3  * attrib.c - NTFS attribute operations.  Part of the Linux-NTFS project.
28  * @ctx:	active attribute search context if present or NULL if not
40  * attribute on return as on entry.  However, the actual pointers in @ctx may
54  * the attribute has zero allocated size, i.e. there simply is no runlist.
114 		 * If we already have the attribute extent containing @vcn in  in ntfs_map_runlist_nolock()
118 		 * the right attribute extent.  in ntfs_map_runlist_nolock()
145 			 * needed attribute extent.  in ntfs_map_runlist_nolock()
185 		 * If there is no attribute list, restoring the search context  in ntfs_map_runlist_nolock()
187 		 * the caller supplied context.  If there is an attribute list,  in ntfs_map_runlist_nolock()
299  * @ni:			ntfs inode of the attribute whose runlist to search
303  * Find the virtual cluster number @vcn in the runlist of the ntfs attribute
307  * If the @vcn is not mapped yet, the attempt is made to map the attribute
397  * @ctx:	active attribute search context if present or NULL if not
402  * If the @vcn is not mapped yet, the attempt is made to map the attribute
413  * attribute on return as on entry.  However, the actual pointers in @ctx may
519  * ntfs_attr_find - find (next) attribute in mft record
520  * @type:	attribute type to find
521  * @name:	attribute name to find (optional, i.e. NULL means don't care)
522  * @name_len:	attribute name length (only needed if @name present)
524  * @val:	attribute value to find (optional, resident attributes only)
525  * @val_len:	attribute value length
526  * @ctx:	search context with mft record and attribute to search from
533  * attribute of @type, optionally @name and @val.
535  * If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will
536  * point to the found attribute.
538  * If the attribute is not found, ntfs_attr_find() returns -ENOENT and
539  * @ctx->attr will point to the attribute before which the attribute being
555  * If @name is not present (NULL), we assume that the unnamed attribute is
558  * Finally, the resident attribute value @val is looked for, if present.  If
562  * presence of an attribute list attribute (unless it is the one being searched
563  * for, obviously).  If you need to take attribute lists into consideration,
567  * attribute list attribute only. - Note that it is possible that the first
568  * extent is only in the attribute list while the last extent is in the base
572  * Warning: Never use @val when looking for attribute types which can be
586 	 * attribute following that, if @ctx->is_first is 'true'.  in ntfs_attr_find()
603 		/* check whether Attribute Record Header is within bounds */  in ntfs_attr_find()
632 		 * missing, assume we want an unnamed attribute.  in ntfs_attr_find()
635 			/* The search failed if the found attribute is named. */  in ntfs_attr_find()
650 			 * matching attribute.  in ntfs_attr_find()
668 		 * The names match or @name not present and attribute is  in ntfs_attr_find()
669 		 * unnamed.  If no @val specified, we have found the attribute  in ntfs_attr_find()
683 			 * If @val collates before the current attribute's  in ntfs_attr_find()
684 			 * value, there is no matching attribute.  in ntfs_attr_find()
705  * load_attribute_list - load an attribute list into memory
707  * @runlist:		runlist of the attribute list
710  * @initialized_size:	initialized size of the attribute list
748 		ntfs_error(sb, "Cannot read attribute list since runlist is "  in load_attribute_list()
758 		/* The attribute list cannot be sparse. */  in load_attribute_list()
761 					"read attribute list.");  in load_attribute_list()
774 						"read attribute list.");  in load_attribute_list()
797 		 * Note: The attribute list can be smaller than its allocation  in load_attribute_list()
810 	ntfs_error(sb, "Attribute list buffer overflow. Read attribute list "  in load_attribute_list()
818  * ntfs_external_attr_find - find an attribute in the attribute list of an inode
819  * @type:	attribute type to find
820  * @name:	attribute name to find (optional, i.e. NULL means don't care)
821  * @name_len:	attribute name length (only needed if @name present)
824  * @val:	attribute value to find (optional, resident attributes only)
825  * @val_len:	attribute value length
826  * @ctx:	search context with mft record and attribute to search from
831  * Find an attribute by searching the attribute list for the corresponding
832  * attribute list entry.  Having found the entry, map the mft record if the
833  * attribute is in a different mft record/inode, ntfs_attr_find() the attribute
841  * After finishing with the attribute/mft record you need to call
845  * If the attribute is found, ntfs_external_attr_find() returns 0 and
846  * @ctx->attr will point to the found attribute.  @ctx->mrec will point to the
848  * the attribute list entry for the attribute.
850  * If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and
851  * @ctx->attr will point to the attribute in the base mft record before which
852  * the attribute being searched for would need to be inserted if such an action
854  * @ctx->attr is located and @ctx->al_entry will point to the attribute list
855  * entry of the attribute before which the attribute being searched for would
858  * Thus to insert the not found attribute, one wants to add the attribute to
860  * attribute should be placed in a newly allocated extent mft record.  The
861  * attribute list entry for the inserted attribute should be inserted in the
862  * attribute list attribute at @ctx->al_entry.
900 	 * Iterate over entries in attribute list starting at @ctx->al_entry,  in ntfs_external_attr_find()
915 		/* Catch the end of the attribute list. */  in ntfs_external_attr_find()
931 		 * missing, assume we want an unnamed attribute.  in ntfs_external_attr_find()
947 			 * matching attribute.  in ntfs_external_attr_find()
971 		 * The names match or @name not present and attribute is  in ntfs_external_attr_find()
973 		 * next attribute list entry still fits @lowest_vcn.  Otherwise  in ntfs_external_attr_find()
994 						"reference in attribute list "  in ntfs_external_attr_find()
1036 		 * mft record containing the attribute represented by the  in ntfs_external_attr_find()
1041 		 * attribute in this mft record but this would be less  in ntfs_external_attr_find()
1043 		 * the attribute instance numbers for example which become  in ntfs_external_attr_find()
1044 		 * important when one plays with attribute lists.  Also,  in ntfs_external_attr_find()
1045 		 * because a proper match has been found in the attribute list  in ntfs_external_attr_find()
1066 		 * attribute list entry and the attribute record, there is  in ntfs_external_attr_find()
1090 		/* Proceed to the next attribute in the current mft record. */  in ntfs_external_attr_find()
1096 				"attribute list attribute.%s", base_ni->mft_no,  in ntfs_external_attr_find()
1121 	 * The attribute was not found.  Before we return, we want to ensure  in ntfs_external_attr_find()
1123 	 * attribute should be inserted in the base mft record.  Since we also  in ntfs_external_attr_find()
1145 	 * keep enumerating until we get an attribute not found response (or  in ntfs_external_attr_find()
1146 	 * another error), otherwise we would keep returning the same attribute  in ntfs_external_attr_find()
1159  * ntfs_attr_lookup - find an attribute in an ntfs inode
1160  * @type:	attribute type to find
1161  * @name:	attribute name to find (optional, i.e. NULL means don't care)
1162  * @name_len:	attribute name length (only needed if @name present)
1165  * @val:	attribute value to find (optional, resident attributes only)
1166  * @val_len:	attribute value length
1167  * @ctx:	search context with mft record and attribute to search from
1169  * Find an attribute in an ntfs inode.  On first search @ctx->ntfs_ino must
1173  * This function transparently handles attribute lists and @ctx is used to
1176  * After finishing with the attribute/mft record you need to call
1182  * When 0, @ctx->attr is the found attribute and it is in mft record
1183  * @ctx->mrec.  If an attribute list attribute is present, @ctx->al_entry is
1184  * the attribute list entry of the found attribute.
1186  * When -ENOENT, @ctx->attr is the attribute which collates just after the
1187  * attribute being searched for, i.e. if one wants to add the attribute to the
1188  * mft record this is the correct place to insert it into.  If an attribute
1189  * list attribute is present, @ctx->al_entry is the attribute list entry which
1190  * collates just after the attribute list entry of the attribute being searched
1191  * for, i.e. if one wants to add the attribute to the mft record this is the
1192  * correct place to insert its attribute list entry into.
1220  * ntfs_attr_init_search_ctx - initialize an attribute search context
1221  * @ctx:	attribute search context to initialize
1225  * Initialize the attribute search context @ctx with @ni and @mrec.
1241  * ntfs_attr_reinit_search_ctx - reinitialize an attribute search context
1242  * @ctx:	attribute search context to reinitialize
1244  * Reinitialize the attribute search context @ctx, unmapping an associated
1247  * This is used when a search for a new attribute is being started to reset
1253 		/* No attribute list. */  in ntfs_attr_reinit_search_ctx()
1264 	} /* Attribute list. */  in ntfs_attr_reinit_search_ctx()
1272  * ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context
1276  * Allocate a new attribute search context, initialize it with @ni and @mrec,
1290  * ntfs_attr_put_search_ctx - release an attribute search context
1291  * @ctx:	attribute search context to free
1293  * Release the attribute search context @ctx, unmapping an associated extent
1307  * ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file
1308  * @vol:	ntfs volume to which the attribute belongs
1309  * @type:	attribute type which to find
1311  * Search for the attribute definition record corresponding to the attribute
1314  * Return the attribute type definition record if found and NULL if not found.
1328 		/* We found the attribute; return it. */  in ntfs_attr_find_in_attrdef()
1334 	/* Attribute not found. */  in ntfs_attr_find_in_attrdef()
1335 	ntfs_debug("Attribute type 0x%x not found in $AttrDef.",  in ntfs_attr_find_in_attrdef()
1341  * ntfs_attr_size_bounds_check - check a size of an attribute type for validity
1342  * @vol:	ntfs volume to which the attribute belongs
1343  * @type:	attribute type which to check
1346  * Check whether the @size in bytes is valid for an attribute of @type on the
1349  * Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not
1364 	/* Get the $AttrDef entry for the attribute @type. */  in ntfs_attr_size_bounds_check()
1378  * ntfs_attr_can_be_non_resident - check if an attribute can be non-resident
1379  * @vol:	ntfs volume to which the attribute belongs
1380  * @type:	attribute type which to check
1382  * Check whether the attribute of @type on the ntfs volume @vol is allowed to
1385  * Return 0 if the attribute is allowed to be non-resident, -EPERM if not, and
1386  * -ENOENT if the attribute is not listed in $AttrDef.
1392 	/* Find the attribute definition record in $AttrDef. */  in ntfs_attr_can_be_non_resident()
1403  * ntfs_attr_can_be_resident - check if an attribute can be resident
1404  * @vol:	ntfs volume to which the attribute belongs
1405  * @type:	attribute type which to check
1407  * Check whether the attribute of @type on the ntfs volume @vol is allowed to
1413  * Return 0 if the attribute is allowed to be non-resident and -EPERM if not.
1415  * Warning: In the system file $MFT the attribute $Bitmap must be non-resident
1428  * ntfs_attr_record_resize - resize an attribute record
1429  * @m:		mft record containing attribute record
1430  * @a:		attribute record to resize
1431  * @new_size:	new size in bytes to which to resize the attribute record @a
1433  * Resize the attribute record @a, i.e. the resident part of the attribute, in
1451 	/* If the actual attribute length has changed, move things around. */  in ntfs_attr_record_resize()
1472  * ntfs_resident_attr_value_resize - resize the value of a resident attribute
1473  * @m:		mft record containing attribute record
1474  * @a:		attribute record whose value to resize
1475  * @new_size:	new size in bytes to which to resize the attribute value of @a
1477  * Resize the value of the attribute @a in the mft record @m to @new_size bytes.
1494 	/* Resize the resident part of the attribute record. */  in ntfs_resident_attr_value_resize()
1499 	 * The resize succeeded!  If we made the attribute value bigger, clear  in ntfs_resident_attr_value_resize()
1506 	/* Finally update the length of the attribute value. */  in ntfs_resident_attr_value_resize()
1512  * ntfs_attr_make_non_resident - convert a resident to a non-resident attribute
1513  * @ni:		ntfs inode describing the attribute to convert
1514  * @data_size:	size of the resident data to copy to the non-resident attribute
1516  * Convert the resident ntfs attribute described by the ntfs inode @ni to a
1519  * @data_size must be equal to the attribute value size.  This is needed since
1527  *	-EPERM	- The attribute is not allowed to be non-resident.
1530  *	-EINVAL	- Attribute not defined on the volume.
1537  * again in case the attribute may then fit in a resident state so no need to
1540  * NOTE to self: No changes in the attribute list are required to move from
1541  *		 a resident to a non-resident attribute.
1562 	/* Check that the attribute is allowed to be non-resident. */  in ntfs_attr_make_non_resident()
1566 			ntfs_debug("Attribute is not allowed to be "  in ntfs_attr_make_non_resident()
1569 			ntfs_debug("Attribute not defined on the NTFS "  in ntfs_attr_make_non_resident()
1594 		/* Start by allocating clusters to hold the attribute value. */  in ntfs_attr_make_non_resident()
1659 	 * attribute record.  in ntfs_attr_make_non_resident()
1664 	 * attribute value.  in ntfs_attr_make_non_resident()
1678 	/* Backup the attribute flag. */  in ntfs_attr_make_non_resident()
1680 	/* Resize the resident part of the attribute record. */  in ntfs_attr_make_non_resident()
1685 	 * Convert the resident part of the attribute record to describe a  in ntfs_attr_make_non_resident()
1686 	 * non-resident attribute.  in ntfs_attr_make_non_resident()
1689 	/* Move the attribute name if it exists and update the offset. */  in ntfs_attr_make_non_resident()
1713 	/* Generate the mapping pairs array into the attribute record. */  in ntfs_attr_make_non_resident()
1721 	/* Setup the in-memory attribute structure to be non-resident. */  in ntfs_attr_make_non_resident()
1766 	/* Convert the attribute back into a resident attribute. */  in ntfs_attr_make_non_resident()
1768 	/* Move the attribute name if it exists and update the offset. */  in ntfs_attr_make_non_resident()
1777 	/* Resize the resident part of the attribute record. */  in ntfs_attr_make_non_resident()
1783 		 * If the old size is too small, truncate the attribute,  in ntfs_attr_make_non_resident()
1793 					"to non-resident attribute "  in ntfs_attr_make_non_resident()
1795 					"attribute type 0x%x from %i bytes to "  in ntfs_attr_make_non_resident()
1803 					!ni->name_len) ? "FILE": "ATTRIBUTE");  in ntfs_attr_make_non_resident()
1816 	/* Copy the data from the page back to the attribute value. */  in ntfs_attr_make_non_resident()
1856  * ntfs_attr_extend_allocation - extend the allocated space of an attribute
1857  * @ni:			ntfs inode of the attribute whose allocation to extend
1862  * Extend the allocated space of an attribute described by the ntfs inode @ni
1871  * of the attribute is extended to @new_data_size.  Note that the i_size of the
1872  * vfs inode is not updated.  Only the data size in the base attribute record
1877  * For resident attributes this involves resizing the attribute record and if
1879  * converting the attribute to a non-resident attribute which in turn involves
1880  * extending the allocation of a non-resident attribute as described below.
1885  * updating the mapping pairs array of the attribute.  This in turn involves
1886  * resizing the attribute record and if necessary moving it and/or other
1887  * attributes into extent mft records and/or splitting the attribute record
1888  * into multiple extent attribute records.
1890  * Also, the attribute list attribute is updated if present and in some of the
1892  * an attribute list attribute is created if not already present.
1906  * attribute can be resized safely and so that it can for example be converted
1909  * TODO: At present attribute list attribute handling is not implemented.
1912  * than the $DATA attribute(s) of an uncompressed and unencrypted file.
1935 	ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "  in ntfs_attr_extend_allocation()
1967 						"of inode 0x%lx, attribute "  in ntfs_attr_extend_allocation()
1971 						"this attribute type.",  in ntfs_attr_extend_allocation()
1976 						"of inode 0x%lx, attribute "  in ntfs_attr_extend_allocation()
1978 						"attribute type is not "  in ntfs_attr_extend_allocation()
2025 	 * just converted the attribute from resident to non-resident it is  in ntfs_attr_extend_allocation()
2035 		 * We want the first attribute extent so that we can update the  in ntfs_attr_extend_allocation()
2053 	/* The total length of the attribute value. */  in ntfs_attr_extend_allocation()
2056 	 * Extend the attribute record to be able to store the new attribute  in ntfs_attr_extend_allocation()
2088 	 * Not enough space in the mft record, try to make the attribute  in ntfs_attr_extend_allocation()
2096 	 * permitted for this attribute type or there not being enough space,  in ntfs_attr_extend_allocation()
2106 					"inode 0x%lx, attribute type 0x%x, "  in ntfs_attr_extend_allocation()
2108 					"to non-resident attribute failed "  in ntfs_attr_extend_allocation()
2123 					"attribute value.  This case is not "  in ntfs_attr_extend_allocation()
2126 			ntfs_error(vol->sb, "This attribute type may not be "  in ntfs_attr_extend_allocation()
2137 	 * Both the attribute list attribute and the standard information  in ntfs_attr_extend_allocation()
2138 	 * attribute must remain in the base inode.  Thus, if this is one of  in ntfs_attr_extend_allocation()
2151 	// TODO: Attempt to move this attribute to an extent mft record, but  in ntfs_attr_extend_allocation()
2152 	// only if it is not already the only attribute in an mft record in  in ntfs_attr_extend_allocation()
2168 	 * $DATA attribute and sparse attributes are enabled on the volume and  in ntfs_attr_extend_allocation()
2188 	/* If this attribute extent is not mapped, map it now. */  in ntfs_attr_extend_allocation()
2199 						"of inode 0x%lx, attribute "  in ntfs_attr_extend_allocation()
2219 	 * there are no valid LCNs in the attribute we let the cluster  in ntfs_attr_extend_allocation()
2237 					"inode 0x%lx, attribute type 0x%x, "  in ntfs_attr_extend_allocation()
2250 					"inode 0x%lx, attribute type 0x%x, "  in ntfs_attr_extend_allocation()
2269 	/* Find the runlist element with which the attribute extent starts. */  in ntfs_attr_extend_allocation()
2282 					"inode 0x%lx, attribute type 0x%x, "  in ntfs_attr_extend_allocation()
2290 	/* Extend the attribute record to fit the bigger mapping pairs array. */  in ntfs_attr_extend_allocation()
2304 					"record for the extended attribute "  in ntfs_attr_extend_allocation()
2318 					"inode 0x%lx, attribute type 0x%x, "  in ntfs_attr_extend_allocation()
2329 	 * We now have extended the allocated size of the attribute.  Reflect  in ntfs_attr_extend_allocation()
2330 	 * this in the ntfs_inode structure and the attribute record.  in ntfs_attr_extend_allocation()
2334 		 * We are not in the first attribute extent, switch to it, but  in ntfs_attr_extend_allocation()
2356 	 * regular files, and only for their $DATA attribute(s).  in ntfs_attr_extend_allocation()
2388 				"of inode 0x%lx, attribute type 0x%x, because "  in ntfs_attr_extend_allocation()
2389 				"lookup of first attribute extent failed with "  in ntfs_attr_extend_allocation()
2398 		ntfs_error(vol->sb, "Failed to find last attribute extent of "  in ntfs_attr_extend_allocation()
2399 				"attribute in error code path.  Run chkdsk to "  in ntfs_attr_extend_allocation()
2420 		 * base attribute extent which chkdsk should be able to fix.  in ntfs_attr_extend_allocation()
2439 	 * longer valid, we cannot resize the attribute record or build the  in ntfs_attr_extend_allocation()
2446 				"restore attribute search context" :  in ntfs_attr_extend_allocation()
2447 				"truncate attribute runlist");  in ntfs_attr_extend_allocation()
2451 			ntfs_error(vol->sb, "Failed to restore attribute "  in ntfs_attr_extend_allocation()
2484  * ntfs_attr_set - fill (a part of) an attribute with a byte
2485  * @ni:		ntfs inode describing the attribute to fill
2486  * @ofs:	offset inside the attribute at which to start to fill
2488  * @val:	the unsigned 8-bit value with which to fill the attribute
2490  * Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at
2491  * byte offset @ofs inside the attribute with the constant byte @val.
2493  * This function is effectively like memset() applied to an ntfs attribute.
2495  * to the ntfs attribute and it marks them dirty after doing the memset().
2500  * that @ofs + @cnt were outside the end of the attribute and no write was
2533 		ntfs_error(vol->sb, "Request exceeds end of attribute.");  in ntfs_attr_set()