mirror of
https://github.com/tbsdtv/linux_media.git
synced 2025-07-23 04:33:26 +02:00
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 <dhowells@redhat.com> Co-developed-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
107
fs/super.c
107
fs/super.c
@@ -836,28 +836,35 @@ rescan:
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}
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/**
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* do_remount_sb - asks filesystem to change mount options.
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* @sb: superblock in question
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* @sb_flags: revised superblock flags
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* @data: the rest of options
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* @force: whether or not to force the change
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* reconfigure_super - asks filesystem to change superblock parameters
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* @fc: The superblock and configuration
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*
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* Alters the mount options of a mounted file system.
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* Alters the configuration parameters of a live superblock.
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*/
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int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
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int reconfigure_super(struct fs_context *fc)
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{
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struct super_block *sb = fc->root->d_sb;
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int retval;
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int remount_ro;
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bool remount_ro = false;
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bool force = fc->sb_flags & SB_FORCE;
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if (fc->sb_flags_mask & ~MS_RMT_MASK)
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return -EINVAL;
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if (sb->s_writers.frozen != SB_UNFROZEN)
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return -EBUSY;
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retval = security_sb_remount(sb, fc->security);
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if (retval)
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return retval;
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if (fc->sb_flags_mask & SB_RDONLY) {
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#ifdef CONFIG_BLOCK
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if (!(sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev))
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return -EACCES;
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if (!(fc->sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev))
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return -EACCES;
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#endif
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remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb);
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remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb);
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}
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if (remount_ro) {
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if (!hlist_empty(&sb->s_pins)) {
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@@ -868,13 +875,14 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
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return 0;
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if (sb->s_writers.frozen != SB_UNFROZEN)
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return -EBUSY;
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remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb);
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remount_ro = !sb_rdonly(sb);
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}
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}
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shrink_dcache_sb(sb);
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/* If we are remounting RDONLY and current sb is read/write,
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make sure there are no rw files opened */
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/* If we are reconfiguring to RDONLY and current sb is read/write,
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* make sure there are no files open for writing.
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*/
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if (remount_ro) {
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if (force) {
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sb->s_readonly_remount = 1;
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@@ -886,17 +894,17 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
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}
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}
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if (sb->s_op->remount_fs) {
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retval = sb->s_op->remount_fs(sb, &sb_flags, data);
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if (retval) {
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if (!force)
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goto cancel_readonly;
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/* If forced remount, go ahead despite any errors */
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WARN(1, "forced remount of a %s fs returned %i\n",
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sb->s_type->name, retval);
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}
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retval = legacy_reconfigure(fc);
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if (retval) {
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if (!force)
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goto cancel_readonly;
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/* If forced remount, go ahead despite any errors */
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WARN(1, "forced remount of a %s fs returned %i\n",
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sb->s_type->name, retval);
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}
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sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (sb_flags & MS_RMT_MASK);
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WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) |
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(fc->sb_flags & fc->sb_flags_mask)));
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/* Needs to be ordered wrt mnt_is_readonly() */
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smp_wmb();
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sb->s_readonly_remount = 0;
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@@ -923,10 +931,15 @@ static void do_emergency_remount_callback(struct super_block *sb)
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down_write(&sb->s_umount);
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if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
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!sb_rdonly(sb)) {
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/*
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* What lock protects sb->s_flags??
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*/
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do_remount_sb(sb, SB_RDONLY, NULL, 1);
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struct fs_context *fc;
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fc = fs_context_for_reconfigure(sb->s_root,
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SB_RDONLY | SB_FORCE, SB_RDONLY);
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if (!IS_ERR(fc)) {
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if (parse_monolithic_mount_data(fc, NULL) == 0)
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(void)reconfigure_super(fc);
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put_fs_context(fc);
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}
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}
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up_write(&sb->s_umount);
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}
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@@ -1213,6 +1226,31 @@ struct dentry *mount_nodev(struct file_system_type *fs_type,
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}
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EXPORT_SYMBOL(mount_nodev);
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static int reconfigure_single(struct super_block *s,
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int flags, void *data)
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{
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struct fs_context *fc;
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int ret;
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/* The caller really need to be passing fc down into mount_single(),
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* then a chunk of this can be removed. [Bollocks -- AV]
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* Better yet, reconfiguration shouldn't happen, but rather the second
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* mount should be rejected if the parameters are not compatible.
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*/
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fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);
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if (IS_ERR(fc))
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return PTR_ERR(fc);
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ret = parse_monolithic_mount_data(fc, data);
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if (ret < 0)
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goto out;
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ret = reconfigure_super(fc);
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out:
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put_fs_context(fc);
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return ret;
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}
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static int compare_single(struct super_block *s, void *p)
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{
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return 1;
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@@ -1230,13 +1268,14 @@ struct dentry *mount_single(struct file_system_type *fs_type,
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return ERR_CAST(s);
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if (!s->s_root) {
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error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
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if (error) {
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deactivate_locked_super(s);
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return ERR_PTR(error);
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}
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s->s_flags |= SB_ACTIVE;
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if (!error)
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s->s_flags |= SB_ACTIVE;
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} else {
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do_remount_sb(s, flags, data, 0);
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error = reconfigure_single(s, flags, data);
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}
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if (unlikely(error)) {
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deactivate_locked_super(s);
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return ERR_PTR(error);
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}
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return dget(s->s_root);
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}
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