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d63b70902b
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> |
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| .. | ||
| balloc.c | ||
| cylinder.c | ||
| dir.c | ||
| file.c | ||
| ialloc.c | ||
| inode.c | ||
| Makefile | ||
| namei.c | ||
| super.c | ||
| swab.h | ||
| symlink.c | ||
| truncate.c | ||
| util.c | ||
| util.h | ||