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Subject[RFC PATCH 6/6] squashfs: Convert to fs_context
From
Date
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Phillip Lougher <phillip@squashfs.org.uk>
cc: squashfs-devel@lists.sourceforge.net
---

fs/squashfs/super.c | 100 ++++++++++++++++++++++++++++-----------------------
1 file changed, 55 insertions(+), 45 deletions(-)

diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 40e657386fa5..672011725eb2 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -30,6 +30,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fs.h>
+#include <linux/fs_context.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/mutex.h>
@@ -49,26 +50,27 @@
static struct file_system_type squashfs_fs_type;
static const struct super_operations squashfs_super_ops;

-static const struct squashfs_decompressor *supported_squashfs_filesystem(short
- major, short minor, short id)
+static const struct squashfs_decompressor *supported_squashfs_filesystem(
+ struct fs_context *fc,
+ short major, short minor, short id)
{
const struct squashfs_decompressor *decompressor;

if (major < SQUASHFS_MAJOR) {
- ERROR("Major/Minor mismatch, older Squashfs %d.%d "
- "filesystems are unsupported\n", major, minor);
+ errorf(fc, "Major/Minor mismatch, older Squashfs %d.%d "
+ "filesystems are unsupported", major, minor);
return NULL;
} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
- ERROR("Major/Minor mismatch, trying to mount newer "
- "%d.%d filesystem\n", major, minor);
- ERROR("Please update your kernel\n");
+ errorf(fc, "Major/Minor mismatch, trying to mount newer "
+ "%d.%d filesystem", major, minor);
+ errorf(fc, "Please update your kernel");
return NULL;
}

decompressor = squashfs_lookup_decompressor(id);
if (!decompressor->supported) {
- ERROR("Filesystem uses \"%s\" compression. This is not "
- "supported\n", decompressor->name);
+ errorf(fc, "Filesystem uses \"%s\" compression. This is not supported",
+ decompressor->name);
return NULL;
}

@@ -76,7 +78,7 @@ static const struct squashfs_decompressor *supported_squashfs_filesystem(short
}


-static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
+static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct squashfs_sb_info *msblk;
struct squashfs_super_block *sblk = NULL;
@@ -111,7 +113,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));

if (IS_ERR(sblk)) {
- ERROR("unable to read squashfs_super_block\n");
+ errorf(fc, "unable to read squashfs_super_block");
err = PTR_ERR(sblk);
sblk = NULL;
goto failed_mount;
@@ -122,14 +124,15 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
/* Check it is a SQUASHFS superblock */
sb->s_magic = le32_to_cpu(sblk->s_magic);
if (sb->s_magic != SQUASHFS_MAGIC) {
- if (!silent)
- ERROR("Can't find a SQUASHFS superblock on %pg\n",
- sb->s_bdev);
+ if (!(fc->sb_flags & SB_SILENT))
+ errorf(fc, "Can't find a SQUASHFS superblock on %pg",
+ sb->s_bdev);
goto failed_mount;
}

/* Check the MAJOR & MINOR versions and lookup compression type */
msblk->decompressor = supported_squashfs_filesystem(
+ fc,
le16_to_cpu(sblk->s_major),
le16_to_cpu(sblk->s_minor),
le16_to_cpu(sblk->compression));
@@ -146,15 +149,15 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
/* Check block size for sanity */
msblk->block_size = le32_to_cpu(sblk->block_size);
if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
- goto failed_mount;
+ goto insanity;

/*
* Check the system page size is not larger than the filesystem
* block size (by default 128K). This is currently not supported.
*/
if (PAGE_SIZE > msblk->block_size) {
- ERROR("Page size > filesystem block size (%d). This is "
- "currently not supported!\n", msblk->block_size);
+ errorf(fc, "Page size > filesystem block size (%d). This is "
+ "currently not supported!", msblk->block_size);
goto failed_mount;
}

@@ -165,12 +168,12 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)

/* Check that block_size and block_log match */
if (msblk->block_size != (1 << msblk->block_log))
- goto failed_mount;
+ goto insanity;

/* Check the root inode for sanity */
root_inode = le64_to_cpu(sblk->root_inode);
if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
- goto failed_mount;
+ goto insanity;

msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
@@ -210,7 +213,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
msblk->read_page = squashfs_cache_init("data",
squashfs_max_decompressors(), msblk->block_size);
if (msblk->read_page == NULL) {
- ERROR("Failed to allocate read_page block\n");
+ errorf(fc, "Failed to allocate read_page block");
goto failed_mount;
}

@@ -218,7 +221,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
if (IS_ERR(msblk->stream)) {
err = PTR_ERR(msblk->stream);
msblk->stream = NULL;
- goto failed_mount;
+ goto insanity;
}

/* Handle xattrs */
@@ -233,7 +236,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
if (IS_ERR(msblk->xattr_id_table)) {
- ERROR("unable to read xattr id index table\n");
+ errorf(fc, "unable to read xattr id index table");
err = PTR_ERR(msblk->xattr_id_table);
msblk->xattr_id_table = NULL;
if (err != -ENOTSUPP)
@@ -247,7 +250,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
le64_to_cpu(sblk->id_table_start), next_table,
le16_to_cpu(sblk->no_ids));
if (IS_ERR(msblk->id_table)) {
- ERROR("unable to read id index table\n");
+ errorf(fc, "unable to read id index table");
err = PTR_ERR(msblk->id_table);
msblk->id_table = NULL;
goto failed_mount;
@@ -263,7 +266,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
lookup_table_start, next_table, msblk->inodes);
if (IS_ERR(msblk->inode_lookup_table)) {
- ERROR("unable to read inode lookup table\n");
+ errorf(fc, "unable to read inode lookup table");
err = PTR_ERR(msblk->inode_lookup_table);
msblk->inode_lookup_table = NULL;
goto failed_mount;
@@ -288,7 +291,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
msblk->fragment_index = squashfs_read_fragment_index_table(sb,
le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
if (IS_ERR(msblk->fragment_index)) {
- ERROR("unable to read fragment index table\n");
+ errorf(fc, "unable to read fragment index table");
err = PTR_ERR(msblk->fragment_index);
msblk->fragment_index = NULL;
goto failed_mount;
@@ -299,13 +302,13 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
/* Sanity check directory_table */
if (msblk->directory_table > next_table) {
err = -EINVAL;
- goto failed_mount;
+ goto insanity;
}

/* Sanity check inode_table */
if (msblk->inode_table >= msblk->directory_table) {
err = -EINVAL;
- goto failed_mount;
+ goto insanity;
}

/* allocate root */
@@ -334,6 +337,8 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
kfree(sblk);
return 0;

+insanity:
+ errorf(fc, "squashfs image failed sanity check");
failed_mount:
squashfs_cache_delete(msblk->block_cache);
squashfs_cache_delete(msblk->fragment_cache);
@@ -349,6 +354,28 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
return err;
}

+static int squashfs_get_tree(struct fs_context *fc)
+{
+ return vfs_get_block_super(fc, squashfs_fill_super);
+}
+
+static int squashfs_reconfigure(struct fs_context *fc)
+{
+ sync_filesystem(fc->root->d_sb);
+ fc->sb_flags |= SB_RDONLY;
+ return 0;
+}
+
+static const struct fs_context_operations squashfs_context_ops = {
+ .get_tree = squashfs_get_tree,
+ .reconfigure = squashfs_reconfigure,
+};
+
+static int squashfs_init_fs_context(struct fs_context *fc)
+{
+ fc->ops = &squashfs_context_ops;
+ return 0;
+}

static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
@@ -371,14 +398,6 @@ static int squashfs_statfs(struct dentry *dentry, struct kstatfs *buf)
}


-static int squashfs_remount(struct super_block *sb, int *flags, char *data)
-{
- sync_filesystem(sb);
- *flags |= SB_RDONLY;
- return 0;
-}
-
-
static void squashfs_put_super(struct super_block *sb)
{
if (sb->s_fs_info) {
@@ -397,14 +416,6 @@ static void squashfs_put_super(struct super_block *sb)
}
}

-
-static struct dentry *squashfs_mount(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
-{
- return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
-}
-
-
static struct kmem_cache *squashfs_inode_cachep;


@@ -488,7 +499,7 @@ static void squashfs_destroy_inode(struct inode *inode)
static struct file_system_type squashfs_fs_type = {
.owner = THIS_MODULE,
.name = "squashfs",
- .mount = squashfs_mount,
+ .init_fs_context = squashfs_init_fs_context,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV
};
@@ -499,7 +510,6 @@ static const struct super_operations squashfs_super_ops = {
.destroy_inode = squashfs_destroy_inode,
.statfs = squashfs_statfs,
.put_super = squashfs_put_super,
- .remount_fs = squashfs_remount
};

module_init(init_squashfs_fs);
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