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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-06-29 15:06:57 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2022-07-16 09:18:56 -0400 |
| commit | e7478158e1378325907edfdd960eca98a1be405b (patch) | |
| tree | 69d1ab990e63cf106b1a81fede39cef603991a5c /fs | |
| parent | b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3 (diff) | |
| download | lwn-e7478158e1378325907edfdd960eca98a1be405b.tar.gz lwn-e7478158e1378325907edfdd960eca98a1be405b.zip | |
fs: clear or set FMODE_LSEEK based on llseek function
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@zx2c4.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/file_table.c | 2 | ||||
| -rw-r--r-- | fs/open.c | 4 |
2 files changed, 6 insertions, 0 deletions
diff --git a/fs/file_table.c b/fs/file_table.c index 5424e3a8df5f..0658b822beeb 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -235,6 +235,8 @@ static struct file *alloc_file(const struct path *path, int flags, 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; diff --git a/fs/open.c b/fs/open.c index 1d57fbde2feb..4488bd77c390 100644 --- a/fs/open.c +++ b/fs/open.c @@ -858,6 +858,10 @@ 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; if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO) f->f_mode |= FMODE_CAN_ODIRECT; |