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authorEvgeniy Dushistov <dushistov@mail.ru>2007-01-05 16:37:04 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2007-01-05 23:55:29 -0800
commitd63b70902befe189ba2672925f28ec3f4db41352 (patch)
tree727b00bf66ebb3d1de20d630f310429fa5063325 /fs/ufs/balloc.c
parent7ba3485947ee7bc89a17f86250fe9b692a615dff (diff)
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[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 <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/ufs/balloc.c')
-rw-r--r--fs/ufs/balloc.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/fs/ufs/balloc.c b/fs/ufs/balloc.c
index b8238147577..2e0021e8f36 100644
--- a/fs/ufs/balloc.c
+++ b/fs/ufs/balloc.c
@@ -275,6 +275,25 @@ static void ufs_change_blocknr(struct inode *inode, unsigned int baseblk,
UFSD("EXIT\n");
}
+static void ufs_clear_frags(struct inode *inode, sector_t beg, unsigned int n,
+ int sync)
+{
+ struct buffer_head *bh;
+ sector_t end = beg + n;
+
+ for (; beg < end; ++beg) {
+ bh = sb_getblk(inode->i_sb, beg);
+ 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)
+ sync_dirty_buffer(bh);
+ brelse(bh);
+ }
+}
+
unsigned ufs_new_fragments(struct inode * inode, __fs32 * p, unsigned fragment,
unsigned goal, unsigned count, int * err, struct page *locked_page)
{
@@ -350,6 +369,8 @@ unsigned ufs_new_fragments(struct inode * inode, __fs32 * p, unsigned fragment,
*p = cpu_to_fs32(sb, result);
*err = 0;
UFS_I(inode)->i_lastfrag = max_t(u32, UFS_I(inode)->i_lastfrag, fragment + count);
+ ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
+ locked_page != NULL);
}
unlock_super(sb);
UFSD("EXIT, result %u\n", result);
@@ -363,6 +384,8 @@ unsigned ufs_new_fragments(struct inode * inode, __fs32 * p, unsigned fragment,
if (result) {
*err = 0;
UFS_I(inode)->i_lastfrag = max_t(u32, UFS_I(inode)->i_lastfrag, fragment + count);
+ ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
+ locked_page != NULL);
unlock_super(sb);
UFSD("EXIT, result %u\n", result);
return result;
@@ -398,6 +421,8 @@ unsigned ufs_new_fragments(struct inode * inode, __fs32 * p, unsigned fragment,
*p = cpu_to_fs32(sb, result);
*err = 0;
UFS_I(inode)->i_lastfrag = max_t(u32, UFS_I(inode)->i_lastfrag, fragment + count);
+ ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
+ locked_page != NULL);
unlock_super(sb);
if (newcount < request)
ufs_free_fragments (inode, result + newcount, request - newcount);