{
+ memset(attr, 0, sizeof(*attr));
+ attr->ino = sx->ino;
+ attr->size = sx->size;
+ attr->blocks = sx->blocks;
+ attr->atime = sx->atime.tv_sec;
+ attr->mtime = sx->mtime.tv_sec;
+ attr->ctime = sx->ctime.tv_sec;
+ attr->atimensec = sx->atime.tv_nsec;
+ attr->mtimensec = sx->mtime.tv_nsec;
+ attr->ctimensec = sx->ctime.tv_nsec;
+ attr->mode = sx->mode;
+ attr->nlink = sx->nlink;
+ attr->uid = sx->uid;
+ attr->gid = sx->gid;
+ attr->rdev = new_encode_dev(MKDEV(sx->rdev_major, sx->rdev_minor));
+ attr->blksize = sx->blksize;
+}
+
+static int fuse_do_statx(struct inode *inode, struct file *file,
+ struct kstat *stat)
+{
+ int err;
+ struct fuse_attr attr;
+ struct fuse_statx *sx;
+ struct fuse_statx_in inarg;
+ struct fuse_statx_out outarg;
+ struct fuse_mount *fm = get_fuse_mount(inode);
+ u64 attr_version = fuse_get_attr_version(fm->fc);
+ FUSE_ARGS(args);
+
+ 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;
+ }
+ /* For now leave sync hints as the default, request all stats. */
+ inarg.sx_flags = 0;
+ inarg.sx_mask = STATX_BASIC_STATS | STATX_BTIME;
+ 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)
+ return err;
+
+ sx = &outarg.stat;
+ if (((sx->mask & STATX_SIZE) && !fuse_valid_size(sx->size)) ||
+ ((sx->mask & STATX_TYPE) && (!fuse_valid_type(sx->mode) ||
+ inode_wrong_type(inode, sx->mode)))) {
+ make_bad_inode(inode);
+ return -EIO;
+ }
+
+ fuse_statx_to_attr(&outarg.stat, &attr);
+ if ((sx->mask & STATX_BASIC_STATS) == STATX_BASIC_STATS) {
+ fuse_change_attributes(inode, &attr, ATTR_TIMEOUT(&outarg),
+ attr_version);
+ }
+ stat->result_mask = sx->mask & (STATX_BASIC_STATS | STATX_BTIME);
+ stat->btime.tv_sec = sx->btime.tv_sec;
+ stat->btime.tv_nsec = min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
+ fuse_fillattr(inode, &attr, stat);
+ stat->result_mask |= STATX_TYPE;
+
+ return 0;
+}
Hmm, unconditionally using stat is potentially a NULL ptr with future
updates. I think not right now, as fuse_update_get_attr() has the
(request_mask & ~STATX_BASIC_STATS) condition and no caller
that passes 'stat = NULL' requests anything beyond STATX_BASIC_STATS,
but wouldn't it be more safe to access stat only conditionally?
Thanks,
Bernd
