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/map.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/hpfs/map.c') diff --git a/fs/hpfs/map.c b/fs/hpfs/map.c index 4acb19d78359..803d3da3a0fe 100644 --- a/fs/hpfs/map.c +++ b/fs/hpfs/map.c @@ -17,7 +17,8 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block, struct quad_buffer_head *qbh, char *id) { secno sec; - if (hpfs_sb(s)->sb_chk) if (bmp_block * 16384 > hpfs_sb(s)->sb_fs_size) { + unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; + if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) { hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id); return NULL; } -- 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/map.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'fs/hpfs/map.c') diff --git a/fs/hpfs/map.c b/fs/hpfs/map.c index 803d3da3a0fe..3aa66ae1031e 100644 --- a/fs/hpfs/map.c +++ b/fs/hpfs/map.c @@ -17,6 +17,7 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block, struct quad_buffer_head *qbh, char *id) { secno sec; + __le32 *ret; unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) { hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id); @@ -27,7 +28,23 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block, hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id); return NULL; } - return hpfs_map_4sectors(s, sec, qbh, 4); + ret = hpfs_map_4sectors(s, sec, qbh, 4); + if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1); + return ret; +} + +void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block) +{ + unsigned to_prefetch, next_prefetch; + unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; + if (unlikely(bmp_block >= n_bands)) + return; + to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]); + if (unlikely(bmp_block + 1 >= n_bands)) + next_prefetch = 0; + else + next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]); + hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch)); } /* -- cgit v1.2.3