/**
- * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project.
+ * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project.
*
* Copyright (c) 2001-2004 Anton Altaparmakov
* Copyright (c) 2002 Richard Russon
*/
#include <linux/buffer_head.h>
-#include "ntfs.h"
-#include "dir.h"
-
-/* Temporary helper functions -- might become macros */
-
-/**
- * ntfs_rl_mm - runlist memmove
- *
- * It is up to the caller to serialize access to the runlist @base.
- */
-static inline void ntfs_rl_mm(runlist_element *base, int dst, int src,
- int size)
-{
- if (likely((dst != src) && (size > 0)))
- memmove(base + dst, base + src, size * sizeof (*base));
-}
-
-/**
- * ntfs_rl_mc - runlist memory copy
- *
- * It is up to the caller to serialize access to the runlists @dstbase and
- * @srcbase.
- */
-static inline void ntfs_rl_mc(runlist_element *dstbase, int dst,
- runlist_element *srcbase, int src, int size)
-{
- if (likely(size > 0))
- memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase));
-}
-
-/**
- * ntfs_rl_realloc - Reallocate memory for runlists
- * @rl: original runlist
- * @old_size: number of runlist elements in the original runlist @rl
- * @new_size: number of runlist elements we need space for
- *
- * As the runlists grow, more memory will be required. To prevent the
- * kernel having to allocate and reallocate large numbers of small bits of
- * memory, this function returns and entire page of memory.
- *
- * It is up to the caller to serialize access to the runlist @rl.
- *
- * N.B. If the new allocation doesn't require a different number of pages in
- * memory, the function will return the original pointer.
- *
- * On success, return a pointer to the newly allocated, or recycled, memory.
- * On error, return -errno. The following error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EINVAL - Invalid parameters were passed in.
- */
-static inline runlist_element *ntfs_rl_realloc(runlist_element *rl,
- int old_size, int new_size)
-{
- runlist_element *new_rl;
-
- old_size = PAGE_ALIGN(old_size * sizeof(*rl));
- new_size = PAGE_ALIGN(new_size * sizeof(*rl));
- if (old_size == new_size)
- return rl;
-
- new_rl = ntfs_malloc_nofs(new_size);
- if (unlikely(!new_rl))
- return ERR_PTR(-ENOMEM);
-
- if (likely(rl != NULL)) {
- if (unlikely(old_size > new_size))
- old_size = new_size;
- memcpy(new_rl, rl, old_size);
- ntfs_free(rl);
- }
- return new_rl;
-}
-
-/**
- * ntfs_are_rl_mergeable - test if two runlists can be joined together
- * @dst: original runlist
- * @src: new runlist to test for mergeability with @dst
- *
- * Test if two runlists can be joined together. For this, their VCNs and LCNs
- * must be adjacent.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- *
- * Return: TRUE Success, the runlists can be merged.
- * FALSE Failure, the runlists cannot be merged.
- */
-static inline BOOL ntfs_are_rl_mergeable(runlist_element *dst,
- runlist_element *src)
-{
- BUG_ON(!dst);
- BUG_ON(!src);
-
- if ((dst->lcn < 0) || (src->lcn < 0)) /* Are we merging holes? */
- return FALSE;
- if ((dst->lcn + dst->length) != src->lcn) /* Are the runs contiguous? */
- return FALSE;
- if ((dst->vcn + dst->length) != src->vcn) /* Are the runs misaligned? */
- return FALSE;
-
- return TRUE;
-}
-
-/**
- * __ntfs_rl_merge - merge two runlists without testing if they can be merged
- * @dst: original, destination runlist
- * @src: new runlist to merge with @dst
- *
- * Merge the two runlists, writing into the destination runlist @dst. The
- * caller must make sure the runlists can be merged or this will corrupt the
- * destination runlist.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- */
-static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src)
-{
- dst->length += src->length;
-}
-
-/**
- * ntfs_rl_merge - test if two runlists can be joined together and merge them
- * @dst: original, destination runlist
- * @src: new runlist to merge with @dst
- *
- * Test if two runlists can be joined together. For this, their VCNs and LCNs
- * must be adjacent. If they can be merged, perform the merge, writing into
- * the destination runlist @dst.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- *
- * Return: TRUE Success, the runlists have been merged.
- * FALSE Failure, the runlists cannot be merged and have not been
- * modified.
- */
-static inline BOOL ntfs_rl_merge(runlist_element *dst, runlist_element *src)
-{
- BOOL merge = ntfs_are_rl_mergeable(dst, src);
-
- if (merge)
- __ntfs_rl_merge(dst, src);
- return merge;
-}
-
-/**
- * ntfs_rl_append - append a runlist after a given element
- * @dst: original runlist to be worked on
- * @dsize: number of elements in @dst (including end marker)
- * @src: runlist to be inserted into @dst
- * @ssize: number of elements in @src (excluding end marker)
- * @loc: append the new runlist @src after this element in @dst
- *
- * Append the runlist @src after element @loc in @dst. Merge the right end of
- * the new runlist, if necessary. Adjust the size of the hole before the
- * appended runlist.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- *
- * On success, return a pointer to the new, combined, runlist. Note, both
- * runlists @dst and @src are deallocated before returning so you cannot use
- * the pointers for anything any more. (Strictly speaking the returned runlist
- * may be the same as @dst but this is irrelevant.)
- *
- * On error, return -errno. Both runlists are left unmodified. The following
- * error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EINVAL - Invalid parameters were passed in.
- */
-static inline runlist_element *ntfs_rl_append(runlist_element *dst,
- int dsize, runlist_element *src, int ssize, int loc)
-{
- BOOL right;
- int magic;
-
- BUG_ON(!dst);
- BUG_ON(!src);
-
- /* First, check if the right hand end needs merging. */
- right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
-
- /* Space required: @dst size + @src size, less one if we merged. */
- dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right);
- if (IS_ERR(dst))
- return dst;
- /*
- * We are guaranteed to succeed from here so can start modifying the
- * original runlists.
- */
-
- /* First, merge the right hand end, if necessary. */
- if (right)
- __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
-
- magic = loc + ssize;
-
- /* Move the tail of @dst out of the way, then copy in @src. */
- ntfs_rl_mm(dst, magic + 1, loc + 1 + right, dsize - loc - 1 - right);
- ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
-
- /* Adjust the size of the preceding hole. */
- dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
-
- /* We may have changed the length of the file, so fix the end marker */
- if (dst[magic + 1].lcn == LCN_ENOENT)
- dst[magic + 1].vcn = dst[magic].vcn + dst[magic].length;
-
- return dst;
-}
-
-/**
- * ntfs_rl_insert - insert a runlist into another
- * @dst: original runlist to be worked on
- * @dsize: number of elements in @dst (including end marker)
- * @src: new runlist to be inserted
- * @ssize: number of elements in @src (excluding end marker)
- * @loc: insert the new runlist @src before this element in @dst
- *
- * Insert the runlist @src before element @loc in the runlist @dst. Merge the
- * left end of the new runlist, if necessary. Adjust the size of the hole
- * after the inserted runlist.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- *
- * On success, return a pointer to the new, combined, runlist. Note, both
- * runlists @dst and @src are deallocated before returning so you cannot use
- * the pointers for anything any more. (Strictly speaking the returned runlist
- * may be the same as @dst but this is irrelevant.)
- *
- * On error, return -errno. Both runlists are left unmodified. The following
- * error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EINVAL - Invalid parameters were passed in.
- */
-static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
- int dsize, runlist_element *src, int ssize, int loc)
-{
- BOOL left = FALSE;
- BOOL disc = FALSE; /* Discontinuity */
- BOOL hole = FALSE; /* Following a hole */
- int magic;
-
- BUG_ON(!dst);
- BUG_ON(!src);
-
- /* disc => Discontinuity between the end of @dst and the start of @src.
- * This means we might need to insert a hole.
- * hole => @dst ends with a hole or an unmapped region which we can
- * extend to match the discontinuity. */
- if (loc == 0)
- disc = (src[0].vcn > 0);
- else {
- s64 merged_length;
-
- left = ntfs_are_rl_mergeable(dst + loc - 1, src);
-
- merged_length = dst[loc - 1].length;
- if (left)
- merged_length += src->length;
-
- disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
- if (disc)
- hole = (dst[loc - 1].lcn == LCN_HOLE);
- }
-
- /* Space required: @dst size + @src size, less one if we merged, plus
- * one if there was a discontinuity, less one for a trailing hole. */
- dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc - hole);
- if (IS_ERR(dst))
- return dst;
- /*
- * We are guaranteed to succeed from here so can start modifying the
- * original runlist.
- */
-
- if (left)
- __ntfs_rl_merge(dst + loc - 1, src);
-
- magic = loc + ssize - left + disc - hole;
-
- /* Move the tail of @dst out of the way, then copy in @src. */
- ntfs_rl_mm(dst, magic, loc, dsize - loc);
- ntfs_rl_mc(dst, loc + disc - hole, src, left, ssize - left);
-
- /* Adjust the VCN of the last run ... */
- if (dst[magic].lcn <= LCN_HOLE)
- dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
- /* ... and the length. */
- if (dst[magic].lcn == LCN_HOLE || dst[magic].lcn == LCN_RL_NOT_MAPPED)
- dst[magic].length = dst[magic + 1].vcn - dst[magic].vcn;
-
- /* Writing beyond the end of the file and there's a discontinuity. */
- if (disc) {
- if (hole)
- dst[loc - 1].length = dst[loc].vcn - dst[loc - 1].vcn;
- else {
- if (loc > 0) {
- dst[loc].vcn = dst[loc - 1].vcn +
- dst[loc - 1].length;
- dst[loc].length = dst[loc + 1].vcn -
- dst[loc].vcn;
- } else {
- dst[loc].vcn = 0;
- dst[loc].length = dst[loc + 1].vcn;
- }
- dst[loc].lcn = LCN_RL_NOT_MAPPED;
- }
-
- magic += hole;
-
- if (dst[magic].lcn == LCN_ENOENT)
- dst[magic].vcn = dst[magic - 1].vcn +
- dst[magic - 1].length;
- }
- return dst;
-}
-
-/**
- * ntfs_rl_replace - overwrite a runlist element with another runlist
- * @dst: original runlist to be worked on
- * @dsize: number of elements in @dst (including end marker)
- * @src: new runlist to be inserted
- * @ssize: number of elements in @src (excluding end marker)
- * @loc: index in runlist @dst to overwrite with @src
- *
- * Replace the runlist element @dst at @loc with @src. Merge the left and
- * right ends of the inserted runlist, if necessary.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- *
- * On success, return a pointer to the new, combined, runlist. Note, both
- * runlists @dst and @src are deallocated before returning so you cannot use
- * the pointers for anything any more. (Strictly speaking the returned runlist
- * may be the same as @dst but this is irrelevant.)
- *
- * On error, return -errno. Both runlists are left unmodified. The following
- * error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EINVAL - Invalid parameters were passed in.
- */
-static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
- int dsize, runlist_element *src, int ssize, int loc)
-{
- BOOL left = FALSE;
- BOOL right;
- int magic;
-
- BUG_ON(!dst);
- BUG_ON(!src);
-
- /* First, merge the left and right ends, if necessary. */
- right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
- if (loc > 0)
- left = ntfs_are_rl_mergeable(dst + loc - 1, src);
-
- /* Allocate some space. We'll need less if the left, right, or both
- * ends were merged. */
- dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right);
- if (IS_ERR(dst))
- return dst;
- /*
- * We are guaranteed to succeed from here so can start modifying the
- * original runlists.
- */
- if (right)
- __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
- if (left)
- __ntfs_rl_merge(dst + loc - 1, src);
-
- /* FIXME: What does this mean? (AIA) */
- magic = loc + ssize - left;
-
- /* Move the tail of @dst out of the way, then copy in @src. */
- ntfs_rl_mm(dst, magic, loc + right + 1, dsize - loc - right - 1);
- ntfs_rl_mc(dst, loc, src, left, ssize - left);
-
- /* We may have changed the length of the file, so fix the end marker */
- if (dst[magic].lcn == LCN_ENOENT)
- dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
- return dst;
-}
-
-/**
- * ntfs_rl_split - insert a runlist into the centre of a hole
- * @dst: original runlist to be worked on
- * @dsize: number of elements in @dst (including end marker)
- * @src: new runlist to be inserted
- * @ssize: number of elements in @src (excluding end marker)
- * @loc: index in runlist @dst at which to split and insert @src
- *
- * Split the runlist @dst at @loc into two and insert @new in between the two
- * fragments. No merging of runlists is necessary. Adjust the size of the
- * holes either side.
- *
- * It is up to the caller to serialize access to the runlists @dst and @src.
- *
- * On success, return a pointer to the new, combined, runlist. Note, both
- * runlists @dst and @src are deallocated before returning so you cannot use
- * the pointers for anything any more. (Strictly speaking the returned runlist
- * may be the same as @dst but this is irrelevant.)
- *
- * On error, return -errno. Both runlists are left unmodified. The following
- * error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EINVAL - Invalid parameters were passed in.
- */
-static inline runlist_element *ntfs_rl_split(runlist_element *dst, int dsize,
- runlist_element *src, int ssize, int loc)
-{
- BUG_ON(!dst);
- BUG_ON(!src);
-
- /* Space required: @dst size + @src size + one new hole. */
- dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1);
- if (IS_ERR(dst))
- return dst;
- /*
- * We are guaranteed to succeed from here so can start modifying the
- * original runlists.
- */
-
- /* Move the tail of @dst out of the way, then copy in @src. */
- ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc);
- ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
-
- /* Adjust the size of the holes either size of @src. */
- dst[loc].length = dst[loc+1].vcn - dst[loc].vcn;
- dst[loc+ssize+1].vcn = dst[loc+ssize].vcn + dst[loc+ssize].length;
- dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn;
-
- return dst;
-}
-
-/**
- * ntfs_merge_runlists - merge two runlists into one
- * @drl: original runlist to be worked on
- * @srl: new runlist to be merged into @drl
- *
- * First we sanity check the two runlists @srl and @drl to make sure that they
- * are sensible and can be merged. The runlist @srl must be either after the
- * runlist @drl or completely within a hole (or unmapped region) in @drl.
- *
- * It is up to the caller to serialize access to the runlists @drl and @srl.
- *
- * Merging of runlists is necessary in two cases:
- * 1. When attribute lists are used and a further extent is being mapped.
- * 2. When new clusters are allocated to fill a hole or extend a file.
- *
- * There are four possible ways @srl can be merged. It can:
- * - be inserted at the beginning of a hole,
- * - split the hole in two and be inserted between the two fragments,
- * - be appended at the end of a hole, or it can
- * - replace the whole hole.
- * It can also be appended to the end of the runlist, which is just a variant
- * of the insert case.
- *
- * On success, return a pointer to the new, combined, runlist. Note, both
- * runlists @drl and @srl are deallocated before returning so you cannot use
- * the pointers for anything any more. (Strictly speaking the returned runlist
- * may be the same as @dst but this is irrelevant.)
- *
- * On error, return -errno. Both runlists are left unmodified. The following
- * error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EINVAL - Invalid parameters were passed in.
- * -ERANGE - The runlists overlap and cannot be merged.
- */
-runlist_element *ntfs_merge_runlists(runlist_element *drl,
- runlist_element *srl)
-{
- int di, si; /* Current index into @[ds]rl. */
- int sstart; /* First index with lcn > LCN_RL_NOT_MAPPED. */
- int dins; /* Index into @drl at which to insert @srl. */
- int dend, send; /* Last index into @[ds]rl. */
- int dfinal, sfinal; /* The last index into @[ds]rl with
- lcn >= LCN_HOLE. */
- int marker = 0;
- VCN marker_vcn = 0;
-
-#ifdef DEBUG
- ntfs_debug("dst:");
- ntfs_debug_dump_runlist(drl);
- ntfs_debug("src:");
- ntfs_debug_dump_runlist(srl);
-#endif
-
- /* Check for silly calling... */
- if (unlikely(!srl))
- return drl;
- if (IS_ERR(srl) || IS_ERR(drl))
- return ERR_PTR(-EINVAL);
-
- /* Check for the case where the first mapping is being done now. */
- if (unlikely(!drl)) {
- drl = srl;
- /* Complete the source runlist if necessary. */
- if (unlikely(drl[0].vcn)) {
- /* Scan to the end of the source runlist. */
- for (dend = 0; likely(drl[dend].length); dend++)
- ;
- drl = ntfs_rl_realloc(drl, dend, dend + 1);
- if (IS_ERR(drl))
- return drl;
- /* Insert start element at the front of the runlist. */
- ntfs_rl_mm(drl, 1, 0, dend);
- drl[0].vcn = 0;
- drl[0].lcn = LCN_RL_NOT_MAPPED;
- drl[0].length = drl[1].vcn;
- }
- goto finished;
- }
-
- si = di = 0;
-
- /* Skip any unmapped start element(s) in the source runlist. */
- while (srl[si].length && srl[si].lcn < (LCN)LCN_HOLE)
- si++;
-
- /* Can't have an entirely unmapped source runlist. */
- BUG_ON(!srl[si].length);
-
- /* Record the starting points. */
- sstart = si;
-
- /*
- * Skip forward in @drl until we reach the position where @srl needs to
- * be inserted. If we reach the end of @drl, @srl just needs to be
- * appended to @drl.
- */
- for (; drl[di].length; di++) {
- if (drl[di].vcn + drl[di].length > srl[sstart].vcn)
- break;
- }
- dins = di;
-
- /* Sanity check for illegal overlaps. */
- if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) &&
- (srl[si].lcn >= 0)) {
- ntfs_error(NULL, "Run lists overlap. Cannot merge!");
- return ERR_PTR(-ERANGE);
- }
-
- /* Scan to the end of both runlists in order to know their sizes. */
- for (send = si; srl[send].length; send++)
- ;
- for (dend = di; drl[dend].length; dend++)
- ;
-
- if (srl[send].lcn == (LCN)LCN_ENOENT)
- marker_vcn = srl[marker = send].vcn;
-
- /* Scan to the last element with lcn >= LCN_HOLE. */
- for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--)
- ;
- for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--)
- ;
-
- {
- BOOL start;
- BOOL finish;
- int ds = dend + 1; /* Number of elements in drl & srl */
- int ss = sfinal - sstart + 1;
-
- start = ((drl[dins].lcn < LCN_RL_NOT_MAPPED) || /* End of file */
- (drl[dins].vcn == srl[sstart].vcn)); /* Start of hole */
- finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) && /* End of file */
- ((drl[dins].vcn + drl[dins].length) <= /* End of hole */
- (srl[send - 1].vcn + srl[send - 1].length)));
-
- /* Or we'll lose an end marker */
- if (start && finish && (drl[dins].length == 0))
- ss++;
- if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn))
- finish = FALSE;
-#if 0
- ntfs_debug("dfinal = %i, dend = %i", dfinal, dend);
- ntfs_debug("sstart = %i, sfinal = %i, send = %i", sstart, sfinal, send);
- ntfs_debug("start = %i, finish = %i", start, finish);
- ntfs_debug("ds = %i, ss = %i, dins = %i", ds, ss, dins);
-#endif
- if (start) {
- if (finish)
- drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins);
- else
- drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins);
- } else {
- if (finish)
- drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins);
- else
- drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins);
- }
- if (IS_ERR(drl)) {
- ntfs_error(NULL, "Merge failed.");
- return drl;
- }
- ntfs_free(srl);
- if (marker) {
- ntfs_debug("Triggering marker code.");
- for (ds = dend; drl[ds].length; ds++)
- ;
- /* We only need to care if @srl ended after @drl. */
- if (drl[ds].vcn <= marker_vcn) {
- int slots = 0;
-
- if (drl[ds].vcn == marker_vcn) {
- ntfs_debug("Old marker = 0x%llx, replacing "
- "with LCN_ENOENT.",
- (unsigned long long)
- drl[ds].lcn);
- drl[ds].lcn = (LCN)LCN_ENOENT;
- goto finished;
- }
- /*
- * We need to create an unmapped runlist element in
- * @drl or extend an existing one before adding the
- * ENOENT terminator.
- */
- if (drl[ds].lcn == (LCN)LCN_ENOENT) {
- ds--;
- slots = 1;
- }
- if (drl[ds].lcn != (LCN)LCN_RL_NOT_MAPPED) {
- /* Add an unmapped runlist element. */
- if (!slots) {
- /* FIXME/TODO: We need to have the
- * extra memory already! (AIA) */
- drl = ntfs_rl_realloc(drl, ds, ds + 2);
- if (!drl)
- goto critical_error;
- slots = 2;
- }
- ds++;
- /* Need to set vcn if it isn't set already. */
- if (slots != 1)
- drl[ds].vcn = drl[ds - 1].vcn +
- drl[ds - 1].length;
- drl[ds].lcn = (LCN)LCN_RL_NOT_MAPPED;
- /* We now used up a slot. */
- slots--;
- }
- drl[ds].length = marker_vcn - drl[ds].vcn;
- /* Finally add the ENOENT terminator. */
- ds++;
- if (!slots) {
- /* FIXME/TODO: We need to have the extra
- * memory already! (AIA) */
- drl = ntfs_rl_realloc(drl, ds, ds + 1);
- if (!drl)
- goto critical_error;
- }
- drl[ds].vcn = marker_vcn;
- drl[ds].lcn = (LCN)LCN_ENOENT;
- drl[ds].length = (s64)0;
- }
- }
- }
-
-finished:
- /* The merge was completed successfully. */
- ntfs_debug("Merged runlist:");
- ntfs_debug_dump_runlist(drl);
- return drl;
-
-critical_error:
- /* Critical error! We cannot afford to fail here. */
- ntfs_error(NULL, "Critical error! Not enough memory.");
- panic("NTFS: Cannot continue.");
-}
-
-/**
- * decompress_mapping_pairs - convert mapping pairs array to runlist
- * @vol: ntfs volume on which the attribute resides
- * @attr: attribute record whose mapping pairs array to decompress
- * @old_rl: optional runlist in which to insert @attr's runlist
- *
- * It is up to the caller to serialize access to the runlist @old_rl.
- *
- * Decompress the attribute @attr's mapping pairs array into a runlist. On
- * success, return the decompressed runlist.
- *
- * If @old_rl is not NULL, decompressed runlist is inserted into the
- * appropriate place in @old_rl and the resultant, combined runlist is
- * returned. The original @old_rl is deallocated.
- *
- * On error, return -errno. @old_rl is left unmodified in that case.
- *
- * The following error codes are defined:
- * -ENOMEM - Not enough memory to allocate runlist array.
- * -EIO - Corrupt runlist.
- * -EINVAL - Invalid parameters were passed in.
- * -ERANGE - The two runlists overlap.
- *
- * FIXME: For now we take the conceptionally simplest approach of creating the
- * new runlist disregarding the already existing one and then splicing the
- * two into one, if that is possible (we check for overlap and discard the new
- * runlist if overlap present before returning ERR_PTR(-ERANGE)).
- */
-runlist_element *decompress_mapping_pairs(const ntfs_volume *vol,
- const ATTR_RECORD *attr, runlist_element *old_rl)
-{
- VCN vcn; /* Current vcn. */
- LCN lcn; /* Current lcn. */
- s64 deltaxcn; /* Change in [vl]cn. */
- runlist_element *rl; /* The output runlist. */
- u8 *buf; /* Current position in mapping pairs array. */
- u8 *attr_end; /* End of attribute. */
- int rlsize; /* Size of runlist buffer. */
- u16 rlpos; /* Current runlist position in units of
- runlist_elements. */
- u8 b; /* Current byte offset in buf. */
-
-#ifdef DEBUG
- /* Make sure attr exists and is non-resident. */
- if (!attr || !attr->non_resident || sle64_to_cpu(
- attr->data.non_resident.lowest_vcn) < (VCN)0) {
- ntfs_error(vol->sb, "Invalid arguments.");
- return ERR_PTR(-EINVAL);
- }
-#endif
- /* Start at vcn = lowest_vcn and lcn 0. */
- vcn = sle64_to_cpu(attr->data.non_resident.lowest_vcn);
- lcn = 0;
- /* Get start of the mapping pairs array. */
- buf = (u8*)attr + le16_to_cpu(
- attr->data.non_resident.mapping_pairs_offset);
- attr_end = (u8*)attr + le32_to_cpu(attr->length);
- if (unlikely(buf < (u8*)attr || buf > attr_end)) {
- ntfs_error(vol->sb, "Corrupt attribute.");
- return ERR_PTR(-EIO);
- }
- /* Current position in runlist array. */
- rlpos = 0;
- /* Allocate first page and set current runlist size to one page. */
- rl = ntfs_malloc_nofs(rlsize = PAGE_SIZE);
- if (unlikely(!rl))
- return ERR_PTR(-ENOMEM);
- /* Insert unmapped starting element if necessary. */
- if (vcn) {
- rl->vcn = (VCN)0;
- rl->lcn = (LCN)LCN_RL_NOT_MAPPED;
- rl->length = vcn;
- rlpos++;
- }
- while (buf < attr_end && *buf) {
- /*
- * Allocate more memory if needed, including space for the
- * not-mapped and terminator elements. ntfs_malloc_nofs()
- * operates on whole pages only.
- */
- if (((rlpos + 3) * sizeof(*old_rl)) > rlsize) {
- runlist_element *rl2;
-
- rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
- if (unlikely(!rl2)) {
- ntfs_free(rl);
- return ERR_PTR(-ENOMEM);
- }
- memcpy(rl2, rl, rlsize);
- ntfs_free(rl);
- rl = rl2;
- rlsize += PAGE_SIZE;
- }
- /* Enter the current vcn into the current runlist element. */
- rl[rlpos].vcn = vcn;
- /*
- * Get the change in vcn, i.e. the run length in clusters.
- * Doing it this way ensures that we signextend negative values.
- * A negative run length doesn't make any sense, but hey, I
- * didn't make up the NTFS specs and Windows NT4 treats the run
- * length as a signed value so that's how it is...
- */
- b = *buf & 0xf;
- if (b) {
- if (unlikely(buf + b > attr_end))
- goto io_error;
- for (deltaxcn = (s8)buf[b--]; b; b--)
- deltaxcn = (deltaxcn << 8) + buf[b];
- } else { /* The length entry is compulsory. */
- ntfs_error(vol->sb, "Missing length entry in mapping "
- "pairs array.");
- deltaxcn = (s64)-1;
- }
- /*
- * Assume a negative length to indicate data corruption and
- * hence clean-up and return NULL.
- */
- if (unlikely(deltaxcn < 0)) {
- ntfs_error(vol->sb, "Invalid length in mapping pairs "
- "array.");
- goto err_out;
- }
- /*
- * Enter the current run length into the current runlist
- * element.
- */
- rl[rlpos].length = deltaxcn;
- /* Increment the current vcn by the current run length. */
- vcn += deltaxcn;
- /*
- * There might be no lcn change at all, as is the case for
- * sparse clusters on NTFS 3.0+, in which case we set the lcn
- * to LCN_HOLE.
- */
- if (!(*buf & 0xf0))
- rl[rlpos].lcn = (LCN)LCN_HOLE;
- else {
- /* Get the lcn change which really can be negative. */
- u8 b2 = *buf & 0xf;
- b = b2 + ((*buf >> 4) & 0xf);
- if (buf + b > attr_end)
- goto io_error;
- for (deltaxcn = (s8)buf[b--]; b > b2; b--)
- deltaxcn = (deltaxcn << 8) + buf[b];
- /* Change the current lcn to its new value. */
- lcn += deltaxcn;
-#ifdef DEBUG
- /*
- * On NTFS 1.2-, apparently can have lcn == -1 to
- * indicate a hole. But we haven't verified ourselves
- * whether it is really the lcn or the deltaxcn that is
- * -1. So if either is found give us a message so we
- * can investigate it further!
- */
- if (vol->major_ver < 3) {
- if (unlikely(deltaxcn == (LCN)-1))
- ntfs_error(vol->sb, "lcn delta == -1");
- if (unlikely(lcn == (LCN)-1))
- ntfs_error(vol->sb, "lcn == -1");
- }
-#endif
- /* Check lcn is not below -1. */
- if (unlikely(lcn < (LCN)-1)) {
- ntfs_error(vol->sb, "Invalid LCN < -1 in "
- "mapping pairs array.");
- goto err_out;
- }
- /* Enter the current lcn into the runlist element. */
- rl[rlpos].lcn = lcn;
- }
- /* Get to the next runlist element. */
- rlpos++;
- /* Increment the buffer position to the next mapping pair. */
- buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1;
- }
- if (unlikely(buf >= attr_end))
- goto io_error;
- /*
- * If there is a highest_vcn specified, it must be equal to the final
- * vcn in the runlist - 1, or something has gone badly wrong.
- */
- deltaxcn = sle64_to_cpu(attr->data.non_resident.highest_vcn);
- if (unlikely(deltaxcn && vcn - 1 != deltaxcn)) {
-mpa_err:
- ntfs_error(vol->sb, "Corrupt mapping pairs array in "
- "non-resident attribute.");
- goto err_out;
- }
- /* Setup not mapped runlist element if this is the base extent. */
- if (!attr->data.non_resident.lowest_vcn) {
- VCN max_cluster;
-
- max_cluster = (sle64_to_cpu(
- attr->data.non_resident.allocated_size) +
- vol->cluster_size - 1) >>
- vol->cluster_size_bits;
- /*
- * If there is a difference between the highest_vcn and the
- * highest cluster, the runlist is either corrupt or, more
- * likely, there are more extents following this one.
- */
- if (deltaxcn < --max_cluster) {
- ntfs_debug("More extents to follow; deltaxcn = 0x%llx, "
- "max_cluster = 0x%llx",
- (unsigned long long)deltaxcn,
- (unsigned long long)max_cluster);
- rl[rlpos].vcn = vcn;
- vcn += rl[rlpos].length = max_cluster - deltaxcn;
- rl[rlpos].lcn = (LCN)LCN_RL_NOT_MAPPED;
- rlpos++;
- } else if (unlikely(deltaxcn > max_cluster)) {
- ntfs_error(vol->sb, "Corrupt attribute. deltaxcn = "
- "0x%llx, max_cluster = 0x%llx",
- (unsigned long long)deltaxcn,
- (unsigned long long)max_cluster);
- goto mpa_err;
- }
- rl[rlpos].lcn = (LCN)LCN_ENOENT;
- } else /* Not the base extent. There may be more extents to follow. */
- rl[rlpos].lcn = (LCN)LCN_RL_NOT_MAPPED;
- /* Setup terminating runlist element. */
- rl[rlpos].vcn = vcn;
- rl[rlpos].length = (s64)0;
- /* If no existing runlist was specified, we are done. */
- if (!old_rl) {
- ntfs_debug("Mapping pairs array successfully decompressed:");
- ntfs_debug_dump_runlist(rl);
- return rl;
- }
- /* Now combine the new and old runlists checking for overlaps. */
- old_rl = ntfs_merge_runlists(old_rl, rl);
- if (likely(!IS_ERR(old_rl)))
- return old_rl;
- ntfs_free(rl);
- ntfs_error(vol->sb, "Failed to merge runlists.");
- return old_rl;
-io_error:
- ntfs_error(vol->sb, "Corrupt attribute.");
-err_out:
- ntfs_free(rl);
- return ERR_PTR(-EIO);
-}
+#include "attrib.h"
+#include "debug.h"
+#include "layout.h"
+#include "mft.h"
+#include "ntfs.h"
+#include "types.h"
/**
* ntfs_map_runlist - map (a part of) a runlist of an ntfs inode
down_write(&ni->runlist.lock);
/* Make sure someone else didn't do the work while we were sleeping. */
- if (likely(ntfs_vcn_to_lcn(ni->runlist.rl, vcn) <= LCN_RL_NOT_MAPPED)) {
+ if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
+ LCN_RL_NOT_MAPPED)) {
runlist_element *rl;
- rl = decompress_mapping_pairs(ni->vol, ctx->attr,
+ rl = ntfs_mapping_pairs_decompress(ni->vol, ctx->attr,
ni->runlist.rl);
if (IS_ERR(rl))
err = PTR_ERR(rl);
return err;
}
-/**
- * ntfs_vcn_to_lcn - convert a vcn into a lcn given a runlist
- * @rl: runlist to use for conversion
- * @vcn: vcn to convert
- *
- * Convert the virtual cluster number @vcn of an attribute into a logical
- * cluster number (lcn) of a device using the runlist @rl to map vcns to their
- * corresponding lcns.
- *
- * It is up to the caller to serialize access to the runlist @rl.
- *
- * Since lcns must be >= 0, we use negative return values with special meaning:
- *
- * Return value Meaning / Description
- * ==================================================
- * -1 = LCN_HOLE Hole / not allocated on disk.
- * -2 = LCN_RL_NOT_MAPPED This is part of the runlist which has not been
- * inserted into the runlist yet.
- * -3 = LCN_ENOENT There is no such vcn in the attribute.
- *
- * Locking: - The caller must have locked the runlist (for reading or writing).
- * - This function does not touch the lock.
- */
-LCN ntfs_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
-{
- int i;
-
- BUG_ON(vcn < 0);
- /*
- * If rl is NULL, assume that we have found an unmapped runlist. The
- * caller can then attempt to map it and fail appropriately if
- * necessary.
- */
- if (unlikely(!rl))
- return (LCN)LCN_RL_NOT_MAPPED;
-
- /* Catch out of lower bounds vcn. */
- if (unlikely(vcn < rl[0].vcn))
- return (LCN)LCN_ENOENT;
-
- for (i = 0; likely(rl[i].length); i++) {
- if (unlikely(vcn < rl[i+1].vcn)) {
- if (likely(rl[i].lcn >= (LCN)0))
- return rl[i].lcn + (vcn - rl[i].vcn);
- return rl[i].lcn;
- }
- }
- /*
- * The terminator element is setup to the correct value, i.e. one of
- * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
- */
- if (likely(rl[i].lcn < (LCN)0))
- return rl[i].lcn;
- /* Just in case... We could replace this with BUG() some day. */
- return (LCN)LCN_ENOENT;
-}
-
/**
* ntfs_find_vcn - find a vcn in the runlist described by an ntfs inode
* @ni: ntfs inode describing the runlist to search
if (likely(rl && vcn >= rl[0].vcn)) {
while (likely(rl->length)) {
if (likely(vcn < rl[1].vcn)) {
- if (likely(rl->lcn >= (LCN)LCN_HOLE)) {
+ if (likely(rl->lcn >= LCN_HOLE)) {
ntfs_debug("Done.");
return rl;
}
}
rl++;
}
- if (likely(rl->lcn != (LCN)LCN_RL_NOT_MAPPED)) {
- if (likely(rl->lcn == (LCN)LCN_ENOENT))
+ if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) {
+ if (likely(rl->lcn == LCN_ENOENT))
err = -ENOENT;
else
err = -EIO;
const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
{
ATTR_RECORD *a;
- ntfs_volume *vol;
- ntfschar *upcase;
- u32 upcase_len;
+ ntfs_volume *vol = ctx->ntfs_ino->vol;
+ ntfschar *upcase = vol->upcase;
+ u32 upcase_len = vol->upcase_len;
- if (ic == IGNORE_CASE) {
- vol = ctx->ntfs_ino->vol;
- upcase = vol->upcase;
- upcase_len = vol->upcase_len;
- } else {
- vol = NULL;
- upcase = NULL;
- upcase_len = 0;
- }
/*
* Iterate over attributes in mft record starting at @ctx->attr, or the
* attribute following that, if @ctx->is_first is TRUE.
return -ENOENT;
}
}
- ntfs_error(NULL, "Inode is corrupt. Run chkdsk.");
+ ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk.");
NVolSetErrors(vol);
return -EIO;
}
rl = runlist->rl;
/* Read all clusters specified by the runlist one run at a time. */
while (rl->length) {
- lcn = ntfs_vcn_to_lcn(rl, rl->vcn);
+ lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn);
ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.",
(unsigned long long)rl->vcn,
(unsigned long long)lcn);
/* The attribute list cannot be sparse. */
if (lcn < 0) {
- ntfs_error(sb, "ntfs_vcn_to_lcn() failed. Cannot read "
- "attribute list.");
+ ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot "
+ "read attribute list.");
goto err_out;
}
block = lcn << vol->cluster_size_bits >> block_size_bits;
ctx->mrec = map_extent_mft_record(base_ni,
le64_to_cpu(
al_entry->mft_reference), &ni);
- ctx->ntfs_ino = ni;
if (IS_ERR(ctx->mrec)) {
ntfs_error(vol->sb, "Failed to map "
"extent mft record "
err = PTR_ERR(ctx->mrec);
if (err == -ENOENT)
err = -EIO;
+ /* Cause @ctx to be sanitized below. */
+ ni = NULL;
break;
}
+ ctx->ntfs_ino = ni;
}
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
le16_to_cpu(ctx->mrec->attrs_offset));
err = -EIO;
}
if (ni != base_ni) {
- unmap_extent_mft_record(ni);
+ if (ni)
+ unmap_extent_mft_record(ni);
ctx->ntfs_ino = base_ni;
ctx->mrec = ctx->base_mrec;
ctx->attr = ctx->base_attr;
kmem_cache_free(ntfs_attr_ctx_cache, ctx);
return;
}
+
+/**
+ * ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file
+ * @vol: ntfs volume to which the attribute belongs
+ * @type: attribute type which to find
+ *
+ * Search for the attribute definition record corresponding to the attribute
+ * @type in the $AttrDef system file.
+ *
+ * Return the attribute type definition record if found and NULL if not found.
+ */
+static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol,
+ const ATTR_TYPE type)
+{
+ ATTR_DEF *ad;
+
+ BUG_ON(!vol->attrdef);
+ BUG_ON(!type);
+ for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef <
+ vol->attrdef_size && ad->type; ++ad) {
+ /* We have not found it yet, carry on searching. */
+ if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type)))
+ continue;
+ /* We found the attribute; return it. */
+ if (likely(ad->type == type))
+ return ad;
+ /* We have gone too far already. No point in continuing. */
+ break;
+ }
+ /* Attribute not found. */
+ ntfs_debug("Attribute type 0x%x not found in $AttrDef.",
+ le32_to_cpu(type));
+ return NULL;
+}
+
+/**
+ * ntfs_attr_size_bounds_check - check a size of an attribute type for validity
+ * @vol: ntfs volume to which the attribute belongs
+ * @type: attribute type which to check
+ * @size: size which to check
+ *
+ * Check whether the @size in bytes is valid for an attribute of @type on the
+ * ntfs volume @vol. This information is obtained from $AttrDef system file.
+ *
+ * Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not
+ * listed in $AttrDef.
+ */
+int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type,
+ const s64 size)
+{
+ ATTR_DEF *ad;
+
+ BUG_ON(size < 0);
+ /*
+ * $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not
+ * listed in $AttrDef.
+ */
+ if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024))
+ return -ERANGE;
+ /* Get the $AttrDef entry for the attribute @type. */
+ ad = ntfs_attr_find_in_attrdef(vol, type);
+ if (unlikely(!ad))
+ return -ENOENT;
+ /* Do the bounds check. */
+ if (((sle64_to_cpu(ad->min_size) > 0) &&
+ size < sle64_to_cpu(ad->min_size)) ||
+ ((sle64_to_cpu(ad->max_size) > 0) && size >
+ sle64_to_cpu(ad->max_size)))
+ return -ERANGE;
+ return 0;
+}
+
+/**
+ * ntfs_attr_can_be_non_resident - check if an attribute can be non-resident
+ * @vol: ntfs volume to which the attribute belongs
+ * @type: attribute type which to check
+ *
+ * Check whether the attribute of @type on the ntfs volume @vol is allowed to
+ * be non-resident. This information is obtained from $AttrDef system file.
+ *
+ * Return 0 if the attribute is allowed to be non-resident, -EPERM if not, or
+ * -ENOENT if the attribute is not listed in $AttrDef.
+ */
+int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type)
+{
+ ATTR_DEF *ad;
+
+ /*
+ * $DATA is always allowed to be non-resident even if $AttrDef does not
+ * specify this in the flags of the $DATA attribute definition record.
+ */
+ if (type == AT_DATA)
+ return 0;
+ /* Find the attribute definition record in $AttrDef. */
+ ad = ntfs_attr_find_in_attrdef(vol, type);
+ if (unlikely(!ad))
+ return -ENOENT;
+ /* Check the flags and return the result. */
+ if (ad->flags & CAN_BE_NON_RESIDENT)
+ return 0;
+ return -EPERM;
+}
+
+/**
+ * ntfs_attr_can_be_resident - check if an attribute can be resident
+ * @vol: ntfs volume to which the attribute belongs
+ * @type: attribute type which to check
+ *
+ * Check whether the attribute of @type on the ntfs volume @vol is allowed to
+ * be resident. This information is derived from our ntfs knowledge and may
+ * not be completely accurate, especially when user defined attributes are
+ * present. Basically we allow everything to be resident except for index
+ * allocation and $EA attributes.
+ *
+ * Return 0 if the attribute is allowed to be non-resident and -EPERM if not.
+ *
+ * Warning: In the system file $MFT the attribute $Bitmap must be non-resident
+ * otherwise windows will not boot (blue screen of death)! We cannot
+ * check for this here as we do not know which inode's $Bitmap is
+ * being asked about so the caller needs to special case this.
+ */
+int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type)
+{
+ if (type != AT_INDEX_ALLOCATION && type != AT_EA)
+ return 0;
+ return -EPERM;
+}
+
+/**
+ * ntfs_attr_record_resize - resize an attribute record
+ * @m: mft record containing attribute record
+ * @a: attribute record to resize
+ * @new_size: new size in bytes to which to resize the attribute record @a
+ *
+ * Resize the attribute record @a, i.e. the resident part of the attribute, in
+ * the mft record @m to @new_size bytes.
+ *
+ * Return 0 on success and -errno on error. The following error codes are
+ * defined:
+ * -ENOSPC - Not enough space in the mft record @m to perform the resize.
+ *
+ * Note: On error, no modifications have been performed whatsoever.
+ *
+ * Warning: If you make a record smaller without having copied all the data you
+ * are interested in the data may be overwritten.
+ */
+int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size)
+{
+ ntfs_debug("Entering for new_size %u.", new_size);
+ /* Align to 8 bytes if it is not already done. */
+ if (new_size & 7)
+ new_size = (new_size + 7) & ~7;
+ /* If the actual attribute length has changed, move things around. */
+ if (new_size != le32_to_cpu(a->length)) {
+ u32 new_muse = le32_to_cpu(m->bytes_in_use) -
+ le32_to_cpu(a->length) + new_size;
+ /* Not enough space in this mft record. */
+ if (new_muse > le32_to_cpu(m->bytes_allocated))
+ return -ENOSPC;
+ /* Move attributes following @a to their new location. */
+ memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length),
+ le32_to_cpu(m->bytes_in_use) - ((u8*)a -
+ (u8*)m) - le32_to_cpu(a->length));
+ /* Adjust @m to reflect the change in used space. */
+ m->bytes_in_use = cpu_to_le32(new_muse);
+ /* Adjust @a to reflect the new size. */
+ if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length))
+ a->length = cpu_to_le32(new_size);
+ }
+ return 0;
+}
+
+/**
+ * ntfs_attr_set - fill (a part of) an attribute with a byte
+ * @ni: ntfs inode describing the attribute to fill
+ * @ofs: offset inside the attribute at which to start to fill
+ * @cnt: number of bytes to fill
+ * @val: the unsigned 8-bit value with which to fill the attribute
+ *
+ * Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at
+ * byte offset @ofs inside the attribute with the constant byte @val.
+ *
+ * This function is effectively like memset() applied to an ntfs attribute.
+ *
+ * Return 0 on success and -errno on error. An error code of -ESPIPE means
+ * that @ofs + @cnt were outside the end of the attribute and no write was
+ * performed.
+ */
+int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
+{
+ ntfs_volume *vol = ni->vol;
+ struct address_space *mapping;
+ struct page *page;
+ u8 *kaddr;
+ pgoff_t idx, end;
+ unsigned int start_ofs, end_ofs, size;
+
+ ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.",
+ (long long)ofs, (long long)cnt, val);
+ BUG_ON(ofs < 0);
+ BUG_ON(cnt < 0);
+ if (!cnt)
+ goto done;
+ mapping = VFS_I(ni)->i_mapping;
+ /* Work out the starting index and page offset. */
+ idx = ofs >> PAGE_CACHE_SHIFT;
+ start_ofs = ofs & ~PAGE_CACHE_MASK;
+ /* Work out the ending index and page offset. */
+ end = ofs + cnt;
+ end_ofs = end & ~PAGE_CACHE_MASK;
+ /* If the end is outside the inode size return -ESPIPE. */
+ if (unlikely(end > VFS_I(ni)->i_size)) {
+ ntfs_error(vol->sb, "Request exceeds end of attribute.");
+ return -ESPIPE;
+ }
+ end >>= PAGE_CACHE_SHIFT;
+ /* If there is a first partial page, need to do it the slow way. */
+ if (start_ofs) {
+ page = read_cache_page(mapping, idx,
+ (filler_t*)mapping->a_ops->readpage, NULL);
+ if (IS_ERR(page)) {
+ ntfs_error(vol->sb, "Failed to read first partial "
+ "page (sync error, index 0x%lx).", idx);
+ return PTR_ERR(page);
+ }
+ wait_on_page_locked(page);
+ if (unlikely(!PageUptodate(page))) {
+ ntfs_error(vol->sb, "Failed to read first partial page "
+ "(async error, index 0x%lx).", idx);
+ page_cache_release(page);
+ return PTR_ERR(page);
+ }
+ /*
+ * If the last page is the same as the first page, need to
+ * limit the write to the end offset.
+ */
+ size = PAGE_CACHE_SIZE;
+ if (idx == end)
+ size = end_ofs;
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + start_ofs, val, size - start_ofs);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ set_page_dirty(page);
+ page_cache_release(page);
+ if (idx == end)
+ goto done;
+ idx++;
+ }
+ /* Do the whole pages the fast way. */
+ for (; idx < end; idx++) {
+ /* Find or create the current page. (The page is locked.) */
+ page = grab_cache_page(mapping, idx);
+ if (unlikely(!page)) {
+ ntfs_error(vol->sb, "Insufficient memory to grab "
+ "page (index 0x%lx).", idx);
+ return -ENOMEM;
+ }
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr, val, PAGE_CACHE_SIZE);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ /*
+ * If the page has buffers, mark them uptodate since buffer
+ * state and not page state is definitive in 2.6 kernels.
+ */
+ if (page_has_buffers(page)) {
+ struct buffer_head *bh, *head;
+
+ bh = head = page_buffers(page);
+ do {
+ set_buffer_uptodate(bh);
+ } while ((bh = bh->b_this_page) != head);
+ }
+ /* Now that buffers are uptodate, set the page uptodate, too. */
+ SetPageUptodate(page);
+ /*
+ * Set the page and all its buffers dirty and mark the inode
+ * dirty, too. The VM will write the page later on.
+ */
+ set_page_dirty(page);
+ /* Finally unlock and release the page. */
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ /* If there is a last partial page, need to do it the slow way. */
+ if (end_ofs) {
+ page = read_cache_page(mapping, idx,
+ (filler_t*)mapping->a_ops->readpage, NULL);
+ if (IS_ERR(page)) {
+ ntfs_error(vol->sb, "Failed to read last partial page "
+ "(sync error, index 0x%lx).", idx);
+ return PTR_ERR(page);
+ }
+ wait_on_page_locked(page);
+ if (unlikely(!PageUptodate(page))) {
+ ntfs_error(vol->sb, "Failed to read last partial page "
+ "(async error, index 0x%lx).", idx);
+ page_cache_release(page);
+ return PTR_ERR(page);
+ }
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr, val, end_ofs);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ set_page_dirty(page);
+ page_cache_release(page);
+ }
+done:
+ ntfs_debug("Done.");
+ return 0;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff