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-rw-r--r--fs/ext4/ext4.h3
-rw-r--r--fs/ext4/ext4_jbd2.h8
-rw-r--r--fs/ext4/inode.c131
3 files changed, 108 insertions, 34 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6c7924d..38e661b 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1072,6 +1072,7 @@ extern void ext4_set_inode_flags(struct inode *);
extern void ext4_get_inode_flags(struct ext4_inode_info *);
extern void ext4_set_aops(struct inode *inode);
extern int ext4_writepage_trans_blocks(struct inode *);
+extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int idxblocks);
extern int ext4_block_truncate_page(handle_t *handle,
struct address_space *mapping, loff_t from);
extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page);
@@ -1227,6 +1228,8 @@ extern const struct inode_operations ext4_fast_symlink_inode_operations;
/* extents.c */
extern int ext4_ext_tree_init(handle_t *handle, struct inode *);
extern int ext4_ext_writepage_trans_blocks(struct inode *, int);
+extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
+ int chunk);
extern int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock,
unsigned long max_blocks, struct buffer_head *bh_result,
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index eb8bc3a..b455c68 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -51,6 +51,14 @@
EXT4_XATTR_TRANS_BLOCKS - 2 + \
2*EXT4_QUOTA_TRANS_BLOCKS(sb))
+/*
+ * Define the number of metadata blocks we need to account to modify data.
+ *
+ * This include super block, inode block, quota blocks and xattr blocks
+ */
+#define EXT4_META_TRANS_BLOCKS(sb) (EXT4_XATTR_TRANS_BLOCKS + \
+ 2*EXT4_QUOTA_TRANS_BLOCKS(sb))
+
/* Delete operations potentially hit one directory's namespace plus an
* entire inode, plus arbitrary amounts of bitmap/indirection data. Be
* generous. We can grow the delete transaction later if necessary. */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5e17d5f..a271290 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4354,56 +4354,119 @@ int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
return 0;
}
+static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
+ int chunk)
+{
+ int indirects;
+
+ /* if nrblocks are contiguous */
+ if (chunk) {
+ /*
+ * With N contiguous data blocks, it need at most
+ * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
+ * 2 dindirect blocks
+ * 1 tindirect block
+ */
+ indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
+ return indirects + 3;
+ }
+ /*
+ * if nrblocks are not contiguous, worse case, each block touch
+ * a indirect block, and each indirect block touch a double indirect
+ * block, plus a triple indirect block
+ */
+ indirects = nrblocks * 2 + 1;
+ return indirects;
+}
+
+static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+ if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+ return ext4_indirect_trans_blocks(inode, nrblocks, 0);
+ return ext4_ext_index_trans_blocks(inode, nrblocks, 0);
+}
/*
- * How many blocks doth make a writepage()?
+ * Account for index blocks, block groups bitmaps and block group
+ * descriptor blocks if modify datablocks and index blocks
+ * worse case, the indexs blocks spread over different block groups
*
- * With N blocks per page, it may be:
- * N data blocks
- * 2 indirect block
- * 2 dindirect
- * 1 tindirect
- * N+5 bitmap blocks (from the above)
- * N+5 group descriptor summary blocks
- * 1 inode block
- * 1 superblock.
- * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
+ * If datablocks are discontiguous, they are possible to spread over
+ * different block groups too. If they are contiugous, with flexbg,
+ * they could still across block group boundary.
*
- * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
+ * Also account for superblock, inode, quota and xattr blocks
+ */
+int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+ int groups, gdpblocks;
+ int idxblocks;
+ int ret = 0;
+
+ /*
+ * How many index blocks need to touch to modify nrblocks?
+ * The "Chunk" flag indicating whether the nrblocks is
+ * physically contiguous on disk
+ *
+ * For Direct IO and fallocate, they calls get_block to allocate
+ * one single extent at a time, so they could set the "Chunk" flag
+ */
+ idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
+
+ ret = idxblocks;
+
+ /*
+ * Now let's see how many group bitmaps and group descriptors need
+ * to account
+ */
+ groups = idxblocks;
+ if (chunk)
+ groups += 1;
+ else
+ groups += nrblocks;
+
+ gdpblocks = groups;
+ if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
+ groups = EXT4_SB(inode->i_sb)->s_groups_count;
+ if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
+ gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
+
+ /* bitmaps and block group descriptor blocks */
+ ret += groups + gdpblocks;
+
+ /* Blocks for super block, inode, quota and xattr blocks */
+ ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
+
+ return ret;
+}
+
+/*
+ * Calulate the total number of credits to reserve to fit
+ * the modification of a single pages into a single transaction
*
- * With ordered or writeback data it's the same, less the N data blocks.
+ * This could be called via ext4_write_begin() or later
+ * ext4_da_writepages() in delalyed allocation case.
*
- * If the inode's direct blocks can hold an integral number of pages then a
- * page cannot straddle two indirect blocks, and we can only touch one indirect
- * and dindirect block, and the "5" above becomes "3".
+ * In both case it's possible that we could allocating multiple
+ * chunks of blocks. We need to consider the worse case, when
+ * one new block per extent.
*
- * This still overestimates under most circumstances. If we were to pass the
- * start and end offsets in here as well we could do block_to_path() on each
- * block and work out the exact number of indirects which are touched. Pah.
+ * For Direct IO and fallocate, the journal credits reservation
+ * is based on one single extent allocation, so they could use
+ * EXT4_DATA_TRANS_BLOCKS to get the needed credit to log a single
+ * chunk of allocation needs.
*/
-
int ext4_writepage_trans_blocks(struct inode *inode)
{
int bpp = ext4_journal_blocks_per_page(inode);
- int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
int ret;
- if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
- return ext4_ext_writepage_trans_blocks(inode, bpp);
+ ret = ext4_meta_trans_blocks(inode, bpp, 0);
+ /* Account for data blocks for journalled mode */
if (ext4_should_journal_data(inode))
- ret = 3 * (bpp + indirects) + 2;
- else
- ret = 2 * (bpp + indirects) + 2;
-
-#ifdef CONFIG_QUOTA
- /* We know that structure was already allocated during DQUOT_INIT so
- * we will be updating only the data blocks + inodes */
- ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
-#endif
-
+ ret += bpp;
return ret;
}
-
/*
* The caller must have previously called ext4_reserve_inode_write().
* Give this, we know that the caller already has write access to iloc->bh.
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