xfs: Introduce per-inode 64-bit extent counters

This commit introduces new fields in the on-disk inode format to support
64-bit data fork extent counters and 32-bit attribute fork extent
counters. The new fields will be used only when an inode has
XFS_DIFLAG2_NREXT64 flag set. Otherwise we continue to use the regular 32-bit
data fork extent counters and 16-bit attribute fork extent counters.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Suggested-by: Dave Chinner <dchinner@redhat.com>

4 files changed, 109 insertions, 12 deletions

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index eb85bc9b229b..82b404c99b80 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -792,16 +792,41 @@ struct xfs_dinode {
 	__be32		di_nlink;	/* number of links to file */
 	__be16		di_projid_lo;	/* lower part of owner's project id */
 	__be16		di_projid_hi;	/* higher part owner's project id */
-	__u8		di_pad[6];	/* unused, zeroed space */
-	__be16		di_flushiter;	/* incremented on flush */
+	union {
+		/* Number of data fork extents if NREXT64 is set */
+		__be64	di_big_nextents;
+
+		/* Padding for V3 inodes without NREXT64 set. */
+		__be64	di_v3_pad;
+
+		/* Padding and inode flush counter for V2 inodes. */
+		struct {
+			__u8	di_v2_pad[6];
+			__be16	di_flushiter;
+		};
+	};
 	xfs_timestamp_t	di_atime;	/* time last accessed */
 	xfs_timestamp_t	di_mtime;	/* time last modified */
 	xfs_timestamp_t	di_ctime;	/* time created/inode modified */
 	__be64		di_size;	/* number of bytes in file */
 	__be64		di_nblocks;	/* # of direct & btree blocks used */
 	__be32		di_extsize;	/* basic/minimum extent size for file */
-	__be32		di_nextents;	/* number of extents in data fork */
-	__be16		di_anextents;	/* number of extents in attribute fork*/
+	union {
+		/*
+		 * For V2 inodes and V3 inodes without NREXT64 set, this
+		 * is the number of data and attr fork extents.
+		 */
+		struct {
+			__be32	di_nextents;
+			__be16	di_anextents;
+		} __packed;
+
+		/* Number of attr fork extents if NREXT64 is set. */
+		struct {
+			__be32	di_big_anextents;
+			__be16	di_nrext64_pad;
+		} __packed;
+	} __packed;
 	__u8		di_forkoff;	/* attr fork offs, <<3 for 64b align */
 	__s8		di_aformat;	/* format of attr fork's data */
 	__be32		di_dmevmask;	/* DMIG event mask */
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index e0d3140c3622..ee8d4eb7d048 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -279,6 +279,25 @@ xfs_inode_to_disk_ts(
 	return ts;
 }
 
+static inline void
+xfs_inode_to_disk_iext_counters(
+	struct xfs_inode	*ip,
+	struct xfs_dinode	*to)
+{
+	if (xfs_inode_has_large_extent_counts(ip)) {
+		to->di_big_nextents = cpu_to_be64(xfs_ifork_nextents(&ip->i_df));
+		to->di_big_anextents = cpu_to_be32(xfs_ifork_nextents(ip->i_afp));
+		/*
+		 * We might be upgrading the inode to use larger extent counters
+		 * than was previously used. Hence zero the unused field.
+		 */
+		to->di_nrext64_pad = cpu_to_be16(0);
+	} else {
+		to->di_nextents = cpu_to_be32(xfs_ifork_nextents(&ip->i_df));
+		to->di_anextents = cpu_to_be16(xfs_ifork_nextents(ip->i_afp));
+	}
+}
+
 void
 xfs_inode_to_disk(
 	struct xfs_inode	*ip,
@@ -296,7 +315,6 @@ xfs_inode_to_disk(
 	to->di_projid_lo = cpu_to_be16(ip->i_projid & 0xffff);
 	to->di_projid_hi = cpu_to_be16(ip->i_projid >> 16);
 
-	memset(to->di_pad, 0, sizeof(to->di_pad));
 	to->di_atime = xfs_inode_to_disk_ts(ip, inode->i_atime);
 	to->di_mtime = xfs_inode_to_disk_ts(ip, inode->i_mtime);
 	to->di_ctime = xfs_inode_to_disk_ts(ip, inode->i_ctime);
@@ -307,8 +325,6 @@ xfs_inode_to_disk(
 	to->di_size = cpu_to_be64(ip->i_disk_size);
 	to->di_nblocks = cpu_to_be64(ip->i_nblocks);
 	to->di_extsize = cpu_to_be32(ip->i_extsize);
-	to->di_nextents = cpu_to_be32(xfs_ifork_nextents(&ip->i_df));
-	to->di_anextents = cpu_to_be16(xfs_ifork_nextents(ip->i_afp));
 	to->di_forkoff = ip->i_forkoff;
 	to->di_aformat = xfs_ifork_format(ip->i_afp);
 	to->di_flags = cpu_to_be16(ip->i_diflags);
@@ -323,11 +339,14 @@ xfs_inode_to_disk(
 		to->di_lsn = cpu_to_be64(lsn);
 		memset(to->di_pad2, 0, sizeof(to->di_pad2));
 		uuid_copy(&to->di_uuid, &ip->i_mount->m_sb.sb_meta_uuid);
-		to->di_flushiter = 0;
+		to->di_v3_pad = 0;
 	} else {
 		to->di_version = 2;
 		to->di_flushiter = cpu_to_be16(ip->i_flushiter);
+		memset(to->di_v2_pad, 0, sizeof(to->di_v2_pad));
 	}
+
+	xfs_inode_to_disk_iext_counters(ip, to);
 }
 
 static xfs_failaddr_t
@@ -398,6 +417,24 @@ xfs_dinode_verify_forkoff(
 	return NULL;
 }
 
+static xfs_failaddr_t
+xfs_dinode_verify_nrext64(
+	struct xfs_mount	*mp,
+	struct xfs_dinode	*dip)
+{
+	if (xfs_dinode_has_large_extent_counts(dip)) {
+		if (!xfs_has_large_extent_counts(mp))
+			return __this_address;
+		if (dip->di_nrext64_pad != 0)
+			return __this_address;
+	} else if (dip->di_version >= 3) {
+		if (dip->di_v3_pad != 0)
+			return __this_address;
+	}
+
+	return NULL;
+}
+
 xfs_failaddr_t
 xfs_dinode_verify(
 	struct xfs_mount	*mp,
@@ -442,6 +479,10 @@ xfs_dinode_verify(
 	if ((S_ISLNK(mode) || S_ISDIR(mode)) && di_size == 0)
 		return __this_address;
 
+	fa = xfs_dinode_verify_nrext64(mp, dip);
+	if (fa)
+		return fa;
+
 	nextents = xfs_dfork_data_extents(dip);
 	naextents = xfs_dfork_attr_extents(dip);
 	nblocks = be64_to_cpu(dip->di_nblocks);
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 967837a88860..fd5c3c2d77e0 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -158,6 +158,9 @@ static inline xfs_extnum_t
 xfs_dfork_data_extents(
 	struct xfs_dinode	*dip)
 {
+	if (xfs_dinode_has_large_extent_counts(dip))
+		return be64_to_cpu(dip->di_big_nextents);
+
 	return be32_to_cpu(dip->di_nextents);
 }
 
@@ -165,6 +168,9 @@ static inline xfs_extnum_t
 xfs_dfork_attr_extents(
 	struct xfs_dinode	*dip)
 {
+	if (xfs_dinode_has_large_extent_counts(dip))
+		return be32_to_cpu(dip->di_big_anextents);
+
 	return be16_to_cpu(dip->di_anextents);
 }
 
diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index fd66e70248f7..12234a880e94 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -388,16 +388,41 @@ struct xfs_log_dinode {
 	uint32_t	di_nlink;	/* number of links to file */
 	uint16_t	di_projid_lo;	/* lower part of owner's project id */
 	uint16_t	di_projid_hi;	/* higher part of owner's project id */
-	uint8_t		di_pad[6];	/* unused, zeroed space */
-	uint16_t	di_flushiter;	/* incremented on flush */
+	union {
+		/* Number of data fork extents if NREXT64 is set */
+		uint64_t	di_big_nextents;
+
+		/* Padding for V3 inodes without NREXT64 set. */
+		uint64_t	di_v3_pad;
+
+		/* Padding and inode flush counter for V2 inodes. */
+		struct {
+			uint8_t	di_v2_pad[6];	/* V2 inode zeroed space */
+			uint16_t di_flushiter;	/* V2 inode incremented on flush */
+		};
+	};
 	xfs_log_timestamp_t di_atime;	/* time last accessed */
 	xfs_log_timestamp_t di_mtime;	/* time last modified */
 	xfs_log_timestamp_t di_ctime;	/* time created/inode modified */
 	xfs_fsize_t	di_size;	/* number of bytes in file */
 	xfs_rfsblock_t	di_nblocks;	/* # of direct & btree blocks used */
 	xfs_extlen_t	di_extsize;	/* basic/minimum extent size for file */
-	uint32_t	di_nextents;	/* number of extents in data fork */
-	uint16_t	di_anextents;	/* number of extents in attribute fork*/
+	union {
+		/*
+		 * For V2 inodes and V3 inodes without NREXT64 set, this
+		 * is the number of data and attr fork extents.
+		 */
+		struct {
+			uint32_t  di_nextents;
+			uint16_t  di_anextents;
+		} __packed;
+
+		/* Number of attr fork extents if NREXT64 is set. */
+		struct {
+			uint32_t  di_big_anextents;
+			uint16_t  di_nrext64_pad;
+		} __packed;
+	} __packed;
 	uint8_t		di_forkoff;	/* attr fork offs, <<3 for 64b align */
 	int8_t		di_aformat;	/* format of attr fork's data */
 	uint32_t	di_dmevmask;	/* DMIG event mask */