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authorEric Biggers <ebiggers@google.com>2020-09-22 19:44:18 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2021-01-04 22:02:08 +0300
commit14e43bf435612639cab01541fce7cc41bf7e370b (patch)
treed0a418ace1f97fbdc4ad4fcf88ce5119237bccdd /include/linux/mount.h
parent5c8fe583cce542aa0b84adc939ce85293de36e5e (diff)
downloadlinux-14e43bf435612639cab01541fce7cc41bf7e370b.tar.xz
vfs: don't unnecessarily clone write access for writable fds
There's no need for mnt_want_write_file() to increment mnt_writers when the file is already open for writing, provided that mnt_drop_write_file() is changed to conditionally decrement it. We seem to have ended up in the current situation because mnt_want_write_file() used to be paired with mnt_drop_write(), due to mnt_drop_write_file() not having been added yet. So originally mnt_want_write_file() had to always increment mnt_writers. But later mnt_drop_write_file() was added, and all callers of mnt_want_write_file() were paired with it. This makes the compatibility between mnt_want_write_file() and mnt_drop_write() no longer necessary. Therefore, make __mnt_want_write_file() and __mnt_drop_write_file() skip incrementing mnt_writers on files already open for writing. This removes the only caller of mnt_clone_write(), so remove that too. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/mount.h')
-rw-r--r--include/linux/mount.h1
1 files changed, 0 insertions, 1 deletions
diff --git a/include/linux/mount.h b/include/linux/mount.h
index aaf343b38671..b43191fe6af7 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -79,7 +79,6 @@ struct path;
extern int mnt_want_write(struct vfsmount *mnt);
extern int mnt_want_write_file(struct file *file);
-extern int mnt_clone_write(struct vfsmount *mnt);
extern void mnt_drop_write(struct vfsmount *mnt);
extern void mnt_drop_write_file(struct file *file);
extern void mntput(struct vfsmount *mnt);