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floppy: bail out in open() if drive is not responding to block0 read
In case reading of block 0 during open() fails, it is not the right thing to let open() succeed. Fix this by introducing FD_OPEN_SHOULD_FAIL_BIT flag, and setting it in case the bio callback encounters an error while trying to read block 0. As a bonus, this works around certain broken userspace (blkid), which is not able to properly handle read()s returning IO errors. Hence be nice to those, and bail out during open() already; if block 0 is not readable, read()s are not going to provide any meaningful data anyway. Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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parent
8586ea96b4
commit
7b7b68bba5
2 changed files with 29 additions and 10 deletions
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@ -3691,9 +3691,12 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
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if (!(mode & FMODE_NDELAY)) {
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if (mode & (FMODE_READ|FMODE_WRITE)) {
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UDRS->last_checked = 0;
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clear_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags);
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check_disk_change(bdev);
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if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
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goto out;
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if (test_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags))
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goto out;
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}
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res = -EROFS;
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if ((mode & FMODE_WRITE) &&
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@ -3746,17 +3749,29 @@ static unsigned int floppy_check_events(struct gendisk *disk,
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* a disk in the drive, and whether that disk is writable.
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*/
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static void floppy_rb0_complete(struct bio *bio, int err)
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struct rb0_cbdata {
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int drive;
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struct completion complete;
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};
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static void floppy_rb0_cb(struct bio *bio, int err)
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{
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complete((struct completion *)bio->bi_private);
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struct rb0_cbdata *cbdata = (struct rb0_cbdata *)bio->bi_private;
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int drive = cbdata->drive;
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if (err) {
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pr_info("floppy: error %d while reading block 0", err);
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set_bit(FD_OPEN_SHOULD_FAIL_BIT, &UDRS->flags);
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}
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complete(&cbdata->complete);
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}
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static int __floppy_read_block_0(struct block_device *bdev)
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static int __floppy_read_block_0(struct block_device *bdev, int drive)
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{
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struct bio bio;
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struct bio_vec bio_vec;
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struct completion complete;
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struct page *page;
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struct rb0_cbdata cbdata;
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size_t size;
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page = alloc_page(GFP_NOIO);
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@ -3769,6 +3784,8 @@ static int __floppy_read_block_0(struct block_device *bdev)
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if (!size)
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size = 1024;
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cbdata.drive = drive;
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bio_init(&bio);
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bio.bi_io_vec = &bio_vec;
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bio_vec.bv_page = page;
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@ -3779,13 +3796,14 @@ static int __floppy_read_block_0(struct block_device *bdev)
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bio.bi_bdev = bdev;
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bio.bi_iter.bi_sector = 0;
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bio.bi_flags = (1 << BIO_QUIET);
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init_completion(&complete);
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bio.bi_private = &complete;
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bio.bi_end_io = floppy_rb0_complete;
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bio.bi_private = &cbdata;
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bio.bi_end_io = floppy_rb0_cb;
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submit_bio(READ, &bio);
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process_fd_request();
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wait_for_completion(&complete);
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init_completion(&cbdata.complete);
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wait_for_completion(&cbdata.complete);
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__free_page(page);
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@ -3827,7 +3845,7 @@ static int floppy_revalidate(struct gendisk *disk)
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UDRS->generation++;
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if (drive_no_geom(drive)) {
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/* auto-sensing */
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res = __floppy_read_block_0(opened_bdev[drive]);
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res = __floppy_read_block_0(opened_bdev[drive], drive);
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} else {
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if (cf)
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poll_drive(false, FD_RAW_NEED_DISK);
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@ -185,7 +185,8 @@ enum {
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* to clear media change status */
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FD_UNUSED_BIT,
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FD_DISK_CHANGED_BIT, /* disk has been changed since last i/o */
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FD_DISK_WRITABLE_BIT /* disk is writable */
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FD_DISK_WRITABLE_BIT, /* disk is writable */
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FD_OPEN_SHOULD_FAIL_BIT
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};
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#define FDSETDRVPRM _IOW(2, 0x90, struct floppy_drive_params)
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