... returning -E... upon error and amount of data left in iter after
(possible) truncation upon success. Note, that normal case gives
a non-zero (positive) return value, so any tests for != 0 _must_ be
updated.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Conflicts:
fs/ext4/file.c
Alignment checks for dio depend upon the range truncation done by
generic_write_checks(). They can be done as soon as we got ocfs2_rw_lock()
and that actually makes ocfs2_prepare_inode_for_write() simpler.
The only thing to watch out for is restoring the original count
in "unlock and redo without dio" case. Position doesn't need to be
restored, since we change it only in O_APPEND case and in that case it
will be reassigned anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
already done by caller. We used to call __fuse_direct_write(), which
called generic_write_checks(); now the former got expanded, bringing
the latter to the surface. It used to be called all along and calling
it from there had been wrong all along...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
That allows ->write_iter() instances much more convenient life wrt
iocb->ki_pos (and fixes several filesystems with borderline POSIX
violations when zero-length write succeeds and changes the current
position).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The rw parameter to direct_IO is redundant with iov_iter->type, and
treated slightly differently just about everywhere it's used: some users
do rw & WRITE, and others do rw == WRITE where they should be doing a
bitwise check. Simplify this with the new iov_iter_rw() helper, which
always returns either READ or WRITE.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Most filesystems call through to these at some point, so we'll start
here.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
all remaining instances of aio_{read,write} (all 4 of them) have explicit
->read and ->write resp.; do_sync_read/do_sync_write is never called by
__vfs_read/__vfs_write anymore and no other users had been left.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All places outside of core VFS that checked ->read and ->write for being NULL or
called the methods directly are gone now, so NULL {read,write} with non-NULL
{read,write}_iter will do the right thing in all cases.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and request the same from the local cache - all filesystems with
anything usable for that support those already.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We check if ->ki_pos is positive. However, by that point we have
already done rw_verify_area(), which would have rejected such
unless the file had been one of /dev/mem, /dev/kmem and /proc/kcore.
All of which do not have vectored rw methods, so we would've bailed
out even earlier.
This check had been introduced before rw_verify_area() had been added there
- in fact, it was a subset of checks done on sync paths by rw_verify_area()
(back then the /dev/mem exception didn't exist at all). The rest of checks
(mandatory locking, etc.) hadn't been added until later. Unfortunately,
by the time the call of rw_verify_area() got added, the /dev/mem exception
had already appeared, so it wasn't obvious that the older explicit check
downstream had become dead code. It *is* a dead code, though, since the few
files for which the exception applies do not have ->aio_{read,write}() or
->{read,write}_iter() and for them we won't reach that check anyway.
What's more, even if we ever introduce vectored methods for /dev/mem
and friends, they'll have to cope with negative positions anyway, since
readv(2) and writev(2) are using the same checks as read(2) and write(2) -
i.e. rw_verify_area().
Let's bury it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Way, way back kiocb used to be picked from arrays, so ioctx_alloc()
checked for multiplication overflow when calculating the size of
such array. By the time fs/aio.c went into the tree (in 2002) they
were already allocated one-by-one by kmem_cache_alloc(), so that
check had already become pointless. Let's bury it...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We don't need req in either of those. We don't need nr_segs in caller.
We don't really need len in caller either - iov_iter_count(&iter) will do.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
Omar Sandoval