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Message-Id: <20220605143815.2330891-4-willy@infradead.org>
Date: Sun, 5 Jun 2022 15:38:15 +0100
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
To: Jan Kara <jack@...e.com>
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>, tytso@....edu,
Andreas Dilger <adilger.kernel@...ger.ca>,
linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 3/3] ext4: Use generic_quota_read()
The comment about the page cache is rather stale; the buffer cache will
read into the page cache if the buffer isn't present, and the page cache
will not take any locks if the page is present.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
fs/ext4/super.c | 81 ++++++++++++-------------------------------------
1 file changed, 20 insertions(+), 61 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 450c918d68fc..1780649ed224 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1506,8 +1506,6 @@ static int ext4_mark_dquot_dirty(struct dquot *dquot);
static int ext4_write_info(struct super_block *sb, int type);
static int ext4_quota_on(struct super_block *sb, int type, int format_id,
const struct path *path);
-static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
- size_t len, loff_t off);
static ssize_t ext4_quota_write(struct super_block *sb, int type,
const char *data, size_t len, loff_t off);
static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
@@ -1535,7 +1533,7 @@ static const struct dquot_operations ext4_quota_operations = {
static const struct quotactl_ops ext4_qctl_operations = {
.quota_on = ext4_quota_on,
.quota_off = ext4_quota_off,
- .quota_sync = dquot_quota_sync,
+ .quota_sync = generic_quota_sync,
.get_state = dquot_get_state,
.set_info = dquot_set_dqinfo,
.get_dqblk = dquot_get_dqblk,
@@ -1559,7 +1557,7 @@ static const struct super_operations ext4_sops = {
.statfs = ext4_statfs,
.show_options = ext4_show_options,
#ifdef CONFIG_QUOTA
- .quota_read = ext4_quota_read,
+ .quota_read = generic_quota_read,
.quota_write = ext4_quota_write,
.get_dquots = ext4_get_dquots,
#endif
@@ -6856,55 +6854,15 @@ static int ext4_quota_off(struct super_block *sb, int type)
return dquot_quota_off(sb, type);
}
-/* Read data from quotafile - avoid pagecache and such because we cannot afford
- * acquiring the locks... As quota files are never truncated and quota code
- * itself serializes the operations (and no one else should touch the files)
- * we don't have to be afraid of races */
-static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
- size_t len, loff_t off)
-{
- struct inode *inode = sb_dqopt(sb)->files[type];
- ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
- int offset = off & (sb->s_blocksize - 1);
- int tocopy;
- size_t toread;
- struct buffer_head *bh;
- loff_t i_size = i_size_read(inode);
-
- if (off > i_size)
- return 0;
- if (off+len > i_size)
- len = i_size-off;
- toread = len;
- while (toread > 0) {
- tocopy = sb->s_blocksize - offset < toread ?
- sb->s_blocksize - offset : toread;
- bh = ext4_bread(NULL, inode, blk, 0);
- if (IS_ERR(bh))
- return PTR_ERR(bh);
- if (!bh) /* A hole? */
- memset(data, 0, tocopy);
- else
- memcpy(data, bh->b_data+offset, tocopy);
- brelse(bh);
- offset = 0;
- toread -= tocopy;
- data += tocopy;
- blk++;
- }
- return len;
-}
-
/* Write to quotafile (we know the transaction is already started and has
* enough credits) */
static ssize_t ext4_quota_write(struct super_block *sb, int type,
const char *data, size_t len, loff_t off)
{
struct inode *inode = sb_dqopt(sb)->files[type];
- ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
- int err = 0, err2 = 0, offset = off & (sb->s_blocksize - 1);
- int retries = 0;
- struct buffer_head *bh;
+ int err = 0, offset = off & (sb->s_blocksize - 1);
+ struct buffer_head *bh, *head;
+ struct folio *folio;
handle_t *handle = journal_current_handle();
if (!handle) {
@@ -6924,20 +6882,21 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
return -EIO;
}
- do {
- bh = ext4_bread(handle, inode, blk,
- EXT4_GET_BLOCKS_CREATE |
- EXT4_GET_BLOCKS_METADATA_NOFAIL);
- } while (PTR_ERR(bh) == -ENOSPC &&
- ext4_should_retry_alloc(inode->i_sb, &retries));
- if (IS_ERR(bh))
- return PTR_ERR(bh);
- if (!bh)
+ folio = read_mapping_folio(inode->i_mapping, off / PAGE_SIZE, NULL);
+ if (IS_ERR(folio))
+ return PTR_ERR(folio);
+ head = folio_buffers(folio);
+ if (!head)
+ head = alloc_page_buffers(&folio->page, sb->s_blocksize, false);
+ if (!head)
goto out;
+ bh = head;
+ while ((bh_offset(bh) + sb->s_blocksize) <= (off % PAGE_SIZE))
+ bh = bh->b_this_page;
BUFFER_TRACE(bh, "get write access");
err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
if (err) {
- brelse(bh);
+ folio_put(folio);
return err;
}
lock_buffer(bh);
@@ -6945,14 +6904,14 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
flush_dcache_page(bh->b_page);
unlock_buffer(bh);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
- brelse(bh);
out:
+ folio_put(folio);
+ if (err)
+ return err;
if (inode->i_size < off + len) {
i_size_write(inode, off + len);
EXT4_I(inode)->i_disksize = inode->i_size;
- err2 = ext4_mark_inode_dirty(handle, inode);
- if (unlikely(err2 && !err))
- err = err2;
+ err = ext4_mark_inode_dirty(handle, inode);
}
return err ? err : len;
}
--
2.35.1
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