| Message ID | 20181212074234.20613-3-nborisov@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Cleanups around btrfs_get_extent_fiemap | expand |
On Wed, Dec 12, 2018 at 09:42:33AM +0200, Nikolay Borisov wrote: > Make btrfs_get_extent_fiemap a bit more friendly. First step is to > rename the closely related, yet arbitrary named > range_start/found_end/found variables. They define the delalloc range > that is found in case a real extent wasn't found. Subsequently remove > an unnecessary check for hole_em since it's guaranteed to be set i.e the > check is always true. Top it off by giving all comments a refresh. > > No functional changes. > > Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> > --- > fs/btrfs/inode.c | 84 ++++++++++++++++++++++++++---------------------- > 1 file changed, 45 insertions(+), 39 deletions(-) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 67eee4d345c9..95eb18779c19 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -6965,10 +6965,10 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, > { > struct extent_map *em; > struct extent_map *hole_em = NULL; > - u64 range_start = start; > + u64 delalloc_start = start; > u64 end; > - u64 found; > - u64 found_end; > + u64 delalloc_len; > + u64 delalloc_end; > int err = 0; > > em = btrfs_get_extent(inode, NULL, 0, start, len, 0); > @@ -6996,37 +6996,42 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, > em = NULL; > > /* ok, we didn't find anything, lets look for delalloc */ > - found = count_range_bits(&inode->io_tree, &range_start, > + delalloc_len = count_range_bits(&inode->io_tree, &delalloc_start, > end, len, EXTENT_DELALLOC, 1); > - found_end = range_start + found; > - if (found_end < range_start) > - found_end = (u64)-1; > + delalloc_end = delalloc_start + delalloc_len; > + if (delalloc_end < delalloc_start) > + delalloc_end = (u64)-1; > > /* > - * we didn't find anything useful, return > - * the original results from get_extent() > + * we didn't find anything useful, return the original results from > + * get_extent() > */ > - if (range_start > end || found_end <= start) { > + if (delalloc_start > end || delalloc_end <= start) { > em = hole_em; > hole_em = NULL; > goto out; > } > > - /* adjust the range_start to make sure it doesn't > - * go backwards from the start they passed in > + /* > + * adjust the delalloc_start to make sure it doesn't go backwards from > + * the start they passed in > */ > - range_start = max(start, range_start); > - found = found_end - range_start; > + delalloc_start = max(start, delalloc_start); > + delalloc_len = delalloc_end - delalloc_start; > > - if (found > 0) { > - u64 hole_start = start; > + if (delalloc_len) { > + u64 hole_start; > u64 hole_len = len; > + u64 hole_end = extent_map_end(hole_em); > > em = alloc_extent_map(); > if (!em) { > err = -ENOMEM; > goto out; > } > + em->bdev = NULL; > + > + ASSERT(hole_em); > /* > * when btrfs_get_extent can't find anything it > * returns one huge hole > @@ -7035,41 +7040,42 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, > * adjust to make sure it is based on the start from > * the caller > */ > - if (hole_em) { > - u64 calc_end = extent_map_end(hole_em); > - > - if (calc_end <= start || (hole_em->start > end)) { > - free_extent_map(hole_em); > - hole_em = NULL; > - } else { > - hole_start = max(hole_em->start, start); > - hole_len = calc_end - hole_start; > - } > + if (hole_end <= start || (hole_em->start > end)) { > + free_extent_map(hole_em); > + hole_em = NULL; > + } else { > + hole_start = max(hole_em->start, start); > + hole_len = hole_end - hole_start; > } > - em->bdev = NULL; > - if (hole_em && range_start > hole_start) { > - /* our hole starts before our delalloc, so we > - * have to return just the parts of the hole > - * that go until the delalloc starts > + > + if (hole_em && delalloc_start > hole_start) { > + /* > + * our hole starts before our delalloc, so we have to > + * return just the parts of the hole that go until the > + * delalloc starts > */ > - em->len = min(hole_len, > - range_start - hole_start); > + em->len = min(hole_len, delalloc_start - hole_start); > em->start = hole_start; > em->orig_start = hole_start; > /* > - * don't adjust block start at all, > - * it is fixed at EXTENT_MAP_HOLE > + * don't adjust block start at all, it is fixed at > + * EXTENT_MAP_HOLE > */ > em->block_start = hole_em->block_start; > em->block_len = hole_len; > if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags)) > set_bit(EXTENT_FLAG_PREALLOC, &em->flags); > } else { > - em->start = range_start; > - em->len = found; > - em->orig_start = range_start; > + > + /* > + * Hole is out of passed range or it starts after > + * delalloc range > + */ > + em->start = delalloc_start; > + em->len = delalloc_len; > + em->orig_start = delalloc_start; > em->block_start = EXTENT_MAP_DELALLOC; > - em->block_len = found; > + em->block_len = delalloc_len; > } > } else { > return hole_em; > -- > 2.17.1
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 67eee4d345c9..95eb18779c19 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -6965,10 +6965,10 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, { struct extent_map *em; struct extent_map *hole_em = NULL; - u64 range_start = start; + u64 delalloc_start = start; u64 end; - u64 found; - u64 found_end; + u64 delalloc_len; + u64 delalloc_end; int err = 0; em = btrfs_get_extent(inode, NULL, 0, start, len, 0); @@ -6996,37 +6996,42 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, em = NULL; /* ok, we didn't find anything, lets look for delalloc */ - found = count_range_bits(&inode->io_tree, &range_start, + delalloc_len = count_range_bits(&inode->io_tree, &delalloc_start, end, len, EXTENT_DELALLOC, 1); - found_end = range_start + found; - if (found_end < range_start) - found_end = (u64)-1; + delalloc_end = delalloc_start + delalloc_len; + if (delalloc_end < delalloc_start) + delalloc_end = (u64)-1; /* - * we didn't find anything useful, return - * the original results from get_extent() + * we didn't find anything useful, return the original results from + * get_extent() */ - if (range_start > end || found_end <= start) { + if (delalloc_start > end || delalloc_end <= start) { em = hole_em; hole_em = NULL; goto out; } - /* adjust the range_start to make sure it doesn't - * go backwards from the start they passed in + /* + * adjust the delalloc_start to make sure it doesn't go backwards from + * the start they passed in */ - range_start = max(start, range_start); - found = found_end - range_start; + delalloc_start = max(start, delalloc_start); + delalloc_len = delalloc_end - delalloc_start; - if (found > 0) { - u64 hole_start = start; + if (delalloc_len) { + u64 hole_start; u64 hole_len = len; + u64 hole_end = extent_map_end(hole_em); em = alloc_extent_map(); if (!em) { err = -ENOMEM; goto out; } + em->bdev = NULL; + + ASSERT(hole_em); /* * when btrfs_get_extent can't find anything it * returns one huge hole @@ -7035,41 +7040,42 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, * adjust to make sure it is based on the start from * the caller */ - if (hole_em) { - u64 calc_end = extent_map_end(hole_em); - - if (calc_end <= start || (hole_em->start > end)) { - free_extent_map(hole_em); - hole_em = NULL; - } else { - hole_start = max(hole_em->start, start); - hole_len = calc_end - hole_start; - } + if (hole_end <= start || (hole_em->start > end)) { + free_extent_map(hole_em); + hole_em = NULL; + } else { + hole_start = max(hole_em->start, start); + hole_len = hole_end - hole_start; } - em->bdev = NULL; - if (hole_em && range_start > hole_start) { - /* our hole starts before our delalloc, so we - * have to return just the parts of the hole - * that go until the delalloc starts + + if (hole_em && delalloc_start > hole_start) { + /* + * our hole starts before our delalloc, so we have to + * return just the parts of the hole that go until the + * delalloc starts */ - em->len = min(hole_len, - range_start - hole_start); + em->len = min(hole_len, delalloc_start - hole_start); em->start = hole_start; em->orig_start = hole_start; /* - * don't adjust block start at all, - * it is fixed at EXTENT_MAP_HOLE + * don't adjust block start at all, it is fixed at + * EXTENT_MAP_HOLE */ em->block_start = hole_em->block_start; em->block_len = hole_len; if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags)) set_bit(EXTENT_FLAG_PREALLOC, &em->flags); } else { - em->start = range_start; - em->len = found; - em->orig_start = range_start; + + /* + * Hole is out of passed range or it starts after + * delalloc range + */ + em->start = delalloc_start; + em->len = delalloc_len; + em->orig_start = delalloc_start; em->block_start = EXTENT_MAP_DELALLOC; - em->block_len = found; + em->block_len = delalloc_len; } } else { return hole_em;
Make btrfs_get_extent_fiemap a bit more friendly. First step is to rename the closely related, yet arbitrary named range_start/found_end/found variables. They define the delalloc range that is found in case a real extent wasn't found. Subsequently remove an unnecessary check for hole_em since it's guaranteed to be set i.e the check is always true. Top it off by giving all comments a refresh. No functional changes. Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- fs/btrfs/inode.c | 84 ++++++++++++++++++++++++++---------------------- 1 file changed, 45 insertions(+), 39 deletions(-)