linux-ext4 - [RFC PATCH] ext4: Fix fallocate to update the file size in each transaction.

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Message-Id: <1204887200-9929-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Date:	Fri,  7 Mar 2008 16:23:20 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	cmm@...ibm.com, tytso@....edu, sandeen@...hat.com
Cc:	linux-ext4@...r.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [RFC PATCH] ext4: Fix fallocate to update the file size in each transaction.

ext4_fallocate need to update file size in each transaction. Otherwise
ife we crash the file size won't be updated. We were also not marking
the inode dirty after updating file size before. Also when we try to
retry allocation due to ENOSPC make sure we reset the variable ret so
that we actually do a retry.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
 fs/ext4/extents.c |   78 +++++++++++++++++++++--------------------------------
 1 files changed, 31 insertions(+), 47 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index dcdf92a..09dd3c5 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2783,6 +2783,26 @@ int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
 	return needed;
 }
 
+static void ext4_falloc_update_inode(struct inode *inode,
+					int mode, loff_t new_size)
+{
+	struct timespec now;
+
+	now = current_fs_time(inode->i_sb);
+	if (!timespec_equal(&inode->i_ctime, &now))
+		inode->i_ctime = now;
+	/*
+	 * Update only when preallocation was requested beyond
+	 * the file size.
+	 */
+	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+				new_size > i_size_read(inode)) {
+		i_size_write(inode, new_size);
+		EXT4_I(inode)->i_disksize = i_size_read(inode);
+	}
+
+}
+
 /*
  * preallocate space for a file. This implements ext4's fallocate inode
  * operation, which gets called from sys_fallocate system call.
@@ -2794,8 +2814,8 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
 {
 	handle_t *handle;
 	ext4_lblk_t block;
+	loff_t new_size;
 	unsigned long max_blocks;
-	ext4_fsblk_t nblocks = 0;
 	int ret = 0;
 	int ret2 = 0;
 	int retries = 0;
@@ -2814,8 +2834,7 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
 		return -ENODEV;
 
 	block = offset >> blkbits;
-	max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
-			- block;
+	max_blocks = EXT4_BLOCK_ALIGN(len, blkbits) >> blkbits;
 
 	/*
 	 * credits to insert 1 extent into extent tree + buffers to be able to
@@ -2848,28 +2867,13 @@ retry:
 			ret2 = ext4_journal_stop(handle);
 			break;
 		}
-		if (ret > 0) {
-			/* check wrap through sign-bit/zero here */
-			if ((block + ret) < 0 || (block + ret) < block) {
-				ret = -EIO;
-				ext4_mark_inode_dirty(handle, inode);
-				ret2 = ext4_journal_stop(handle);
-				break;
-			}
-			if (buffer_new(&map_bh) && ((block + ret) >
-			    (EXT4_BLOCK_ALIGN(i_size_read(inode), blkbits)
-			    >> blkbits)))
-					nblocks = nblocks + ret;
-		}
+		if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
+						blkbits) >> blkbits))
+			new_size = offset + len;
+		else
+			new_size = (block + ret) << blkbits;
 
-		/* Update ctime if new blocks get allocated */
-		if (nblocks) {
-			struct timespec now;
-
-			now = current_fs_time(inode->i_sb);
-			if (!timespec_equal(&inode->i_ctime, &now))
-				inode->i_ctime = now;
-		}
+		ext4_falloc_update_inode(inode, mode, new_size);
 
 		ext4_mark_inode_dirty(handle, inode);
 		ret2 = ext4_journal_stop(handle);
@@ -2877,30 +2881,10 @@ retry:
 			break;
 	}
 
-	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+	if (ret == -ENOSPC &&
+			ext4_should_retry_alloc(inode->i_sb, &retries)) {
+		ret = 0;
 		goto retry;
-
-	/*
-	 * Time to update the file size.
-	 * Update only when preallocation was requested beyond the file size.
-	 */
-	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
-	    (offset + len) > i_size_read(inode)) {
-		if (ret > 0) {
-			/*
-			 * if no error, we assume preallocation succeeded
-			 * completely
-			 */
-			i_size_write(inode, offset + len);
-			EXT4_I(inode)->i_disksize = i_size_read(inode);
-		} else if (ret < 0 && nblocks) {
-			/* Handle partial allocation scenario */
-			loff_t newsize;
-
-			newsize  = (nblocks << blkbits) + i_size_read(inode);
-			i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits));
-			EXT4_I(inode)->i_disksize = i_size_read(inode);
-		}
 	}
 
 	mutex_unlock(&inode->i_mutex);
-- 
1.5.4.3.422.g34cd6.dirty

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