The patch titled
Subject: squashfs: add option to panic on errors
has been added to the -mm tree. Its filename is
squashfs-add-option-to-panic-on-errors.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/squashfs-add-option-to-panic-on-errors.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/squashfs-add-option-to-panic-on-errors.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Subject: squashfs: add option to panic on errors
Add an errors=panic mount option to make squashfs trigger a panic when
errors are encountered, similar to several other filesystems. This allows
a kernel dump to be saved using which the corruption can be analysed and
debugged.
Inspired by a pre-fs_context patch by Anton Eliasson.
Link: https://lkml.kernel.org/r/20210527125019.14511-1-vincent.whitchurch@xxxxxxxx
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Cc: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/squashfs/block.c | 5 +
fs/squashfs/squashfs_fs_sb.h | 1
fs/squashfs/super.c | 86 +++++++++++++++++++++++++++++++++
3 files changed, 91 insertions(+), 1 deletion(-)
--- a/fs/squashfs/block.c~squashfs-add-option-to-panic-on-errors
+++ a/fs/squashfs/block.c
@@ -226,8 +226,11 @@ out_free_bio:
bio_free_pages(bio);
bio_put(bio);
out:
- if (res < 0)
+ if (res < 0) {
ERROR("Failed to read block 0x%llx: %d\n", index, res);
+ if (msblk->panic_on_errors)
+ panic("squashfs read failed");
+ }
return res;
}
--- a/fs/squashfs/squashfs_fs_sb.h~squashfs-add-option-to-panic-on-errors
+++ a/fs/squashfs/squashfs_fs_sb.h
@@ -65,5 +65,6 @@ struct squashfs_sb_info {
unsigned int fragments;
int xattr_ids;
unsigned int ids;
+ bool panic_on_errors;
};
#endif
--- a/fs/squashfs/super.c~squashfs-add-option-to-panic-on-errors
+++ a/fs/squashfs/super.c
@@ -18,9 +18,11 @@
#include <linux/fs.h>
#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/mutex.h>
+#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/module.h>
@@ -37,6 +39,51 @@
static struct file_system_type squashfs_fs_type;
static const struct super_operations squashfs_super_ops;
+enum Opt_errors {
+ Opt_errors_continue,
+ Opt_errors_panic,
+};
+
+enum squashfs_param {
+ Opt_errors,
+};
+
+struct squashfs_mount_opts {
+ enum Opt_errors errors;
+};
+
+static const struct constant_table squashfs_param_errors[] = {
+ {"continue", Opt_errors_continue },
+ {"panic", Opt_errors_panic },
+ {}
+};
+
+static const struct fs_parameter_spec squashfs_fs_parameters[] = {
+ fsparam_enum("errors", Opt_errors, squashfs_param_errors),
+ {}
+};
+
+static int squashfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+ struct squashfs_mount_opts *opts = fc->fs_private;
+ struct fs_parse_result result;
+ int opt;
+
+ opt = fs_parse(fc, squashfs_fs_parameters, param, &result);
+ if (opt < 0)
+ return opt;
+
+ switch (opt) {
+ case Opt_errors:
+ opts->errors = result.uint_32;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static const struct squashfs_decompressor *supported_squashfs_filesystem(
struct fs_context *fc,
short major, short minor, short id)
@@ -67,6 +114,7 @@ static const struct squashfs_decompresso
static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
+ struct squashfs_mount_opts *opts = fc->fs_private;
struct squashfs_sb_info *msblk;
struct squashfs_super_block *sblk = NULL;
struct inode *root;
@@ -85,6 +133,8 @@ static int squashfs_fill_super(struct su
}
msblk = sb->s_fs_info;
+ msblk->panic_on_errors = (opts->errors == Opt_errors_panic);
+
msblk->devblksize = sb_min_blocksize(sb, SQUASHFS_DEVBLK_SIZE);
msblk->devblksize_log2 = ffz(~msblk->devblksize);
@@ -350,18 +400,52 @@ static int squashfs_get_tree(struct fs_c
static int squashfs_reconfigure(struct fs_context *fc)
{
+ struct super_block *sb = fc->root->d_sb;
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ struct squashfs_mount_opts *opts = fc->fs_private;
+
sync_filesystem(fc->root->d_sb);
fc->sb_flags |= SB_RDONLY;
+
+ msblk->panic_on_errors = (opts->errors == Opt_errors_panic);
+
return 0;
}
+static void squashfs_free_fs_context(struct fs_context *fc)
+{
+ kfree(fc->fs_private);
+}
+
static const struct fs_context_operations squashfs_context_ops = {
.get_tree = squashfs_get_tree,
+ .free = squashfs_free_fs_context,
+ .parse_param = squashfs_parse_param,
.reconfigure = squashfs_reconfigure,
};
+static int squashfs_show_options(struct seq_file *s, struct dentry *root)
+{
+ struct super_block *sb = root->d_sb;
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+
+ if (msblk->panic_on_errors)
+ seq_puts(s, ",errors=panic");
+ else
+ seq_puts(s, ",errors=continue");
+
+ return 0;
+}
+
static int squashfs_init_fs_context(struct fs_context *fc)
{
+ struct squashfs_mount_opts *opts;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+
+ fc->fs_private = opts;
fc->ops = &squashfs_context_ops;
return 0;
}
@@ -481,6 +565,7 @@ static struct file_system_type squashfs_
.owner = THIS_MODULE,
.name = "squashfs",
.init_fs_context = squashfs_init_fs_context,
+ .parameters = squashfs_fs_parameters,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV
};
@@ -491,6 +576,7 @@ static const struct super_operations squ
.free_inode = squashfs_free_inode,
.statfs = squashfs_statfs,
.put_super = squashfs_put_super,
+ .show_options = squashfs_show_options,
};
module_init(init_squashfs_fs);
_
Patches currently in -mm which might be from vincent.whitchurch@xxxxxxxx are
squashfs-add-option-to-panic-on-errors.patch
