From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read 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 Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- block/partitions/atari.c | 156 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 156 insertions(+) create mode 100644 block/partitions/atari.c (limited to 'block/partitions/atari.c') diff --git a/block/partitions/atari.c b/block/partitions/atari.c new file mode 100644 index 000000000..2438d1448 --- /dev/null +++ b/block/partitions/atari.c @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/partitions/atari.c + * + * Code extracted from drivers/block/genhd.c + * + * Copyright (C) 1991-1998 Linus Torvalds + * Re-organised Feb 1998 Russell King + */ + +#include +#include "check.h" +#include "atari.h" + +/* ++guenther: this should be settable by the user ("make config")?. + */ +#define ICD_PARTS + +/* check if a partition entry looks valid -- Atari format is assumed if at + least one of the primary entries is ok this way */ +#define VALID_PARTITION(pi,hdsiz) \ + (((pi)->flg & 1) && \ + isalnum((pi)->id[0]) && isalnum((pi)->id[1]) && isalnum((pi)->id[2]) && \ + be32_to_cpu((pi)->st) <= (hdsiz) && \ + be32_to_cpu((pi)->st) + be32_to_cpu((pi)->siz) <= (hdsiz)) + +static inline int OK_id(char *s) +{ + return memcmp (s, "GEM", 3) == 0 || memcmp (s, "BGM", 3) == 0 || + memcmp (s, "LNX", 3) == 0 || memcmp (s, "SWP", 3) == 0 || + memcmp (s, "RAW", 3) == 0 ; +} + +int atari_partition(struct parsed_partitions *state) +{ + Sector sect; + struct rootsector *rs; + struct partition_info *pi; + u32 extensect; + u32 hd_size; + int slot; +#ifdef ICD_PARTS + int part_fmt = 0; /* 0:unknown, 1:AHDI, 2:ICD/Supra */ +#endif + + /* + * ATARI partition scheme supports 512 lba only. If this is not + * the case, bail early to avoid miscalculating hd_size. + */ + if (queue_logical_block_size(state->disk->queue) != 512) + return 0; + + rs = read_part_sector(state, 0, §); + if (!rs) + return -1; + + /* Verify this is an Atari rootsector: */ + hd_size = get_capacity(state->disk); + if (!VALID_PARTITION(&rs->part[0], hd_size) && + !VALID_PARTITION(&rs->part[1], hd_size) && + !VALID_PARTITION(&rs->part[2], hd_size) && + !VALID_PARTITION(&rs->part[3], hd_size)) { + /* + * if there's no valid primary partition, assume that no Atari + * format partition table (there's no reliable magic or the like + * :-() + */ + put_dev_sector(sect); + return 0; + } + + pi = &rs->part[0]; + seq_buf_puts(&state->pp_buf, " AHDI"); + for (slot = 1; pi < &rs->part[4] && slot < state->limit; slot++, pi++) { + struct rootsector *xrs; + Sector sect2; + ulong partsect; + + if ( !(pi->flg & 1) ) + continue; + /* active partition */ + if (memcmp (pi->id, "XGM", 3) != 0) { + /* we don't care about other id's */ + put_partition (state, slot, be32_to_cpu(pi->st), + be32_to_cpu(pi->siz)); + continue; + } + /* extension partition */ +#ifdef ICD_PARTS + part_fmt = 1; +#endif + seq_buf_puts(&state->pp_buf, " XGM<"); + partsect = extensect = be32_to_cpu(pi->st); + while (1) { + xrs = read_part_sector(state, partsect, §2); + if (!xrs) { + printk (" block %ld read failed\n", partsect); + put_dev_sector(sect); + return -1; + } + + /* ++roman: sanity check: bit 0 of flg field must be set */ + if (!(xrs->part[0].flg & 1)) { + printk( "\nFirst sub-partition in extended partition is not valid!\n" ); + put_dev_sector(sect2); + break; + } + + put_partition(state, slot, + partsect + be32_to_cpu(xrs->part[0].st), + be32_to_cpu(xrs->part[0].siz)); + + if (!(xrs->part[1].flg & 1)) { + /* end of linked partition list */ + put_dev_sector(sect2); + break; + } + if (memcmp( xrs->part[1].id, "XGM", 3 ) != 0) { + printk("\nID of extended partition is not XGM!\n"); + put_dev_sector(sect2); + break; + } + + partsect = be32_to_cpu(xrs->part[1].st) + extensect; + put_dev_sector(sect2); + if (++slot == state->limit) { + printk( "\nMaximum number of partitions reached!\n" ); + break; + } + } + seq_buf_puts(&state->pp_buf, " >"); + } +#ifdef ICD_PARTS + if ( part_fmt!=1 ) { /* no extended partitions -> test ICD-format */ + pi = &rs->icdpart[0]; + /* sanity check: no ICD format if first partition invalid */ + if (OK_id(pi->id)) { + seq_buf_puts(&state->pp_buf, " ICD<"); + for (; pi < &rs->icdpart[8] && slot < state->limit; slot++, pi++) { + /* accept only GEM,BGM,RAW,LNX,SWP partitions */ + if (!((pi->flg & 1) && OK_id(pi->id))) + continue; + put_partition (state, slot, + be32_to_cpu(pi->st), + be32_to_cpu(pi->siz)); + } + seq_buf_puts(&state->pp_buf, " >"); + } + } +#endif + put_dev_sector(sect); + + seq_buf_puts(&state->pp_buf, "\n"); + + return 1; +} -- cgit v1.3.1