diff options
| author | Steve French <stfrench@microsoft.com> | 2021-11-10 01:47:48 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-01 09:19:08 +0100 |
| commit | 5655b8bccb8a19a34c83225a1c7bf2adca50c2c3 (patch) | |
| tree | 800c4d2b24bae03a0e8e92b992c2c060f0eb54cb /fs | |
| parent | c380062d0850d854578ef47ca714f135e6597a99 (diff) | |
smb3: do not error on fsync when readonly
[ Upstream commit 71e6864eacbef0b2645ca043cdfbac272cb6cea3 ]
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: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/cifs/file.c | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 67139f9d583f..6c06870f9018 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2618,12 +2618,23 @@ int cifs_strict_fsync(struct file *file, loff_t start, loff_t end, 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; } @@ -2635,6 +2646,7 @@ int cifs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 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); @@ -2651,12 +2663,23 @@ int cifs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 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; } |