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9 dayssmb: client: split cifsFileInfo bitfields to avoid shared-byte RMW racesFrank Sorenson
The invalidHandle, swapfile, oplock_break_cancelled, offload, and status_file_deleted fields are stored in the same bitfield byte in struct cifsFileInfo, but are updated in different code paths that may run simultaneously, and are protected by different locks. Since bitfield assignments generate byte-level read-modify-write operations, a modification to one flag can overwrite a concurrent modification to another flag. To avoid these races, convert these flags from a bitfield to separate bool fields. Closes: https://lore.kernel.org/r/7689764e-c0f6-4016-9557-b54cf4a3de4e@redhat.com Fixes: 3bc303c254335 ("cifs: convert oplock breaks to use slow_work facility (try #4)") Fixes: 4e8aea30f7751 ("smb3: enable swap on SMB3 mounts") Fixes: ffceb7640cbfe ("smb: client: do not defer close open handles to deleted files") Fixes: 173217bd73365 ("smb3: retrying on failed server close") Signed-off-by: Frank Sorenson <sorenson@redhat.com> Cc: stable@vger.kernel.org Reviewed-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Paulo Alcantara <pc@manguebit.org>
10 dayssmb: client: require stable pages for signed connectionsPaulo Alcantara
When signing, cifs computes the SMB signature over the pagecache folios in place and then hands those same folios to the socket. If a buffered write mutates a folio while a write subrequest is still in flight, the signature no longer matches the data that follows it, the server rejects the write with STATUS_ACCESS_DENIED (-EACCES), and the error is latched in the mapping, so the next fsync()/fallocate() returns -EIO. Mark the mapping for stable writes so netfs_perform_write() waits for writeback to complete before modifying an in-flight folio. This is only needed when the connection is signed. Fixes: 3ee1a1fc3981 ("cifs: Cut over to using netfslib") 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
10 dayssmb: client: distinguish real EOF from a stale remote_i_size on readPaulo Alcantara
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: 1da29f2c39b6 ("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
10 daysnetfs: zero the tail of a short DIO/unbuffered readgraftedPaulo Alcantara
The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") 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