From c5ea3065586d790ea5193a679b85585173d59866 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sun, 7 Sep 2025 21:24:06 -0300 Subject: smb: client: fix data loss due to broken rename(2) Rename of open files in SMB2+ has been broken for a very long time, resulting in data loss as the CIFS client would fail the rename(2) call with -ENOENT and then removing the target file. Fix this by implementing ->rename_pending_delete() for SMB2+, which will rename busy files to random filenames (e.g. silly rename) during unlink(2) or rename(2), and then marking them to delete-on-close. Besides, introduce a FIND_WR_NO_PENDING_DELETE flag to prevent open(2) from reusing open handles that had been marked as delete pending. Handle it in cifs_get_readable_path() as well. Reported-by: Jean-Baptiste Denis Closes: https://marc.info/?i=16aeb380-30d4-4551-9134-4e7d1dc833c0@pasteur.fr Reviewed-by: David Howells Cc: stable@vger.kernel.org Signed-off-by: Paulo Alcantara (Red Hat) Cc: Frank Sorenson Cc: Olga Kornievskaia Cc: Benjamin Coddington Cc: Scott Mayhew Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French --- fs/smb/client/file.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'fs/smb/client/file.c') diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 186e061068be..cb907e18cc35 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -998,7 +998,10 @@ int cifs_open(struct inode *inode, struct file *file) /* Get the cached handle as SMB2 close is deferred */ if (OPEN_FMODE(file->f_flags) & FMODE_WRITE) { - rc = cifs_get_writable_path(tcon, full_path, FIND_WR_FSUID_ONLY, &cfile); + rc = cifs_get_writable_path(tcon, full_path, + FIND_WR_FSUID_ONLY | + FIND_WR_NO_PENDING_DELETE, + &cfile); } else { rc = cifs_get_readable_path(tcon, full_path, &cfile); } @@ -2530,6 +2533,9 @@ refind_writable: continue; if (with_delete && !(open_file->fid.access & DELETE)) continue; + if ((flags & FIND_WR_NO_PENDING_DELETE) && + open_file->status_file_deleted) + continue; if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) { if (!open_file->invalidHandle) { /* found a good writable file */ @@ -2647,6 +2653,16 @@ cifs_get_readable_path(struct cifs_tcon *tcon, const char *name, spin_unlock(&tcon->open_file_lock); free_dentry_path(page); *ret_file = find_readable_file(cinode, 0); + if (*ret_file) { + spin_lock(&cinode->open_file_lock); + if ((*ret_file)->status_file_deleted) { + spin_unlock(&cinode->open_file_lock); + cifsFileInfo_put(*ret_file); + *ret_file = NULL; + } else { + spin_unlock(&cinode->open_file_lock); + } + } return *ret_file ? 0 : -ENOENT; } -- cgit v1.2.3