From 3ebacb05044f82c5f0bb456a894eb9dc57d0ed90 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 4 Jul 2013 18:42:29 +0200 Subject: hpfs: better test for errors The test if bitmap access is out of bound could errorneously pass if the device size is divisible by 16384 sectors and we are asking for one bitmap after the end. Check for invalid size in the superblock. Invalid size could cause integer overflows in the rest of the code. Signed-off-by: Mikulas Patocka Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- fs/hpfs/super.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'fs/hpfs/super.c') diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c index a0617e706957..962e90c37aec 100644 --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -558,7 +558,13 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent) sbi->sb_cp_table = NULL; sbi->sb_c_bitmap = -1; sbi->sb_max_fwd_alloc = 0xffffff; - + + if (sbi->sb_fs_size >= 0x80000000) { + hpfs_error(s, "invalid size in superblock: %08x", + (unsigned)sbi->sb_fs_size); + goto bail4; + } + /* Load bitmap directory */ if (!(sbi->sb_bmp_dir = hpfs_load_bitmap_directory(s, le32_to_cpu(superblock->bitmaps)))) goto bail4; -- cgit v1.2.3 From 275f495dbe34300d793466a7d96c70f83fbae1bc Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 4 Jul 2013 19:04:01 +0200 Subject: hpfs: implement prefetch to improve performance This patch implements prefetch to improve performance. It helps mostly when scanning the bitmaps to calculate free space. Signed-off-by: Mikulas Patocka Signed-off-by: Linus Torvalds --- fs/hpfs/super.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/hpfs/super.c') diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c index 962e90c37aec..4334cda8dba1 100644 --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -121,7 +121,7 @@ unsigned hpfs_count_one_bitmap(struct super_block *s, secno secno) unsigned long *bits; unsigned count; - bits = hpfs_map_4sectors(s, secno, &qbh, 4); + bits = hpfs_map_4sectors(s, secno, &qbh, 0); if (!bits) return 0; count = bitmap_weight(bits, 2048 * BITS_PER_BYTE); @@ -134,8 +134,13 @@ static unsigned count_bitmaps(struct super_block *s) unsigned n, count, n_bands; n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; count = 0; - for (n = 0; n < n_bands; n++) + for (n = 0; n < COUNT_RD_AHEAD; n++) { + hpfs_prefetch_bitmap(s, n); + } + for (n = 0; n < n_bands; n++) { + hpfs_prefetch_bitmap(s, n + COUNT_RD_AHEAD); count += hpfs_count_one_bitmap(s, le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[n])); + } return count; } -- cgit v1.2.3