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| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-04-27 08:11:55 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-06-15 23:29:29 +0300 |
| commit | 6f8d26fded55fd29df8008b61ec4195f1009b9b3 (patch) | |
| tree | f3edfd542d24508d8d8912c8e986ece74e49542e /fs/namei.c | |
| parent | ff6845cfc68f6be7acc44bde3ba50f35ada1c937 (diff) | |
| download | linux-6f8d26fded55fd29df8008b61ec4195f1009b9b3.tar.xz | |
atomic_open(): fix the handling of create_error
commit 10c64cea04d3c75c306b3f990586ffb343b63287 upstream.
* if we have a hashed negative dentry and either CREAT|EXCL on
r/o filesystem, or CREAT|TRUNC on r/o filesystem, or CREAT|EXCL
with failing may_o_create(), we should fail with EROFS or the
error may_o_create() has returned, but not ENOENT. Which is what
the current code ends up returning.
* if we have CREAT|TRUNC hitting a regular file on a read-only
filesystem, we can't fail with EROFS here. At the very least,
not until we'd done follow_managed() - we might have a writable
file (or a device, for that matter) bound on top of that one.
Moreover, the code downstream will see that O_TRUNC and attempt
to grab the write access (*after* following possible mount), so
if we really should fail with EROFS, it will happen. No need
to do that inside atomic_open().
The real logics is much simpler than what the current code is
trying to do - if we decided to go for simple lookup, ended
up with a negative dentry *and* had create_error set, fail with
create_error. No matter whether we'd got that negative dentry
from lookup_real() or had found it in dcache.
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.16: deleted code was slightly different]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 20 |
1 files changed, 4 insertions, 16 deletions
diff --git a/fs/namei.c b/fs/namei.c index 34f8224be4ed..55c97a75e5a7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2797,22 +2797,10 @@ no_open: dentry = lookup_real(dir, dentry, nd->flags); if (IS_ERR(dentry)) return PTR_ERR(dentry); - - if (create_error) { - int open_flag = op->open_flag; - - error = create_error; - if ((open_flag & O_EXCL)) { - if (!dentry->d_inode) - goto out; - } else if (!dentry->d_inode) { - goto out; - } else if ((open_flag & O_TRUNC) && - S_ISREG(dentry->d_inode->i_mode)) { - goto out; - } - /* will fail later, go on to get the right error */ - } + } + if (create_error && !dentry->d_inode) { + error = create_error; + goto out; } looked_up: path->dentry = dentry; |