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    SubjectRe: [RFC v10][PATCH 08/13] Dump open file descriptors
    On Wed, Nov 26, 2008 at 08:04:39PM -0500, Oren Laadan wrote:
    > +int cr_scan_fds(struct files_struct *files, int **fdtable)
    > +{
    > + struct fdtable *fdt;
    > + int *fds;
    > + int i, n = 0;
    > + int tot = CR_DEFAULT_FDTABLE;
    > +
    > + fds = kmalloc(tot * sizeof(*fds), GFP_KERNEL);
    > + if (!fds)
    > + return -ENOMEM;
    > +
    > + /*
    > + * We assume that the target task is frozen (or that we checkpoint
    > + * ourselves), so we can safely proceed after krealloc() from where
    > + * we left off; in the worst cases restart will fail.
    > + */

    Task may be frozen, but it may share the table with any number of other
    tasks...

    > + spin_lock(&files->file_lock);
    > + rcu_read_lock();
    > + fdt = files_fdtable(files);
    > + for (i = 0; i < fdt->max_fds; i++) {
    > + if (!fcheck_files(files, i))
    > + continue;
    > + if (n == tot) {
    > + /*
    > + * fcheck_files() is safe with drop/re-acquire
    > + * of the lock, because it tests: fd < max_fds
    > + */
    > + spin_unlock(&files->file_lock);
    > + rcu_read_unlock();
    > + tot *= 2; /* won't overflow: kmalloc will fail */
    > + fds = krealloc(fds, tot * sizeof(*fds), GFP_KERNEL);
    > + if (!fds)
    > + return -ENOMEM;
    > + rcu_read_lock();
    > + spin_lock(&files->file_lock);
    > + }
    > + fds[n++] = i;
    > + }
    > + rcu_read_unlock();
    > + spin_unlock(&files->file_lock);
    > +
    > + *fdtable = fds;
    > + return n;
    > +}

    > + switch (inode->i_mode & S_IFMT) {
    > + case S_IFREG:
    > + fd_type = CR_FD_FILE;
    > + break;
    > + case S_IFDIR:
    > + fd_type = CR_FD_DIR;
    > + break;
    > + case S_IFLNK:
    > + fd_type = CR_FD_LINK;

    Opened symlinks? May I have whatever you'd been smoking, please?


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