From d63b70902befe189ba2672925f28ec3f4db41352 Mon Sep 17 00:00:00 2001 From: Evgeniy Dushistov Date: Fri, 5 Jan 2007 16:37:04 -0800 Subject: [PATCH] fix garbage instead of zeroes in UFS Looks like this is the problem, which point Al Viro some time ago: ufs's get_block callback allocates 16k of disk at a time, and links that entire 16k into the file's metadata. But because get_block is called for only a single buffer_head (a 2k buffer_head in this case?) we are only able to tell the VFS that this 2k is buffer_new(). So when ufs_getfrag_block() is later called to map some more data in the file, and when that data resides within the remaining 14k of this fragment, ufs_getfrag_block() will incorrectly return a !buffer_new() buffer_head. I don't see _right_ way to do nullification of whole block, if use inode page cache, some pages may be outside of inode limits (inode size), and will be lost; if use blockdev page cache it is possible to zero real data, if later inode page cache will be used. The simpliest way, as can I see usage of block device page cache, but not only mark dirty, but also sync it during "nullification". I use my simple tests collection, which I used for check that create,open,write,read,close works on ufs, and I see that this patch makes ufs code 18% slower then before. Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ufs/inode.c | 41 +++++------------------------------------ 1 file changed, 5 insertions(+), 36 deletions(-) (limited to 'fs/ufs/inode.c') diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c index ee1eaa6f4ec2..2fbab0aab688 100644 --- a/fs/ufs/inode.c +++ b/fs/ufs/inode.c @@ -156,36 +156,6 @@ out: return ret; } -static void ufs_clear_frag(struct inode *inode, struct buffer_head *bh) -{ - lock_buffer(bh); - memset(bh->b_data, 0, inode->i_sb->s_blocksize); - set_buffer_uptodate(bh); - mark_buffer_dirty(bh); - unlock_buffer(bh); - if (IS_SYNC(inode)) - sync_dirty_buffer(bh); -} - -static struct buffer_head * -ufs_clear_frags(struct inode *inode, sector_t beg, - unsigned int n, sector_t want) -{ - struct buffer_head *res = NULL, *bh; - sector_t end = beg + n; - - for (; beg < end; ++beg) { - bh = sb_getblk(inode->i_sb, beg); - ufs_clear_frag(inode, bh); - if (want != beg) - brelse(bh); - else - res = bh; - } - BUG_ON(!res); - return res; -} - /** * ufs_inode_getfrag() - allocate new fragment(s) * @inode - pointer to inode @@ -302,7 +272,7 @@ repeat: } if (!phys) { - result = ufs_clear_frags(inode, tmp, required, tmp + blockoff); + result = sb_getblk(sb, tmp + blockoff); } else { *phys = tmp + blockoff; result = NULL; @@ -403,8 +373,7 @@ repeat: if (!phys) { - result = ufs_clear_frags(inode, tmp, uspi->s_fpb, - tmp + blockoff); + result = sb_getblk(sb, tmp + blockoff); } else { *phys = tmp + blockoff; *new = 1; @@ -471,13 +440,13 @@ int ufs_getfrag_block(struct inode *inode, sector_t fragment, struct buffer_head #define GET_INODE_DATABLOCK(x) \ ufs_inode_getfrag(inode, x, fragment, 1, &err, &phys, &new, bh_result->b_page) #define GET_INODE_PTR(x) \ - ufs_inode_getfrag(inode, x, fragment, uspi->s_fpb, &err, NULL, NULL, bh_result->b_page) + ufs_inode_getfrag(inode, x, fragment, uspi->s_fpb, &err, NULL, NULL, NULL) #define GET_INDIRECT_DATABLOCK(x) \ ufs_inode_getblock(inode, bh, x, fragment, \ - &err, &phys, &new, bh_result->b_page); + &err, &phys, &new, bh_result->b_page) #define GET_INDIRECT_PTR(x) \ ufs_inode_getblock(inode, bh, x, fragment, \ - &err, NULL, NULL, bh_result->b_page); + &err, NULL, NULL, NULL) if (ptr < UFS_NDIR_FRAGMENT) { bh = GET_INODE_DATABLOCK(ptr); -- cgit v1.2.3