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ad017f6537
Teach the extended attribute reading functions to pass along a transaction context if one was supplied. The extended attribute scrub code will use transactions to lock buffers and avoid deadlocking with itself in the case of loops; since it will already have the inode locked, also create xattr get/list helpers that don't take locks. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
158 lines
6.0 KiB
C
158 lines
6.0 KiB
C
/*
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* Copyright (c) 2000,2002-2003,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_ATTR_H__
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#define __XFS_ATTR_H__
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struct xfs_inode;
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struct xfs_da_args;
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struct xfs_attr_list_context;
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/*
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* Large attribute lists are structured around Btrees where all the data
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* elements are in the leaf nodes. Attribute names are hashed into an int,
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* then that int is used as the index into the Btree. Since the hashval
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* of an attribute name may not be unique, we may have duplicate keys.
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* The internal links in the Btree are logical block offsets into the file.
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*
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* Small attribute lists use a different format and are packed as tightly
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* as possible so as to fit into the literal area of the inode.
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*/
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/*========================================================================
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* External interfaces
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*========================================================================*/
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#define ATTR_DONTFOLLOW 0x0001 /* -- unused, from IRIX -- */
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#define ATTR_ROOT 0x0002 /* use attrs in root (trusted) namespace */
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#define ATTR_TRUST 0x0004 /* -- unused, from IRIX -- */
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#define ATTR_SECURE 0x0008 /* use attrs in security namespace */
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#define ATTR_CREATE 0x0010 /* pure create: fail if attr already exists */
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#define ATTR_REPLACE 0x0020 /* pure set: fail if attr does not exist */
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#define ATTR_KERNOTIME 0x1000 /* [kernel] don't update inode timestamps */
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#define ATTR_KERNOVAL 0x2000 /* [kernel] get attr size only, not value */
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#define XFS_ATTR_FLAGS \
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{ ATTR_DONTFOLLOW, "DONTFOLLOW" }, \
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{ ATTR_ROOT, "ROOT" }, \
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{ ATTR_TRUST, "TRUST" }, \
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{ ATTR_SECURE, "SECURE" }, \
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{ ATTR_CREATE, "CREATE" }, \
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{ ATTR_REPLACE, "REPLACE" }, \
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{ ATTR_KERNOTIME, "KERNOTIME" }, \
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{ ATTR_KERNOVAL, "KERNOVAL" }
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/*
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* The maximum size (into the kernel or returned from the kernel) of an
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* attribute value or the buffer used for an attr_list() call. Larger
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* sizes will result in an ERANGE return code.
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*/
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#define ATTR_MAX_VALUELEN (64*1024) /* max length of a value */
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/*
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* Define how lists of attribute names are returned to the user from
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* the attr_list() call. A large, 32bit aligned, buffer is passed in
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* along with its size. We put an array of offsets at the top that each
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* reference an attrlist_ent_t and pack the attrlist_ent_t's at the bottom.
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*/
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typedef struct attrlist {
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__s32 al_count; /* number of entries in attrlist */
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__s32 al_more; /* T/F: more attrs (do call again) */
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__s32 al_offset[1]; /* byte offsets of attrs [var-sized] */
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} attrlist_t;
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/*
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* Show the interesting info about one attribute. This is what the
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* al_offset[i] entry points to.
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*/
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typedef struct attrlist_ent { /* data from attr_list() */
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__u32 a_valuelen; /* number bytes in value of attr */
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char a_name[1]; /* attr name (NULL terminated) */
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} attrlist_ent_t;
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/*
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* Given a pointer to the (char*) buffer containing the attr_list() result,
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* and an index, return a pointer to the indicated attribute in the buffer.
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*/
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#define ATTR_ENTRY(buffer, index) \
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((attrlist_ent_t *) \
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&((char *)buffer)[ ((attrlist_t *)(buffer))->al_offset[index] ])
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/*
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* Kernel-internal version of the attrlist cursor.
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*/
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typedef struct attrlist_cursor_kern {
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__u32 hashval; /* hash value of next entry to add */
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__u32 blkno; /* block containing entry (suggestion) */
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__u32 offset; /* offset in list of equal-hashvals */
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__u16 pad1; /* padding to match user-level */
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__u8 pad2; /* padding to match user-level */
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__u8 initted; /* T/F: cursor has been initialized */
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} attrlist_cursor_kern_t;
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/*========================================================================
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* Structure used to pass context around among the routines.
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*========================================================================*/
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/* void; state communicated via *context */
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typedef void (*put_listent_func_t)(struct xfs_attr_list_context *, int,
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unsigned char *, int, int);
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typedef struct xfs_attr_list_context {
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struct xfs_trans *tp;
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struct xfs_inode *dp; /* inode */
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struct attrlist_cursor_kern *cursor; /* position in list */
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char *alist; /* output buffer */
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int seen_enough; /* T/F: seen enough of list? */
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ssize_t count; /* num used entries */
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int dupcnt; /* count dup hashvals seen */
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int bufsize; /* total buffer size */
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int firstu; /* first used byte in buffer */
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int flags; /* from VOP call */
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int resynch; /* T/F: resynch with cursor */
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put_listent_func_t put_listent; /* list output fmt function */
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int index; /* index into output buffer */
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} xfs_attr_list_context_t;
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/*========================================================================
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* Function prototypes for the kernel.
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*========================================================================*/
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/*
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* Overall external interface routines.
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*/
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int xfs_attr_inactive(struct xfs_inode *dp);
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int xfs_attr_list_int_ilocked(struct xfs_attr_list_context *);
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int xfs_attr_list_int(struct xfs_attr_list_context *);
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int xfs_inode_hasattr(struct xfs_inode *ip);
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int xfs_attr_get_ilocked(struct xfs_inode *ip, struct xfs_da_args *args);
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int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
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unsigned char *value, int *valuelenp, int flags);
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int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
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unsigned char *value, int valuelen, int flags);
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int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
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int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
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int flags, struct attrlist_cursor_kern *cursor);
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#endif /* __XFS_ATTR_H__ */
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