This is a note to let you know that I've just added the patch titled
fs: clear or set FMODE_LSEEK based on llseek function
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-clear-or-set-fmode_lseek-based-on-llseek-function.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e7478158e1378325907edfdd960eca98a1be405b Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Date: Wed, 29 Jun 2022 15:06:57 +0200
Subject: fs: clear or set FMODE_LSEEK based on llseek function
From: Jason A. Donenfeld <Jason@xxxxxxxxx>
commit e7478158e1378325907edfdd960eca98a1be405b upstream.
Pipe-like behaviour on llseek(2) (i.e. unconditionally failing with
-ESPIPE) can be expresses in 3 ways:
1) ->llseek set to NULL in file_operations
2) ->llseek set to no_llseek in file_operations
3) FMODE_LSEEK *not* set in ->f_mode.
Enforce (3) in cases (1) and (2); that will allow to simplify the
checks and eventually get rid of no_llseek boilerplate.
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@xxxxxxxxxx>
---
fs/file_table.c | 2 ++
fs/open.c | 4 ++++
2 files changed, 6 insertions(+)
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -198,6 +198,8 @@ static struct file *alloc_file(const str
file->f_mapping = path->dentry->d_inode->i_mapping;
file->f_wb_err = filemap_sample_wb_err(file->f_mapping);
file->f_sb_err = file_sample_sb_err(file);
+ if (fop->llseek && fop->llseek != no_llseek)
+ file->f_mode |= FMODE_LSEEK;
if ((file->f_mode & FMODE_READ) &&
likely(fop->read || fop->read_iter))
file->f_mode |= FMODE_CAN_READ;
--- a/fs/open.c
+++ b/fs/open.c
@@ -834,6 +834,10 @@ static int do_dentry_open(struct file *f
if ((f->f_mode & FMODE_WRITE) &&
likely(f->f_op->write || f->f_op->write_iter))
f->f_mode |= FMODE_CAN_WRITE;
+ if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek)
+ f->f_mode &= ~FMODE_LSEEK;
+ if ((f->f_mode & FMODE_LSEEK) && f->f_op->llseek == no_llseek)
+ f->f_mode &= ~FMODE_LSEEK;
f->f_write_hint = WRITE_LIFE_NOT_SET;
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
Patches currently in stable-queue which might be from Jason@xxxxxxxxx are
queue-5.15/fs-clear-or-set-fmode_lseek-based-on-llseek-function.patch
