lkml.org 
[lkml]   [2020]   [Jun]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 210/314] ceph: dont return -ESTALE if theres still an open file
    Date
    From: Luis Henriques <lhenriques@suse.com>

    [ Upstream commit 878dabb64117406abd40977b87544d05bb3031fc ]

    Similarly to commit 03f219041fdb ("ceph: check i_nlink while converting
    a file handle to dentry"), this fixes another corner case with
    name_to_handle_at/open_by_handle_at. The issue has been detected by
    xfstest generic/467, when doing:

    - name_to_handle_at("/cephfs/myfile")
    - open("/cephfs/myfile")
    - unlink("/cephfs/myfile")
    - sync; sync;
    - drop caches
    - open_by_handle_at()

    The call to open_by_handle_at should not fail because the file hasn't been
    deleted yet (only unlinked) and we do have a valid handle to it. -ESTALE
    shall be returned only if i_nlink is 0 *and* i_count is 1.

    This patch also makes sure we have LINK caps before checking i_nlink.

    Signed-off-by: Luis Henriques <lhenriques@suse.com>
    Reviewed-by: Jeff Layton <jlayton@kernel.org>
    Acked-by: Amir Goldstein <amir73il@gmail.com>
    Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/ceph/export.c | 9 ++++++++-
    1 file changed, 8 insertions(+), 1 deletion(-)

    diff --git a/fs/ceph/export.c b/fs/ceph/export.c
    index 79dc06881e78e..e088843a7734c 100644
    --- a/fs/ceph/export.c
    +++ b/fs/ceph/export.c
    @@ -172,9 +172,16 @@ struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino)
    static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
    {
    struct inode *inode = __lookup_inode(sb, ino);
    + int err;
    +
    if (IS_ERR(inode))
    return ERR_CAST(inode);
    - if (inode->i_nlink == 0) {
    + /* We need LINK caps to reliably check i_nlink */
    + err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false);
    + if (err)
    + return ERR_PTR(err);
    + /* -ESTALE if inode as been unlinked and no file is open */
    + if ((inode->i_nlink == 0) && (atomic_read(&inode->i_count) == 1)) {
    iput(inode);
    return ERR_PTR(-ESTALE);
    }
    --
    2.25.1


    \
     
     \ /
      Last update: 2020-06-23 22:31    [W:4.078 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site