[Libguestfs] [supermin] [PATCH] ext2: check for needed block size
Richard W.M. Jones
rjones at redhat.com
Fri Jan 22 18:44:21 UTC 2016
On Fri, Jan 22, 2016 at 05:37:22PM +0100, Pino Toscano wrote:
> Check early that there are enough free blocks to store each file,
> erroring out with ENOSPC if not; this avoids slightly more obscure
> errors later on.
> ---
> src/ext2fs-c.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/src/ext2fs-c.c b/src/ext2fs-c.c
> index f01ca9d..e45980a 100644
> --- a/src/ext2fs-c.c
> +++ b/src/ext2fs-c.c
> @@ -52,6 +52,9 @@
> /* fts.h in glibc is broken, forcing us to use the GNUlib alternative. */
> #include "fts_.h"
>
> +/* How many blocks of size S are needed for storing N bytes. */
> +#define ROUND_UP(N, S) (((N) + (S) - 1) / (S))
> +
> struct ext2_data
> {
> ext2_filsys fs;
> @@ -629,6 +632,7 @@ ext2_copy_file (struct ext2_data *data, const char *src, const char *dest)
> errcode_t err;
> struct stat statbuf;
> struct statvfs statvfsbuf;
> + size_t blocks;
>
> if (data->debug >= 3)
> printf ("supermin: ext2: copy_file %s -> %s\n", src, dest);
> @@ -649,6 +653,20 @@ ext2_copy_file (struct ext2_data *data, const char *src, const char *dest)
> caml_copy_string (data->fs->device_name));
> }
>
> + /* Check that we have enough free blocks to store the resulting blocks
> + * for this file. The file might need more than that in the filesystem,
> + * but at least this provides a quick check to avoid failing later on.
> + */
> + blocks = ROUND_UP (statbuf.st_size, data->fs->blocksize);
> + if (blocks > ext2fs_free_blocks_count (data->fs->super)) {
> + fprintf (stderr, "supermin: %s: needed %lu blocks (%d each) for "
> + "%lu bytes, available only %llu\n",
> + src, blocks, data->fs->blocksize, statbuf.st_size,
> + ext2fs_free_blocks_count (data->fs->super));
> + unix_error (ENOSPC, (char *) "block size",
> + data->fs->device_name ? caml_copy_string (data->fs->device_name) : Val_none);
> + }
> +
> /* Sanity check the path. These rules are always true for the paths
> * passed to us here from the appliance layer. The assertions just
> * verify that the rules haven't changed.
> --
> 2.5.0
ACK.
Rich.
--
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