Messages in this thread | | | Date | Fri, 28 Nov 2008 10:19:19 +0000 | From | Al Viro <> | Subject | Re: [RFC v10][PATCH 08/13] Dump open file descriptors |
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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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