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Date: Fri, 17 Feb 2017 17:20:12 -0800
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: "Theodore Ts'o" <tytso@....edu>
Cc: linux-ext4@...r.kernel.org
Subject: [PATCH] ext4: create an ioctl report fs geometry
From: Darrick J. Wong <darrick.wong@...cle.com>
Add an ioctl to report the geometry of a mounted filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
---
fs/ext4/ext4.h | 36 ++++++++++++++++++++++++++++++++++
fs/ext4/ioctl.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 94 insertions(+)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2163c1e..bee511d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -614,6 +614,41 @@ enum {
#define EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER 0x0010
#define EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER 0x0020
+/* ext4 fs geometry. */
+struct ext4_fsop_geom {
+ __u32 blocksize; /* filesystem (data) block size */
+ __u32 inodecount; /* inode count */
+ __u32 agblocks; /* fsblocks in an AG */
+ __u32 agcount; /* number of allocation groups */
+ __u32 logblocks; /* fsblocks in the log */
+ __u32 resvblocks; /* number of reserved blocks */
+ __u32 inodesize; /* inode size in bytes */
+ __u32 agiblocks; /* inode blocks per AG */
+ __u64 datablocks; /* fsblocks in data subvolume */
+ unsigned char uuid[16]; /* unique id of the filesystem */
+ __u32 sunit; /* stripe unit, fsblocks */
+ __u32 swidth; /* stripe width, fsblocks */
+ __s32 version; /* structure version */
+ __u32 flags; /* superblock version flags */
+ __u32 clustersize; /* fs cluster size */
+ __u32 flexbgsize; /* number of bg's in a flexbg */
+ __u64 resv[6];
+};
+
+#define EXT4_FSOP_GEOM_VERSION 0
+
+#define EXT4_FSOP_GEOM_FLAGS_ATTR 0x00001 /* attributes in use */
+#define EXT4_FSOP_GEOM_FLAGS_NLINK 0x00002 /* 32-bit nlink values */
+#define EXT4_FSOP_GEOM_FLAGS_QUOTA 0x00004 /* quotas enabled */
+#define EXT4_FSOP_GEOM_FLAGS_PROJQ 0x00008 /* project quotas */
+#define EXT4_FSOP_GEOM_FLAGS_METACRC 0x00010 /* metadata checksums */
+#define EXT4_FSOP_GEOM_FLAGS_FTYPE 0x00020 /* inode directory types */
+#define EXT4_FSOP_GEOM_FLAGS_64BIT 0x00040 /* 64-bit support */
+#define EXT4_FSOP_GEOM_FLAGS_INLINEDATA 0x00080 /* inline data */
+#define EXT4_FSOP_GEOM_FLAGS_ENCRYPT 0x00100 /* encrypted files */
+#define EXT4_FSOP_GEOM_FLAGS_LARGEDIR 0x00200 /* large directories */
+#define EXT4_FSOP_GEOM_FLAGS_EXTENTS 0x00400 /* extents */
+
/*
* ioctl commands
*/
@@ -638,6 +673,7 @@ enum {
#define EXT4_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY
#define EXT4_IOC_GET_ENCRYPTION_PWSALT FS_IOC_GET_ENCRYPTION_PWSALT
#define EXT4_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY
+#define EXT4_IOC_FSGEOMETRY _IOR ('f', 19, struct ext4_fsop_geom)
#ifndef FS_IOC_FSGETXATTR
/* Until the uapi changes get merged for project quota... */
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index ed62465..e0b695b 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -547,6 +547,62 @@ ext4_ioc_getfsmap(
return 0;
}
+static int
+ext4_ioc_fsgeometry(
+ struct super_block *sb,
+ void __user *arg)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ journal_t *journal = sbi->s_journal;
+ struct ext4_fsop_geom geom;
+
+ memset(&geom, 0, sizeof(geom));
+ geom.version = EXT4_FSOP_GEOM_VERSION;
+ geom.blocksize = EXT4_BLOCK_SIZE(sb);
+ geom.inodecount = le32_to_cpu(sbi->s_es->s_inodes_count);
+ geom.agblocks = EXT4_BLOCKS_PER_GROUP(sb);
+ geom.agcount = sbi->s_groups_count;
+ geom.logblocks = journal ? journal->j_maxlen : 0;
+ geom.resvblocks = ext4_r_blocks_count(sbi->s_es);
+ geom.inodesize = EXT4_INODE_SIZE(sb);
+ geom.agiblocks = sbi->s_itb_per_group;
+ geom.datablocks = ext4_blocks_count(sbi->s_es);
+ memcpy(geom.uuid, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
+ geom.sunit = le16_to_cpu(sbi->s_es->s_raid_stride);
+ geom.swidth = le16_to_cpu(sbi->s_es->s_raid_stripe_width);
+ geom.flags = 0;
+ if (ext4_has_feature_xattr(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_ATTR;
+ if (ext4_has_feature_dir_nlink(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_NLINK;
+ if (ext4_has_feature_quota(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_QUOTA;
+ if (ext4_has_feature_project(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_PROJQ;
+ if (ext4_has_metadata_csum(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_METACRC;
+ if (ext4_has_feature_filetype(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_FTYPE;
+ if (ext4_has_feature_64bit(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_64BIT;
+ if (ext4_has_feature_inline_data(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_INLINEDATA;
+ if (ext4_has_feature_encrypt(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_ENCRYPT;
+ if (ext4_has_feature_largedir(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_LARGEDIR;
+ if (ext4_has_feature_extents(sb))
+ geom.flags |= EXT4_FSOP_GEOM_FLAGS_EXTENTS;
+ if (ext4_has_feature_bigalloc(sb))
+ geom.clustersize = EXT4_C2B(sbi, 1);
+ if (ext4_has_feature_flex_bg(sb))
+ geom.flexbgsize = ext4_flex_bg_size(sbi);
+
+ if (copy_to_user(arg, &geom, sizeof(geom)))
+ return -EFAULT;
+ return 0;
+}
+
long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -557,6 +613,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
switch (cmd) {
+ case EXT4_IOC_FSGEOMETRY:
+ return ext4_ioc_fsgeometry(sb, (void __user *)arg);
case FS_IOC_GETFSMAP:
return ext4_ioc_getfsmap(sb, (void __user *)arg);
case EXT4_IOC_GETFLAGS:
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