smb: client: distinguish real EOF from a stale remote_i_size on read

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smb2_readv_callback() sets NETFS_SREQ_HIT_EOF whenever a short read
lines up with netfs_read_remote_i_size(inode), the server's EOF as the
client currently believes it. That belief can be stale: after a lease
downgrade and handle reopen, the tracked remote_i_size can sit below
the client's own i_size while an extending write hasn't reached the
server yet. A read in that gap comes back short for a reason that has
nothing to do with the file's real size, but was still marked HIT_EOF,
and netfs reports a short read for it as-is.

Only treat it as real EOF when the position is also at or past the
client's own i_size; otherwise mark it NETFS_SREQ_CLEAR_TAIL instead,
which tells netfs the shortfall is safe to zero-fill rather than
report as a short read.

This is what fsx (generic/363) sees as "short read: 0x0 bytes instead
of 0x<n>" against a Windows server.

Fixes: 1da29f2c39 ("netfs, cifs: Fix handling of short DIO read")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

...

This commit is contained in:

Paulo Alcantara 2026-09-27 18:56:55 -03:00

parent dd05add7b2

commit 75aa4b4d55

1 changed files with 8 additions and 2 deletions

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fs/smb/client/smb2pdu.c

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