Add missing field definitions for various data structures.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
.../allocation_groups.asciidoc | 32 +++
.../XFS_Filesystem_Structure/data_extents.asciidoc | 27 ++
.../XFS_Filesystem_Structure/directories.asciidoc | 240 ++++++++++++++++++++
design/XFS_Filesystem_Structure/docinfo.xml | 1
.../extended_attributes.asciidoc | 86 +++++++
5 files changed, 386 insertions(+)
diff --git a/design/XFS_Filesystem_Structure/allocation_groups.asciidoc b/design/XFS_Filesystem_Structure/allocation_groups.asciidoc
index 680f90c..e958039 100644
--- a/design/XFS_Filesystem_Structure/allocation_groups.asciidoc
+++ b/design/XFS_Filesystem_Structure/allocation_groups.asciidoc
@@ -501,6 +501,23 @@ struct xfs_btree_sblock {
};
----
+*bb_magic*::
+Specifies the magic number for the per-AG B+tree block.
+
+*bb_level*::
+The level of the tree in which this block is found. If this value is 0, this
+is a leaf block and contains records; otherwise, it is a node block and
+contains keys and pointers.
+
+*bb_numrecs*::
+Number of records in this block.
+
+*bb_leftsib*::
+AG block number of the left sibling of this B+tree node.
+
+*bb_rightsib*::
+AG block number of the right sibling of this B+tree node.
+
[[AG_Free_Space_Btrees]]
=== AG Free Space B+trees
@@ -519,6 +536,12 @@ struct xfs_alloc_rec {
};
----
+*ar_startblock*::
+AG block number of the start of the free space.
+
+*ar_blockcount*::
+Length of the free space.
+
Node pointers are an AG relative block pointer:
[source, c]
@@ -776,6 +799,15 @@ struct xfs_inobt_rec {
};
----
+*ir_startino*::
+The lowest-numbered inode in this chunk.
+
+*ir_freecount*::
+Number of free inodes in this chunk.
+
+*ir_free*::
+A 64 element bitmap showing which inodes in this chunk are free.
+
Nodes contain key/pointer pairs using the following types:
[source,c]
diff --git a/design/XFS_Filesystem_Structure/data_extents.asciidoc b/design/XFS_Filesystem_Structure/data_extents.asciidoc
index a09fcc2..d1617f1 100644
--- a/design/XFS_Filesystem_Structure/data_extents.asciidoc
+++ b/design/XFS_Filesystem_Structure/data_extents.asciidoc
@@ -33,8 +33,16 @@ struct xfs_bmbt_irec {
};
----
+*br_startoff*::
+Logical block offset of this mapping.
+*br_startblock*::
+Filesystem block of this mapping.
+*br_blockcount*::
+The length of this mapping.
+
+*br_state*::
The extent +br_state+ field uses the following enum declaration:
[source, c]
@@ -250,6 +258,25 @@ struct xfs_btree_lblock {
};
----
+*bb_magic*::
+Specifies the magic number for the BMBT block: "BMAP" (0x424d4150).
+
+*bb_level*::
+The level of the tree in which this block is found. If this value is 0, this
+is a leaf block and contains records; otherwise, it is a node block and
+contains keys and pointers.
+
+*bb_numrecs*::
+Number of records in this block.
+
+*bb_leftsib*::
+FS block number of the left sibling of this B+tree node.
+
+*bb_rightsib*::
+FS block number of the right sibling of this B+tree node.
+
+// force-split the lists
+
* For intermediate nodes, the data following +xfs_btree_lblock+ is the same as
the root node: array of +xfs_bmbt_key+ value followed by an array of
+xfs_bmbt_ptr_t+ values that starts halfway through the block (offset 0x808 for
diff --git a/design/XFS_Filesystem_Structure/directories.asciidoc b/design/XFS_Filesystem_Structure/directories.asciidoc
index 3521749..2df118e 100644
--- a/design/XFS_Filesystem_Structure/directories.asciidoc
+++ b/design/XFS_Filesystem_Structure/directories.asciidoc
@@ -75,11 +75,35 @@ typedef struct xfs_dir2_sf {
xfs_dir2_sf_hdr_t hdr;
xfs_dir2_sf_entry_t list[1];
} xfs_dir2_sf_t;
+----
+
+*hdr*::
+Short form directory header.
+
+*list*::
+An array of variable-length directory entry records.
+
+[source, c]
+----
typedef struct xfs_dir2_sf_hdr {
__uint8_t count;
__uint8_t i8count;
xfs_dir2_inou_t parent;
} xfs_dir2_sf_hdr_t;
+----
+
+*count*::
+Number of directory entries.
+
+*i8count*::
+Number of directory entries requiring 64-bit entries, if any inode numbers
+require 64-bits. Zero otherwise.
+
+*parent*::
+The absolute inode number of this directory's parent.
+
+[source, c]
+----
typedef struct xfs_dir2_sf_entry {
__uint8_t namelen;
xfs_dir2_sf_off_t offset;
@@ -89,6 +113,25 @@ typedef struct xfs_dir2_sf_entry {
} xfs_dir2_sf_entry_t;
----
+*namelen*::
+Length of the name, in bytes.
+
+*offset*::
+Offset tag used to assist with directory iteration.
+
+*name*::
+The name of the directory entry. The entry is not NULL-terminated.
+
+*ftype*::
+The type of the inode. This is used to avoid reading the inode while iterating
+a directory. The +XFS_SB_VERSION2_FTYPE+ feature must be set, or this field
+will not be present.
+
+*inumber*::
+The inode number that this entry points to. The length is either 32 or 64
+bits, depending on whether +icount+ or +i8count+, respectively, are set in the
+header.
+
.Short form directory layout
image::images/39.png[]
@@ -259,18 +302,67 @@ typedef struct xfs_dir2_block {
xfs_dir2_leaf_entry_t leaf[1];
xfs_dir2_block_tail_t tail;
} xfs_dir2_block_t;
+----
+
+*hdr*::
+Directory block header.
+
+*u*::
+Union of directory and unused entries.
+
+*leaf*::
+Hash values of the entries in this block.
+
+*tail*::
+Bookkeeping for the leaf entries.
+
+[source, c]
+----
typedef struct xfs_dir2_data_hdr {
__uint32_t magic;
xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
} xfs_dir2_data_hdr_t;
+----
+
+*magic*::
+Magic number for this directory block.
+
+*bestfree*::
+An array pointing to free regions in the directory block.
+
+[source, c]
+----
typedef struct xfs_dir2_data_free {
xfs_dir2_data_off_t offset;
xfs_dir2_data_off_t length;
} xfs_dir2_data_free_t;
+----
+
+*offset*::
+Block offset of a free block, in bytes.
+
+*length*::
+Length of the free block, in bytes.
+
+Space inside the directory block can be used for directory entries or unused
+entries. This is signified via a union of the two types:
+
+[source, c]
+-----
typedef union {
xfs_dir2_data_entry_t entry;
xfs_dir2_data_unused_t unused;
} xfs_dir2_data_union_t;
+----
+
+*entry*::
+A directory entry.
+
+*unused*::
+An unused entry.
+
+[source, c]
+-----
typedef struct xfs_dir2_data_entry {
xfs_ino_t inumber;
__uint8_t namelen;
@@ -278,21 +370,74 @@ typedef struct xfs_dir2_data_entry {
__uint8_t ftype;
xfs_dir2_data_off_t tag;
} xfs_dir2_data_entry_t;
+----
+
+*inumber*::
+The inode number that this entry points to.
+
+*namelen*::
+Length of the name, in bytes.
+
+*name*::
+The name associated with this entry.
+
+*ftype*::
+The type of the inode. This is used to avoid reading the inode while iterating
+a directory. The +XFS_SB_VERSION2_FTYPE+ feature must be set, or this field
+will not be present.
+
+*tag*::
+Starting offset of the entry, in bytes. This is used for directory iteration.
+
+[source, c]
+-----
typedef struct xfs_dir2_data_unused {
__uint16_t freetag; /* 0xffff */
xfs_dir2_data_off_t length;
xfs_dir2_data_off_t tag;
} xfs_dir2_data_unused_t;
+----
+
+*freetag*::
+Magic number signifying that this is an unused entry. Must be 0xFFFF.
+
+*length*::
+Length of this unused entry, in bytes.
+
+*tag*::
+Starting offset of the entry, in bytes.
+
+[source, c]
+-----
typedef struct xfs_dir2_leaf_entry {
xfs_dahash_t hashval;
xfs_dir2_dataptr_t address;
} xfs_dir2_leaf_entry_t;
+----
+
+*hashval*::
+Hash value of the name of the directory entry. This is used to speed up entry
+lookups.
+
+*address*::
+Block offset of the entry, in eight byte units.
+
+[source, c]
+-----
typedef struct xfs_dir2_block_tail {
__uint32_t count;
__uint32_t stale;
} xfs_dir2_block_tail_t;
----
+*count*::
+Number of leaf entries.
+
+*stale*::
+Number of free leaf entries.
+
+Following is a diagram of how these pieces fit together for a block directory.
+
.Block directory layout
image::images/43.png[]
@@ -550,6 +695,14 @@ typedef struct xfs_dir2_data {
} xfs_dir2_data_t;
----
+*hdr*::
+Data block header.
+
+*u*::
+Union of directory and unused entries, exactly the same as in a block directory.
+
+// split lists
+
* The "leaf" extent uses the following structures:
[source, c]
@@ -560,16 +713,48 @@ typedef struct xfs_dir2_leaf {
xfs_dir2_data_off_t bests[1];
xfs_dir2_leaf_tail_t tail;
} xfs_dir2_leaf_t;
+----
+
+*hdr*::
+Directory leaf header.
+
+*ents*::
+Hash values of the entries in this block.
+
+*bests*::
+An array pointing to free regions in the directory block.
+
+*tail*::
+Bookkeeping for the leaf entries.
+
+[source, c]
+----
typedef struct xfs_dir2_leaf_hdr {
xfs_da_blkinfo_t info;
__uint16_t count;
__uint16_t stale;
} xfs_dir2_leaf_hdr_t;
+----
+
+*info*::
+Leaf btree block header.
+
+*count*::
+Number of leaf entries.
+
+*stale*::
+Number of stale/zeroed leaf entries.
+
+[source, c]
+----
typedef struct xfs_dir2_leaf_tail {
__uint32_t bestcount;
} xfs_dir2_leaf_tail_t;
----
+*bestcount*::
+Number of best free entries.
+
[[Directory_Attribute_Block_Header]]
=== Directory and Attribute Block Headers
@@ -587,6 +772,20 @@ typedef struct xfs_da_blkinfo {
} xfs_da_blkinfo_t;
----
+*forw*::
+Logical block offset of the previous B+tree block at this level.
+
+*back*::
+Logical block offset of the next B+tree block at this level.
+
+*magic*::
+Magic number for this directory/attribute block.
+
+*pad*::
+Padding to maintain alignment.
+
+// split lists
+
* The magic number of the leaf block is +XFS_DIR2_LEAF1_MAGIC+ (0xd2f1).
* The size of the +ents+ array is specified by +hdr.count+.
@@ -879,12 +1078,36 @@ typedef struct xfs_dir2_free_hdr {
__int32_t nvalid;
__int32_t nused;
} xfs_dir2_free_hdr_t;
+----
+
+*magic*::
+The magic number of the free block, "XD2F" (0x0x58443246).
+
+*firstdb*::
+The starting directory block number for the bests array.
+
+*nvalid*::
+Number of elements in the bests array.
+
+*nused*::
+Number of valid elements in the bests array.
+
+[source, c]
+----
typedef struct xfs_dir2_free {
xfs_dir2_free_hdr_t hdr;
xfs_dir2_data_off_t bests[1];
} xfs_dir2_free_t;
----
+*hdr*::
+Free block header.
+
+*bests*::
+An array specifying the best free counts in each directory data block.
+
+// split lists
+
* The location of the leaf blocks can be in any order, the only way to determine
the appropriate is by the node block hash/before values. Given a hash to look up,
you read the node's +btree+ array and first +hashval+ in the array that exceeds
@@ -912,6 +1135,23 @@ typedef struct xfs_da_intnode {
} xfs_da_intnode_t;
----
+*info*::
+Directory/attribute block info. The magic number is +XFS_DA_NODE_MAGIC+
+(0xfebe).
+
+*count*::
+Number of node entries in this block.
+
+*level*::
+The level of this block in the B+tree.
+
+*hashval*::
+The hash value of a particular record.
+
+*before*::
+The directory/attribute logical block containing all entries up to the
+corresponding hash value.
+
* The freeindex's +bests+ array starts from the end of the block and grows to the
start of the block.
diff --git a/design/XFS_Filesystem_Structure/docinfo.xml b/design/XFS_Filesystem_Structure/docinfo.xml
index 856c01d..32a502d 100644
--- a/design/XFS_Filesystem_Structure/docinfo.xml
+++ b/design/XFS_Filesystem_Structure/docinfo.xml
@@ -82,6 +82,7 @@
<revdescription>
<simplelist>
<member>Miscellaneous fixes.</member>
+ <member>Add missing field definitions.</member>
</simplelist>
</revdescription>
</revision>
diff --git a/design/XFS_Filesystem_Structure/extended_attributes.asciidoc b/design/XFS_Filesystem_Structure/extended_attributes.asciidoc
index 18a4568..2499f12 100644
--- a/design/XFS_Filesystem_Structure/extended_attributes.asciidoc
+++ b/design/XFS_Filesystem_Structure/extended_attributes.asciidoc
@@ -334,7 +334,16 @@ typedef struct xfs_attr_leaf_map {
__be16 base;
__be16 size;
} xfs_attr_leaf_map_t;
+----
+
+*base*::
+Block offset of the free area, in bytes.
+
+*size*::
+Size of the free area, in bytes.
+[source, c]
+----
typedef struct xfs_attr_leaf_hdr {
xfs_da_blkinfo_t info;
__be16 count;
@@ -344,27 +353,90 @@ typedef struct xfs_attr_leaf_hdr {
__u8 pad1;
xfs_attr_leaf_map_t freemap[3];
} xfs_attr_leaf_hdr_t;
+----
+
+*info*::
+Directory/attribute block header.
+
+*count*::
+Number of entries.
+
+*usedbytes*::
+Number of bytes used in the leaf block.
+*firstused*::
+Block offset of the first entry in use, in bytes.
+
+*holes*::
+Set to 1 if block compaction is necessary.
+
+*pad1*::
+Padding to maintain alignment to 64-bit boundaries.
+
+[source, c]
+-----
typedef struct xfs_attr_leaf_entry {
__be32 hashval;
__be16 nameidx;
__u8 flags;
__u8 pad2;
} xfs_attr_leaf_entry_t;
+----
+
+*hashval*::
+Hash value of the attribute name.
+
+*nameidx*::
+Block offset of the name entry, in bytes.
+
+*flags*::
+Attribute flags, as specified xref:Attribute_Flags[above].
+
+*pad2*::
+Pads the structure to 64-bit boundaries.
+[source, c]
+----
typedef struct xfs_attr_leaf_name_local {
__be16 valuelen;
__u8 namelen;
__u8 nameval[1];
} xfs_attr_leaf_name_local_t;
+----
+
+*valuelen*::
+Length of the value, in bytes.
+
+*namelen*::
+Length of the name, in bytes.
+*nameval*::
+The name and the value. String values are not zero-terminated.
+
+[source, c]
+----
typedef struct xfs_attr_leaf_name_remote {
__be32 valueblk;
__be32 valuelen;
__u8 namelen;
__u8 name[1];
} xfs_attr_leaf_name_remote_t;
+----
+
+*valueblk*::
+The logical block in the attribute map where the value is located.
+*valuelen*::
+Length of the value, in bytes.
+
+*namelen*::
+Length of the name, in bytes.
+
+*nameval*::
+The name. String values are not zero-terminated.
+
+[source, c]
+----
typedef struct xfs_attr_leafblock {
xfs_attr_leaf_hdr_t hdr;
xfs_attr_leaf_entry_t entries[1];
@@ -373,6 +445,20 @@ typedef struct xfs_attr_leafblock {
} xfs_attr_leafblock_t;
----
+*hdr*::
+Attribute block header.
+
+*entries*::
+A variable-length array of attribute entries.
+
+*namelist*::
+A variable-length array of descriptors of local attributes. The location and
+size of these entries is determined dynamically.
+
+*valuelist*::
+A variable-length array of descriptors of remote attributes. The location and
+size of these entries is determined dynamically.
+
Each leaf header uses the magic number +XFS_ATTR_LEAF_MAGIC+ (0xfbee).
The hash/index elements in the +entries[]+ array are packed from the top of the
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