From a0c9a8b8fd9fd572b0d60276beb2142c8f59f9b8 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 4 Nov 2018 07:18:51 -0500 Subject: teach vfs_get_tree() to handle subtype, switch do_new_mount() to it Roll the handling of subtypes into do_new_mount() and vfs_get_tree(). The former determines any subtype string and hangs it off the fs_context; the latter applies it. Make do_new_mount() create, parameterise and commit an fs_context and create a mount for itself rather than calling vfs_kern_mount(). [AV -- missing kstrdup()] [AV -- ... and no kstrdup() if we get to setting ->s_submount - we simply transfer it from fc, leaving NULL behind] [AV -- constify ->s_submount, while we are at it] Reviewed-by: David Howells Signed-off-by: Al Viro --- include/linux/fs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 811c77743dad..36fff12ab890 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1447,7 +1447,7 @@ struct super_block { * Filesystem subtype. If non-empty the filesystem type field * in /proc/mounts will be "type.subtype" */ - char *s_subtype; + const char *s_subtype; const struct dentry_operations *s_d_op; /* default d_op for dentries */ -- cgit v1.2.3 From 8d0347f6c3a9d4953ddd636a31c6584da082e084 Mon Sep 17 00:00:00 2001 From: David Howells Date: Sun, 4 Nov 2018 09:28:36 -0500 Subject: convert do_remount_sb() to fs_context Replace do_remount_sb() with a function, reconfigure_super(), that's fs_context aware. The fs_context is expected to be parameterised already and have ->root pointing to the superblock to be reconfigured. A legacy wrapper is provided that is intended to be called from the fs_context ops when those appear, but for now is called directly from reconfigure_super(). This wrapper invokes the ->remount_fs() superblock op for the moment. It is intended that the remount_fs() op will be phased out. The fs_context->purpose is set to FS_CONTEXT_FOR_RECONFIGURE to indicate that the context is being used for reconfiguration. do_umount_root() is provided to consolidate remount-to-R/O for umount and emergency remount by creating a context and invoking reconfiguration. do_remount(), do_umount() and do_emergency_remount_callback() are switched to use the new process. [AV -- fold UMOUNT and EMERGENCY_REMOUNT in; fixes the umount / bug, gets rid of pointless complexity] [AV -- set ->net_ns in all cases; nfs remount will need that] [AV -- shift security_sb_remount() call into reconfigure_super(); the callers that didn't do security_sb_remount() have NULL fc->security anyway, so it's a no-op for them] Signed-off-by: David Howells Co-developed-by: Al Viro Signed-off-by: Al Viro --- include/linux/fs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 36fff12ab890..c65d02c5c512 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1337,6 +1337,7 @@ extern int send_sigurg(struct fown_struct *fown); /* These sb flags are internal to the kernel */ #define SB_SUBMOUNT (1<<26) +#define SB_FORCE (1<<27) #define SB_NOSEC (1<<28) #define SB_BORN (1<<29) #define SB_ACTIVE (1<<30) -- cgit v1.2.3 From f3a09c92018a91ad0981146a4ac59414f814d801 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 23 Dec 2018 18:55:56 -0500 Subject: introduce fs_context methods Signed-off-by: Al Viro --- include/linux/fs.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index c65d02c5c512..8d578a9e1e8c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -61,6 +61,7 @@ struct workqueue_struct; struct iov_iter; struct fscrypt_info; struct fscrypt_operations; +struct fs_context; extern void __init inode_init(void); extern void __init inode_init_early(void); @@ -2173,6 +2174,7 @@ struct file_system_type { #define FS_HAS_SUBTYPE 4 #define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */ #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */ + int (*init_fs_context)(struct fs_context *); struct dentry *(*mount) (struct file_system_type *, int, const char *, void *); void (*kill_sb) (struct super_block *); -- cgit v1.2.3 From 3e1aeb00e6d132efc151dacc062b38269bc9eccc Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 1 Nov 2018 23:07:25 +0000 Subject: vfs: Implement a filesystem superblock creation/configuration context [AV - unfuck kern_mount_data(); we want non-NULL ->mnt_ns on long-living mounts] [AV - reordering fs/namespace.c is badly overdue, but let's keep it separate from that series] [AV - drop simple_pin_fs() change] [AV - clean vfs_kern_mount() failure exits up] Implement a filesystem context concept to be used during superblock creation for mount and superblock reconfiguration for remount. The mounting procedure then becomes: (1) Allocate new fs_context context. (2) Configure the context. (3) Create superblock. (4) Query the superblock. (5) Create a mount for the superblock. (6) Destroy the context. Rather than calling fs_type->mount(), an fs_context struct is created and fs_type->init_fs_context() is called to set it up. Pointers exist for the filesystem and LSM to hang their private data off. A set of operations has to be set by ->init_fs_context() to provide freeing, duplication, option parsing, binary data parsing, validation, mounting and superblock filling. Legacy filesystems are supported by the provision of a set of legacy fs_context operations that build up a list of mount options and then invoke fs_type->mount() from within the fs_context ->get_tree() operation. This allows all filesystems to be accessed using fs_context. It should be noted that, whilst this patch adds a lot of lines of code, there is quite a bit of duplication with existing code that can be eliminated should all filesystems be converted over. Signed-off-by: David Howells Signed-off-by: Al Viro --- include/linux/fs.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 8d578a9e1e8c..cf6e9ea161eb 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -62,6 +62,7 @@ struct iov_iter; struct fscrypt_info; struct fscrypt_operations; struct fs_context; +struct fs_parameter_description; extern void __init inode_init(void); extern void __init inode_init_early(void); @@ -2175,6 +2176,7 @@ struct file_system_type { #define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */ #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */ int (*init_fs_context)(struct fs_context *); + const struct fs_parameter_description *parameters; struct dentry *(*mount) (struct file_system_type *, int, const char *, void *); void (*kill_sb) (struct super_block *); -- cgit v1.2.3 From cb50b348c71ffa90d7d1b2a494b553b5099bc090 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 23 Dec 2018 17:25:47 -0500 Subject: convenience helpers: vfs_get_super() and sget_fc() the former is an analogue of mount_{single,nodev} for use in ->get_tree() instances, the latter - analogue of sget() for the same. These are fairly similar to the originals, but the callback signature for sget_fc() is different from sget() ones, so getting bits and pieces shared would be too convoluted; we might get around to that later, but for now let's just remember to keep them in sync. They do live next to each other, and changes in either won't be hard to spot. Signed-off-by: Al Viro --- include/linux/fs.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index cf6e9ea161eb..9d05c128ccf6 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2232,8 +2232,12 @@ void kill_litter_super(struct super_block *sb); void deactivate_super(struct super_block *sb); void deactivate_locked_super(struct super_block *sb); int set_anon_super(struct super_block *s, void *data); +int set_anon_super_fc(struct super_block *s, struct fs_context *fc); int get_anon_bdev(dev_t *); void free_anon_bdev(dev_t); +struct super_block *sget_fc(struct fs_context *fc, + int (*test)(struct super_block *, struct fs_context *), + int (*set)(struct super_block *, struct fs_context *)); struct super_block *sget_userns(struct file_system_type *type, int (*test)(struct super_block *,void *), int (*set)(struct super_block *,void *), -- cgit v1.2.3 From d911b4585eb3501f752160e8e0f1bb00c3c7c4e5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 1 Nov 2018 23:07:26 +0000 Subject: vfs: Remove kern_mount_data() The kern_mount_data() isn't used any more so remove it. Signed-off-by: David Howells Signed-off-by: Al Viro --- include/linux/fs.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 9d05c128ccf6..3e85cb8e8c20 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2280,8 +2280,7 @@ mount_pseudo(struct file_system_type *fs_type, char *name, extern int register_filesystem(struct file_system_type *); extern int unregister_filesystem(struct file_system_type *); -extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data); -#define kern_mount(type) kern_mount_data(type, NULL) +extern struct vfsmount *kern_mount(struct file_system_type *); extern void kern_unmount(struct vfsmount *mnt); extern int may_umount_tree(struct vfsmount *); extern int may_umount(struct vfsmount *); -- cgit v1.2.3