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gfs2: Turn trunc_dealloc into punch_hole
Add an upper bound to the range of blocks to deallocate blocks to function trunc_dealloc so that this function can be used for truncating a file as well as for punching a hole into a file. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
Andreas Gruenbacher
parent
5cf26b1e88
commit
10d2cf94c2
179
fs/gfs2/bmap.c
179
fs/gfs2/bmap.c
@ -461,13 +461,6 @@ enum alloc_state {
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/* ALLOC_UNSTUFF = 3, TBD and rather complicated */
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};
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static inline unsigned int hptrs(struct gfs2_sbd *sdp, const unsigned int hgt)
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{
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if (hgt)
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return sdp->sd_inptrs;
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return sdp->sd_diptrs;
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}
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/**
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* gfs2_bmap_alloc - Build a metadata tree of the requested height
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* @inode: The GFS2 inode
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@ -1243,38 +1236,48 @@ out:
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return ret;
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}
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static bool mp_eq_to_hgt(struct metapath *mp, __u16 *list, unsigned int h)
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{
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if (memcmp(mp->mp_list, list, h * sizeof(mp->mp_list[0])))
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return false;
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return true;
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}
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/**
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* find_nonnull_ptr - find a non-null pointer given a metapath and height
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* assumes the metapath is valid (with buffers) out to height h
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* @mp: starting metapath
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* @h: desired height to search
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*
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* Assumes the metapath is valid (with buffers) out to height h.
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* Returns: true if a non-null pointer was found in the metapath buffer
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* false if all remaining pointers are NULL in the buffer
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*/
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static bool find_nonnull_ptr(struct gfs2_sbd *sdp, struct metapath *mp,
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unsigned int h)
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unsigned int h,
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__u16 *end_list, unsigned int end_aligned)
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{
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__be64 *ptr;
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unsigned int ptrs = hptrs(sdp, h) - 1;
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struct buffer_head *bh = mp->mp_bh[h];
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__be64 *first, *ptr, *end;
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while (true) {
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ptr = metapointer(h, mp);
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first = metaptr1(h, mp);
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ptr = first + mp->mp_list[h];
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end = (__be64 *)(bh->b_data + bh->b_size);
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if (end_list && mp_eq_to_hgt(mp, end_list, h)) {
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bool keep_end = h < end_aligned;
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end = first + end_list[h] + keep_end;
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}
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while (ptr < end) {
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if (*ptr) { /* if we have a non-null pointer */
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/* Now zero the metapath after the current height. */
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mp->mp_list[h] = ptr - first;
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h++;
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if (h < GFS2_MAX_META_HEIGHT)
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memset(&mp->mp_list[h], 0,
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(GFS2_MAX_META_HEIGHT - h) *
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sizeof(mp->mp_list[0]));
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mp->mp_list[h] = 0;
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return true;
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}
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if (mp->mp_list[h] < ptrs)
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mp->mp_list[h]++;
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else
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return false; /* no more pointers in this buffer */
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ptr++;
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}
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return false;
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}
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enum dealloc_states {
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@ -1284,16 +1287,10 @@ enum dealloc_states {
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DEALLOC_DONE = 3, /* process complete */
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};
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static bool mp_eq_to_hgt(struct metapath *mp, __u16 *list, unsigned int h)
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{
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if (memcmp(mp->mp_list, list, h * sizeof(mp->mp_list[0])))
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return false;
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return true;
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}
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static inline void
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metapointer_range(struct metapath *mp, int height,
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__u16 *start_list, unsigned int start_aligned,
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__u16 *end_list, unsigned int end_aligned,
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__be64 **start, __be64 **end)
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{
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struct buffer_head *bh = mp->mp_bh[height];
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@ -1306,29 +1303,55 @@ metapointer_range(struct metapath *mp, int height,
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*start = first + start_list[height] + keep_start;
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}
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*end = (__be64 *)(bh->b_data + bh->b_size);
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if (end_list && mp_eq_to_hgt(mp, end_list, height)) {
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bool keep_end = height < end_aligned;
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*end = first + end_list[height] + keep_end;
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}
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}
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static inline bool walk_done(struct gfs2_sbd *sdp,
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struct metapath *mp, int height,
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__u16 *end_list, unsigned int end_aligned)
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{
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__u16 end;
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if (end_list) {
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bool keep_end = height < end_aligned;
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if (!mp_eq_to_hgt(mp, end_list, height))
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return false;
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end = end_list[height] + keep_end;
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} else
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end = (height > 0) ? sdp->sd_inptrs : sdp->sd_diptrs;
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return mp->mp_list[height] >= end;
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}
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/**
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* trunc_dealloc - truncate a file down to a desired size
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* punch_hole - deallocate blocks in a file
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* @ip: inode to truncate
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* @newsize: The desired size of the file
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* @offset: the start of the hole
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* @length: the size of the hole (or 0 for truncate)
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*
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* This function truncates a file to newsize. It works from the
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* bottom up, and from the right to the left. In other words, it strips off
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* the highest layer (data) before stripping any of the metadata. Doing it
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* this way is best in case the operation is interrupted by power failure, etc.
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* The dinode is rewritten in every transaction to guarantee integrity.
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* Punch a hole into a file or truncate a file at a given position. This
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* function operates in whole blocks (@offset and @length are rounded
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* accordingly); partially filled blocks must be cleared otherwise.
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*
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* This function works from the bottom up, and from the right to the left. In
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* other words, it strips off the highest layer (data) before stripping any of
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* the metadata. Doing it this way is best in case the operation is interrupted
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* by power failure, etc. The dinode is rewritten in every transaction to
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* guarantee integrity.
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*/
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static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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static int punch_hole(struct gfs2_inode *ip, u64 offset, u64 length)
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{
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struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
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struct metapath mp;
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struct metapath mp = {};
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struct buffer_head *dibh, *bh;
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struct gfs2_holder rd_gh;
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unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift;
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u64 lblock = (newsize + (1 << bsize_shift) - 1) >> bsize_shift;
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__u16 start_list[GFS2_MAX_META_HEIGHT]; /* new beginning of truncation */
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unsigned int start_aligned;
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u64 lblock = (offset + (1 << bsize_shift) - 1) >> bsize_shift;
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__u16 start_list[GFS2_MAX_META_HEIGHT];
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__u16 __end_list[GFS2_MAX_META_HEIGHT], *end_list = NULL;
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unsigned int start_aligned, end_aligned;
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unsigned int strip_h = ip->i_height - 1;
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u32 btotal = 0;
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int ret, state;
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@ -1336,19 +1359,49 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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u64 prev_bnr = 0;
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__be64 *start, *end;
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memset(&mp, 0, sizeof(mp));
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find_metapath(sdp, lblock, &mp, ip->i_height);
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/*
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* The start position of the hole is defined by lblock, start_list, and
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* start_aligned. The end position of the hole is defined by lend,
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* end_list, and end_aligned.
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*
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* start_aligned and end_aligned define down to which height the start
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* and end positions are aligned to the metadata tree (i.e., the
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* position is a multiple of the metadata granularity at the height
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* above). This determines at which heights additional meta pointers
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* needs to be preserved for the remaining data.
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*/
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if (length) {
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u64 maxsize = sdp->sd_heightsize[ip->i_height];
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u64 end_offset = offset + length;
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u64 lend;
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/*
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* Clip the end at the maximum file size for the given height:
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* that's how far the metadata goes; files bigger than that
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* will have additional layers of indirection.
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*/
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if (end_offset > maxsize)
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end_offset = maxsize;
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lend = end_offset >> bsize_shift;
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if (lblock >= lend)
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return 0;
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find_metapath(sdp, lend, &mp, ip->i_height);
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end_list = __end_list;
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memcpy(end_list, mp.mp_list, sizeof(mp.mp_list));
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for (mp_h = ip->i_height - 1; mp_h > 0; mp_h--) {
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if (end_list[mp_h])
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break;
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}
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end_aligned = mp_h;
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}
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find_metapath(sdp, lblock, &mp, ip->i_height);
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memcpy(start_list, mp.mp_list, sizeof(start_list));
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/*
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* Set start_aligned to the metadata height up to which the truncate
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* point is aligned to the metadata tree (i.e., the truncate point is a
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* multiple of the granularity at the height above). This determines
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* at which heights an additional meta pointer needs to be preserved:
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* an additional meta pointer is needed at a given height if
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* height < start_aligned.
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*/
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for (mp_h = ip->i_height - 1; mp_h > 0; mp_h--) {
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if (start_list[mp_h])
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break;
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@ -1367,7 +1420,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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/* issue read-ahead on metadata */
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for (mp_h = 0; mp_h < mp.mp_aheight - 1; mp_h++) {
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metapointer_range(&mp, mp_h, start_list, start_aligned,
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&start, &end);
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end_list, end_aligned, &start, &end);
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gfs2_metapath_ra(ip->i_gl, start, end);
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}
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@ -1411,7 +1464,14 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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goto out;
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}
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/*
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* Below, passing end_aligned as 0 gives us the
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* metapointer range excluding the end point: the end
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* point is the first metapath we must not deallocate!
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*/
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metapointer_range(&mp, mp_h, start_list, start_aligned,
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end_list, 0 /* end_aligned */,
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&start, &end);
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ret = sweep_bh_for_rgrps(ip, &rd_gh, mp.mp_bh[mp_h],
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start, end,
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@ -1448,13 +1508,13 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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}
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mp.mp_list[mp_h] = 0;
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mp_h--; /* search one metadata height down */
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if (mp.mp_list[mp_h] >= hptrs(sdp, mp_h) - 1)
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break; /* loop around in the same state */
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mp.mp_list[mp_h]++;
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if (walk_done(sdp, &mp, mp_h, end_list, end_aligned))
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break;
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/* Here we've found a part of the metapath that is not
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* allocated. We need to search at that height for the
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* next non-null pointer. */
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if (find_nonnull_ptr(sdp, &mp, mp_h)) {
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if (find_nonnull_ptr(sdp, &mp, mp_h, end_list, end_aligned)) {
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state = DEALLOC_FILL_MP;
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mp_h++;
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}
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@ -1474,6 +1534,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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for (; ret > 1; ret--) {
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metapointer_range(&mp, mp.mp_aheight - ret,
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start_list, start_aligned,
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end_list, end_aligned,
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&start, &end);
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gfs2_metapath_ra(ip->i_gl, start, end);
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}
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@ -1490,7 +1551,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize)
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/* If we find a non-null block pointer, crawl a bit
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higher up in the metapath and try again, otherwise
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we need to look lower for a new starting point. */
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if (find_nonnull_ptr(sdp, &mp, mp_h))
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if (find_nonnull_ptr(sdp, &mp, mp_h, end_list, end_aligned))
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mp_h++;
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else
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state = DEALLOC_MP_LOWER;
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@ -1587,7 +1648,7 @@ static int do_shrink(struct inode *inode, u64 newsize)
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if (gfs2_is_stuffed(ip))
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return 0;
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error = trunc_dealloc(ip, newsize);
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error = punch_hole(ip, newsize, 0);
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if (error == 0)
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error = trunc_end(ip);
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@ -1719,7 +1780,7 @@ out:
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int gfs2_truncatei_resume(struct gfs2_inode *ip)
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{
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int error;
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error = trunc_dealloc(ip, i_size_read(&ip->i_inode));
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error = punch_hole(ip, i_size_read(&ip->i_inode), 0);
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if (!error)
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error = trunc_end(ip);
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return error;
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@ -1727,7 +1788,7 @@ int gfs2_truncatei_resume(struct gfs2_inode *ip)
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int gfs2_file_dealloc(struct gfs2_inode *ip)
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{
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return trunc_dealloc(ip, 0);
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return punch_hole(ip, 0, 0);
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}
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/**
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