vfs: remove LOOKUP_NO_AUTOMOUNT flag (b6c8069d) · Commits · 戴 / test

That flag no longer makes sense, since we don't look up automount points as eagerly any more. Additionally, it turns out that the NO_AUTOMOUNT handling was buggy to begin with: it would avoid automounting even for cases where we really *needed* to do the automount handling, and could return ENOENT for autofs entries that hadn't been instantiated yet. With our new non-eager automount semantics, one discussion has been about adding a AT_AUTOMOUNT flag to vfs_fstatat (and thus the newfstatat() and fstatat64() system calls), but it's probably not worth it: you can always force at least directory automounting by simply adding the final '/' to the filename, which works for *all* of the stat family system calls, old and new. So AT_NO_AUTOMOUNT (and thus LOOKUP_NO_AUTOMOUNT) really were just a result of our bad default behavior. Acked-by:

Ian Kent <raven@themaw.net> Acked-by:

Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/namei.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -721,12 +721,6 @@ static int follow_automount(struct path *path, unsigned flags,
		if (!path->dentry->d_op \|\| !path->dentry->d_op->d_automount)
		return -EREMOTE;

		/* We don't want to mount if someone supplied AT_NO_AUTOMOUNT
		* and this is the terminal part of the path.
		*/
		if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_PARENT))
		return -EISDIR; /* we actually want to stop here */

		/* We don't want to mount if someone's just doing a stat -
		* unless they're stat'ing a directory and appended a '/' to
		* the name.

fs/stat.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -81,8 +81,6 @@ int vfs_fstatat(int dfd, const char __user filename, struct kstat stat,

		if (!(flag & AT_SYMLINK_NOFOLLOW))
		lookup_flags \|= LOOKUP_FOLLOW;
		if (flag & AT_NO_AUTOMOUNT)
		lookup_flags \|= LOOKUP_NO_AUTOMOUNT;
		if (flag & AT_EMPTY_PATH)
		lookup_flags \|= LOOKUP_EMPTY;

include/linux/namei.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -53,7 +53,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
		#define LOOKUP_PARENT 0x0010
		#define LOOKUP_REVAL 0x0020
		#define LOOKUP_RCU 0x0040
		#define LOOKUP_NO_AUTOMOUNT 0x0080

		/*
		* Intent data
		*/

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