From 10d2cf94c23d48ef1b141084216e7580011e4790 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Tue, 19 Dec 2017 00:06:44 +0100 Subject: [PATCH] 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 Signed-off-by: Bob Peterson --- fs/gfs2/bmap.c | 179 ++++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 120 insertions(+), 59 deletions(-) diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index 8fd42ae..f6dbd2f 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -461,13 +461,6 @@ enum alloc_state { /* ALLOC_UNSTUFF = 3, TBD and rather complicated */ }; -static inline unsigned int hptrs(struct gfs2_sbd *sdp, const unsigned int hgt) -{ - if (hgt) - return sdp->sd_inptrs; - return sdp->sd_diptrs; -} - /** * gfs2_bmap_alloc - Build a metadata tree of the requested height * @inode: The GFS2 inode @@ -1243,38 +1236,48 @@ out: return ret; } +static bool mp_eq_to_hgt(struct metapath *mp, __u16 *list, unsigned int h) +{ + if (memcmp(mp->mp_list, list, h * sizeof(mp->mp_list[0]))) + return false; + return true; +} + /** * find_nonnull_ptr - find a non-null pointer given a metapath and height - * assumes the metapath is valid (with buffers) out to height h * @mp: starting metapath * @h: desired height to search * + * Assumes the metapath is valid (with buffers) out to height h. * Returns: true if a non-null pointer was found in the metapath buffer * false if all remaining pointers are NULL in the buffer */ static bool find_nonnull_ptr(struct gfs2_sbd *sdp, struct metapath *mp, - unsigned int h) + unsigned int h, + __u16 *end_list, unsigned int end_aligned) { - __be64 *ptr; - unsigned int ptrs = hptrs(sdp, h) - 1; + struct buffer_head *bh = mp->mp_bh[h]; + __be64 *first, *ptr, *end; + + first = metaptr1(h, mp); + ptr = first + mp->mp_list[h]; + end = (__be64 *)(bh->b_data + bh->b_size); + if (end_list && mp_eq_to_hgt(mp, end_list, h)) { + bool keep_end = h < end_aligned; + end = first + end_list[h] + keep_end; + } - while (true) { - ptr = metapointer(h, mp); + while (ptr < end) { if (*ptr) { /* if we have a non-null pointer */ - /* Now zero the metapath after the current height. */ + mp->mp_list[h] = ptr - first; h++; if (h < GFS2_MAX_META_HEIGHT) - memset(&mp->mp_list[h], 0, - (GFS2_MAX_META_HEIGHT - h) * - sizeof(mp->mp_list[0])); + mp->mp_list[h] = 0; return true; } - - if (mp->mp_list[h] < ptrs) - mp->mp_list[h]++; - else - return false; /* no more pointers in this buffer */ + ptr++; } + return false; } enum dealloc_states { @@ -1284,16 +1287,10 @@ enum dealloc_states { DEALLOC_DONE = 3, /* process complete */ }; -static bool mp_eq_to_hgt(struct metapath *mp, __u16 *list, unsigned int h) -{ - if (memcmp(mp->mp_list, list, h * sizeof(mp->mp_list[0]))) - return false; - return true; -} - static inline void metapointer_range(struct metapath *mp, int height, __u16 *start_list, unsigned int start_aligned, + __u16 *end_list, unsigned int end_aligned, __be64 **start, __be64 **end) { struct buffer_head *bh = mp->mp_bh[height]; @@ -1306,29 +1303,55 @@ metapointer_range(struct metapath *mp, int height, *start = first + start_list[height] + keep_start; } *end = (__be64 *)(bh->b_data + bh->b_size); + if (end_list && mp_eq_to_hgt(mp, end_list, height)) { + bool keep_end = height < end_aligned; + *end = first + end_list[height] + keep_end; + } +} + +static inline bool walk_done(struct gfs2_sbd *sdp, + struct metapath *mp, int height, + __u16 *end_list, unsigned int end_aligned) +{ + __u16 end; + + if (end_list) { + bool keep_end = height < end_aligned; + if (!mp_eq_to_hgt(mp, end_list, height)) + return false; + end = end_list[height] + keep_end; + } else + end = (height > 0) ? sdp->sd_inptrs : sdp->sd_diptrs; + return mp->mp_list[height] >= end; } /** - * trunc_dealloc - truncate a file down to a desired size + * punch_hole - deallocate blocks in a file * @ip: inode to truncate - * @newsize: The desired size of the file + * @offset: the start of the hole + * @length: the size of the hole (or 0 for truncate) + * + * Punch a hole into a file or truncate a file at a given position. This + * function operates in whole blocks (@offset and @length are rounded + * accordingly); partially filled blocks must be cleared otherwise. * - * This function truncates a file to newsize. It works from the - * bottom up, and from the right to the left. In other words, it strips off - * the highest layer (data) before stripping any of the metadata. Doing it - * this way is best in case the operation is interrupted by power failure, etc. - * The dinode is rewritten in every transaction to guarantee integrity. + * This function works from the bottom up, and from the right to the left. In + * other words, it strips off the highest layer (data) before stripping any of + * the metadata. Doing it this way is best in case the operation is interrupted + * by power failure, etc. The dinode is rewritten in every transaction to + * guarantee integrity. */ -static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) +static int punch_hole(struct gfs2_inode *ip, u64 offset, u64 length) { struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); - struct metapath mp; + struct metapath mp = {}; struct buffer_head *dibh, *bh; struct gfs2_holder rd_gh; unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift; - u64 lblock = (newsize + (1 << bsize_shift) - 1) >> bsize_shift; - __u16 start_list[GFS2_MAX_META_HEIGHT]; /* new beginning of truncation */ - unsigned int start_aligned; + u64 lblock = (offset + (1 << bsize_shift) - 1) >> bsize_shift; + __u16 start_list[GFS2_MAX_META_HEIGHT]; + __u16 __end_list[GFS2_MAX_META_HEIGHT], *end_list = NULL; + unsigned int start_aligned, end_aligned; unsigned int strip_h = ip->i_height - 1; u32 btotal = 0; int ret, state; @@ -1336,19 +1359,49 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) u64 prev_bnr = 0; __be64 *start, *end; - memset(&mp, 0, sizeof(mp)); - find_metapath(sdp, lblock, &mp, ip->i_height); + /* + * The start position of the hole is defined by lblock, start_list, and + * start_aligned. The end position of the hole is defined by lend, + * end_list, and end_aligned. + * + * start_aligned and end_aligned define down to which height the start + * and end positions are aligned to the metadata tree (i.e., the + * position is a multiple of the metadata granularity at the height + * above). This determines at which heights additional meta pointers + * needs to be preserved for the remaining data. + */ + + if (length) { + u64 maxsize = sdp->sd_heightsize[ip->i_height]; + u64 end_offset = offset + length; + u64 lend; + + /* + * Clip the end at the maximum file size for the given height: + * that's how far the metadata goes; files bigger than that + * will have additional layers of indirection. + */ + if (end_offset > maxsize) + end_offset = maxsize; + lend = end_offset >> bsize_shift; + + if (lblock >= lend) + return 0; + find_metapath(sdp, lend, &mp, ip->i_height); + end_list = __end_list; + memcpy(end_list, mp.mp_list, sizeof(mp.mp_list)); + + for (mp_h = ip->i_height - 1; mp_h > 0; mp_h--) { + if (end_list[mp_h]) + break; + } + end_aligned = mp_h; + } + + find_metapath(sdp, lblock, &mp, ip->i_height); memcpy(start_list, mp.mp_list, sizeof(start_list)); - /* - * Set start_aligned to the metadata height up to which the truncate - * point is aligned to the metadata tree (i.e., the truncate point is a - * multiple of the granularity at the height above). This determines - * at which heights an additional meta pointer needs to be preserved: - * an additional meta pointer is needed at a given height if - * height < start_aligned. - */ for (mp_h = ip->i_height - 1; mp_h > 0; mp_h--) { if (start_list[mp_h]) break; @@ -1367,7 +1420,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) /* issue read-ahead on metadata */ for (mp_h = 0; mp_h < mp.mp_aheight - 1; mp_h++) { metapointer_range(&mp, mp_h, start_list, start_aligned, - &start, &end); + end_list, end_aligned, &start, &end); gfs2_metapath_ra(ip->i_gl, start, end); } @@ -1411,7 +1464,14 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) goto out; } + /* + * Below, passing end_aligned as 0 gives us the + * metapointer range excluding the end point: the end + * point is the first metapath we must not deallocate! + */ + metapointer_range(&mp, mp_h, start_list, start_aligned, + end_list, 0 /* end_aligned */, &start, &end); ret = sweep_bh_for_rgrps(ip, &rd_gh, mp.mp_bh[mp_h], start, end, @@ -1448,13 +1508,13 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) } mp.mp_list[mp_h] = 0; mp_h--; /* search one metadata height down */ - if (mp.mp_list[mp_h] >= hptrs(sdp, mp_h) - 1) - break; /* loop around in the same state */ mp.mp_list[mp_h]++; + if (walk_done(sdp, &mp, mp_h, end_list, end_aligned)) + break; /* Here we've found a part of the metapath that is not * allocated. We need to search at that height for the * next non-null pointer. */ - if (find_nonnull_ptr(sdp, &mp, mp_h)) { + if (find_nonnull_ptr(sdp, &mp, mp_h, end_list, end_aligned)) { state = DEALLOC_FILL_MP; mp_h++; } @@ -1474,6 +1534,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) for (; ret > 1; ret--) { metapointer_range(&mp, mp.mp_aheight - ret, start_list, start_aligned, + end_list, end_aligned, &start, &end); gfs2_metapath_ra(ip->i_gl, start, end); } @@ -1490,7 +1551,7 @@ static int trunc_dealloc(struct gfs2_inode *ip, u64 newsize) /* If we find a non-null block pointer, crawl a bit higher up in the metapath and try again, otherwise we need to look lower for a new starting point. */ - if (find_nonnull_ptr(sdp, &mp, mp_h)) + if (find_nonnull_ptr(sdp, &mp, mp_h, end_list, end_aligned)) mp_h++; else state = DEALLOC_MP_LOWER; @@ -1587,7 +1648,7 @@ static int do_shrink(struct inode *inode, u64 newsize) if (gfs2_is_stuffed(ip)) return 0; - error = trunc_dealloc(ip, newsize); + error = punch_hole(ip, newsize, 0); if (error == 0) error = trunc_end(ip); @@ -1719,7 +1780,7 @@ out: int gfs2_truncatei_resume(struct gfs2_inode *ip) { int error; - error = trunc_dealloc(ip, i_size_read(&ip->i_inode)); + error = punch_hole(ip, i_size_read(&ip->i_inode), 0); if (!error) error = trunc_end(ip); return error; @@ -1727,7 +1788,7 @@ int gfs2_truncatei_resume(struct gfs2_inode *ip) int gfs2_file_dealloc(struct gfs2_inode *ip) { - return trunc_dealloc(ip, 0); + return punch_hole(ip, 0, 0); } /** -- 2.7.4