[PATCH 1/2] xfs_mdrestore: Add -i option to built-in help

[PATCH 1/2] xfs_mdrestore: Add -i option to built-in help

[Marco A Benatto]

Currently we are missing -i option from usage().
This patch adds it to this biult-in help.

Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
---
 mdrestore/xfs_mdrestore.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
index c49c13a..0bb4ac8 100644
--- a/mdrestore/xfs_mdrestore.c
+++ b/mdrestore/xfs_mdrestore.c
@@ -194,7 +194,7 @@ perform_restore(
 static void
 usage(void)
 {
-	fprintf(stderr, "Usage: %s [-V] [-g] source target\n", progname);
+	fprintf(stderr, "Usage: %s [-V] [-g] [-i] source target\n", progname);
 	exit(1);
 }
 
-- 
1.8.3.1

[PATCH 2/2] xfs_mdrestore: Don't rewind source file stream

[Marco A Benatto]

Today, xfs_mdrestore from stdin will fail if the -i flag is
specified, because it attempts to rewind the stream after
the initial read of the metablock.  This fails, and
results in an abort with "specified file is not a metadata
dump."

Read the metablock exactly once in main(), validate the magic,
print informational flags if requested, and then pass it to
perform_restore() which will then continue the restore process.

Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
---
 mdrestore/xfs_mdrestore.c | 52 +++++++++++++++++++++++------------------------
 1 file changed, 25 insertions(+), 27 deletions(-)

diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
index 0bb4ac8..15231a1 100644
--- a/mdrestore/xfs_mdrestore.c
+++ b/mdrestore/xfs_mdrestore.c
@@ -51,11 +51,22 @@ print_progress(const char *fmt, ...)
 	progress_since_warning = 1;
 }
 
+/*
+ * perform_restore() -- do the actual work to restore the metadump 
+ *
+ * @src_f: A FILE pointer to the source metadump
+ * @dst_fd: the file descriptor for the target file
+ * @is_target_file: designates whether the target is a regular file
+ * @mb: the metadump's first xfs_metablock_t, read and verified by the caller
+ *  
+ * src_f should be positioned just past a read the previously validated metablock
+ */
 static void
 perform_restore(
 	FILE			*src_f,
 	int			dst_fd,
-	int			is_target_file)
+	int			is_target_file,
+	const xfs_metablock_t	tmb)
 {
 	xfs_metablock_t 	*metablock;	/* header + index + blocks */
 	__be64			*block_index;
@@ -64,22 +75,9 @@ perform_restore(
 	int			max_indices;
 	int			cur_index;
 	int			mb_count;
-	xfs_metablock_t		tmb;
 	xfs_sb_t		sb;
 	int64_t			bytes_read;
 
-	/*
-	 * read in first blocks (superblock 0), set "inprogress" flag for it,
-	 * read in the rest of the file, and if complete, clear SB 0's
-	 * "inprogress flag"
-	 */
-
-	if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
-		fatal("error reading from file: %s\n", strerror(errno));
-
-	if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
-		fatal("specified file is not a metadata dump\n");
-
 	block_size = 1 << tmb.mb_blocklog;
 	max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
 
@@ -211,6 +209,7 @@ main(
 	int		open_flags;
 	struct stat	statbuf;
 	int		is_target_file;
+	xfs_metablock_t		mb;
 
 	progname = basename(argv[0]);
 
@@ -237,7 +236,12 @@ main(
 	if (!show_info && argc - optind != 2)
 		usage();
 
-	/* open source */
+	/*
+	 * open source and test if this really is a dump. The first metadatablock
+	 * will be passed to perform_restore() which will continue to read the
+	 * file from this point. This avoids rewind the stream, which causes
+	 * restore to fail when source was being read from stdin.
+ 	 */
 	if (strcmp(argv[optind], "-") == 0) {
 		src_f = stdin;
 		if (isatty(fileno(stdin)))
@@ -248,15 +252,12 @@ main(
 			fatal("cannot open source dump file\n");
 	}
 
-	if (show_info) {
-		xfs_metablock_t		mb;
-
-		if (fread(&mb, sizeof(mb), 1, src_f) != 1)
-			fatal("error reading from file: %s\n", strerror(errno));
-
-		if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
-			fatal("specified file is not a metadata dump\n");
+	if (fread(&mb, sizeof(mb), 1, src_f) != 1)
+		fatal("error reading from file: %s\n", strerror(errno));
+	if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
+		fatal("specified file is not a metadata dump\n");
 
+	if (show_info) {
 		if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
 			printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
 			argv[optind],
@@ -270,9 +271,6 @@ main(
 
 		if (argc - optind == 1)
 			exit(0);
-
-		/* Go back to the beginning for the restore function */
-		fseek(src_f, 0L, SEEK_SET);
 	}
 
 	optind++;
@@ -301,7 +299,7 @@ main(
 	if (dst_fd < 0)
 		fatal("couldn't open target \"%s\"\n", argv[optind]);
 
-	perform_restore(src_f, dst_fd, is_target_file);
+	perform_restore(src_f, dst_fd, is_target_file, mb);
 
 	close(dst_fd);
 	if (src_f != stdin)
-- 
1.8.3.1

Re: [PATCH 1/2] xfs_mdrestore: Add -i option to built-in help

[Darrick J. Wong]

On Fri, Feb 02, 2018 at 05:11:13PM -0200, Marco A Benatto wrote:
> Currently we are missing -i option from usage().
> This patch adds it to this biult-in help.

"built-in"

> Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>

Otherwise looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

> ---
>  mdrestore/xfs_mdrestore.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> index c49c13a..0bb4ac8 100644
> --- a/mdrestore/xfs_mdrestore.c
> +++ b/mdrestore/xfs_mdrestore.c
> @@ -194,7 +194,7 @@ perform_restore(
>  static void
>  usage(void)
>  {
> -	fprintf(stderr, "Usage: %s [-V] [-g] source target\n", progname);
> +	fprintf(stderr, "Usage: %s [-V] [-g] [-i] source target\n", progname);
>  	exit(1);
>  }
>  
> -- 
> 1.8.3.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 2/2] xfs_mdrestore: Don't rewind source file stream

[Darrick J. Wong]

On Fri, Feb 02, 2018 at 05:11:14PM -0200, Marco A Benatto wrote:
> Today, xfs_mdrestore from stdin will fail if the -i flag is
> specified, because it attempts to rewind the stream after
> the initial read of the metablock.  This fails, and
> results in an abort with "specified file is not a metadata
> dump."
> 
> Read the metablock exactly once in main(), validate the magic,
> print informational flags if requested, and then pass it to
> perform_restore() which will then continue the restore process.
> 
> Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
> ---
>  mdrestore/xfs_mdrestore.c | 52 +++++++++++++++++++++++------------------------
>  1 file changed, 25 insertions(+), 27 deletions(-)
> 
> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> index 0bb4ac8..15231a1 100644
> --- a/mdrestore/xfs_mdrestore.c
> +++ b/mdrestore/xfs_mdrestore.c
> @@ -51,11 +51,22 @@ print_progress(const char *fmt, ...)
>  	progress_since_warning = 1;
>  }
>  
> +/*
> + * perform_restore() -- do the actual work to restore the metadump 
> + *
> + * @src_f: A FILE pointer to the source metadump
> + * @dst_fd: the file descriptor for the target file
> + * @is_target_file: designates whether the target is a regular file
> + * @mb: the metadump's first xfs_metablock_t, read and verified by the caller
> + *  
> + * src_f should be positioned just past a read the previously validated metablock
> + */
>  static void
>  perform_restore(
>  	FILE			*src_f,
>  	int			dst_fd,
> -	int			is_target_file)
> +	int			is_target_file,
> +	const xfs_metablock_t	tmb)

"const struct xfs_metablock	*tmp"

Please don't pass the whole structure on the stack, and since this is
new code, don't use the structure typedef aliases (which we are slowly
trying to eliminate).

>  {
>  	xfs_metablock_t 	*metablock;	/* header + index + blocks */
>  	__be64			*block_index;
> @@ -64,22 +75,9 @@ perform_restore(
>  	int			max_indices;
>  	int			cur_index;
>  	int			mb_count;
> -	xfs_metablock_t		tmb;
>  	xfs_sb_t		sb;
>  	int64_t			bytes_read;
>  
> -	/*
> -	 * read in first blocks (superblock 0), set "inprogress" flag for it,
> -	 * read in the rest of the file, and if complete, clear SB 0's
> -	 * "inprogress flag"
> -	 */
> -
> -	if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
> -		fatal("error reading from file: %s\n", strerror(errno));
> -
> -	if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
> -		fatal("specified file is not a metadata dump\n");
> -
>  	block_size = 1 << tmb.mb_blocklog;
>  	max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
>  
> @@ -211,6 +209,7 @@ main(
>  	int		open_flags;
>  	struct stat	statbuf;
>  	int		is_target_file;
> +	xfs_metablock_t		mb;

struct xfs_metablock	mb;

>  
>  	progname = basename(argv[0]);
>  
> @@ -237,7 +236,12 @@ main(
>  	if (!show_info && argc - optind != 2)
>  		usage();
>  
> -	/* open source */
> +	/*
> +	 * open source and test if this really is a dump. The first metadatablock

"The first metadump block..."

> +	 * will be passed to perform_restore() which will continue to read the
> +	 * file from this point. This avoids rewind the stream, which causes
> +	 * restore to fail when source was being read from stdin.
> + 	 */
>  	if (strcmp(argv[optind], "-") == 0) {
>  		src_f = stdin;
>  		if (isatty(fileno(stdin)))
> @@ -248,15 +252,12 @@ main(
>  			fatal("cannot open source dump file\n");
>  	}
>  
> -	if (show_info) {
> -		xfs_metablock_t		mb;
> -
> -		if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> -			fatal("error reading from file: %s\n", strerror(errno));
> -
> -		if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
> -			fatal("specified file is not a metadata dump\n");
> +	if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> +		fatal("error reading from file: %s\n", strerror(errno));
> +	if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)

if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))

...so that we can let the horrible macro definitions turn that into a
byteswapped constant instead of a function call.  It's not critical
here, but it's a convention we try to maintain everywhere else.

The rest looks fine.

--D

> +		fatal("specified file is not a metadata dump\n");
>  
> +	if (show_info) {
>  		if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
>  			printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
>  			argv[optind],
> @@ -270,9 +271,6 @@ main(
>  
>  		if (argc - optind == 1)
>  			exit(0);
> -
> -		/* Go back to the beginning for the restore function */
> -		fseek(src_f, 0L, SEEK_SET);
>  	}
>  
>  	optind++;
> @@ -301,7 +299,7 @@ main(
>  	if (dst_fd < 0)
>  		fatal("couldn't open target \"%s\"\n", argv[optind]);
>  
> -	perform_restore(src_f, dst_fd, is_target_file);
> +	perform_restore(src_f, dst_fd, is_target_file, mb);
>  
>  	close(dst_fd);
>  	if (src_f != stdin)
> -- 
> 1.8.3.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH] xfs_mdrestore: Don't rewind source file stream

[Marco A Benatto]

Today, xfs_mdrestore from stdin will fail if the -i flag is
specified, because it attempts to rewind the stream after
the initial read of the metablock.  This fails, and
results in an abort with "specified file is not a metadata
dump."

Read the metablock exactly once in main(), validate the magic,
print informational flags if requested, and then pass it to
perform_restore() which will then continue the restore process.

Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
---
 mdrestore/xfs_mdrestore.c | 55 +++++++++++++++++++++++------------------------
 1 file changed, 27 insertions(+), 28 deletions(-)

diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
index 0bb4ac8..3db740d 100644
--- a/mdrestore/xfs_mdrestore.c
+++ b/mdrestore/xfs_mdrestore.c
@@ -51,35 +51,34 @@ print_progress(const char *fmt, ...)
 	progress_since_warning = 1;
 }
 
+/*
+ * perform_restore() -- do the actual work to restore the metadump 
+ *
+ * @src_f: A FILE pointer to the source metadump
+ * @dst_fd: the file descriptor for the target file
+ * @is_target_file: designates whether the target is a regular file
+ * @mbp: pointer to metadump's first xfs_metablock, read and verified by the caller
+ *  
+ * src_f should be positioned just past a read the previously validated metablock
+ */
 static void
 perform_restore(
 	FILE			*src_f,
 	int			dst_fd,
-	int			is_target_file)
+	int			is_target_file,
+	const struct xfs_metablock	*mbp)
 {
-	xfs_metablock_t 	*metablock;	/* header + index + blocks */
+	struct xfs_metablock 	*metablock, tmb;	/* header + index + blocks */
 	__be64			*block_index;
 	char			*block_buffer;
 	int			block_size;
 	int			max_indices;
 	int			cur_index;
 	int			mb_count;
-	xfs_metablock_t		tmb;
 	xfs_sb_t		sb;
 	int64_t			bytes_read;
 
-	/*
-	 * read in first blocks (superblock 0), set "inprogress" flag for it,
-	 * read in the rest of the file, and if complete, clear SB 0's
-	 * "inprogress flag"
-	 */
-
-	if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
-		fatal("error reading from file: %s\n", strerror(errno));
-
-	if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
-		fatal("specified file is not a metadata dump\n");
-
+	tmb = *mbp;
 	block_size = 1 << tmb.mb_blocklog;
 	max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
 
@@ -211,6 +210,7 @@ main(
 	int		open_flags;
 	struct stat	statbuf;
 	int		is_target_file;
+	xfs_metablock_t		mb;
 
 	progname = basename(argv[0]);
 
@@ -237,7 +237,12 @@ main(
 	if (!show_info && argc - optind != 2)
 		usage();
 
-	/* open source */
+	/*
+	 * open source and test if this really is a dump. The first metadump block
+	 * will be passed to perform_restore() which will continue to read the
+	 * file from this point. This avoids rewind the stream, which causes
+	 * restore to fail when source was being read from stdin.
+ 	 */
 	if (strcmp(argv[optind], "-") == 0) {
 		src_f = stdin;
 		if (isatty(fileno(stdin)))
@@ -248,15 +253,12 @@ main(
 			fatal("cannot open source dump file\n");
 	}
 
-	if (show_info) {
-		xfs_metablock_t		mb;
-
-		if (fread(&mb, sizeof(mb), 1, src_f) != 1)
-			fatal("error reading from file: %s\n", strerror(errno));
-
-		if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
-			fatal("specified file is not a metadata dump\n");
+	if (fread(&mb, sizeof(mb), 1, src_f) != 1)
+		fatal("error reading from file: %s\n", strerror(errno));
+	if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))
+		fatal("specified file is not a metadata dump\n");
 
+	if (show_info) {
 		if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
 			printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
 			argv[optind],
@@ -270,9 +272,6 @@ main(
 
 		if (argc - optind == 1)
 			exit(0);
-
-		/* Go back to the beginning for the restore function */
-		fseek(src_f, 0L, SEEK_SET);
 	}
 
 	optind++;
@@ -301,7 +300,7 @@ main(
 	if (dst_fd < 0)
 		fatal("couldn't open target \"%s\"\n", argv[optind]);
 
-	perform_restore(src_f, dst_fd, is_target_file);
+	perform_restore(src_f, dst_fd, is_target_file, &mb);
 
 	close(dst_fd);
 	if (src_f != stdin)
-- 
1.8.3.1

Re: [PATCH] xfs_mdrestore: Don't rewind source file stream

[Marco Benatto]

Hi Darrick,

just resent with the changes for the reviews you mentioned.

Please, let me know if this seems ok now.

Thanks,

On Sat, Feb 3, 2018 at 11:16 AM, Marco A Benatto
<marco.antonio.780@gmail.com> wrote:
> Today, xfs_mdrestore from stdin will fail if the -i flag is
> specified, because it attempts to rewind the stream after
> the initial read of the metablock.  This fails, and
> results in an abort with "specified file is not a metadata
> dump."
>
> Read the metablock exactly once in main(), validate the magic,
> print informational flags if requested, and then pass it to
> perform_restore() which will then continue the restore process.
>
> Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
> ---
>  mdrestore/xfs_mdrestore.c | 55 +++++++++++++++++++++++------------------------
>  1 file changed, 27 insertions(+), 28 deletions(-)
>
> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> index 0bb4ac8..3db740d 100644
> --- a/mdrestore/xfs_mdrestore.c
> +++ b/mdrestore/xfs_mdrestore.c
> @@ -51,35 +51,34 @@ print_progress(const char *fmt, ...)
>         progress_since_warning = 1;
>  }
>
> +/*
> + * perform_restore() -- do the actual work to restore the metadump
> + *
> + * @src_f: A FILE pointer to the source metadump
> + * @dst_fd: the file descriptor for the target file
> + * @is_target_file: designates whether the target is a regular file
> + * @mbp: pointer to metadump's first xfs_metablock, read and verified by the caller
> + *
> + * src_f should be positioned just past a read the previously validated metablock
> + */
>  static void
>  perform_restore(
>         FILE                    *src_f,
>         int                     dst_fd,
> -       int                     is_target_file)
> +       int                     is_target_file,
> +       const struct xfs_metablock      *mbp)
>  {
> -       xfs_metablock_t         *metablock;     /* header + index + blocks */
> +       struct xfs_metablock    *metablock, tmb;        /* header + index + blocks */
>         __be64                  *block_index;
>         char                    *block_buffer;
>         int                     block_size;
>         int                     max_indices;
>         int                     cur_index;
>         int                     mb_count;
> -       xfs_metablock_t         tmb;
>         xfs_sb_t                sb;
>         int64_t                 bytes_read;
>
> -       /*
> -        * read in first blocks (superblock 0), set "inprogress" flag for it,
> -        * read in the rest of the file, and if complete, clear SB 0's
> -        * "inprogress flag"
> -        */
> -
> -       if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
> -               fatal("error reading from file: %s\n", strerror(errno));
> -
> -       if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
> -               fatal("specified file is not a metadata dump\n");
> -
> +       tmb = *mbp;
>         block_size = 1 << tmb.mb_blocklog;
>         max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
>
> @@ -211,6 +210,7 @@ main(
>         int             open_flags;
>         struct stat     statbuf;
>         int             is_target_file;
> +       xfs_metablock_t         mb;
>
>         progname = basename(argv[0]);
>
> @@ -237,7 +237,12 @@ main(
>         if (!show_info && argc - optind != 2)
>                 usage();
>
> -       /* open source */
> +       /*
> +        * open source and test if this really is a dump. The first metadump block
> +        * will be passed to perform_restore() which will continue to read the
> +        * file from this point. This avoids rewind the stream, which causes
> +        * restore to fail when source was being read from stdin.
> +        */
>         if (strcmp(argv[optind], "-") == 0) {
>                 src_f = stdin;
>                 if (isatty(fileno(stdin)))
> @@ -248,15 +253,12 @@ main(
>                         fatal("cannot open source dump file\n");
>         }
>
> -       if (show_info) {
> -               xfs_metablock_t         mb;
> -
> -               if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> -                       fatal("error reading from file: %s\n", strerror(errno));
> -
> -               if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
> -                       fatal("specified file is not a metadata dump\n");
> +       if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> +               fatal("error reading from file: %s\n", strerror(errno));
> +       if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))
> +               fatal("specified file is not a metadata dump\n");
>
> +       if (show_info) {
>                 if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
>                         printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
>                         argv[optind],
> @@ -270,9 +272,6 @@ main(
>
>                 if (argc - optind == 1)
>                         exit(0);
> -
> -               /* Go back to the beginning for the restore function */
> -               fseek(src_f, 0L, SEEK_SET);
>         }
>
>         optind++;
> @@ -301,7 +300,7 @@ main(
>         if (dst_fd < 0)
>                 fatal("couldn't open target \"%s\"\n", argv[optind]);
>
> -       perform_restore(src_f, dst_fd, is_target_file);
> +       perform_restore(src_f, dst_fd, is_target_file, &mb);
>
>         close(dst_fd);
>         if (src_f != stdin)
> --
> 1.8.3.1
>



-- 
Marco Antonio Benatto
Linux user ID: #506236

Re: [PATCH] xfs_mdrestore: Don't rewind source file stream

[Darrick J. Wong]

On Sat, Feb 03, 2018 at 11:16:36AM -0200, Marco A Benatto wrote:
> Today, xfs_mdrestore from stdin will fail if the -i flag is
> specified, because it attempts to rewind the stream after
> the initial read of the metablock.  This fails, and
> results in an abort with "specified file is not a metadata
> dump."
> 
> Read the metablock exactly once in main(), validate the magic,
> print informational flags if requested, and then pass it to
> perform_restore() which will then continue the restore process.
> 
> Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
> ---
>  mdrestore/xfs_mdrestore.c | 55 +++++++++++++++++++++++------------------------
>  1 file changed, 27 insertions(+), 28 deletions(-)
> 
> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> index 0bb4ac8..3db740d 100644
> --- a/mdrestore/xfs_mdrestore.c
> +++ b/mdrestore/xfs_mdrestore.c
> @@ -51,35 +51,34 @@ print_progress(const char *fmt, ...)
>  	progress_since_warning = 1;
>  }
>  
> +/*
> + * perform_restore() -- do the actual work to restore the metadump 
> + *
> + * @src_f: A FILE pointer to the source metadump
> + * @dst_fd: the file descriptor for the target file
> + * @is_target_file: designates whether the target is a regular file
> + * @mbp: pointer to metadump's first xfs_metablock, read and verified by the caller
> + *  
> + * src_f should be positioned just past a read the previously validated metablock
> + */
>  static void
>  perform_restore(
>  	FILE			*src_f,
>  	int			dst_fd,
> -	int			is_target_file)
> +	int			is_target_file,
> +	const struct xfs_metablock	*mbp)
>  {
> -	xfs_metablock_t 	*metablock;	/* header + index + blocks */
> +	struct xfs_metablock 	*metablock, tmb;	/* header + index + blocks */
>  	__be64			*block_index;
>  	char			*block_buffer;
>  	int			block_size;
>  	int			max_indices;
>  	int			cur_index;
>  	int			mb_count;
> -	xfs_metablock_t		tmb;
>  	xfs_sb_t		sb;
>  	int64_t			bytes_read;
>  
> -	/*
> -	 * read in first blocks (superblock 0), set "inprogress" flag for it,
> -	 * read in the rest of the file, and if complete, clear SB 0's
> -	 * "inprogress flag"
> -	 */
> -
> -	if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
> -		fatal("error reading from file: %s\n", strerror(errno));
> -
> -	if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
> -		fatal("specified file is not a metadata dump\n");
> -
> +	tmb = *mbp;
>  	block_size = 1 << tmb.mb_blocklog;

Why not avoid the structure copy and dereference the pointer directly?

block_size = 1 << mbp->mb_blocklog;

etc.

>  	max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
>  
> @@ -211,6 +210,7 @@ main(
>  	int		open_flags;
>  	struct stat	statbuf;
>  	int		is_target_file;
> +	xfs_metablock_t		mb;

struct xfs_metablock	mb;

--D

>  
>  	progname = basename(argv[0]);
>  
> @@ -237,7 +237,12 @@ main(
>  	if (!show_info && argc - optind != 2)
>  		usage();
>  
> -	/* open source */
> +	/*
> +	 * open source and test if this really is a dump. The first metadump block
> +	 * will be passed to perform_restore() which will continue to read the
> +	 * file from this point. This avoids rewind the stream, which causes
> +	 * restore to fail when source was being read from stdin.
> + 	 */
>  	if (strcmp(argv[optind], "-") == 0) {
>  		src_f = stdin;
>  		if (isatty(fileno(stdin)))
> @@ -248,15 +253,12 @@ main(
>  			fatal("cannot open source dump file\n");
>  	}
>  
> -	if (show_info) {
> -		xfs_metablock_t		mb;
> -
> -		if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> -			fatal("error reading from file: %s\n", strerror(errno));
> -
> -		if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
> -			fatal("specified file is not a metadata dump\n");
> +	if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> +		fatal("error reading from file: %s\n", strerror(errno));
> +	if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))
> +		fatal("specified file is not a metadata dump\n");
>  
> +	if (show_info) {
>  		if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
>  			printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
>  			argv[optind],
> @@ -270,9 +272,6 @@ main(
>  
>  		if (argc - optind == 1)
>  			exit(0);
> -
> -		/* Go back to the beginning for the restore function */
> -		fseek(src_f, 0L, SEEK_SET);
>  	}
>  
>  	optind++;
> @@ -301,7 +300,7 @@ main(
>  	if (dst_fd < 0)
>  		fatal("couldn't open target \"%s\"\n", argv[optind]);
>  
> -	perform_restore(src_f, dst_fd, is_target_file);
> +	perform_restore(src_f, dst_fd, is_target_file, &mb);
>  
>  	close(dst_fd);
>  	if (src_f != stdin)
> -- 
> 1.8.3.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH] xfs_mdrestore: Don't rewind source file stream

[Marco A Benatto]

Today, xfs_mdrestore from stdin will fail if the -i flag is
specified, because it attempts to rewind the stream after
the initial read of the metablock.  This fails, and
results in an abort with "specified file is not a metadata
dump."

Read the metablock exactly once in main(), validate the magic,
print informational flags if requested, and then pass it to
perform_restore() which will then continue the restore process.

Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>
---
 mdrestore/xfs_mdrestore.c | 68 +++++++++++++++++++++++------------------------
 1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
index 0bb4ac8..cbabd56 100644
--- a/mdrestore/xfs_mdrestore.c
+++ b/mdrestore/xfs_mdrestore.c
@@ -51,57 +51,55 @@ print_progress(const char *fmt, ...)
 	progress_since_warning = 1;
 }
 
+/*
+ * perform_restore() -- do the actual work to restore the metadump 
+ *
+ * @src_f: A FILE pointer to the source metadump
+ * @dst_fd: the file descriptor for the target file
+ * @is_target_file: designates whether the target is a regular file
+ * @mbp: pointer to metadump's first xfs_metablock, read and verified by the caller
+ *  
+ * src_f should be positioned just past a read the previously validated metablock
+ */
 static void
 perform_restore(
 	FILE			*src_f,
 	int			dst_fd,
-	int			is_target_file)
+	int			is_target_file,
+	const struct xfs_metablock	*mbp)
 {
-	xfs_metablock_t 	*metablock;	/* header + index + blocks */
+	struct xfs_metablock 	*metablock;	/* header + index + blocks */
 	__be64			*block_index;
 	char			*block_buffer;
 	int			block_size;
 	int			max_indices;
 	int			cur_index;
 	int			mb_count;
-	xfs_metablock_t		tmb;
 	xfs_sb_t		sb;
 	int64_t			bytes_read;
 
-	/*
-	 * read in first blocks (superblock 0), set "inprogress" flag for it,
-	 * read in the rest of the file, and if complete, clear SB 0's
-	 * "inprogress flag"
-	 */
-
-	if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
-		fatal("error reading from file: %s\n", strerror(errno));
-
-	if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
-		fatal("specified file is not a metadata dump\n");
-
-	block_size = 1 << tmb.mb_blocklog;
+	block_size = 1 << mbp->mb_blocklog;
 	max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
 
 	metablock = (xfs_metablock_t *)calloc(max_indices + 1, block_size);
 	if (metablock == NULL)
 		fatal("memory allocation failure\n");
 
-	mb_count = be16_to_cpu(tmb.mb_count);
+	mb_count = be16_to_cpu(mbp->mb_count);
 	if (mb_count == 0 || mb_count > max_indices)
 		fatal("bad block count: %u\n", mb_count);
 
 	block_index = (__be64 *)((char *)metablock + sizeof(xfs_metablock_t));
 	block_buffer = (char *)metablock + block_size;
 
-	if (fread(block_index, block_size - sizeof(tmb), 1, src_f) != 1)
+	if (fread(block_index, block_size - sizeof(struct xfs_metablock), 1, src_f) != 1)
 		fatal("error reading from file: %s\n", strerror(errno));
 
 	if (block_index[0] != 0)
 		fatal("first block is not the primary superblock\n");
 
 
-	if (fread(block_buffer, mb_count << tmb.mb_blocklog,
+	if (fread(block_buffer, mb_count << mbp->mb_blocklog,
 			1, src_f) != 1)
 		fatal("error reading from file: %s\n", strerror(errno));
 
@@ -148,7 +146,7 @@ perform_restore(
 
 		for (cur_index = 0; cur_index < mb_count; cur_index++) {
 			if (pwrite(dst_fd, &block_buffer[cur_index <<
-					tmb.mb_blocklog], block_size,
+					mbp->mb_blocklog], block_size,
 					be64_to_cpu(block_index[cur_index]) <<
 						BBSHIFT) < 0)
 				fatal("error writing block %llu: %s\n",
@@ -167,11 +165,11 @@ perform_restore(
 		if (mb_count > max_indices)
 			fatal("bad block count: %u\n", mb_count);
 
-		if (fread(block_buffer, mb_count << tmb.mb_blocklog,
+		if (fread(block_buffer, mb_count << mbp->mb_blocklog,
 								1, src_f) != 1)
 			fatal("error reading from file: %s\n", strerror(errno));
 
-		bytes_read += block_size + (mb_count << tmb.mb_blocklog);
+		bytes_read += block_size + (mb_count << mbp->mb_blocklog);
 	}
 
 	if (progress_since_warning)
@@ -211,6 +209,7 @@ main(
 	int		open_flags;
 	struct stat	statbuf;
 	int		is_target_file;
+	struct xfs_metablock	mb;
 
 	progname = basename(argv[0]);
 
@@ -237,7 +236,12 @@ main(
 	if (!show_info && argc - optind != 2)
 		usage();
 
-	/* open source */
+	/*
+	 * open source and test if this really is a dump. The first metadump block
+	 * will be passed to perform_restore() which will continue to read the
+	 * file from this point. This avoids rewind the stream, which causes
+	 * restore to fail when source was being read from stdin.
+ 	 */
 	if (strcmp(argv[optind], "-") == 0) {
 		src_f = stdin;
 		if (isatty(fileno(stdin)))
@@ -248,15 +252,12 @@ main(
 			fatal("cannot open source dump file\n");
 	}
 
-	if (show_info) {
-		xfs_metablock_t		mb;
-
-		if (fread(&mb, sizeof(mb), 1, src_f) != 1)
-			fatal("error reading from file: %s\n", strerror(errno));
-
-		if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
-			fatal("specified file is not a metadata dump\n");
+	if (fread(&mb, sizeof(mb), 1, src_f) != 1)
+		fatal("error reading from file: %s\n", strerror(errno));
+	if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))
+		fatal("specified file is not a metadata dump\n");
 
+	if (show_info) {
 		if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
 			printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
 			argv[optind],
@@ -270,9 +271,6 @@ main(
 
 		if (argc - optind == 1)
 			exit(0);
-
-		/* Go back to the beginning for the restore function */
-		fseek(src_f, 0L, SEEK_SET);
 	}
 
 	optind++;
@@ -301,7 +299,7 @@ main(
 	if (dst_fd < 0)
 		fatal("couldn't open target \"%s\"\n", argv[optind]);
 
-	perform_restore(src_f, dst_fd, is_target_file);
+	perform_restore(src_f, dst_fd, is_target_file, &mb);
 
 	close(dst_fd);
 	if (src_f != stdin)
-- 
1.8.3.1

Re: [PATCH] xfs_mdrestore: Don't rewind source file stream

[Darrick J. Wong]

On Mon, Feb 05, 2018 at 09:50:34AM -0200, Marco A Benatto wrote:
> Today, xfs_mdrestore from stdin will fail if the -i flag is
> specified, because it attempts to rewind the stream after
> the initial read of the metablock.  This fails, and
> results in an abort with "specified file is not a metadata
> dump."
> 
> Read the metablock exactly once in main(), validate the magic,
> print informational flags if requested, and then pass it to
> perform_restore() which will then continue the restore process.
> 
> Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Marco A Benatto <marco.antonio.780@gmail.com>

Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

> ---
>  mdrestore/xfs_mdrestore.c | 68 +++++++++++++++++++++++------------------------
>  1 file changed, 33 insertions(+), 35 deletions(-)
> 
> diff --git a/mdrestore/xfs_mdrestore.c b/mdrestore/xfs_mdrestore.c
> index 0bb4ac8..cbabd56 100644
> --- a/mdrestore/xfs_mdrestore.c
> +++ b/mdrestore/xfs_mdrestore.c
> @@ -51,57 +51,55 @@ print_progress(const char *fmt, ...)
>  	progress_since_warning = 1;
>  }
>  
> +/*
> + * perform_restore() -- do the actual work to restore the metadump 
> + *
> + * @src_f: A FILE pointer to the source metadump
> + * @dst_fd: the file descriptor for the target file
> + * @is_target_file: designates whether the target is a regular file
> + * @mbp: pointer to metadump's first xfs_metablock, read and verified by the caller
> + *  
> + * src_f should be positioned just past a read the previously validated metablock
> + */
>  static void
>  perform_restore(
>  	FILE			*src_f,
>  	int			dst_fd,
> -	int			is_target_file)
> +	int			is_target_file,
> +	const struct xfs_metablock	*mbp)
>  {
> -	xfs_metablock_t 	*metablock;	/* header + index + blocks */
> +	struct xfs_metablock 	*metablock;	/* header + index + blocks */
>  	__be64			*block_index;
>  	char			*block_buffer;
>  	int			block_size;
>  	int			max_indices;
>  	int			cur_index;
>  	int			mb_count;
> -	xfs_metablock_t		tmb;
>  	xfs_sb_t		sb;
>  	int64_t			bytes_read;
>  
> -	/*
> -	 * read in first blocks (superblock 0), set "inprogress" flag for it,
> -	 * read in the rest of the file, and if complete, clear SB 0's
> -	 * "inprogress flag"
> -	 */
> -
> -	if (fread(&tmb, sizeof(tmb), 1, src_f) != 1)
> -		fatal("error reading from file: %s\n", strerror(errno));
> -
> -	if (be32_to_cpu(tmb.mb_magic) != XFS_MD_MAGIC)
> -		fatal("specified file is not a metadata dump\n");
> -
> -	block_size = 1 << tmb.mb_blocklog;
> +	block_size = 1 << mbp->mb_blocklog;
>  	max_indices = (block_size - sizeof(xfs_metablock_t)) / sizeof(__be64);
>  
>  	metablock = (xfs_metablock_t *)calloc(max_indices + 1, block_size);
>  	if (metablock == NULL)
>  		fatal("memory allocation failure\n");
>  
> -	mb_count = be16_to_cpu(tmb.mb_count);
> +	mb_count = be16_to_cpu(mbp->mb_count);
>  	if (mb_count == 0 || mb_count > max_indices)
>  		fatal("bad block count: %u\n", mb_count);
>  
>  	block_index = (__be64 *)((char *)metablock + sizeof(xfs_metablock_t));
>  	block_buffer = (char *)metablock + block_size;
>  
> -	if (fread(block_index, block_size - sizeof(tmb), 1, src_f) != 1)
> +	if (fread(block_index, block_size - sizeof(struct xfs_metablock), 1, src_f) != 1)
>  		fatal("error reading from file: %s\n", strerror(errno));
>  
>  	if (block_index[0] != 0)
>  		fatal("first block is not the primary superblock\n");
>  
>  
> -	if (fread(block_buffer, mb_count << tmb.mb_blocklog,
> +	if (fread(block_buffer, mb_count << mbp->mb_blocklog,
>  			1, src_f) != 1)
>  		fatal("error reading from file: %s\n", strerror(errno));
>  
> @@ -148,7 +146,7 @@ perform_restore(
>  
>  		for (cur_index = 0; cur_index < mb_count; cur_index++) {
>  			if (pwrite(dst_fd, &block_buffer[cur_index <<
> -					tmb.mb_blocklog], block_size,
> +					mbp->mb_blocklog], block_size,
>  					be64_to_cpu(block_index[cur_index]) <<
>  						BBSHIFT) < 0)
>  				fatal("error writing block %llu: %s\n",
> @@ -167,11 +165,11 @@ perform_restore(
>  		if (mb_count > max_indices)
>  			fatal("bad block count: %u\n", mb_count);
>  
> -		if (fread(block_buffer, mb_count << tmb.mb_blocklog,
> +		if (fread(block_buffer, mb_count << mbp->mb_blocklog,
>  								1, src_f) != 1)
>  			fatal("error reading from file: %s\n", strerror(errno));
>  
> -		bytes_read += block_size + (mb_count << tmb.mb_blocklog);
> +		bytes_read += block_size + (mb_count << mbp->mb_blocklog);
>  	}
>  
>  	if (progress_since_warning)
> @@ -211,6 +209,7 @@ main(
>  	int		open_flags;
>  	struct stat	statbuf;
>  	int		is_target_file;
> +	struct xfs_metablock	mb;
>  
>  	progname = basename(argv[0]);
>  
> @@ -237,7 +236,12 @@ main(
>  	if (!show_info && argc - optind != 2)
>  		usage();
>  
> -	/* open source */
> +	/*
> +	 * open source and test if this really is a dump. The first metadump block
> +	 * will be passed to perform_restore() which will continue to read the
> +	 * file from this point. This avoids rewind the stream, which causes
> +	 * restore to fail when source was being read from stdin.
> + 	 */
>  	if (strcmp(argv[optind], "-") == 0) {
>  		src_f = stdin;
>  		if (isatty(fileno(stdin)))
> @@ -248,15 +252,12 @@ main(
>  			fatal("cannot open source dump file\n");
>  	}
>  
> -	if (show_info) {
> -		xfs_metablock_t		mb;
> -
> -		if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> -			fatal("error reading from file: %s\n", strerror(errno));
> -
> -		if (be32_to_cpu(mb.mb_magic) != XFS_MD_MAGIC)
> -			fatal("specified file is not a metadata dump\n");
> +	if (fread(&mb, sizeof(mb), 1, src_f) != 1)
> +		fatal("error reading from file: %s\n", strerror(errno));
> +	if (mb.mb_magic != cpu_to_be32(XFS_MD_MAGIC))
> +		fatal("specified file is not a metadata dump\n");
>  
> +	if (show_info) {
>  		if (mb.mb_info & XFS_METADUMP_INFO_FLAGS) {
>  			printf("%s: %sobfuscated, %s log, %s metadata blocks\n",
>  			argv[optind],
> @@ -270,9 +271,6 @@ main(
>  
>  		if (argc - optind == 1)
>  			exit(0);
> -
> -		/* Go back to the beginning for the restore function */
> -		fseek(src_f, 0L, SEEK_SET);
>  	}
>  
>  	optind++;
> @@ -301,7 +299,7 @@ main(
>  	if (dst_fd < 0)
>  		fatal("couldn't open target \"%s\"\n", argv[optind]);
>  
> -	perform_restore(src_f, dst_fd, is_target_file);
> +	perform_restore(src_f, dst_fd, is_target_file, &mb);
>  
>  	close(dst_fd);
>  	if (src_f != stdin)
> -- 
> 1.8.3.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html