From: David Howells Subject: [PATCH 09/12] fsinfo: Ext4: Return information through the filesystem info syscall Date: Fri, 20 Nov 2015 14:56:13 +0000 Message-ID: <20151120145613.18930.78846.stgit@warthog.procyon.org.uk> References: <20151120145422.18930.72662.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-afs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org To: arnd@arndb.de Return-path: In-Reply-To: <20151120145422.18930.72662.stgit@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Return Ext4 filesystem information through the filesystem info retrieval system call. This includes the following: (1) information about the capacity and resolution of the inode timestamps; (2) the volume label as the volume name, setting FSINFO_VOLUME_NAME; (3) the remote FSID as the volume ID, setting FSINFO_VOLUME_ID; (4) the statfs information; (5) a list of supported IOC flags. Example output: [root@andromeda ~]# ./test-fsinfo /var/cache/fscache/ fsinfo(/var/cache/fscache/) = 0 mask : 9f dev : 08:06 fs : type=ef53 name=ext4 ioc : 4bdfff nameln: 255 flags : 1020 times : range=ffffffff80000000-37fffffff atime : gran=1e-09s btime : gran=1e-09s ctime : gran=1e-09s mtime : gran=1e-09s blocks: n=1123529 fr=208887 av=146054 files : n=293760 fr=225334 av=225334 bsize : 4096 frsize: 4096 fsid : 48bc815f32464608 volume: 'fred' Signed-off-by: David Howells --- fs/ext4/super.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a63c7b0a10cf..fbd1cad4ff3b 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -73,6 +73,8 @@ static void ext4_clear_journal_err(struct super_block *sb, static int ext4_sync_fs(struct super_block *sb, int wait); static int ext4_remount(struct super_block *sb, int *flags, char *data); static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf); +static int ext4_get_fsinfo(struct dentry *dentry, struct fsinfo *f, + unsigned flags); static int ext4_unfreeze(struct super_block *sb); static int ext4_freeze(struct super_block *sb); static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags, @@ -1122,6 +1124,7 @@ static const struct super_operations ext4_sops = { .freeze_fs = ext4_freeze, .unfreeze_fs = ext4_unfreeze, .statfs = ext4_statfs, + .get_fsinfo = ext4_get_fsinfo, .remount_fs = ext4_remount, .show_options = ext4_show_options, #ifdef CONFIG_QUOTA @@ -3524,6 +3527,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) if (sb->s_magic != EXT4_SUPER_MAGIC) goto cantfind_ext4; sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written); + memcpy(sb->s_uuid, es->s_uuid, sizeof(sb->s_uuid)); /* Warn if metadata_csum and gdt_csum are both set. */ if (EXT4_HAS_RO_COMPAT_FEATURE(sb, @@ -5179,6 +5183,41 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf) return 0; } +/* + * Read filesystem information. + */ +static int ext4_get_fsinfo(struct dentry *dentry, struct fsinfo *f, + unsigned flags) +{ + struct super_block *sb = dentry->d_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + struct inode *inode = d_inode(dentry); + struct ext4_inode *raw_inode; + struct ext4_inode_info *ei = EXT4_I(inode); + + strcpy(f->f_volume_name, es->s_volume_name); + + f->f_mask = FSINFO_FSID | FSINFO_VOLUME_NAME; + f->f_supported_ioc_flags = EXT4_FL_USER_VISIBLE; + + f->f_min_time = S32_MIN; + f->f_max_time = S32_MAX; + + if (EXT4_FITS_IN_INODE(raw_inode, ei, i_ctime_extra)) + f->f_ctime_gran_exponent = -9; + if (EXT4_FITS_IN_INODE(raw_inode, ei, i_mtime_extra)) + f->f_mtime_gran_exponent = -9; + if (EXT4_FITS_IN_INODE(raw_inode, ei, i_atime_extra)) { + f->f_atime_gran_exponent = -9; + f->f_max_time += ((1 << EXT4_EPOCH_BITS) - 1) * 0x100000000LL; + } + if (EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime_extra)) + f->f_btime_gran_exponent = -9; + + return vfs_get_fsinfo_from_statfs(dentry, f, flags); +} + /* Helper function for writing quotas on sync - we need to start transaction * before quota file is locked for write. Otherwise the are possible deadlocks: * Process 1 Process 2