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ocfs2: support for removing file regions
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Provide an internal interface for the removal of arbitrary file regions.

ocfs2_remove_inode_range() takes a byte range within a file and will remove
existing extents within that range. Partial clusters will be zeroed so that
any read from within the region will return zeros.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
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Mark Fasheh committed Jul 11, 2007
1 parent 35edec1 commit 063c456
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Showing 4 changed files with 262 additions and 12 deletions.
20 changes: 10 additions & 10 deletions fs/ocfs2/alloc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4373,10 +4373,10 @@ static int ocfs2_truncate_rec(struct inode *inode, handle_t *handle,
return ret;
}

static int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
u32 cpos, u32 len, handle_t *handle,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
u32 cpos, u32 len, handle_t *handle,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret, index;
u32 rec_range, trunc_range;
Expand Down Expand Up @@ -4506,7 +4506,7 @@ static int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
return ret;
}

static inline int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
{
struct buffer_head *tl_bh = osb->osb_tl_bh;
struct ocfs2_dinode *di;
Expand Down Expand Up @@ -4539,10 +4539,10 @@ static int ocfs2_truncate_log_can_coalesce(struct ocfs2_truncate_log *tl,
return current_tail == new_start;
}

static int ocfs2_truncate_log_append(struct ocfs2_super *osb,
handle_t *handle,
u64 start_blk,
unsigned int num_clusters)
int ocfs2_truncate_log_append(struct ocfs2_super *osb,
handle_t *handle,
u64 start_blk,
unsigned int num_clusters)
{
int status, index;
unsigned int start_cluster, tl_count;
Expand Down Expand Up @@ -4698,7 +4698,7 @@ static int ocfs2_replay_truncate_records(struct ocfs2_super *osb,
}

/* Expects you to already be holding tl_inode->i_mutex */
static int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
{
int status;
unsigned int num_to_flush;
Expand Down
10 changes: 10 additions & 0 deletions fs/ocfs2/alloc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,10 @@ int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
handle_t *handle, u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
u32 cpos, u32 len, handle_t *handle,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_num_free_extents(struct ocfs2_super *osb,
struct inode *inode,
struct ocfs2_dinode *fe);
Expand Down Expand Up @@ -68,6 +72,12 @@ int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
struct ocfs2_dinode **tl_copy);
int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
struct ocfs2_dinode *tl_copy);
int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb);
int ocfs2_truncate_log_append(struct ocfs2_super *osb,
handle_t *handle,
u64 start_blk,
unsigned int num_clusters);
int __ocfs2_flush_truncate_log(struct ocfs2_super *osb);

/*
* Process local structure which describes the block unlinks done
Expand Down
242 changes: 240 additions & 2 deletions fs/ocfs2/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -541,12 +541,15 @@ int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
struct ocfs2_alloc_context **data_ac,
struct ocfs2_alloc_context **meta_ac)
{
int ret, num_free_extents;
int ret = 0, num_free_extents;
unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

*meta_ac = NULL;
*data_ac = NULL;
if (data_ac)
*data_ac = NULL;

BUG_ON(clusters_to_add != 0 && data_ac == NULL);

mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "
"clusters_to_add = %u, extents_to_split = %u\n",
Expand Down Expand Up @@ -583,6 +586,9 @@ int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
}
}

if (clusters_to_add == 0)
goto out;

ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
if (ret < 0) {
if (ret != -ENOSPC)
Expand Down Expand Up @@ -1252,6 +1258,238 @@ static int ocfs2_allocate_unwritten_extents(struct inode *inode,
return ret;
}

static int __ocfs2_remove_inode_range(struct inode *inode,
struct buffer_head *di_bh,
u32 cpos, u32 phys_cpos, u32 len,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret;
u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
struct inode *tl_inode = osb->osb_tl_inode;
handle_t *handle;
struct ocfs2_alloc_context *meta_ac = NULL;
struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;

ret = ocfs2_lock_allocators(inode, di, 0, 1, NULL, &meta_ac);
if (ret) {
mlog_errno(ret);
return ret;
}

mutex_lock(&tl_inode->i_mutex);

if (ocfs2_truncate_log_needs_flush(osb)) {
ret = __ocfs2_flush_truncate_log(osb);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
}

handle = ocfs2_start_trans(osb, OCFS2_REMOVE_EXTENT_CREDITS);
if (handle == NULL) {
ret = -ENOMEM;
mlog_errno(ret);
goto out;
}

ret = ocfs2_journal_access(handle, inode, di_bh,
OCFS2_JOURNAL_ACCESS_WRITE);
if (ret) {
mlog_errno(ret);
goto out;
}

ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
dealloc);
if (ret) {
mlog_errno(ret);
goto out_commit;
}

OCFS2_I(inode)->ip_clusters -= len;
di->i_clusters = cpu_to_le32(OCFS2_I(inode)->ip_clusters);

ret = ocfs2_journal_dirty(handle, di_bh);
if (ret) {
mlog_errno(ret);
goto out_commit;
}

ret = ocfs2_truncate_log_append(osb, handle, phys_blkno, len);
if (ret)
mlog_errno(ret);

out_commit:
ocfs2_commit_trans(osb, handle);
out:
mutex_unlock(&tl_inode->i_mutex);

if (meta_ac)
ocfs2_free_alloc_context(meta_ac);

return ret;
}

/*
* Truncate a byte range, avoiding pages within partial clusters. This
* preserves those pages for the zeroing code to write to.
*/
static void ocfs2_truncate_cluster_pages(struct inode *inode, u64 byte_start,
u64 byte_len)
{
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
loff_t start, end;
struct address_space *mapping = inode->i_mapping;

start = (loff_t)ocfs2_align_bytes_to_clusters(inode->i_sb, byte_start);
end = byte_start + byte_len;
end = end & ~(osb->s_clustersize - 1);

if (start < end) {
unmap_mapping_range(mapping, start, end - start, 0);
truncate_inode_pages_range(mapping, start, end - 1);
}
}

static int ocfs2_zero_partial_clusters(struct inode *inode,
u64 start, u64 len)
{
int ret = 0;
u64 tmpend, end = start + len;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
unsigned int csize = osb->s_clustersize;
handle_t *handle;

/*
* The "start" and "end" values are NOT necessarily part of
* the range whose allocation is being deleted. Rather, this
* is what the user passed in with the request. We must zero
* partial clusters here. There's no need to worry about
* physical allocation - the zeroing code knows to skip holes.
*/
mlog(0, "byte start: %llu, end: %llu\n",
(unsigned long long)start, (unsigned long long)end);

/*
* If both edges are on a cluster boundary then there's no
* zeroing required as the region is part of the allocation to
* be truncated.
*/
if ((start & (csize - 1)) == 0 && (end & (csize - 1)) == 0)
goto out;

handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
if (handle == NULL) {
ret = -ENOMEM;
mlog_errno(ret);
goto out;
}

/*
* We want to get the byte offset of the end of the 1st cluster.
*/
tmpend = (u64)osb->s_clustersize + (start & ~(osb->s_clustersize - 1));
if (tmpend > end)
tmpend = end;

mlog(0, "1st range: start: %llu, tmpend: %llu\n",
(unsigned long long)start, (unsigned long long)tmpend);

ret = ocfs2_zero_range_for_truncate(inode, handle, start, tmpend);
if (ret)
mlog_errno(ret);

if (tmpend < end) {
/*
* This may make start and end equal, but the zeroing
* code will skip any work in that case so there's no
* need to catch it up here.
*/
start = end & ~(osb->s_clustersize - 1);

mlog(0, "2nd range: start: %llu, end: %llu\n",
(unsigned long long)start, (unsigned long long)end);

ret = ocfs2_zero_range_for_truncate(inode, handle, start, end);
if (ret)
mlog_errno(ret);
}

ocfs2_commit_trans(osb, handle);
out:
return ret;
}

static int ocfs2_remove_inode_range(struct inode *inode,
struct buffer_head *di_bh, u64 byte_start,
u64 byte_len)
{
int ret = 0;
u32 trunc_start, trunc_len, cpos, phys_cpos, alloc_size;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
struct ocfs2_cached_dealloc_ctxt dealloc;

ocfs2_init_dealloc_ctxt(&dealloc);

if (byte_len == 0)
return 0;

trunc_start = ocfs2_clusters_for_bytes(osb->sb, byte_start);
trunc_len = (byte_start + byte_len) >> osb->s_clustersize_bits;
if (trunc_len >= trunc_start)
trunc_len -= trunc_start;
else
trunc_len = 0;

mlog(0, "Inode: %llu, start: %llu, len: %llu, cstart: %u, clen: %u\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
(unsigned long long)byte_start,
(unsigned long long)byte_len, trunc_start, trunc_len);

ret = ocfs2_zero_partial_clusters(inode, byte_start, byte_len);
if (ret) {
mlog_errno(ret);
goto out;
}

cpos = trunc_start;
while (trunc_len) {
ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
&alloc_size, NULL);
if (ret) {
mlog_errno(ret);
goto out;
}

if (alloc_size > trunc_len)
alloc_size = trunc_len;

/* Only do work for non-holes */
if (phys_cpos != 0) {
ret = __ocfs2_remove_inode_range(inode, di_bh, cpos,
phys_cpos, alloc_size,
&dealloc);
if (ret) {
mlog_errno(ret);
goto out;
}
}

cpos += alloc_size;
trunc_len -= alloc_size;
}

ocfs2_truncate_cluster_pages(inode, byte_start, byte_len);

out:
ocfs2_schedule_truncate_log_flush(osb, 1);
ocfs2_run_deallocs(osb, &dealloc);

return ret;
}

static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
loff_t *ppos,
size_t count,
Expand Down
2 changes: 2 additions & 0 deletions fs/ocfs2/journal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -289,6 +289,8 @@ int ocfs2_journal_dirty_data(handle_t *handle,
#define OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC (OCFS2_SUBALLOC_FREE \
+ OCFS2_TRUNCATE_LOG_UPDATE)

#define OCFS2_REMOVE_EXTENT_CREDITS (OCFS2_TRUNCATE_LOG_UPDATE + OCFS2_INODE_UPDATE_CREDITS)

/* data block for new dir/symlink, 2 for bitmap updates (bitmap fe +
* bitmap block for the new bit) */
#define OCFS2_DIR_LINK_ADDITIONAL_CREDITS (1 + 2)
Expand Down

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