linux/fs/xfs/libxfs/xfs_attr.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_bmap_btree.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_attr_remote.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_trace.h"
#include "xfs_attr_item.h"
#include "xfs_xattr.h"
#include "xfs_parent.h"

struct kmem_cache		*xfs_attr_intent_cache;

/*
 * xfs_attr.c
 *
 * Provide the external interfaces to manage attribute lists.
 */

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Internal routines when attribute list fits inside the inode.
 */
STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);

/*
 * Internal routines when attribute list is one block.
 */
STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);

/*
 * Internal routines when attribute list is more than one block.
 */
STATIC int xfs_attr_node_get(xfs_da_args_t *args);
STATIC void xfs_attr_restore_rmt_blk(struct xfs_da_args *args);
static int xfs_attr_node_try_addname(struct xfs_attr_intent *attr);
STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_intent *attr);
STATIC int xfs_attr_node_remove_attr(struct xfs_attr_intent *attr);
STATIC int xfs_attr_node_lookup(struct xfs_da_args *args,
		struct xfs_da_state *state);

int
xfs_inode_hasattr(
	struct xfs_inode	*ip)
{ … }

/*
 * Returns true if the there is exactly only block in the attr fork, in which
 * case the attribute fork consists of a single leaf block entry.
 */
bool
xfs_attr_is_leaf(
	struct xfs_inode	*ip)
{ … }

/*
 * XXX (dchinner): name path state saving and refilling is an optimisation to
 * avoid needing to look up name entries after rolling transactions removing
 * remote xattr blocks between the name entry lookup and name entry removal.
 * This optimisation got sidelined when combining the set and remove state
 * machines, but the code has been left in place because it is worthwhile to
 * restore the optimisation once the combined state machine paths have settled.
 *
 * This comment is a public service announcement to remind Future Dave that he
 * still needs to restore this code to working order.
 */
#if 0
/*
 * Fill in the disk block numbers in the state structure for the buffers
 * that are attached to the state structure.
 * This is done so that we can quickly reattach ourselves to those buffers
 * after some set of transaction commits have released these buffers.
 */
static int
xfs_attr_fillstate(xfs_da_state_t *state)
{
	xfs_da_state_path_t *path;
	xfs_da_state_blk_t *blk;
	int level;

	trace_xfs_attr_fillstate(state->args);

	/*
	 * Roll down the "path" in the state structure, storing the on-disk
	 * block number for those buffers in the "path".
	 */
	path = &state->path;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->bp) {
			blk->disk_blkno = xfs_buf_daddr(blk->bp);
			blk->bp = NULL;
		} else {
			blk->disk_blkno = 0;
		}
	}

	/*
	 * Roll down the "altpath" in the state structure, storing the on-disk
	 * block number for those buffers in the "altpath".
	 */
	path = &state->altpath;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->bp) {
			blk->disk_blkno = xfs_buf_daddr(blk->bp);
			blk->bp = NULL;
		} else {
			blk->disk_blkno = 0;
		}
	}

	return 0;
}

/*
 * Reattach the buffers to the state structure based on the disk block
 * numbers stored in the state structure.
 * This is done after some set of transaction commits have released those
 * buffers from our grip.
 */
static int
xfs_attr_refillstate(xfs_da_state_t *state)
{
	xfs_da_state_path_t *path;
	xfs_da_state_blk_t *blk;
	int level, error;

	trace_xfs_attr_refillstate(state->args);

	/*
	 * Roll down the "path" in the state structure, storing the on-disk
	 * block number for those buffers in the "path".
	 */
	path = &state->path;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->disk_blkno) {
			error = xfs_da3_node_read_mapped(state->args->trans,
					state->args->dp, blk->disk_blkno,
					&blk->bp, XFS_ATTR_FORK);
			if (error)
				return error;
		} else {
			blk->bp = NULL;
		}
	}

	/*
	 * Roll down the "altpath" in the state structure, storing the on-disk
	 * block number for those buffers in the "altpath".
	 */
	path = &state->altpath;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->disk_blkno) {
			error = xfs_da3_node_read_mapped(state->args->trans,
					state->args->dp, blk->disk_blkno,
					&blk->bp, XFS_ATTR_FORK);
			if (error)
				return error;
		} else {
			blk->bp = NULL;
		}
	}

	return 0;
}
#else
static int xfs_attr_fillstate(xfs_da_state_t *state) { … }
#endif

/*========================================================================
 * Overall external interface routines.
 *========================================================================*/

/*
 * Retrieve an extended attribute and its value.  Must have ilock.
 * Returns 0 on successful retrieval, otherwise an error.
 */
int
xfs_attr_get_ilocked(
	struct xfs_da_args	*args)
{ … }

/*
 * Retrieve an extended attribute by name, and its value if requested.
 *
 * If args->valuelen is zero, then the caller does not want the value, just an
 * indication whether the attribute exists and the size of the value if it
 * exists. The size is returned in args.valuelen.
 *
 * If args->value is NULL but args->valuelen is non-zero, allocate the buffer
 * for the value after existence of the attribute has been determined. The
 * caller always has to free args->value if it is set, no matter if this
 * function was successful or not.
 *
 * If the attribute is found, but exceeds the size limit set by the caller in
 * args->valuelen, return -ERANGE with the size of the attribute that was found
 * in args->valuelen.
 */
int
xfs_attr_get(
	struct xfs_da_args	*args)
{ … }

/*
 * Calculate how many blocks we need for the new attribute,
 */
int
xfs_attr_calc_size(
	struct xfs_da_args	*args,
	int			*local)
{ … }

/* Initialize transaction reservation for an xattr set/replace/upsert */
inline struct xfs_trans_res
xfs_attr_set_resv(
	const struct xfs_da_args	*args)
{ … }

/*
 * Add an attr to a shortform fork. If there is no space,
 * xfs_attr_shortform_addname() will convert to leaf format and return -ENOSPC.
 * to use.
 */
STATIC int
xfs_attr_try_sf_addname(
	struct xfs_inode	*dp,
	struct xfs_da_args	*args)
{ … }

static int
xfs_attr_sf_addname(
	struct xfs_attr_intent		*attr)
{ … }

/* Compute the hash value for a user/root/secure extended attribute */
xfs_dahash_t
xfs_attr_hashname(
	const uint8_t		*name,
	int			namelen)
{ … }

/* Compute the hash value for any extended attribute from any namespace. */
xfs_dahash_t
xfs_attr_hashval(
	struct xfs_mount	*mp,
	unsigned int		attr_flags,
	const uint8_t		*name,
	int			namelen,
	const void		*value,
	int			valuelen)
{ … }

/* Save the current remote block info and clear the current pointers. */
static void
xfs_attr_save_rmt_blk(
	struct xfs_da_args	*args)
{ … }

/* Set stored info about a remote block */
static void
xfs_attr_restore_rmt_blk(
	struct xfs_da_args	*args)
{ … }

/*
 * PPTR_REPLACE operations require the caller to set the old and new names and
 * values explicitly.  Update the canonical fields to the new name and value
 * here now that the removal phase has finished.
 */
static void
xfs_attr_update_pptr_replace_args(
	struct xfs_da_args	*args)
{ … }

/*
 * Handle the state change on completion of a multi-state attr operation.
 *
 * If the XFS_DA_OP_REPLACE flag is set, this means the operation was the first
 * modification in a attr replace operation and we still have to do the second
 * state, indicated by @replace_state.
 *
 * We consume the XFS_DA_OP_REPLACE flag so that when we are called again on
 * completion of the second half of the attr replace operation we correctly
 * signal that it is done.
 */
static enum xfs_delattr_state
xfs_attr_complete_op(
	struct xfs_attr_intent	*attr,
	enum xfs_delattr_state	replace_state)
{ … }

/*
 * Try to add an attribute to an inode in leaf form.
 */
static int
xfs_attr_leaf_addname(
	struct xfs_attr_intent	*attr)
{ … }

/*
 * Add an entry to a node format attr tree.
 *
 * Note that we might still have a leaf here - xfs_attr_is_leaf() cannot tell
 * the difference between leaf + remote attr blocks and a node format tree,
 * so we may still end up having to convert from leaf to node format here.
 */
static int
xfs_attr_node_addname(
	struct xfs_attr_intent	*attr)
{ … }

static int
xfs_attr_rmtval_alloc(
	struct xfs_attr_intent		*attr)
{ … }

/*
 * Mark an attribute entry INCOMPLETE and save pointers to the relevant buffers
 * for later deletion of the entry.
 */
static int
xfs_attr_leaf_mark_incomplete(
	struct xfs_da_args	*args,
	struct xfs_da_state	*state)
{ … }

/* Ensure the da state of an xattr deferred work item is ready to go. */
static inline void
xfs_attr_item_init_da_state(
	struct xfs_attr_intent	*attr)
{ … }

/*
 * Initial setup for xfs_attr_node_removename.  Make sure the attr is there and
 * the blocks are valid.  Attr keys with remote blocks will be marked
 * incomplete.
 */
static
int xfs_attr_node_removename_setup(
	struct xfs_attr_intent		*attr)
{ … }

/*
 * Remove the original attr we have just replaced. This is dependent on the
 * original lookup and insert placing the old attr in args->blkno/args->index
 * and the new attr in args->blkno2/args->index2.
 */
static int
xfs_attr_leaf_remove_attr(
	struct xfs_attr_intent		*attr)
{ … }

/*
 * Shrink an attribute from leaf to shortform. Used by the node format remove
 * path when the node format collapses to a single block and so we have to check
 * if it can be collapsed further.
 */
static int
xfs_attr_leaf_shrink(
	struct xfs_da_args	*args)
{ … }

/*
 * Run the attribute operation specified in @attr.
 *
 * This routine is meant to function as a delayed operation and will set the
 * state to XFS_DAS_DONE when the operation is complete.  Calling functions will
 * need to handle this, and recall the function until either an error or
 * XFS_DAS_DONE is detected.
 */
int
xfs_attr_set_iter(
	struct xfs_attr_intent		*attr)
{ … }


/*
 * Return EEXIST if attr is found, or ENOATTR if not
 */
static int
xfs_attr_lookup(
	struct xfs_da_args	*args)
{ … }

int
xfs_attr_add_fork(
	struct xfs_inode	*ip,		/* incore inode pointer */
	int			size,		/* space new attribute needs */
	int			rsvd)		/* xact may use reserved blks */
{ … }

/*
 * Make a change to the xattr structure.
 *
 * The caller must have initialized @args, attached dquots, and must not hold
 * any ILOCKs.  Reserved data blocks may be used if @rsvd is set.
 *
 * Returns -EEXIST for XFS_ATTRUPDATE_CREATE if the name already exists.
 * Returns -ENOATTR for XFS_ATTRUPDATE_REMOVE if the name does not exist.
 * Returns 0 on success, or a negative errno if something else went wrong.
 */
int
xfs_attr_set(
	struct xfs_da_args	*args,
	enum xfs_attr_update	op,
	bool			rsvd)
{ … }

/*========================================================================
 * External routines when attribute list is inside the inode
 *========================================================================*/

int xfs_attr_sf_totsize(struct xfs_inode *dp)
{ … }

/*
 * Add a name to the shortform attribute list structure
 * This is the external routine.
 */
static int
xfs_attr_shortform_addname(
	struct xfs_da_args	*args)
{ … }


/*========================================================================
 * External routines when attribute list is one block
 *========================================================================*/

/*
 * Return EEXIST if attr is found, or ENOATTR if not
 */
STATIC int
xfs_attr_leaf_hasname(
	struct xfs_da_args	*args,
	struct xfs_buf		**bp)
{ … }

/*
 * Remove a name from the leaf attribute list structure
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
STATIC int
xfs_attr_leaf_removename(
	struct xfs_da_args	*args)
{ … }

/*
 * Look up a name in a leaf attribute list structure.
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 *
 * Returns 0 on successful retrieval, otherwise an error.
 */
STATIC int
xfs_attr_leaf_get(xfs_da_args_t *args)
{ … }

/* Return EEXIST if attr is found, or ENOATTR if not. */
STATIC int
xfs_attr_node_lookup(
	struct xfs_da_args	*args,
	struct xfs_da_state	*state)
{ … }

/*========================================================================
 * External routines when attribute list size > geo->blksize
 *========================================================================*/

STATIC int
xfs_attr_node_addname_find_attr(
	 struct xfs_attr_intent	*attr)
{ … }

/*
 * Add a name to a Btree-format attribute list.
 *
 * This will involve walking down the Btree, and may involve splitting leaf
 * nodes and even splitting intermediate nodes up to and including the root
 * node (a special case of an intermediate node).
 *
 * If the tree was still in single leaf format and needs to converted to
 * real node format return 1 and let the caller handle that.
 */
static int
xfs_attr_node_try_addname(
	struct xfs_attr_intent		*attr)
{ … }

static int
xfs_attr_node_removename(
	struct xfs_da_args	*args,
	struct xfs_da_state	*state)
{ … }

static int
xfs_attr_node_remove_attr(
	struct xfs_attr_intent		*attr)
{ … }

/*
 * Retrieve the attribute data from a node attribute list.
 *
 * This routine gets called for any attribute fork that has more than one
 * block, ie: both true Btree attr lists and for single-leaf-blocks with
 * "remote" values taking up more blocks.
 *
 * Returns 0 on successful retrieval, otherwise an error.
 */
STATIC int
xfs_attr_node_get(
	struct xfs_da_args	*args)
{ … }

/* Enforce that there is at most one namespace bit per attr. */
inline bool xfs_attr_check_namespace(unsigned int attr_flags)
{ … }

/* Returns true if the attribute entry name is valid. */
bool
xfs_attr_namecheck(
	unsigned int	attr_flags,
	const void	*name,
	size_t		length)
{ … }

int __init
xfs_attr_intent_init_cache(void)
{ … }

void
xfs_attr_intent_destroy_cache(void)
{ … }