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Diffstat (limited to 'fs/sdcardfs/super.c')
| -rw-r--r-- | fs/sdcardfs/super.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c new file mode 100644 index 000000000000..1d6490128c99 --- /dev/null +++ b/fs/sdcardfs/super.c @@ -0,0 +1,222 @@ +/* + * fs/sdcardfs/super.c + * + * Copyright (c) 2013 Samsung Electronics Co. Ltd + * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun, + * Sunghwan Yun, Sungjong Seo + * + * This program has been developed as a stackable file system based on + * the WrapFS which written by + * + * Copyright (c) 1998-2011 Erez Zadok + * Copyright (c) 2009 Shrikar Archak + * Copyright (c) 2003-2011 Stony Brook University + * Copyright (c) 2003-2011 The Research Foundation of SUNY + * + * This file is dual licensed. It may be redistributed and/or modified + * under the terms of the Apache 2.0 License OR version 2 of the GNU + * General Public License. + */ + +#include "sdcardfs.h" + +/* + * The inode cache is used with alloc_inode for both our inode info and the + * vfs inode. + */ +static struct kmem_cache *sdcardfs_inode_cachep; + +/* final actions when unmounting a file system */ +static void sdcardfs_put_super(struct super_block *sb) +{ + struct sdcardfs_sb_info *spd; + struct super_block *s; + + spd = SDCARDFS_SB(sb); + if (!spd) + return; + + if(spd->obbpath_s) { + kfree(spd->obbpath_s); + path_put(&spd->obbpath); + } + + /* decrement lower super references */ + s = sdcardfs_lower_super(sb); + sdcardfs_set_lower_super(sb, NULL); + atomic_dec(&s->s_active); + + kfree(spd); + sb->s_fs_info = NULL; +} + +static int sdcardfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + int err; + struct path lower_path; + u32 min_blocks; + struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb); + + sdcardfs_get_lower_path(dentry, &lower_path); + err = vfs_statfs(&lower_path, buf); + sdcardfs_put_lower_path(dentry, &lower_path); + + if (sbi->options.reserved_mb) { + /* Invalid statfs informations. */ + if (buf->f_bsize == 0) { + printk(KERN_ERR "Returned block size is zero.\n"); + return -EINVAL; + } + + min_blocks = ((sbi->options.reserved_mb * 1024 * 1024)/buf->f_bsize); + buf->f_blocks -= min_blocks; + + if (buf->f_bavail > min_blocks) + buf->f_bavail -= min_blocks; + else + buf->f_bavail = 0; + + /* Make reserved blocks invisiable to media storage */ + buf->f_bfree = buf->f_bavail; + } + + /* set return buf to our f/s to avoid confusing user-level utils */ + buf->f_type = SDCARDFS_SUPER_MAGIC; + + return err; +} + +/* + * @flags: numeric mount options + * @options: mount options string + */ +static int sdcardfs_remount_fs(struct super_block *sb, int *flags, char *options) +{ + int err = 0; + + /* + * The VFS will take care of "ro" and "rw" flags among others. We + * can safely accept a few flags (RDONLY, MANDLOCK), and honor + * SILENT, but anything else left over is an error. + */ + if ((*flags & ~(MS_RDONLY | MS_MANDLOCK | MS_SILENT)) != 0) { + printk(KERN_ERR + "sdcardfs: remount flags 0x%x unsupported\n", *flags); + err = -EINVAL; + } + + return err; +} + +/* + * Called by iput() when the inode reference count reached zero + * and the inode is not hashed anywhere. Used to clear anything + * that needs to be, before the inode is completely destroyed and put + * on the inode free list. + */ +static void sdcardfs_evict_inode(struct inode *inode) +{ + struct inode *lower_inode; + + truncate_inode_pages(&inode->i_data, 0); + clear_inode(inode); + /* + * Decrement a reference to a lower_inode, which was incremented + * by our read_inode when it was created initially. + */ + lower_inode = sdcardfs_lower_inode(inode); + sdcardfs_set_lower_inode(inode, NULL); + iput(lower_inode); +} + +static struct inode *sdcardfs_alloc_inode(struct super_block *sb) +{ + struct sdcardfs_inode_info *i; + + i = kmem_cache_alloc(sdcardfs_inode_cachep, GFP_KERNEL); + if (!i) + return NULL; + + /* memset everything up to the inode to 0 */ + memset(i, 0, offsetof(struct sdcardfs_inode_info, vfs_inode)); + + i->vfs_inode.i_version = 1; + return &i->vfs_inode; +} + +static void sdcardfs_destroy_inode(struct inode *inode) +{ + kmem_cache_free(sdcardfs_inode_cachep, SDCARDFS_I(inode)); +} + +/* sdcardfs inode cache constructor */ +static void init_once(void *obj) +{ + struct sdcardfs_inode_info *i = obj; + + inode_init_once(&i->vfs_inode); +} + +int sdcardfs_init_inode_cache(void) +{ + int err = 0; + + sdcardfs_inode_cachep = + kmem_cache_create("sdcardfs_inode_cache", + sizeof(struct sdcardfs_inode_info), 0, + SLAB_RECLAIM_ACCOUNT, init_once); + if (!sdcardfs_inode_cachep) + err = -ENOMEM; + return err; +} + +/* sdcardfs inode cache destructor */ +void sdcardfs_destroy_inode_cache(void) +{ + if (sdcardfs_inode_cachep) + kmem_cache_destroy(sdcardfs_inode_cachep); +} + +/* + * Used only in nfs, to kill any pending RPC tasks, so that subsequent + * code can actually succeed and won't leave tasks that need handling. + */ +static void sdcardfs_umount_begin(struct super_block *sb) +{ + struct super_block *lower_sb; + + lower_sb = sdcardfs_lower_super(sb); + if (lower_sb && lower_sb->s_op && lower_sb->s_op->umount_begin) + lower_sb->s_op->umount_begin(lower_sb); +} + +static int sdcardfs_show_options(struct seq_file *m, struct dentry *root) +{ + struct sdcardfs_sb_info *sbi = SDCARDFS_SB(root->d_sb); + struct sdcardfs_mount_options *opts = &sbi->options; + + if (opts->fs_low_uid != 0) + seq_printf(m, ",uid=%u", opts->fs_low_uid); + if (opts->fs_low_gid != 0) + seq_printf(m, ",gid=%u", opts->fs_low_gid); + + if (opts->multiuser) + seq_printf(m, ",multiuser"); + + if (opts->reserved_mb != 0) + seq_printf(m, ",reserved=%uMB", opts->reserved_mb); + + return 0; +}; + +const struct super_operations sdcardfs_sops = { + .put_super = sdcardfs_put_super, + .statfs = sdcardfs_statfs, + .remount_fs = sdcardfs_remount_fs, + .evict_inode = sdcardfs_evict_inode, + .umount_begin = sdcardfs_umount_begin, + .show_options = sdcardfs_show_options, + .alloc_inode = sdcardfs_alloc_inode, + .destroy_inode = sdcardfs_destroy_inode, + .drop_inode = generic_delete_inode, +}; |