statx: add mount_root (80340fe3) · Commits · 戴 / test

Determining whether a path or file descriptor refers to a mountpoint (or more precisely a mount root) is not trivial using current tools. Add a flag to statx that indicates whether the path or fd refers to the root of a mount or not. Cc: linux-api@vger.kernel.org Cc: linux-man@vger.kernel.org Reported-by:

Lennart Poettering <mzxreary@0pointer.de> Reported-by:

J. Bruce Fields <bfields@fieldses.org> Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:

Christoph Hellwig <hch@lst.de>

fs/stat.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -202,6 +202,9 @@ retry:
		error = vfs_getattr(&path, stat, request_mask, flags);
		stat->mnt_id = real_mount(path.mnt)->mnt_id;
		stat->result_mask \|= STATX_MNT_ID;
		if (path.mnt->mnt_root == path.dentry)
		stat->attributes \|= STATX_ATTR_MOUNT_ROOT;
		stat->attributes_mask \|= STATX_ATTR_MOUNT_ROOT;
		path_put(&path);
		if (retry_estale(error, lookup_flags)) {
		lookup_flags \|= LOOKUP_REVAL;

include/uapi/linux/stat.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -181,6 +181,7 @@ struct statx {
		#define STATX_ATTR_NODUMP 0x00000040 /* [I] File is not to be dumped */
		#define STATX_ATTR_ENCRYPTED 0x00000800 /* [I] File requires key to decrypt in fs */
		#define STATX_ATTR_AUTOMOUNT 0x00001000 /* Dir: Automount trigger */
		#define STATX_ATTR_MOUNT_ROOT 0x00002000 /* Root of a mount */
		#define STATX_ATTR_VERITY 0x00100000 /* [I] Verity protected file */

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