David Howells ca9ca1a5d5 netfs: Fix missing zero-length check in unbuffered write ... Fix netfs_unbuffered_write_iter() to return immediately if generic_write_checks() returns 0, indicating there's nothing to write. Note that netfs_file_write_iter() already does this. Also, whilst we're at it, put in checks for the size being zero before we even take the locks. Note that generic_write_checks() can still reduce the size to zero, so we still need that check. Without this, a warning similar to the following is logged to dmesg: netfs: Zero-sized write [R=1b6da] and the syscall fails with EIO, e.g.: /sbin/ldconfig.real: Writing of cache extension data failed: Input/output error This can be reproduced on 9p by: xfs_io -f -c 'pwrite 0 0' /xfstest.test/foo Fixes: 153a9961b5 ("netfs: Implement unbuffered/DIO write support") Reported-by: Eric Van Hensbergen <ericvh@kernel.org> Link: https://lore.kernel.org/r/ZbQUU6QKmIftKsmo@FV7GG9FTHL/ Signed-off-by: David Howells <dhowells@redhat.com> Link: https://lore.kernel.org/r/20240129094924.1221977-3-dhowells@redhat.com Tested-by: Dominique Martinet <asmadeus@codewreck.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: Dominique Martinet <asmadeus@codewreck.org> cc: Jeff Layton <jlayton@kernel.org> cc: <v9fs@lists.linux.dev> cc: <linux_oss@crudebyte.com> cc: <netfs@lists.linux.dev> cc: <linux-fsdevel@vger.kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>		2024-01-29 14:53:21 +01:00
..
buffered_read.c
buffered_write.c	netfs: Fix missing zero-length check in unbuffered write	2024-01-29 14:53:21 +01:00
direct_read.c
direct_write.c	netfs: Fix missing zero-length check in unbuffered write	2024-01-29 14:53:21 +01:00
fscache_cache.c	netfs, fscache: Prevent Oops in fscache_put_cache()	2024-01-22 21:58:35 +00:00
fscache_cookie.c
fscache_internal.h
fscache_io.c
fscache_main.c
fscache_proc.c
fscache_stats.c
fscache_volume.c
internal.h
io.c	netfs: Fix i_dio_count leak on DIO read past i_size	2024-01-29 14:53:18 +01:00
iterator.c
Kconfig
locking.c
main.c
Makefile
misc.c
objects.c
output.c
stats.c