lkml.org 
[lkml]   [2021]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.14 785/849] smb3: do not error on fsync when readonly
    Date
    From: Steve French <stfrench@microsoft.com>

    commit 71e6864eacbef0b2645ca043cdfbac272cb6cea3 upstream.

    Linux allows doing a flush/fsync on a file open for read-only,
    but the protocol does not allow that. If the file passed in
    on the flush is read-only try to find a writeable handle for
    the same inode, if that is not possible skip sending the
    fsync call to the server to avoid breaking the apps.

    Reported-by: Julian Sikorski <belegdol@gmail.com>
    Tested-by: Julian Sikorski <belegdol@gmail.com>
    Suggested-by: Jeremy Allison <jra@samba.org>
    Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
    Signed-off-by: Steve French <stfrench@microsoft.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    fs/cifs/file.c | 35 +++++++++++++++++++++++++++++------
    1 file changed, 29 insertions(+), 6 deletions(-)

    --- a/fs/cifs/file.c
    +++ b/fs/cifs/file.c
    @@ -2689,12 +2689,23 @@ int cifs_strict_fsync(struct file *file,
    tcon = tlink_tcon(smbfile->tlink);
    if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
    server = tcon->ses->server;
    - if (server->ops->flush)
    - rc = server->ops->flush(xid, tcon, &smbfile->fid);
    - else
    + if (server->ops->flush == NULL) {
    rc = -ENOSYS;
    + goto strict_fsync_exit;
    + }
    +
    + if ((OPEN_FMODE(smbfile->f_flags) & FMODE_WRITE) == 0) {
    + smbfile = find_writable_file(CIFS_I(inode), FIND_WR_ANY);
    + if (smbfile) {
    + rc = server->ops->flush(xid, tcon, &smbfile->fid);
    + cifsFileInfo_put(smbfile);
    + } else
    + cifs_dbg(FYI, "ignore fsync for file not open for write\n");
    + } else
    + rc = server->ops->flush(xid, tcon, &smbfile->fid);
    }

    +strict_fsync_exit:
    free_xid(xid);
    return rc;
    }
    @@ -2706,6 +2717,7 @@ int cifs_fsync(struct file *file, loff_t
    struct cifs_tcon *tcon;
    struct TCP_Server_Info *server;
    struct cifsFileInfo *smbfile = file->private_data;
    + struct inode *inode = file_inode(file);
    struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);

    rc = file_write_and_wait_range(file, start, end);
    @@ -2722,12 +2734,23 @@ int cifs_fsync(struct file *file, loff_t
    tcon = tlink_tcon(smbfile->tlink);
    if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
    server = tcon->ses->server;
    - if (server->ops->flush)
    - rc = server->ops->flush(xid, tcon, &smbfile->fid);
    - else
    + if (server->ops->flush == NULL) {
    rc = -ENOSYS;
    + goto fsync_exit;
    + }
    +
    + if ((OPEN_FMODE(smbfile->f_flags) & FMODE_WRITE) == 0) {
    + smbfile = find_writable_file(CIFS_I(inode), FIND_WR_ANY);
    + if (smbfile) {
    + rc = server->ops->flush(xid, tcon, &smbfile->fid);
    + cifsFileInfo_put(smbfile);
    + } else
    + cifs_dbg(FYI, "ignore fsync for file not open for write\n");
    + } else
    + rc = server->ops->flush(xid, tcon, &smbfile->fid);
    }

    +fsync_exit:
    free_xid(xid);
    return rc;
    }

    \
     
     \ /
      Last update: 2021-11-16 00:26    [W:4.025 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site