• J
    vfs: Fix data corruption after failed write in __block_write_begin() · f9f07b6c
    Jan Kara 提交于
    I've got a report of a file corruption from fsxlinux on ext3. The important
    operations to the page were:
    mapwrite to a hole
    partial write to the page
    read - found the page zeroed from the end of the normal write
    
    The culprit seems to be that if get_block() fails in __block_write_begin()
    (e.g. transient ENOSPC in ext3), the function does ClearPageUptodate(page).
    Thus when we retry the write, the logic in __block_write_begin() thinks zeroing
    of the page is needed and overwrites old data.  In fact, I don't see why we
    should ever need to zero the uptodate bit here - either the page was uptodate
    when we entered __block_write_begin() and it should stay so when we leave it,
    or it was not uptodate and noone had right to set it uptodate during
    __block_write_begin() so it remains !uptodate when we leave as well. So just
    remove clearing of the bit.
    Signed-off-by: NJan Kara <jack@suse.cz>
    Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
    f9f07b6c
buffer.c 87.4 KB