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| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-02-26 11:55:02 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-03-13 21:09:13 -0400 |
| commit | abc2c632e0cec6f76883d008c298e31cb3e2d242 (patch) | |
| tree | b80b01d4e9390f9cdf2f058cf7c04a0baa62c5eb /fs/namei.c | |
| parent | a6a7eb7628cfa7e0e8f62e185502facc43bd2ce3 (diff) | |
| download | linux-abc2c632e0cec6f76883d008c298e31cb3e2d242.tar.bz2 | |
follow_dotdot{,_rcu}(): lift switching nd->path to parent out of loop
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/fs/namei.c b/fs/namei.c index 88e5d7920540..772d82daf3b4 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1365,7 +1365,9 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, static int follow_dotdot_rcu(struct nameidata *nd) { + struct dentry *parent = NULL; struct inode *inode = nd->inode; + unsigned seq; while (1) { if (path_equal(&nd->path, &nd->root)) { @@ -1375,15 +1377,12 @@ static int follow_dotdot_rcu(struct nameidata *nd) } if (nd->path.dentry != nd->path.mnt->mnt_root) { struct dentry *old = nd->path.dentry; - struct dentry *parent = old->d_parent; - unsigned seq; + parent = old->d_parent; inode = parent->d_inode; seq = read_seqcount_begin(&parent->d_seq); if (unlikely(read_seqcount_retry(&old->d_seq, nd->seq))) return -ECHILD; - nd->path.dentry = parent; - nd->seq = seq; if (unlikely(!path_connected(nd->path.mnt, parent))) return -ECHILD; break; @@ -1406,6 +1405,10 @@ static int follow_dotdot_rcu(struct nameidata *nd) nd->seq = seq; } } + if (likely(parent)) { + nd->path.dentry = parent; + nd->seq = seq; + } while (unlikely(d_mountpoint(nd->path.dentry))) { struct mount *mounted; mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry); @@ -1442,7 +1445,7 @@ static void follow_mount(struct path *path) static int follow_dotdot(struct nameidata *nd) { - struct dentry *parent; + struct dentry *parent = NULL; while (1) { if (path_equal(&nd->path, &nd->root)) { if (unlikely(nd->flags & LOOKUP_BENEATH)) @@ -1452,13 +1455,10 @@ static int follow_dotdot(struct nameidata *nd) if (nd->path.dentry != nd->path.mnt->mnt_root) { /* rare case of legitimate dget_parent()... */ parent = dget_parent(nd->path.dentry); - if (unlikely(!path_connected(nd->path.mnt, parent))) { dput(parent); return -ENOENT; } - dput(nd->path.dentry); - nd->path.dentry = parent; break; } if (!follow_up(&nd->path)) @@ -1466,6 +1466,10 @@ static int follow_dotdot(struct nameidata *nd) if (unlikely(nd->flags & LOOKUP_NO_XDEV)) return -EXDEV; } + if (likely(parent)) { + dput(nd->path.dentry); + nd->path.dentry = parent; + } follow_mount(&nd->path); nd->inode = nd->path.dentry->d_inode; return 0; |