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linux_dsm_epyc7002/fs/xfs/libxfs/xfs_attr.c
Dave Chinner ddbca70cc4 xfs: allocate xattr buffer on demand 
When doing file lookups and checking for permissions, we end up in
xfs_get_acl() to see if there are any ACLs on the inode. This
requires and xattr lookup, and to do that we have to supply a buffer
large enough to hold an maximum sized xattr.

On workloads were we are accessing a wide range of cache cold files
under memory pressure (e.g. NFS fileservers) we end up spending a
lot of time allocating the buffer. The buffer is 64k in length, so
is a contiguous multi-page allocation, and if that then fails we
fall back to vmalloc(). Hence the allocation here is /expensive/
when we are looking up hundreds of thousands of files a second.

Initial numbers from a bpf trace show average time in xfs_get_acl()
is ~32us, with ~19us of that in the memory allocation. Note these
are average times, so there are going to be affected by the worst
case allocations more than the common fast case...

To avoid this, we could just do a "null"  lookup to see if the ACL
xattr exists and then only do the allocation if it exists. This,
however, optimises the path for the "no ACL present" case at the
expense of the "acl present" case. i.e. we can halve the time in
xfs_get_acl() for the no acl case (i.e down to ~10-15us), but that
then increases the ACL case by 30% (i.e. up to 40-45us).

To solve this and speed up both cases, drive the xattr buffer
allocation into the attribute code once we know what the actual
xattr length is. For the no-xattr case, we avoid the allocation
completely, speeding up that case. For the common ACL case, we'll
end up with a fast heap allocation (because it'll be smaller than a
page), and only for the rarer "we have a remote xattr" will we have
a multi-page allocation occur. Hence the common ACL case will be
much faster, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-08-30 22:43:57 -07:00

1371 lines
34 KiB
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// 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"
/*
* 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_addname(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
/*
* Internal routines when attribute list is more than one block.
*/
STATIC int xfs_attr_node_get(xfs_da_args_t *args);
STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
STATIC int
xfs_attr_args_init(
struct xfs_da_args *args,
struct xfs_inode *dp,
const unsigned char *name,
int flags)
{
if (!name)
return -EINVAL;
memset(args, 0, sizeof(*args));
args->geo = dp->i_mount->m_attr_geo;
args->whichfork = XFS_ATTR_FORK;
args->dp = dp;
args->flags = flags;
args->name = name;
args->namelen = strlen((const char *)name);
if (args->namelen >= MAXNAMELEN)
return -EFAULT; /* match IRIX behaviour */
args->hashval = xfs_da_hashname(args->name, args->namelen);
return 0;
}
int
xfs_inode_hasattr(
struct xfs_inode *ip)
{
if (!XFS_IFORK_Q(ip) ||
(ip->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
ip->i_d.di_anextents == 0))
return 0;
return 1;
}
/*========================================================================
* 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_inode *ip,
struct xfs_da_args *args)
{
ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
if (!xfs_inode_hasattr(ip))
return -ENOATTR;
else if (ip->i_d.di_aformat == XFS_DINODE_FMT_LOCAL)
return xfs_attr_shortform_getvalue(args);
else if (xfs_bmap_one_block(ip, XFS_ATTR_FORK))
return xfs_attr_leaf_get(args);
else
return xfs_attr_node_get(args);
}
/*
* Retrieve an extended attribute by name, and its value if requested.
*
* If ATTR_KERNOVAL is set in @flags, 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 @valuelenp,
*
* If the attribute is found, but exceeds the size limit set by the caller in
* @valuelenp, return -ERANGE with the size of the attribute that was found in
* @valuelenp.
*
* If ATTR_ALLOC is set in @flags, allocate the buffer for the value after
* existence of the attribute has been determined. On success, return that
* buffer to the caller and leave them to free it. On failure, free any
* allocated buffer and ensure the buffer pointer returned to the caller is
* null.
*/
int
xfs_attr_get(
struct xfs_inode *ip,
const unsigned char *name,
unsigned char **value,
int *valuelenp,
int flags)
{
struct xfs_da_args args;
uint lock_mode;
int error;
ASSERT((flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || *value);
XFS_STATS_INC(ip->i_mount, xs_attr_get);
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return -EIO;
error = xfs_attr_args_init(&args, ip, name, flags);
if (error)
return error;
/* Entirely possible to look up a name which doesn't exist */
args.op_flags = XFS_DA_OP_OKNOENT;
if (flags & ATTR_ALLOC)
args.op_flags |= XFS_DA_OP_ALLOCVAL;
else
args.value = *value;
args.valuelen = *valuelenp;
lock_mode = xfs_ilock_attr_map_shared(ip);
error = xfs_attr_get_ilocked(ip, &args);
xfs_iunlock(ip, lock_mode);
*valuelenp = args.valuelen;
/* on error, we have to clean up allocated value buffers */
if (error) {
if (flags & ATTR_ALLOC) {
kmem_free(args.value);
*value = NULL;
}
return error;
}
*value = args.value;
return 0;
}
/*
* Calculate how many blocks we need for the new attribute,
*/
STATIC int
xfs_attr_calc_size(
struct xfs_da_args *args,
int *local)
{
struct xfs_mount *mp = args->dp->i_mount;
int size;
int nblks;
/*
* Determine space new attribute will use, and if it would be
* "local" or "remote" (note: local != inline).
*/
size = xfs_attr_leaf_newentsize(args, local);
nblks = XFS_DAENTER_SPACE_RES(mp, XFS_ATTR_FORK);
if (*local) {
if (size > (args->geo->blksize / 2)) {
/* Double split possible */
nblks *= 2;
}
} else {
/*
* Out of line attribute, cannot double split, but
* make room for the attribute value itself.
*/
uint dblocks = xfs_attr3_rmt_blocks(mp, args->valuelen);
nblks += dblocks;
nblks += XFS_NEXTENTADD_SPACE_RES(mp, dblocks, XFS_ATTR_FORK);
}
return nblks;
}
STATIC int
xfs_attr_try_sf_addname(
struct xfs_inode *dp,
struct xfs_da_args *args)
{
struct xfs_mount *mp = dp->i_mount;
int error, error2;
error = xfs_attr_shortform_addname(args);
if (error == -ENOSPC)
return error;
/*
* Commit the shortform mods, and we're done.
* NOTE: this is also the error path (EEXIST, etc).
*/
if (!error && (args->flags & ATTR_KERNOTIME) == 0)
xfs_trans_ichgtime(args->trans, dp, XFS_ICHGTIME_CHG);
if (mp->m_flags & XFS_MOUNT_WSYNC)
xfs_trans_set_sync(args->trans);
error2 = xfs_trans_commit(args->trans);
args->trans = NULL;
return error ? error : error2;
}
/*
* Set the attribute specified in @args.
*/
int
xfs_attr_set_args(
struct xfs_da_args *args)
{
struct xfs_inode *dp = args->dp;
struct xfs_buf *leaf_bp = NULL;
int error;
/*
* If the attribute list is non-existent or a shortform list,
* upgrade it to a single-leaf-block attribute list.
*/
if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL ||
(dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
dp->i_d.di_anextents == 0)) {
/*
* Build initial attribute list (if required).
*/
if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
xfs_attr_shortform_create(args);
/*
* Try to add the attr to the attribute list in the inode.
*/
error = xfs_attr_try_sf_addname(dp, args);
if (error != -ENOSPC)
return error;
/*
* It won't fit in the shortform, transform to a leaf block.
* GROT: another possible req'mt for a double-split btree op.
*/
error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
if (error)
return error;
/*
* Prevent the leaf buffer from being unlocked so that a
* concurrent AIL push cannot grab the half-baked leaf
* buffer and run into problems with the write verifier.
* Once we're done rolling the transaction we can release
* the hold and add the attr to the leaf.
*/
xfs_trans_bhold(args->trans, leaf_bp);
error = xfs_defer_finish(&args->trans);
xfs_trans_bhold_release(args->trans, leaf_bp);
if (error) {
xfs_trans_brelse(args->trans, leaf_bp);
return error;
}
}
if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
error = xfs_attr_leaf_addname(args);
else
error = xfs_attr_node_addname(args);
return error;
}
/*
* Remove the attribute specified in @args.
*/
int
xfs_attr_remove_args(
struct xfs_da_args *args)
{
struct xfs_inode *dp = args->dp;
int error;
if (!xfs_inode_hasattr(dp)) {
error = -ENOATTR;
} else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
error = xfs_attr_shortform_remove(args);
} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
error = xfs_attr_leaf_removename(args);
} else {
error = xfs_attr_node_removename(args);
}
return error;
}
int
xfs_attr_set(
struct xfs_inode *dp,
const unsigned char *name,
unsigned char *value,
int valuelen,
int flags)
{
struct xfs_mount *mp = dp->i_mount;
struct xfs_da_args args;
struct xfs_trans_res tres;
int rsvd = (flags & ATTR_ROOT) != 0;
int error, local;
XFS_STATS_INC(mp, xs_attr_set);
if (XFS_FORCED_SHUTDOWN(dp->i_mount))
return -EIO;
error = xfs_attr_args_init(&args, dp, name, flags);
if (error)
return error;
args.value = value;
args.valuelen = valuelen;
args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
args.total = xfs_attr_calc_size(&args, &local);
error = xfs_qm_dqattach(dp);
if (error)
return error;
/*
* If the inode doesn't have an attribute fork, add one.
* (inode must not be locked when we call this routine)
*/
if (XFS_IFORK_Q(dp) == 0) {
int sf_size = sizeof(xfs_attr_sf_hdr_t) +
XFS_ATTR_SF_ENTSIZE_BYNAME(args.namelen, valuelen);
error = xfs_bmap_add_attrfork(dp, sf_size, rsvd);
if (error)
return error;
}
tres.tr_logres = M_RES(mp)->tr_attrsetm.tr_logres +
M_RES(mp)->tr_attrsetrt.tr_logres * args.total;
tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
/*
* Root fork attributes can use reserved data blocks for this
* operation if necessary
*/
error = xfs_trans_alloc(mp, &tres, args.total, 0,
rsvd ? XFS_TRANS_RESERVE : 0, &args.trans);
if (error)
return error;
xfs_ilock(dp, XFS_ILOCK_EXCL);
error = xfs_trans_reserve_quota_nblks(args.trans, dp, args.total, 0,
rsvd ? XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
XFS_QMOPT_RES_REGBLKS);
if (error)
goto out_trans_cancel;
xfs_trans_ijoin(args.trans, dp, 0);
error = xfs_attr_set_args(&args);
if (error)
goto out_trans_cancel;
if (!args.trans) {
/* shortform attribute has already been committed */
goto out_unlock;
}
/*
* If this is a synchronous mount, make sure that the
* transaction goes to disk before returning to the user.
*/
if (mp->m_flags & XFS_MOUNT_WSYNC)
xfs_trans_set_sync(args.trans);
if ((flags & ATTR_KERNOTIME) == 0)
xfs_trans_ichgtime(args.trans, dp, XFS_ICHGTIME_CHG);
/*
* Commit the last in the sequence of transactions.
*/
xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
error = xfs_trans_commit(args.trans);
out_unlock:
xfs_iunlock(dp, XFS_ILOCK_EXCL);
return error;
out_trans_cancel:
if (args.trans)
xfs_trans_cancel(args.trans);
goto out_unlock;
}
/*
* Generic handler routine to remove a name from an attribute list.
* Transitions attribute list from Btree to shortform as necessary.
*/
int
xfs_attr_remove(
struct xfs_inode *dp,
const unsigned char *name,
int flags)
{
struct xfs_mount *mp = dp->i_mount;
struct xfs_da_args args;
int error;
XFS_STATS_INC(mp, xs_attr_remove);
if (XFS_FORCED_SHUTDOWN(dp->i_mount))
return -EIO;
error = xfs_attr_args_init(&args, dp, name, flags);
if (error)
return error;
/*
* we have no control over the attribute names that userspace passes us
* to remove, so we have to allow the name lookup prior to attribute
* removal to fail.
*/
args.op_flags = XFS_DA_OP_OKNOENT;
error = xfs_qm_dqattach(dp);
if (error)
return error;
/*
* Root fork attributes can use reserved data blocks for this
* operation if necessary
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_attrrm,
XFS_ATTRRM_SPACE_RES(mp), 0,
(flags & ATTR_ROOT) ? XFS_TRANS_RESERVE : 0,
&args.trans);
if (error)
return error;
xfs_ilock(dp, XFS_ILOCK_EXCL);
/*
* No need to make quota reservations here. We expect to release some
* blocks not allocate in the common case.
*/
xfs_trans_ijoin(args.trans, dp, 0);
error = xfs_attr_remove_args(&args);
if (error)
goto out;
/*
* If this is a synchronous mount, make sure that the
* transaction goes to disk before returning to the user.
*/
if (mp->m_flags & XFS_MOUNT_WSYNC)
xfs_trans_set_sync(args.trans);
if ((flags & ATTR_KERNOTIME) == 0)
xfs_trans_ichgtime(args.trans, dp, XFS_ICHGTIME_CHG);
/*
* Commit the last in the sequence of transactions.
*/
xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
error = xfs_trans_commit(args.trans);
xfs_iunlock(dp, XFS_ILOCK_EXCL);
return error;
out:
if (args.trans)
xfs_trans_cancel(args.trans);
xfs_iunlock(dp, XFS_ILOCK_EXCL);
return error;
}
/*========================================================================
* External routines when attribute list is inside the inode
*========================================================================*/
/*
* Add a name to the shortform attribute list structure
* This is the external routine.
*/
STATIC int
xfs_attr_shortform_addname(xfs_da_args_t *args)
{
int newsize, forkoff, retval;
trace_xfs_attr_sf_addname(args);
retval = xfs_attr_shortform_lookup(args);
if ((args->flags & ATTR_REPLACE) && (retval == -ENOATTR)) {
return retval;
} else if (retval == -EEXIST) {
if (args->flags & ATTR_CREATE)
return retval;
retval = xfs_attr_shortform_remove(args);
if (retval)
return retval;
/*
* Since we have removed the old attr, clear ATTR_REPLACE so
* that the leaf format add routine won't trip over the attr
* not being around.
*/
args->flags &= ~ATTR_REPLACE;
}
if (args->namelen >= XFS_ATTR_SF_ENTSIZE_MAX ||
args->valuelen >= XFS_ATTR_SF_ENTSIZE_MAX)
return -ENOSPC;
newsize = XFS_ATTR_SF_TOTSIZE(args->dp);
newsize += XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);
forkoff = xfs_attr_shortform_bytesfit(args->dp, newsize);
if (!forkoff)
return -ENOSPC;
xfs_attr_shortform_add(args, forkoff);
return 0;
}
/*========================================================================
* External routines when attribute list is one block
*========================================================================*/
/*
* Add a name to 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_addname(
struct xfs_da_args *args)
{
struct xfs_inode *dp;
struct xfs_buf *bp;
int retval, error, forkoff;
trace_xfs_attr_leaf_addname(args);
/*
* Read the (only) block in the attribute list in.
*/
dp = args->dp;
args->blkno = 0;
error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
if (error)
return error;
/*
* Look up the given attribute in the leaf block. Figure out if
* the given flags produce an error or call for an atomic rename.
*/
retval = xfs_attr3_leaf_lookup_int(bp, args);
if ((args->flags & ATTR_REPLACE) && (retval == -ENOATTR)) {
xfs_trans_brelse(args->trans, bp);
return retval;
} else if (retval == -EEXIST) {
if (args->flags & ATTR_CREATE) { /* pure create op */
xfs_trans_brelse(args->trans, bp);
return retval;
}
trace_xfs_attr_leaf_replace(args);
/* save the attribute state for later removal*/
args->op_flags |= XFS_DA_OP_RENAME; /* an atomic rename */
args->blkno2 = args->blkno; /* set 2nd entry info*/
args->index2 = args->index;
args->rmtblkno2 = args->rmtblkno;
args->rmtblkcnt2 = args->rmtblkcnt;
args->rmtvaluelen2 = args->rmtvaluelen;
/*
* clear the remote attr state now that it is saved so that the
* values reflect the state of the attribute we are about to
* add, not the attribute we just found and will remove later.
*/
args->rmtblkno = 0;
args->rmtblkcnt = 0;
args->rmtvaluelen = 0;
}
/*
* Add the attribute to the leaf block, transitioning to a Btree
* if required.
*/
retval = xfs_attr3_leaf_add(bp, args);
if (retval == -ENOSPC) {
/*
* Promote the attribute list to the Btree format, then
* Commit that transaction so that the node_addname() call
* can manage its own transactions.
*/
error = xfs_attr3_leaf_to_node(args);
if (error)
return error;
error = xfs_defer_finish(&args->trans);
if (error)
return error;
/*
* Commit the current trans (including the inode) and start
* a new one.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
if (error)
return error;
/*
* Fob the whole rest of the problem off on the Btree code.
*/
error = xfs_attr_node_addname(args);
return error;
}
/*
* Commit the transaction that added the attr name so that
* later routines can manage their own transactions.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
if (error)
return error;
/*
* If there was an out-of-line value, allocate the blocks we
* identified for its storage and copy the value. This is done
* after we create the attribute so that we don't overflow the
* maximum size of a transaction and/or hit a deadlock.
*/
if (args->rmtblkno > 0) {
error = xfs_attr_rmtval_set(args);
if (error)
return error;
}
/*
* If this is an atomic rename operation, we must "flip" the
* incomplete flags on the "new" and "old" attribute/value pairs
* so that one disappears and one appears atomically. Then we
* must remove the "old" attribute/value pair.
*/
if (args->op_flags & XFS_DA_OP_RENAME) {
/*
* In a separate transaction, set the incomplete flag on the
* "old" attr and clear the incomplete flag on the "new" attr.
*/
error = xfs_attr3_leaf_flipflags(args);
if (error)
return error;
/*
* Dismantle the "old" attribute/value pair by removing
* a "remote" value (if it exists).
*/
args->index = args->index2;
args->blkno = args->blkno2;
args->rmtblkno = args->rmtblkno2;
args->rmtblkcnt = args->rmtblkcnt2;
args->rmtvaluelen = args->rmtvaluelen2;
if (args->rmtblkno) {
error = xfs_attr_rmtval_remove(args);
if (error)
return error;
}
/*
* Read in the block containing the "old" attr, then
* remove the "old" attr from that block (neat, huh!)
*/
error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
-1, &bp);
if (error)
return error;
xfs_attr3_leaf_remove(bp, args);
/*
* If the result is small enough, shrink it all into the inode.
*/
if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
/* bp is gone due to xfs_da_shrink_inode */
if (error)
return error;
error = xfs_defer_finish(&args->trans);
if (error)
return error;
}
/*
* Commit the remove and start the next trans in series.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
} else if (args->rmtblkno > 0) {
/*
* Added a "remote" value, just clear the incomplete flag.
*/
error = xfs_attr3_leaf_clearflag(args);
}
return error;
}
/*
* 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)
{
struct xfs_inode *dp;
struct xfs_buf *bp;
int error, forkoff;
trace_xfs_attr_leaf_removename(args);
/*
* Remove the attribute.
*/
dp = args->dp;
args->blkno = 0;
error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
if (error)
return error;
error = xfs_attr3_leaf_lookup_int(bp, args);
if (error == -ENOATTR) {
xfs_trans_brelse(args->trans, bp);
return error;
}
xfs_attr3_leaf_remove(bp, args);
/*
* If the result is small enough, shrink it all into the inode.
*/
if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
/* bp is gone due to xfs_da_shrink_inode */
if (error)
return error;
error = xfs_defer_finish(&args->trans);
if (error)
return error;
}
return 0;
}
/*
* 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)
{
struct xfs_buf *bp;
int error;
trace_xfs_attr_leaf_get(args);
args->blkno = 0;
error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
if (error)
return error;
error = xfs_attr3_leaf_lookup_int(bp, args);
if (error != -EEXIST) {
xfs_trans_brelse(args->trans, bp);
return error;
}
error = xfs_attr3_leaf_getvalue(bp, args);
xfs_trans_brelse(args->trans, bp);
return error;
}
/*========================================================================
* External routines when attribute list size > geo->blksize
*========================================================================*/
/*
* 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).
*
* "Remote" attribute values confuse the issue and atomic rename operations
* add a whole extra layer of confusion on top of that.
*/
STATIC int
xfs_attr_node_addname(
struct xfs_da_args *args)
{
struct xfs_da_state *state;
struct xfs_da_state_blk *blk;
struct xfs_inode *dp;
struct xfs_mount *mp;
int retval, error;
trace_xfs_attr_node_addname(args);
/*
* Fill in bucket of arguments/results/context to carry around.
*/
dp = args->dp;
mp = dp->i_mount;
restart:
state = xfs_da_state_alloc();
state->args = args;
state->mp = mp;
/*
* Search to see if name already exists, and get back a pointer
* to where it should go.
*/
error = xfs_da3_node_lookup_int(state, &retval);
if (error)
goto out;
blk = &state->path.blk[ state->path.active-1 ];
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
if ((args->flags & ATTR_REPLACE) && (retval == -ENOATTR)) {
goto out;
} else if (retval == -EEXIST) {
if (args->flags & ATTR_CREATE)
goto out;
trace_xfs_attr_node_replace(args);
/* save the attribute state for later removal*/
args->op_flags |= XFS_DA_OP_RENAME; /* atomic rename op */
args->blkno2 = args->blkno; /* set 2nd entry info*/
args->index2 = args->index;
args->rmtblkno2 = args->rmtblkno;
args->rmtblkcnt2 = args->rmtblkcnt;
args->rmtvaluelen2 = args->rmtvaluelen;
/*
* clear the remote attr state now that it is saved so that the
* values reflect the state of the attribute we are about to
* add, not the attribute we just found and will remove later.
*/
args->rmtblkno = 0;
args->rmtblkcnt = 0;
args->rmtvaluelen = 0;
}
retval = xfs_attr3_leaf_add(blk->bp, state->args);
if (retval == -ENOSPC) {
if (state->path.active == 1) {
/*
* Its really a single leaf node, but it had
* out-of-line values so it looked like it *might*
* have been a b-tree.
*/
xfs_da_state_free(state);
state = NULL;
error = xfs_attr3_leaf_to_node(args);
if (error)
goto out;
error = xfs_defer_finish(&args->trans);
if (error)
goto out;
/*
* Commit the node conversion and start the next
* trans in the chain.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
if (error)
goto out;
goto restart;
}
/*
* Split as many Btree elements as required.
* This code tracks the new and old attr's location
* in the index/blkno/rmtblkno/rmtblkcnt fields and
* in the index2/blkno2/rmtblkno2/rmtblkcnt2 fields.
*/
error = xfs_da3_split(state);
if (error)
goto out;
error = xfs_defer_finish(&args->trans);
if (error)
goto out;
} else {
/*
* Addition succeeded, update Btree hashvals.
*/
xfs_da3_fixhashpath(state, &state->path);
}
/*
* Kill the state structure, we're done with it and need to
* allow the buffers to come back later.
*/
xfs_da_state_free(state);
state = NULL;
/*
* Commit the leaf addition or btree split and start the next
* trans in the chain.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
if (error)
goto out;
/*
* If there was an out-of-line value, allocate the blocks we
* identified for its storage and copy the value. This is done
* after we create the attribute so that we don't overflow the
* maximum size of a transaction and/or hit a deadlock.
*/
if (args->rmtblkno > 0) {
error = xfs_attr_rmtval_set(args);
if (error)
return error;
}
/*
* If this is an atomic rename operation, we must "flip" the
* incomplete flags on the "new" and "old" attribute/value pairs
* so that one disappears and one appears atomically. Then we
* must remove the "old" attribute/value pair.
*/
if (args->op_flags & XFS_DA_OP_RENAME) {
/*
* In a separate transaction, set the incomplete flag on the
* "old" attr and clear the incomplete flag on the "new" attr.
*/
error = xfs_attr3_leaf_flipflags(args);
if (error)
goto out;
/*
* Dismantle the "old" attribute/value pair by removing
* a "remote" value (if it exists).
*/
args->index = args->index2;
args->blkno = args->blkno2;
args->rmtblkno = args->rmtblkno2;
args->rmtblkcnt = args->rmtblkcnt2;
args->rmtvaluelen = args->rmtvaluelen2;
if (args->rmtblkno) {
error = xfs_attr_rmtval_remove(args);
if (error)
return error;
}
/*
* Re-find the "old" attribute entry after any split ops.
* The INCOMPLETE flag means that we will find the "old"
* attr, not the "new" one.
*/
args->flags |= XFS_ATTR_INCOMPLETE;
state = xfs_da_state_alloc();
state->args = args;
state->mp = mp;
state->inleaf = 0;
error = xfs_da3_node_lookup_int(state, &retval);
if (error)
goto out;
/*
* Remove the name and update the hashvals in the tree.
*/
blk = &state->path.blk[ state->path.active-1 ];
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
error = xfs_attr3_leaf_remove(blk->bp, args);
xfs_da3_fixhashpath(state, &state->path);
/*
* Check to see if the tree needs to be collapsed.
*/
if (retval && (state->path.active > 1)) {
error = xfs_da3_join(state);
if (error)
goto out;
error = xfs_defer_finish(&args->trans);
if (error)
goto out;
}
/*
* Commit and start the next trans in the chain.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
if (error)
goto out;
} else if (args->rmtblkno > 0) {
/*
* Added a "remote" value, just clear the incomplete flag.
*/
error = xfs_attr3_leaf_clearflag(args);
if (error)
goto out;
}
retval = error = 0;
out:
if (state)
xfs_da_state_free(state);
if (error)
return error;
return retval;
}
/*
* Remove a name from a B-tree attribute list.
*
* This will involve walking down the Btree, and may involve joining
* leaf nodes and even joining intermediate nodes up to and including
* the root node (a special case of an intermediate node).
*/
STATIC int
xfs_attr_node_removename(
struct xfs_da_args *args)
{
struct xfs_da_state *state;
struct xfs_da_state_blk *blk;
struct xfs_inode *dp;
struct xfs_buf *bp;
int retval, error, forkoff;
trace_xfs_attr_node_removename(args);
/*
* Tie a string around our finger to remind us where we are.
*/
dp = args->dp;
state = xfs_da_state_alloc();
state->args = args;
state->mp = dp->i_mount;
/*
* Search to see if name exists, and get back a pointer to it.
*/
error = xfs_da3_node_lookup_int(state, &retval);
if (error || (retval != -EEXIST)) {
if (error == 0)
error = retval;
goto out;
}
/*
* If there is an out-of-line value, de-allocate the blocks.
* This is done before we remove the attribute so that we don't
* overflow the maximum size of a transaction and/or hit a deadlock.
*/
blk = &state->path.blk[ state->path.active-1 ];
ASSERT(blk->bp != NULL);
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
if (args->rmtblkno > 0) {
/*
* Fill in disk block numbers in the state structure
* so that we can get the buffers back after we commit
* several transactions in the following calls.
*/
error = xfs_attr_fillstate(state);
if (error)
goto out;
/*
* Mark the attribute as INCOMPLETE, then bunmapi() the
* remote value.
*/
error = xfs_attr3_leaf_setflag(args);
if (error)
goto out;
error = xfs_attr_rmtval_remove(args);
if (error)
goto out;
/*
* Refill the state structure with buffers, the prior calls
* released our buffers.
*/
error = xfs_attr_refillstate(state);
if (error)
goto out;
}
/*
* Remove the name and update the hashvals in the tree.
*/
blk = &state->path.blk[ state->path.active-1 ];
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
retval = xfs_attr3_leaf_remove(blk->bp, args);
xfs_da3_fixhashpath(state, &state->path);
/*
* Check to see if the tree needs to be collapsed.
*/
if (retval && (state->path.active > 1)) {
error = xfs_da3_join(state);
if (error)
goto out;
error = xfs_defer_finish(&args->trans);
if (error)
goto out;
/*
* Commit the Btree join operation and start a new trans.
*/
error = xfs_trans_roll_inode(&args->trans, dp);
if (error)
goto out;
}
/*
* If the result is small enough, push it all into the inode.
*/
if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
/*
* Have to get rid of the copy of this dabuf in the state.
*/
ASSERT(state->path.active == 1);
ASSERT(state->path.blk[0].bp);
state->path.blk[0].bp = NULL;
error = xfs_attr3_leaf_read(args->trans, args->dp, 0, -1, &bp);
if (error)
goto out;
if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
/* bp is gone due to xfs_da_shrink_inode */
if (error)
goto out;
error = xfs_defer_finish(&args->trans);
if (error)
goto out;
} else
xfs_trans_brelse(args->trans, bp);
}
error = 0;
out:
xfs_da_state_free(state);
return error;
}
/*
* 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_ADDR(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_ADDR(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(state->args->trans,
state->args->dp,
blk->blkno, 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(state->args->trans,
state->args->dp,
blk->blkno, blk->disk_blkno,
&blk->bp, XFS_ATTR_FORK);
if (error)
return error;
} else {
blk->bp = NULL;
}
}
return 0;
}
/*
* 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(xfs_da_args_t *args)
{
xfs_da_state_t *state;
xfs_da_state_blk_t *blk;
int error, retval;
int i;
trace_xfs_attr_node_get(args);
state = xfs_da_state_alloc();
state->args = args;
state->mp = args->dp->i_mount;
/*
* Search to see if name exists, and get back a pointer to it.
*/
error = xfs_da3_node_lookup_int(state, &retval);
if (error) {
retval = error;
goto out_release;
}
if (retval != -EEXIST)
goto out_release;
/*
* Get the value, local or "remote"
*/
blk = &state->path.blk[state->path.active - 1];
retval = xfs_attr3_leaf_getvalue(blk->bp, args);
/*
* If not in a transaction, we have to release all the buffers.
*/
out_release:
for (i = 0; i < state->path.active; i++) {
xfs_trans_brelse(args->trans, state->path.blk[i].bp);
state->path.blk[i].bp = NULL;
}
xfs_da_state_free(state);
return retval;
}
/* Returns true if the attribute entry name is valid. */
bool
xfs_attr_namecheck(
const void *name,
size_t length)
{
/*
* MAXNAMELEN includes the trailing null, but (name/length) leave it
* out, so use >= for the length check.
*/
if (length >= MAXNAMELEN)
return false;
/* There shouldn't be any nulls here */
return !memchr(name, 0, length);
}
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