fuse: fix race in llseek
Fuse doesn't use i_mutex to protect setting i_size, and so generic_file_llseek() can be racy: it doesn't use i_size_read(). So do a fuse specific llseek method, which does use i_size_read(). [akpm@linux-foundation.org: make `retval' loff_t] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1431,8 +1431,33 @@ static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
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return err ? 0 : outarg.block;
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}
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static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
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{
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loff_t retval;
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struct inode *inode = file->f_path.dentry->d_inode;
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mutex_lock(&inode->i_mutex);
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switch (origin) {
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case SEEK_END:
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offset += i_size_read(inode);
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break;
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case SEEK_CUR:
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offset += file->f_pos;
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}
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retval = -EINVAL;
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if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
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if (offset != file->f_pos) {
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file->f_pos = offset;
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file->f_version = 0;
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}
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retval = offset;
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}
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mutex_unlock(&inode->i_mutex);
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return retval;
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}
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static const struct file_operations fuse_file_operations = {
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.llseek = generic_file_llseek,
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.llseek = fuse_file_llseek,
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.read = do_sync_read,
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.aio_read = fuse_file_aio_read,
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.write = do_sync_write,
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@ -1448,7 +1473,7 @@ static const struct file_operations fuse_file_operations = {
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};
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static const struct file_operations fuse_direct_io_file_operations = {
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.llseek = generic_file_llseek,
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.llseek = fuse_file_llseek,
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.read = fuse_direct_read,
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.write = fuse_direct_write,
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.open = fuse_open,
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