Skip to content

Commit

Permalink
fs/ntfs3: Refactoring attr_punch_hole to restore after errors
Browse files Browse the repository at this point in the history 
Added comments to code
Added new function run_clone to make a copy of run
Added done and undo labels for restoring after errors

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
  • Loading branch information
Konstantin Komarov committed Aug 3, 2022
1 parent 0e5b044 commit 20abc64
Show file tree
Hide file tree
Showing 3 changed files with 105 additions and 38 deletions.
117 changes: 79 additions & 38 deletions fs/ntfs3/attrib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -140,7 +140,10 @@ static int run_deallocate_ex(struct ntfs_sb_info *sbi, struct runs_tree *run,
}

if (lcn != SPARSE_LCN) {
mark_as_free_ex(sbi, lcn, clen, trim);
if (sbi) {
/* mark bitmap range [lcn + clen) as free and trim clusters. */
mark_as_free_ex(sbi, lcn, clen, trim);
}
dn += clen;
}

Expand Down Expand Up @@ -2002,10 +2005,11 @@ int attr_punch_hole(struct ntfs_inode *ni, u64 vbo, u64 bytes, u32 *frame_size)
struct ATTRIB *attr = NULL, *attr_b;
struct ATTR_LIST_ENTRY *le, *le_b;
struct mft_inode *mi, *mi_b;
CLST svcn, evcn1, vcn, len, end, alen, dealloc, next_svcn;
CLST svcn, evcn1, vcn, len, end, alen, hole, next_svcn;
u64 total_size, alloc_size;
u32 mask;
__le16 a_flags;
struct runs_tree run2;

if (!bytes)
return 0;
Expand Down Expand Up @@ -2057,14 +2061,17 @@ int attr_punch_hole(struct ntfs_inode *ni, u64 vbo, u64 bytes, u32 *frame_size)
}

down_write(&ni->file.run_lock);
run_init(&run2);
run_truncate(run, 0);

/*
* Enumerate all attribute segments and punch hole where necessary.
*/
alen = alloc_size >> sbi->cluster_bits;
vcn = vbo >> sbi->cluster_bits;
len = bytes >> sbi->cluster_bits;
end = vcn + len;
dealloc = 0;
hole = 0;

svcn = le64_to_cpu(attr_b->nres.svcn);
evcn1 = le64_to_cpu(attr_b->nres.evcn) + 1;
Expand All @@ -2076,84 +2083,106 @@ int attr_punch_hole(struct ntfs_inode *ni, u64 vbo, u64 bytes, u32 *frame_size)
mi = mi_b;
} else if (!le_b) {
err = -EINVAL;
goto out;
goto bad_inode;
} else {
le = le_b;
attr = ni_find_attr(ni, attr_b, &le, ATTR_DATA, NULL, 0, &vcn,
&mi);
if (!attr) {
err = -EINVAL;
goto out;
goto bad_inode;
}

svcn = le64_to_cpu(attr->nres.svcn);
evcn1 = le64_to_cpu(attr->nres.evcn) + 1;
}

while (svcn < end) {
CLST vcn1, zero, dealloc2;
CLST vcn1, zero, hole2 = hole;

err = attr_load_runs(attr, ni, run, &svcn);
if (err)
goto out;
goto done;
vcn1 = max(vcn, svcn);
zero = min(end, evcn1) - vcn1;

dealloc2 = dealloc;
err = run_deallocate_ex(sbi, run, vcn1, zero, &dealloc, true);
/*
* Check range [vcn1 + zero).
* Calculate how many clusters there are.
* Don't do any destructive actions.
*/
err = run_deallocate_ex(NULL, run, vcn1, zero, &hole2, false);
if (err)
goto out;
goto done;

if (dealloc2 == dealloc) {
/* Looks like the required range is already sparsed. */
} else {
if (!run_add_entry(run, vcn1, SPARSE_LCN, zero,
false)) {
err = -ENOMEM;
goto out;
}
/* Check if required range is already hole. */
if (hole2 == hole)
goto next_attr;

err = mi_pack_runs(mi, attr, run, evcn1 - svcn);
/* Make a clone of run to undo. */
err = run_clone(run, &run2);
if (err)
goto done;

/* Make a hole range (sparse) [vcn1 + zero). */
if (!run_add_entry(run, vcn1, SPARSE_LCN, zero, false)) {
err = -ENOMEM;
goto done;
}

/* Update run in attribute segment. */
err = mi_pack_runs(mi, attr, run, evcn1 - svcn);
if (err)
goto done;
next_svcn = le64_to_cpu(attr->nres.evcn) + 1;
if (next_svcn < evcn1) {
/* Insert new attribute segment. */
err = ni_insert_nonresident(ni, ATTR_DATA, NULL, 0, run,
next_svcn,
evcn1 - next_svcn, a_flags,
&attr, &mi, &le);
if (err)
goto out;
next_svcn = le64_to_cpu(attr->nres.evcn) + 1;
if (next_svcn < evcn1) {
err = ni_insert_nonresident(ni, ATTR_DATA, NULL,
0, run, next_svcn,
evcn1 - next_svcn,
a_flags, &attr, &mi,
&le);
if (err)
goto out;
/* Layout of records maybe changed. */
attr_b = NULL;
}
goto undo_punch;

/* Layout of records maybe changed. */
attr_b = NULL;
}

/* Real deallocate. Should not fail. */
run_deallocate_ex(sbi, &run2, vcn1, zero, &hole, true);

next_attr:
/* Free all allocated memory. */
run_truncate(run, 0);

if (evcn1 >= alen)
break;

/* Get next attribute segment. */
attr = ni_enum_attr_ex(ni, attr, &le, &mi);
if (!attr) {
err = -EINVAL;
goto out;
goto bad_inode;
}

svcn = le64_to_cpu(attr->nres.svcn);
evcn1 = le64_to_cpu(attr->nres.evcn) + 1;
}

total_size -= (u64)dealloc << sbi->cluster_bits;
done:
if (!hole)
goto out;

if (!attr_b) {
attr_b = ni_find_attr(ni, NULL, NULL, ATTR_DATA, NULL, 0, NULL,
&mi_b);
if (!attr_b) {
err = -EINVAL;
goto out;
goto bad_inode;
}
}

total_size -= (u64)hole << sbi->cluster_bits;
attr_b->nres.total_size = cpu_to_le64(total_size);
mi_b->dirty = true;

Expand All @@ -2163,11 +2192,23 @@ int attr_punch_hole(struct ntfs_inode *ni, u64 vbo, u64 bytes, u32 *frame_size)
mark_inode_dirty(&ni->vfs_inode);

out:
run_close(&run2);
up_write(&ni->file.run_lock);
if (err)
_ntfs_bad_inode(&ni->vfs_inode);

return err;

bad_inode:
_ntfs_bad_inode(&ni->vfs_inode);
goto out;

undo_punch:
/*
* Restore packed runs.
* 'mi_pack_runs' should not fail, cause we restore original.
*/
if (mi_pack_runs(mi, attr, &run2, evcn1 - svcn))
goto bad_inode;

goto done;
}

/*
Expand Down
1 change: 1 addition & 0 deletions fs/ntfs3/ntfs_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -798,6 +798,7 @@ int run_unpack_ex(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
#define run_unpack_ex run_unpack
#endif
int run_get_highest_vcn(CLST vcn, const u8 *run_buf, u64 *highest_vcn);
int run_clone(const struct runs_tree *run, struct runs_tree *new_run);

/* Globals from super.c */
void *ntfs_set_shared(void *ptr, u32 bytes);
Expand Down
25 changes: 25 additions & 0 deletions fs/ntfs3/run.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1156,3 +1156,28 @@ int run_get_highest_vcn(CLST vcn, const u8 *run_buf, u64 *highest_vcn)
*highest_vcn = vcn64 - 1;
return 0;
}

/*
* run_clone
*
* Make a copy of run
*/
int run_clone(const struct runs_tree *run, struct runs_tree *new_run)
{
size_t bytes = run->count * sizeof(struct ntfs_run);

if (bytes > new_run->allocated) {
struct ntfs_run *new_ptr = kvmalloc(bytes, GFP_KERNEL);

if (!new_ptr)
return -ENOMEM;

kvfree(new_run->runs);
new_run->runs = new_ptr;
new_run->allocated = bytes;
}

memcpy(new_run->runs, run->runs, bytes);
new_run->count = run->count;
return 0;
}

0 comments on commit 20abc64

Please sign in to comment.