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handle_mounts(): start building a sane wrapper for follow_managed()
All callers of follow_managed() follow it on success with the same steps - d_backing_inode(path->dentry) is calculated and stored into some struct inode * variable and, in all but one case, an unsigned variable (nd->seq to be) is zeroed. The single exception is lookup_fast() and there zeroing is correct thing to do - not doing it is a pointless microoptimization. Add a wrapper for follow_managed() that would do that combination. It's mostly a vehicle for code massage - it will be changing quite a bit, and the current calling conventions are by no means final. Right now it takes path, nameidata and (as out params) inode and seq, similar to __follow_mount_rcu(). Which will soon get folded into it... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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parent
31d1726d72
commit
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32
fs/namei.c
32
fs/namei.c
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@ -1385,6 +1385,18 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
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!(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT);
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}
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static inline int handle_mounts(struct path *path, struct nameidata *nd,
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struct inode **inode, unsigned int *seqp)
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{
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int ret = follow_managed(path, nd);
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if (likely(ret >= 0)) {
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*inode = d_backing_inode(path->dentry);
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*seqp = 0; /* out of RCU mode, so the value doesn't matter */
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}
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return ret;
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}
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static int follow_dotdot_rcu(struct nameidata *nd)
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{
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struct inode *inode = nd->inode;
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@ -1607,7 +1619,6 @@ static int lookup_fast(struct nameidata *nd,
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struct vfsmount *mnt = nd->path.mnt;
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struct dentry *dentry, *parent = nd->path.dentry;
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int status = 1;
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int err;
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/*
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* Rename seqlock is not required here because in the off chance
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@ -1677,10 +1688,7 @@ static int lookup_fast(struct nameidata *nd,
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path->mnt = mnt;
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path->dentry = dentry;
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err = follow_managed(path, nd);
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if (likely(err > 0))
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*inode = d_backing_inode(path->dentry);
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return err;
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return handle_mounts(path, nd, inode, seqp);
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}
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/* Fast lookup failed, do it the slow way */
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@ -1875,12 +1883,9 @@ static int walk_component(struct nameidata *nd, int flags)
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return PTR_ERR(path.dentry);
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path.mnt = nd->path.mnt;
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err = follow_managed(&path, nd);
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err = handle_mounts(&path, nd, &inode, &seq);
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if (unlikely(err < 0))
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return err;
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seq = 0; /* we are already out of RCU mode */
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inode = d_backing_inode(path.dentry);
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}
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return step_into(nd, &path, flags, inode, seq);
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@ -2365,11 +2370,9 @@ static int handle_lookup_down(struct nameidata *nd)
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return -ECHILD;
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} else {
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dget(path.dentry);
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err = follow_managed(&path, nd);
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err = handle_mounts(&path, nd, &inode, &seq);
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if (unlikely(err < 0))
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return err;
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inode = d_backing_inode(path.dentry);
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seq = 0;
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}
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path_to_nameidata(&path, nd);
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nd->inode = inode;
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@ -3392,12 +3395,9 @@ static int do_last(struct nameidata *nd,
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got_write = false;
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}
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error = follow_managed(&path, nd);
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error = handle_mounts(&path, nd, &inode, &seq);
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if (unlikely(error < 0))
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return error;
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seq = 0; /* out of RCU mode, so the value doesn't matter */
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inode = d_backing_inode(path.dentry);
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finish_lookup:
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error = step_into(nd, &path, 0, inode, seq);
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if (unlikely(error))
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